future aluminium plant at byneset

TMT4851 Experts in team cr proj V-06Spring 2006, Village 33, Team 2

Future Aluminium plant at BynesetProject Report

Authors:

Stine Skagestad Zhaohui Wang

Gaute Lken Heiko Gaertner

Kyrre Sundseth

Summary

The aim of this project was to find out if it is feasible to build a primary alu-minium production plant with a capacity of 600 000 tpy. The plant is proposedto be built in the coming 5 years at Byneset in the Trondheim area. Choicesof technologies are made with respect to the most environmental friendly andproductive technologies, with focus on current state-of-the-art technology.

The report shows how this project may be a profitable investment, boasting anet present value of 1 215 mill. NOK, with reasonable assumptions to factorslike the prices of energy, alumina and aluminium.

The envisioned plant aims to be the best in class when it comes to environmentalfriendliness through its on site gas powerplant, and CO2-capture technology.

Preface

What is this? This is the documentation of the work done by Group 2 of Vil-lage 33 (A Light and Bright Future with Aluminium and Silicon) in the courseEksperter i team tv prosj V-06 / Experts in team cr proj V-06 (TMT4851)at Norges teknisk-naturvitenskaplige universitet (NTNU), spring 2006.

What is the purpose of the course? The project is part of the participat-ing students master degrees, and is meant to add to their sense of teamworkand give them insight into how they can make themselves useful in a team ofmultiple backgrounds. Through this work they will strengthen their analyti-cal, co-operational and creative skills and learn to lead, follow, listen and makedecisions. They will learn to co-operate past the barrier that is different pro-fessions, learn to use this difference to their advantage and so be prepared foremployment.

Acknowledgements: The group would like to extend a big thanks to NTNUfor the insight of establishing this kind of course, our village chief (TrygveFoosns) for moral support, great leadership of our beloved village and in-valuable feedback on the documentation during the time of writing. Furtherwe are humbled by the willingness the following people from the industry hasshown in explaining things and supplying non-confidential information withoutasking anything in return. It is doubtful we would have had the motivationto go through with such an ambitious project without your support. Thankyou Albert Berveling, Bjorn Petter Moxnes, Jon Kristian Schnell and HalvardSvendsen!

iv

Trondheim, May 4, 2006

Stine Skagestad Zhaohui Wang

Gaute Lken Heiko Gaertner

Kyrre Sundseth

Contents

Summary ii

Preface iii

1 Introduction 11.1 Aim of the project . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2 Reasoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Aluminum Production 42.1 A description of the process . . . . . . . . . . . . . . . . . . . . . 4

2.1.1 Bauxite to Alumina . . . . . . . . . . . . . . . . . . . . . 52.1.2 Smelting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 Technology principles . . . . . . . . . . . . . . . . . . . . . . . . 72.2.1 Looking back . . . . . . . . . . . . . . . . . . . . . . . . . 72.2.2 Industrial cell designs . . . . . . . . . . . . . . . . . . . . 82.2.3 The Sderberg Technology . . . . . . . . . . . . . . . . . 82.2.4 The Prebake Technology . . . . . . . . . . . . . . . . . . . 82.2.5 Environment . . . . . . . . . . . . . . . . . . . . . . . . . 112.2.6 Looking ahead . . . . . . . . . . . . . . . . . . . . . . . . 122.2.7 Selecting a smelter technology . . . . . . . . . . . . . . . 142.2.8 Analysis in current Prebake licenser . . . . . . . . . . . . 14

2.3 Plant Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162.3.2 Plant layout . . . . . . . . . . . . . . . . . . . . . . . . . . 162.3.3 Design Standards and Codes and Regulations . . . . . . . 212.3.4 Design basic . . . . . . . . . . . . . . . . . . . . . . . . . 212.3.5 Final product and consumption . . . . . . . . . . . . . . . 212.3.6 Project Milestones . . . . . . . . . . . . . . . . . . . . . . 22

3 Market 233.1 Increasing demand . . . . . . . . . . . . . . . . . . . . . . . . . . 233.2 Widening gap between supply and demand . . . . . . . . . . . . 25

4 Energy and Environment 264.1 Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.1.1 Prices are going up . . . . . . . . . . . . . . . . . . . . . . 26

CONTENTS vi

4.1.2 Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.1.3 Requirement . . . . . . . . . . . . . . . . . . . . . . . . . 284.1.4 Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284.1.5 Gas power plant . . . . . . . . . . . . . . . . . . . . . . . 284.1.6 Coal power plant . . . . . . . . . . . . . . . . . . . . . . . 294.1.7 Conclusion on energy technology . . . . . . . . . . . . . . 29

4.2 Environmental Evaluation . . . . . . . . . . . . . . . . . . . . . . 304.2.1 Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . 304.2.2 Climate gases . . . . . . . . . . . . . . . . . . . . . . . . . 31

4.3 Waste heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324.3.1 Hot water and power . . . . . . . . . . . . . . . . . . . . . 324.3.2 Smelter heat losses . . . . . . . . . . . . . . . . . . . . . . 324.3.3 Sidewall heat flux recovery . . . . . . . . . . . . . . . . . 334.3.4 Heat loss over pot room roof . . . . . . . . . . . . . . . . 34

4.4 Waste combustion . . . . . . . . . . . . . . . . . . . . . . . . . . 354.4.1 Combustion . . . . . . . . . . . . . . . . . . . . . . . . . . 354.4.2 CO2-capturing technologies . . . . . . . . . . . . . . . . . 354.4.3 Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374.4.4 Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384.4.5 Symbiosis and CO2 capture . . . . . . . . . . . . . . . . . 394.4.6 Conclusion on CO2 capturing . . . . . . . . . . . . . . . . 40

4.5 Local aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414.6 Global aspect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5 Localization 425.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435.3 Fulfilling the requirements . . . . . . . . . . . . . . . . . . . . . . 43

5.3.1 Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435.3.2 Raw materials . . . . . . . . . . . . . . . . . . . . . . . . 435.3.3 Reaching the world market . . . . . . . . . . . . . . . . . 435.3.4 Public support . . . . . . . . . . . . . . . . . . . . . . . . 445.3.5 Infrastructure . . . . . . . . . . . . . . . . . . . . . . . . . 445.3.6 Employment . . . . . . . . . . . . . . . . . . . . . . . . . 44

5.4 Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455.4.1 Research and development . . . . . . . . . . . . . . . . . . 455.4.2 Spin-offs and related effects . . . . . . . . . . . . . . . . . 465.4.3 Waste heat . . . . . . . . . . . . . . . . . . . . . . . . . . 465.4.4 Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . 465.4.5 Economical support . . . . . . . . . . . . . . . . . . . . . 47

5.5 Further advantages . . . . . . . . . . . . . . . . . . . . . . . . . . 475.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

6 Economical Considerations 486.1 Market prices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

6.1.1 Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

CONTENTS vii

6.1.2 Aluminium . . . . . . . . . . . . . . . . . . . . . . . . . . 496.1.3 Alumina . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506.1.4 Anode-cathode-production . . . . . . . . . . . . . . . . . 506.1.5 Production costs . . . . . . . . . . . . . . . . . . . . . . . 50

6.2 Instantaneous costs . . . . . . . . . . . . . . . . . . . . . . . . . . 506.3 Means of profitability estimation . . . . . . . . . . . . . . . . . . 516.4 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

6.4.1 NPV calculation . . . . . . . . . . . . . . . . . . . . . . . 526.4.2 Combining variables . . . . . . . . . . . . . . . . . . . . . 536.4.3 The alternative is coal . . . . . . . . . . . . . . . . . . . . 56

6.5 Omitted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

7 Conclusion 587.1 Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587.2 Market . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587.3 Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587.4 Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597.5 Location and Spin-off . . . . . . . . . . . . . . . . . . . . . . . . 59

7.5.1 Economic considerations . . . . . . . . . . . . . . . . . . . 607.5.2 Future work to be carried though . . . . . . . . . . . . . . 60

A Equations 61

B Flowchart 62

Bibliography 67

Chapter 1

Introduction

Aluminum is an essential material in modern manufacturing. Aluminum oc-cupies a special place in extractive metallurgy because it can be produced asa high-purity product, enabling its special properties to be utilized. Its lightweight, high strength, corrosion resistance and processing possibilities, highelectrical and thermal conductivity coupled with its ease and value for recy-cling strengthen its position as the material of choice in many applications. Itis important in virtually all segments of the world of manufacturing.

The most common applications are automotive engineering, packaging and con-struction. An example of the usage of aluminum is light vehicles; 80 % of amodern airplane consists of aluminium. Other common examples are food pack-ages and the well known aluminium beer can and high rise buildings with itswindow frames and refurbish facades. These are just a few of the main appli-cations for aluminium in its variety of appearance. The Figure 1.1 gives animpression of the variety of aluminium product in our modern everyday life.

Figure 1.1: Variety of Aluminum [Inc02]

1.1 Aim of the project 2

The primary metal production process for aluminum is still fundamentally thesame as invented independently by Hall and Heroult 120 years ago, but envi-ronmental compatibility and economics and therefore efficiency has improveddramatically due to improved process and materials knowledge as well as finetuned process control technology.

1.1 Aim of the project

Were aiming to find out if it is feasible to build a new large (600 000 tpy)primary aluminum production plant at Byneset in Trondheim (Norway), usingstate-of-the-art technology. We want to show a third party that...

1. There is money to be earned

2. It is environmental friendly

3. It is future oriented

Supporting economical growth Supporting technology innovation

We will examine whether or not there is...

A market Sufficient energy supply Basis for a profitable operation:

Reasonable energy price

Reasonable raw material costs

Reasonable aluminum price

Any restrictions concerning the environment CO2

Other emissions

Any other profits to be had, like those coming from.. Exporting technology

Exploiting waste heat from pot-gas scrubbing (cleaning of the gas)

When considering such a project it is imperative that we look at the politicallandscape, and gauge the impact on the local and national community. Furtherthere might be some resistance to such a project, thus we must consider theconcerns of farmers and entrepreneurs alike. Will applying state of the arttechnology lessen any such resistance? Regional effects such as additional hot

1.2 Reasoning 3

water supply for heating and additional tax money might make the communitymore in favor of such a project.

Perhaps the most important issue we will discuss is whether or not such aproject is profitable. We will show by making conservative assumptions onprices that the envisioned plant has a net present value of 1.215 mill. NOK. Wehave to mention that the additional income from sources such as developmentand increased profits from producing premium alloys have not been included.With reasonable, but optimistic assumptions the figure is somewhere around10-11 mill.NOK. (For more on this see Chapter 6.)

We will show that there are good preconditions for building a plant in Norway.And we wish to show that building such a plant to meet the demand will beprofitable, good for Norway and good for the environment.

1.2 Reasoning

When the theoretical basis has been established we will establish that there isa market for a new smelter, followed by a decision where to place the smelter.(Chapter 3)

Companies choose their smelting locations where production conditions arefavourable. Favourable conditions include the availability of skilled and cheaplabor, proximity to consumer markets and to sites with low electricity costs.

Over time the geographic distribution of production has shifted and is still shift-ing, driven especially by the energy factor. With the advent of more inexpensivehydro- and geothermal power and long-term competitive energy contracts, con-struction of new primary production capacity have shifted to countries withlow electrical power costs in preference to regions with higher costs. Recentannouncements of new capacity development in Iceland (Alcoa) [Gla], Bahrein,Quatar (Hydro Aluminium) [Alu06] and in the United Arab Emirates (UAE)are evidence that the energy cost and availability factors are still two of themost important factors when selecting a production site.

The question that arises is whether or not there is sufficiently cheap and abun-dant energy in Norway to support running another aluminum smelter. We willshow that it is possible to produce reasonably cheap energy for the smelter inNorway, and that by doing so we will spare the environment. (Chapter 4)

In Chapter 5 we will consider all the other factors that will decide where tobuild the plant. This includes personnel, knowledge, accessibility, waste heatdistribution etc.

When all these issues have been discussed we will in Chapter 6 put down thefigures and present the estimate of the calculations as is possible with the some-what uncertain price data we have at hand.

Chapter 2

Aluminum Production

This chapter contains three sections. The first section describes how aluminumis produced and gives the reader an overview of the steps involved. In thesecond section, we give a more in-depth description of the smelting process asthe core technology, comparing present state-of-the-art technology and futuredevelopment, followed by a discussion on the available principles of smeltertechnologies. Todays technologies are introduced through looking at the his-torical development. We discuss these technologies in some detail, ending upwith selecting prebake technology and considering its potential for further im-provement. Inspired by actual smelter project we are taking the layout of thoseplants as a guideline. We present an outline of the Byneset plant layout andtechnical data of the main units of the plant in the end of this section.

2.1 A description of the process

Primary aluminum production involves two independent energy intensive pro-cesses to transform the ore (bauxite) to the metal:

1. The Bayer process, where bauxite (ore) is turned into alumina by causticdigestion

2. The Hall-Heroult process, where alumina is turned into aluminum throughelectrolysis

Bauxite is strip-mined and usually processed into alumina close to the extractionpoint (Figure 2.2). The alumina is then taken to a smelter where it is turnedinto aluminium or alloys (Figure 2.3). The primary aluminum products arethen shipped to the customer who produces the end products.

2.1 A description of the process 5

2.1.1 Bauxite to Alumina

Figure 2.1: Bauxite Mineral taken from Wikipedia website

The Bayer process, Figure 2.2, extracts alumina by caustic digestion of crushedbauxite at high temperature and pressure. Bauxite lies relatively close to thesurface and is strip-mined. It contains 40 to 60 % Al203, in the form of severalhydrous alumina phases together with silicon, iron and titanium compounds aswell as other impurities. The bauxite digestion is followed by clarification, pre-cipitation, washing and finally calcination to produce pure anhydrous alumina.

2.1.2 Smelting

Alumina is insoluble in all ordinary chemical reagents at room temperature andits melting point is high (above 2050 C) [Aluminum oxide Wikipedia]. Due tothe high temperatures needed for the reduction process the high melting pointmakes chemical processes used for reducing oxides difficult.

Industrial production of primary aluminum is carried out in alumina reductioncells by the Hall-Heroult process. It is named after its inventors, Charles MartinHall from the United States and Paul Louis Toussaint Heroult from France, whoindependently of each other in 1886 developed and patented an electrolytic pro-cess by which alumina is dissolved in an electrolyte consisting mainly of liquidcryolite. This process allows alumina reduction temperatures of approximately950- 965C [MS94].

The young American student, Charles Martin Hall, became interested in alu-minum in the 1880s, trying to develop a commercial process for extractingaluminum using an electric current. In February 1886 Hall passed a direct cur-rent through a solution of alumina dissolved in cryolite (Na3AlF6) in a carboncrucible. After several hours he allowed the contents to solidify. When he brokeup the solid he found several small buttons of aluminum.

The cryolite in the electrolyte bath dissolves the alumina to aluminum complexions (Al3+). The current supplies the electrons and the heat for the reductionof the aluminum ions to aluminum metal at the cathode. At the other end, thecarbon of the anode is oxidized, forming carbon dioxide (CO2). Chemically theOverall reaction is written as:

2.1 A description of the process 6

Figure 2.2: Sketch of Bauxite to alumina production: Step 1 Mining, Step 2Refining, 3 Alumina as product for chemicals and refractories, Step 4 Aluminais feed to the electrolysis cells [Inc02].

Figure 2.3: The main steps in the continuous smelting process. Step 4 Elec-trolysis called Smelting. Step 5 Casting and Step 6 fabrication of aluminumproducts. [Inc02]

2.2 Technology principles 7

2Al2O3(s) + 3C(s) 3CO2(g) + 4Al(aq) (2.1)

The effect is that the alumina in the bath and the carbon of the anode is con-tinuously consumed. The metallic aluminum is regularly removed from the cellbottom for subsequent casting. Alumina is periodically fed in small portionsinto the cell and dissolves in the electrolyte to maintain the alumina concentra-tion. The consumed carbon is continuously replaced in Sderberg technologyor batch wise by replacing used anodes butts with new blocks in the so calledprebake technology.(This is described in Chapter 2.2).

2.2 Technology principles

In this section a historical review of the aluminium smelter technology is given.

Prebake and Sderberg smelter technology is described and compared, futuredevelopments are presented and their potential for implementation into theprojected plant are discussed.

Choices of technologies are made with respect to most environmental friendlyand most productive technologies.

The new plant at Byneset is proposed to be built in the coming 5 years. There-fore, we focus on the current state-of-the-art technology. Considering bothenergy consumption and environmental impact, the new plant to be built inByneset is proposed to be based on PFPB (point-feed Prebake) technology.Technology for CO2-Capturing It is a major goal to select a technology thathas the lowest emissions.

2.2.1 Looking back

Since 1900, there have been significant improvements in energy consumption.The first commercial aluminum cells at Neuhausen, Switzerland (Heroult) andPittsburgh, Pennsylvania (Hall) required more than 40 kWh/kg aluminum pro-duced and had current efficiencies of about 76 % [Hau86].

Table 2.1 [Paw99] sums up significant improvements from 1948 to 1999. Ofinterest is the impressive improvements in energy efficiency reduction.

The total electricity use of industrial smelters today varies from 12,8 kWh/kgaluminum for the state-of-the-art plants up to more than 15 kWh/kg aluminumand current efficiencies of about 92 to 95 % for different modern point feedreduction technologies [ye06]. 1

1The electrical energy consumed in a primary aluminium cell is measured by the number ofwatts consumed over a period of time. Wattage is determined by multiplying the cell voltageby cell amperage.


Table 2.1: 47 years of developmentParameter 1948 1999

Current (kA) 50-60 300-335Smelter capacity (kg Al/cell*day) 385 2475Energy consumption (kWh/kg Al) 18,5-19 12,9-13,5Average velocity of flow in the cathode (cm/s) 10-15 4-6Cathode fife (days) 600-800 2500-3000Interval for alumina additions (minutes) 80-120 0,7-1,5

Aluminum production from alumina is still electrically energy intensive. Sincethe electricity cost is about one third of the total production cost, energy effi-ciency continues to be a major area of focus for the aluminum industry.

2.2.2 Industrial cell designs

From its invention, the reduction cell has undergone three main stages of de-velopment starting with a small scale prebake cell to the Sderberg cell and tothe modern prebake cell. We will now look at these two technologies.

There are two basic cell designs. The principal differences between the Sder-berg and the prebake technologies is the type of anode used. Sderberg tech-nology uses a continuous anode which is delivered to the cell in the form of acarbon paste which bakes in the pot itself. Prebake technology uses multipleanodes in each cell. These anodes are prebaked in a separate facility. A moredetailed description is given below.

2.2.3 The Sderberg Technology

Sderberg anodes are continuous and self-baking, which in principle is advanta-geous. The raw materials are petroleum coke and coal tar pitch. Anode pasteconsisting of petroleum coke and coal tar pitch binder is added on top of theSderberg anode, and while the paste passes slowly downwards through a steelcasing, it is baked into a solid composite through pyrolysis of the pitch by theheat generated in the bath of the electrolysis cell.

Electric current enters the Sderberg anode either through vertical spikes orhorizontal studs connected to the anode beam. These spikes are pulled andreset at a higher level before they reach the bottom surface of the anode [GK93].

2.2.4 The Prebake Technology

Prebaked anodes are made from a mixture of petroleum coke and coal tarpitch binder. The paste is moulded into blocks and baked in a separate anode


Figure 2.4: Sketch of a typical reduction cell with Sderberg technology [ye06].

baking furnace before they are rodded with iron studs and mounted into thecell superstructure above the cathode lining.

Prebaked anodes have to be removed at regular intervals, usually when theyhave reacted down to about one fourth of their original size. Since most cellshave at least 15-20 prebaked anodes, this means that one anode has to bechanged approximately every day in each cell.

Technology market shares: The Sderberg smelter technology holds a 27 %market share (see Table 2.2) in the primary aluminum industry and is called theold technologycomparing with the modern prebake cell. Sderberg technologyis being phased out in Scandinavian and the European countries in favour ofprebake technology which is more productive and environmental friendly dueto its lower emissions.

Table 2.2: Technology distribution of worldwide primary aluminium productionin 2001[Ins03]

Technology Prebake Sderberg

PFPB (Point Feeder Prebake) 58%CWPB (Center Work Prebake) 9%SWPB (Side Work Prebake) 6%HSS (Horizontal Stud Sderberg) 9%VSS (Vertical Stud Sderberg) 18%Total 73% 27%


Figure 2.5: Sketch of a prebake cell [ye06]

As can be seen from Table 2.2, prebake technology dominates recently estab-lished new smelter projects, called greenfield plants, and upgrading as well asexpansion of existing smelters, called brownfield aluminium plant projects. Ingeneral prebake technology is the preferred choice. Assuming that research inthe field of prebake technology and retrofit is intensive, it can be expected, thatinnovations are more likely to be introduced for prebake technology in the com-ing years. Hence recruiting personnel and specialists will be easiest if prebaketechnology is implemented. This may be the reason why Prebake technology isthe preferred choice, as described by Table 2.2.

Figure 2.6: Prebake cell, Left: Anode removed. Right: Anodes ready for re-placement, c Norsk Hydro.


Electricity consumption: Low energy consumption and lowest possible en-vironmental impact are two of the governing factors when selecting the tech-nology. Table 2.3 contains an overview of electricity consumption for differentsmelting technologies.

Table 2.3: Electricity consumption in aluminum smelting (MWh/ton Al). HerePFPB stands for Point Feeder Prebake, CWPB for Center Worked Prebake,SWPB is use for Side Work Prebake technology, HSS for Horizontal Stud Sder-berg and VSS stands for Vertical Stud Sderberg technology.[HSZ01]

Technology MWh/ton AlAll existing plants 1995 15.5Soderberg 16.6CWPB 15.5SWPB 14.6PFPB 14.4PFPB (Upgrading and expansion of Brownfield) 13.8PFPB (Greenfield) 13.3

The average electricity consumption is approximately 16.6 MWh/ton Al forSderberg technology, while most modern prebake facilities are as low as 13.3MWh/tonAl.

Producing a prebake anode requires 0.66 MWh/ton Al [CG03]. Hence thedifference in energy consumption between a facility utilizing prebake technologyand one utilizing Sderberg technology is:

Energy = 16.6 (13.3 + 0.662) = 2, 64MWh/tonAl (2.2)

If running a plant with a production of 600.000 tpy primary aluminium, andassuming the energy cost to be 18.0 re/kWh, and 180 NOK/MWh respectively,the economic saving will be will be:

Savings = 2.64 600 000 180 = 285 120 000 NOK/y (2.3)

2.2.5 Environment

The environment is of great concern to companies, local communities and politi-cians alike. Hence, it is a major goal to select a technology that has the lowestemission, so that the local and global environment suffers the least.

Table 2.4 shows technology specific emission of perfluorocarbon compounds(PFCs), CF4 and C2F6, which are very potent global warming gases with longatmospheric lifetimes. From the Table, we can see that prebake technology has

20.61 - 0.66 MWh/ton Al energy input required for anode material production for prebaketechnology [CG03]


great advantage in PFC emission intensity, especially the PFPB technology.The total CO2 emissions, consisting of both PFC and CO2, characterized andpresented as CO2 equivalents, is also lower for prebake compared to Sderberg.

Table 2.4: Technology specific emissions of PFC compounds (kg/ton) reportedin the year 2000 [Ins01].

PFPB CWPB SWPB VSS HSSCF4 0.11 0.21 1.06 0.36 0.51C2F6 0.014 0.027 0.106 0.0016 0.051

2.2.6 Looking ahead

Significant engineering changes in cell design and operation have occurred overthe past fifty years aiming for productivity increase and to incorporate energy-reducing technologies. For economic, environmental and strategic reasons, thealuminum industry continues to perform research and development on alter-native raw materials and processes. Two innovative technological changes tothe Hall-Heroult process, the wetted drained cathode and the inert anode, areexpected to improve the energy efficiency significantly.

Wetted drained cathode: In an aluminum production cell there are twomain issues of interest when discussing drained cathodes:

1. Minimizing the energy consumption through minimizing the anode-cathode-distance (ACD).

2. Cathode-corrosion caused by bath and metal movement in the cell, andfriction on the cathode by undissolved alumina.

The aim of building a drained cathode is to minimize the influence of the metalbath on the ACD through constantly removing the surplus aluminum fromthe gab between anode and cathode, making it possible to keep a very smallACD, leading to much lower energy consumption than we have with the currenttechnology.

Inert anode? As mentioned previously, the anodes of the Hall-Heroultprocess are consumed during the electrolysis (see section 2.1.2), forming carbondioxide and amounts of other carbon compounds wearing down the anode body.This makes continuous manufacture of new anodes and constant replacementof consumed anodes necessary. Anode changes disturb the process stability andtherefore the energy efficiency of the cell significantly.

Until today no material is truly inert under the extreme conditions in the cell.Research indicates that a few usable materials will dissolve quite slowly. Metal,ceramics and cements have been in focus for inert anode research. However,their superior performance must still be proven in industrial scale.


In addition to overcoming the technical challenges, the higher costs of manufac-turing inert anodes in commercial scale must be compensated with a longerlifetime and lower energy consumption and higher productivity.

Although research projects indicate the potential for reducing costs, energyconsumption, and the environmental impact, none are near commercializationat least for the next 15 to 20 years [TFH+01].

Future technologies: Conclusion When planning to build a smelter, in-cluding some technology that is currently in development is highly risky at best.However, when planning a plant one should have an eye with recent develop-ment. Having the option to implement or retrofit promising technology intowell approved prebake technology will provide valuable advantages.

The drained cathode design will probably make the cell run more efficient dueto lower energy consumption. The question is whether the lifetime of the cellwill be reduced or increased depending on the control of the new flow patternsinduced.

Hence, the best one can hope to do as regards future technology is to install thecurrent technology that will support upgrading to future inventions the best.

Figure 2.7 suggests that it is possible to simply replace a prebake anode with aninert anode almost as easily as replacing a prebake anode with another prebakeanode is done every day. This would mean that by selecting a prebake designone also supports future inert anode retrofit.

Figure 2.7: Drained cathode [CG03].

IntroducingDrained cathode technology into todays commonly used cathodeconstructions means replacing the pot lining. This can be done during regularrelining the cells.

Thus, choosing prebake technology offers the possibility of both upgrading todrained and inert technology and thereby giving the opportunity of operatingmore energy efficient in the future.


2.2.7 Selecting a smelter technology

The bottom line is that when looking to the future, prebake technology is thesuperior choice.

By selecting prebake technology for the envisioned aluminum plant there are anumber of advantages mentioned above. Here we sum them up:

more qualified personnel available big field of research lower energy consumption lower emissions due to advanced gas scrubbing

Modern prebake smelters give a combination of low investment costs due to itscompact technology, high productivity, low energy consumption and reducedemissions. It is economical and environmentally friendly, when combined withthe most modern technology of CO2-capturing.

Optimization work towards magnetic compensation allow more compact potlines with smaller distances between the reduction cells. The pot-room areaneeded for the same production capacity can be reduced compared to pot lineswithout advanced compensation techniques and thereby investment costs canbe kept at a minimum.

Computerized process control coupled with electrolyte optimization leads to abetter understanding of the subtleties of the processes. Fine tuned feeding andgreater control of the critical anode-cathode distance to smaller tolerances ledto smaller voltage drops in the cells and thereby increased energy efficiency.

Actual development in computerized process control like the Model PredictiveControl (MPC) has the potential to stabilize the electrolysis process further.

This technology is the basis for finely tuned heat balance and high currentefficiencies and can therefore allow larger, more economic cell designs in thenear future.

2.2.8 Analysis in current Prebake licenser

Alcoa (USA), New Alcan (Canada, Alcan acquired Pechiney in Dec. 2003, totalproduction), RusAl, Russia, Hydro (Norwegian), Pechiney (France), Dubal/Comalcoare the top world leading prebake technology licensers. Alcoa has stopped li-censing its technology in the 1980s. Hydro owns the HAL 230 /HAL 250/HAL275technologies [Alc03]. This technology can be licensed to third parties.

The market investigation also showed that in some instances Hydro demandsparticipation in smelters for which it grants a license.


Figure 2.8: Specific Emission of reduction cell based on different technologies[Foo06a]

Dubal and Comalco have co-developed the CD 200 technology based on olderKaiser technology. CD 200 has so far been implemented on a large scale onlyby each company in Dubai and New Zealand [Alc03].

The Russian VAMI has not licensed its technology outside Russia since 1985[Bre05].

Thus, among those licenser, Alcan (Pechiney technology, AP 30) and Hydro(HAL275) could be the possible competitive licensees for the plant in Byne-set. Pechiney, in its 2000 Annual Report, estimated that approximately 80% ofrecently commissioned smelting capacity in the world utilizes Pechiney technol-ogy. Pechiney owns the biggest market share and runs in the highest ampere.

Figure 2.8 shows specific emissions of fluoride and dust of Hydro cells and cells oftheir competitors. Also, Hydro representative, Berveling informed the authorsthat PA 30 pot lines needs more space in design and also have some problemswith huge magnetic fields generated by cell and bus bar.

While, Pechiney has the most energy efficient technology in primary aluminumindustry, Hydro is closer to home which means support, maintenance and co-operation in development will be easier. Hydro, owns relatively smaller marketshare but is also in the lead of the world aluminum smelting technology, es-pecially as regards emissions. This last point will likely be very importantto be allowed to build. Hydro is the most likely licenser with their HAL275equipment, but the final choice will have to be made by the investor.

2.3 Plant Design 16

Figure 2.9: Plant layout of a typical smelter with the capacity of approx. 600000 tpy. The picture shows a plant comparable to the smelter project in Qatar.The picture is taken from the presentation: Hydro Primary Metal, April 2006at NTNU, Trondheim.

2.3 Plant Design

In this chapter, the plant layout will be presented. The main facilities neededwill be described concisely following the value stream, followed by the maintechnical data.

Inspired by actual smelter projects, we take the layout of those plants as guide-line, thinking in terms ofbest quality,most environmental friendly operationrather than best price.

2.3.1 General

The proposed plant is a greenfield plant located in Byneset in Trondheim, Nor-way, with an annual production of 600 000 metric tons aluminum per year byusing point-feed prebake smelting technology and using alumina as the mainraw material.

2.3.2 Plant layout

In this section we describe the plant layout and technical data of each mainunit of the plant.

2.3 Plant Design 17

Figure 2.10: Flowchart of the Aluminium Plant in Byneset

Main plant components According to Figure 2.9 the main plant units areas follows:

1. Anode baking furnaces

2. Anode rodding

3. Casthouses

4. Fume treatment facilities: Dry/wet scrubber facilities

5. Maintenance and storage facilities

6. Auxiliary services, administration

7. General service building

8. Alumina storage silos

9. Harbor

10. Power supply, rectifiers

11. Potrooms

Main units description Figure 2.10 3 shows the flowchart. The main pro-cesses steps for processing alumina to aluminium ingot and foundry alloys arepresented.

The following parts of this Section provide the technical and construction dataof each main units.

3For a bigger version see B.1 in the Appendix B

2.3 Plant Design 18

Storage facilities The main raw materials, alumina and petroleum coke arekept in storage silos. Other hazardous expendables such as, coal tar pitch,cryolite, other fluorides in the form of different salts (AlF3, CaF2...), etc arestored in suitable warehouses. The final products will be kept in special storagewarehouse on the industrial site. The storage requirements for the final plantinclude:

Alumina storage silos: 4 silos with a capacity of 55 000 tons each 4

Bulk material storage building: For other raw materials Warehouses: For baked anodes and used anode butts Warehouse: For tools and spare parts

The overall storage area is expected to be ca. 7400m2 due to estimates basedon scaled data known from an actual smelter project [AHVe02].

Anode plant The anode plant includes three functional units: the greenanode plant, the anode baking furnace and the anode rodding plant.

The carbon anode is consumable during electrolysis process with a gross con-sumption of 0.5 ton anode / ton aluminum. Therefore the capacity of the anodeplant will be 300 000 tons of anodes per year.

Main technical data foranode baking furnace:Capacity: 18 anode blocks/pit, 8 pits/sectionArrangement: 46 sections located in two parallel rows

with cross-over connection in each endFire step: 24 hoursSoaking time: 40 hoursTop gas temperature: up to 1250 CSize of the anodes: 1510 mm 600 mm 700 mmDensity of anode: 1.58 tons/m3

Number of fires: 3Number of furnace: 2 (Equation A.1)

The anode baking plant is estimated to be 15 000m2. The anode roddingfacilities will occupy an area of approximately 7 000 to 8 000m2. The facilitiesfor the anode production, containing the paste production and molding as wellas the baking furnaces, will require an area of approximately 23 000m2 due tocomparison with actual smelter project [AHVe02].

4The silos facilities are needed to ensure a continuous supply of alumina of production.The alumina storage shall secure approximately 2 month production. Based on consumptionmentioned in the section of Final product and consumption, daily alumina demand is 3 288tons. This amounts to a total storage capacity of approximately 200 500 tons. The capacityof each silo is 55 000 tons. Therefore 4 silos are needed.

2.3 Plant Design 19

Pot room There are various pot room designs. Modern smelter designs allowa distance of approximately 6 m between the pot center lines in side-by-side potlines, ca. 25 m between parallel lines in one pot room. The distance betweentwo pot rooms can vary between 50 and 70 meters. The distance between pot-room and the distance to other building should at least equal 1.1 times thewidth of the pot-room [Ber06a].

The above named design parameters result in a pot room area of approximately56 000 m2 per pot room. This area corresponds to a pot room length of 1120m and 50 m widths assuming that 178 pots will be placed side by side in twoparallel lines. 328 pots will connected in line to one rectifier placed in one endof the pot room.

The overall construction area for the 2 pot rooms (including the space betweenrooms) necessary for a 600.000 tpy production with auxiliary buildings is esti-mated to be 220 000 m2.

Main technical data:Type of reduction pot: HAL275Pot room: 2Number of pots: 712 (Equation A.2)Number of pot-line: 2Arrangement: 356 in series connected sidebyside, arranged in 2 parallel lines 5

Operating ampere: 300 kA, expected to increase to 350 kAOperating temperature: 960-970 CFeeding method: 5-point feedersCell voltage: 4.2 V (expect 3.9V or less in operation)Productivity: 2.307 ton/pot pr day (assume current efficiency is 95.5%)(Equation A.3)Anode changing: 2 blocks /per cell per dayTapping: 22 hours

Scrubber facilities Two types of scrubbers will be applied. The Norwegianregulations and EU directives valid for emission limits will be fulfilled.

Dry scrubber: removal and recovery gaseous and particulate fluorides withminimum 99.5% efficiency.

Wet scrubber: removal of SO2 gas by using sea waterTypical suction power per electrolysis cell is about 6000 Nm3/h. For the plantwith a capacity of 600 000 tpy (712 pots) about 4 272 000 Nm3 pot fumes willbe processed every hour. When designing the gas cleaning facilities an extracapacity of 20 % has to be provided for service and additional environmentalapplications, summing up to a total volume of 5 126 400 Nm3/h.

Waste heat recovery and CO2 gas is described in Chapter 4.

This plant in Byneset will be the first green aluminum plant in the worldwith environmentally advanced technology to achieve CO2-free and high energyefficiency [Foo06b].

2.3 Plant Design 20

Refining ans Casting The metal impurities will be removed with help ofbubble flotation and stirring refining processes before casting . Continuouscasting can be applied due to less energy consumption comparing with batchcasting. The production will mainly be standard ingots and primary foundryalloys (PFA) according to the requirement of the clients.

Power station, power converting and rectifier The power station willbe built near by the smelter site. 8.475 TWh/year of electric energy are re-quired. The design and investment cost are not worked out in detail. Furtherinvestigations have to be done.

The transmission lines will be connected directly to an indoor substation at theplant. From the substation, the energy is transmitted to a rectifier where thealternating current is converted to direct current.

Air Compressor Station Produce and transport compressor air for plantuse.

Natural Gas Station Store and transport natural gas to casting house andbaking furnaces.

Combustion plant - waste treatment facilities The plant has strict in-ternal standards for proper disposal of wastes and will not construct an on-sitehazardous waste landfill. Cathode and side wall lining (SPL), useless anodebutts and other carbon scrap will be sent to the combustion plant. The heatfrom combustion will be used to generate electricity The waste heat from com-bustion processes and the electrolysis process (the potroom) will be used to heatthe city of Trondheim. Carbon dioxide captured and sent to Haltenbanken.

Other infrastructure and facilities The main auxiliary facilities includeoperation and administration center, the maintenance shop, laboratory andResearch and Development, fire station, medical center. 6

Harbor The necessary transportation facilities for loading and unloadingfrom raw materials and containers from freighters has to be installed.

6Since this plant is in a big scale, the medical center is suggested to be inside the plantinstead of buying services in town and canteen, kitchen, engineering department, etc. Thelocker rooms and showers will also be located in the general service building.

2.3 Plant Design 21

2.3.3 Design Standards and Codes and Regulations

Norwegian regulations and the EU directives effective since 2005. OSPAR agree-ment. Other standards and regulations necessary for equipment design and civilwork.

2.3.4 Design basic

Natural condition at site Natural conditions at site are important for plantdesign work especially the civil works. The items list below are needed beforethe engineering design.

Elevation Mean monthly temperature in the hottest months Mean monthly temperature in the coldest months Extreme maximum temperature Extreme minimum temperature Mean annual temperature Mean annual relative humidity Mean monthly relative humidity in the hottest months Mean monthly relative humidity in the coldest months Wind Speed Mean annual wind speed Maximum wind speed Mean annual rainfall Maximum hourly rainfall Maximum depth of snow cover Earthquake

2.3.5 Final product and consumption

Product: High and consistent metal quality extrusion aluminum ingot andfoundry alloys according to the requirement of the client.

Consumption: Consumption of raw materials and some utilities are estimatedas mentioned in Tables 2.6 and 2.7.

Wastes: For information on discharge of wastes to the surrounding, see Table2.8.

2.3 Plant Design 22

2.3.6 Project Milestones

In order to get the turnover up as quick as possible. The Potline will be builtand started step-by-step section wise. The 1st section is supposed to start-upand produce aluminium within 1.5 years from the beginning of the civil work.It is meant that the fist section will be started whilst the construction workof the potroom building, concrete foundations, busbar systems and cathodesare assembling in the next section is undergoing. Aluminium wedges are usedduring start-up and construction in oder to bypass the current. Full scale start-up and production will be achieved within 1 year after the start-up of the 1stsection.

Typical construction milestones are as follows, assuming that all the approvalprocedures of project can be done and the project can be started at year 2007:

Table 2.5: Project milestonesDesign: year 2007-2008Equipment purchasing: year 2007-2009civil work and building: year 2008-2009Erection: year 2009-2010Test and start-up: year 2010-2011

Table 2.6: Raw materials consumptionAlumina: 1.9 ton/ton AlCarbon (including petroleum coke, 0.5 ton/ton Al (grass consumptionanode butt and pitch):Aluminum fluorine: 5 kg/ton AlCryolite: 50 kg/ton Al

Table 2.7: Utilities consumptionLiquid gas 550 kWh/ton aluHomogenisation 180 kWh/ton aluCompressor 95 kWh/ton aluElectrolyses 13300 kWh/ton aluWater [not available]

Table 2.8: Discharge of wastes to the surroundingF : 0.1-0.2 kg/ ton AlPAH: 0-1 kg/ton AlSO2: 1-15 kg/ton AlCO2: 1500-2000 kg/ton Al

Discharging of liquid: 0Discharging of solid

Dust: 0.2-10 kg/ton Al

Chapter 3

Market

This chapter will present data on capacities of recent years, the present markedand an outlook on future development of the world market for primary alu-minum.

The reader will find information about why there is a growing demand andwhere the main future markets are located.

It will become evident that there is an increasing gap between aluminum produc-tion and consumption in the near future. This increasing gap between supplyand demand of primary aluminum, represents a save market for the aluminumproduced by the envisioned smelter.

3.1 Increasing demand

While primary aluminum production in the United States has decreased, ship-ments of aluminum in the form of both wrought and cast products has increasedfrom 8 million tonnes in 1992 to 10 million tonnes in 2002 [CG03]. The UnitedStates has increasingly been importing aluminum ingots. Looking at the statis-tics for the last decade, the world primary aluminum production grew from 19.5million tonnes in 1992 to 25.9 million tons in 2002, an average growth rate of3.1 % [CG03].

In 2005 the world production of approximately 30 000 000 tpy has been reported[Fra05]. A further growth in primary aluminum demand to approximately 67500 000 tpy in 2025 is expected, which equals an average growth of 4 to 4.5 %per year [Fra05].

3.1 Increasing demand 24

Figure 3.1: Price trend for aluminum and operational costs for aluminum pro-duction [Fra05].

The independent business analysis and consultancy group CRU | STRATEGIES(CRU consulting for the mining, metals, power and cables sectors) links theprimary aluminum consumption to the income through the s-curve relationship,which describes a rapid growth in the Middle East and Africa of 5 % , otherAsia with 5.2 % and especially China with 7.5 % in the period from 2005 to2025 [Fra05].

Primary aluminum production is a profitable business.With aluminum pricesexpected to be stable at around 2000US$/ton (see Figure 3.1) and a wideninggap between demand and supply for primary aluminum, a smelter project atByneset has the potential of being highly profitable at relatively low risk.

3.2 Widening gap between supply and demand 25

Figure 3.2: Future demand [Fra05]

3.2 Widening gap between supply and demand

Assuming that the boom for aluminum packages and the preferred use of light-weight metals in the electrification, transportation and construction sector willproceed, that there will be an enormous demand for aluminum in the comingdecades.

The predicted increase in demand of approx 37.5 million tonnes in the coming25 years equals new smelter capacity of approximately 1 500 000 tpy. Thismeans that in order to be able to cover the widening gap, 3 plants of the sizeof the Hydro Sunndal plant has to be build every year in the coming decades(Figure 3.2), which supports our claim that there is a market supporting theenvisioned plant.

Chapter 4

Energy and Environment

4.1 Energy

An aluminum plant consumes a lot of energy. The questions then, are:

1. Where to get it?

Produce locally? Import? Build abroad?

2. What to get?

What kind of energy source should the energy come from?A discussion of the development of energy prices and availability is necessary.Naturally there are barriers and limitations of a political nature that needs betaken into consideration when looking at this. When this discussion is done wewill have an answer to the two questions above.

4.1.1 Prices are going up

Today there is a demand for power in Mid Norway. Market forces are expectedto double the energy prices within two years. This means that the productionof power needs to be increased significantly. The main problem for Mid Norwayis that the region is in shortage of power lines and therefore, development ofnew power technologies or expansion of existing power lines is required [Lan05].

4.1 Energy 27

4.1.2 Barriers

Price is not the only barrier. Policy is one more limitation. In Norway, thegovernment has a goal to increase the energy production, and the increaseis meant to be produced by environmental friendly energy technologies. Thedebate has turned on whether to build wind power or gas power, while extensionof hydro power is turned down. For an aluminum plant, the requirementsof power consumption correspond to a technology that can provide for highproduction of electricity. Considering todays political landscape, gas powerwith CO2-capture seems to be the most realistic short-term power alternative.

A high power demanding aluminum production depends on favorable agree-ments on power. Aluminum companies projecting primary aluminum plantprefer countries that can ensure a robust project, with low investment costs perton, combined with a long-term, competitive power contract, to meet the profitrequirements.

Since energy intensive industry depends on low priced power contracts, singlemarkets for industrial power is a preferable solution. But, it seems like a singlemarked for industrial power may be difficult within the agreements of EFTA.The electricity agreements in the aluminum sector expire within year 2011 as aresult of injunction from EU [Fed06]. Expensive energy is a problem in manyEuropean countries, and this will threaten industrial workplaces, and still thereare no countermeasures developed in Norway or EU [Aft06].

Norway is part of a common Nordic power market, Norpool. This makes theprices on electricity similar in the Nordic countries. The power that is producedin Norway, is mostly consisting of hydro power. Norway is annually consum-ing about 123 TWh, yet producing only 120 TWh. The implication is thatNorway is importing power, which is mainly produced by coal, nuclear or windtechnologies elsewhere in Europe [oE06].

Further on, the Norwegian behavior on the power side is very good comparedto other countries. There is no doubt that Norway should utilize the advantageof the gas supplies and build gas power plants. This would replace dirty energyas coal power plants at the European and Nordic continent.

From a global perspective it is more environmental friendly to produce powerfrom gas in a state-of-the-art gas power plants in Norway, than to producepower in outdated plants with much higher levels of pollution abroad.

Technology to capture CO2 emission is highly developed in Norway and can beapplied to the power plant and other CO2 emitting facilities connected to theprojected aluminum production plant. The Technology which provides anothervery important argument for our smelter project will be discussed in a followingchapter.

4.1 Energy 28

4.1.3 Requirement

The bulk of energy used in aluminum production is related to the electricityrequired for the primary electrolysis. Since energy costs are approximatelyone third of the total cost of smelting primary aluminum, smelter productiontechnology influences the total energy cost. It is important to keep the energyexpenses as low as possible to gain profit.

The energy consumption for the Byneset plant is assumed to be close to 8.0TWh/year based on comparison with the Alcoa-Reydaral project and datagained from discussions with specialists at Hydro Aluminium [Ber06a]. Ourown calculations, based on energy needed to run subprocesses in the smelter,indicates a consumption of 8.475 TWh/year. This relationship indicates thatthe consumption we use for our calculations are high.

4.1.4 Supply

Since the local region is not able to provide the energy today, an energy sourcehas to be imported to the region. The cost and time for building the infras-tructure due to hydro power, limits the possibility of using hydro power. It isimportant to keep in mind the most cost effective solution, and it is assumedthat the cheapest way of gaining energy is to produce electricity from gas atByneset. As there are no gas sources in Mid Norway, this gas has to be trans-ported from a source outside this region. The total recoverable reserve on theNorwegian continental shelf is 8.9 billion standard cubic meters oil equivalent(Scm oe). Assuming no new findings and constant production of 264 million oeas reported in 2004 [Gas06] the gas resource will last 33,7 years.

4.1.5 Gas power plant

In the project of current interest, a gas pipe has been planned from Tjeldber-godden to Skogn (160 km). The project is supposed to deliver 1000-1300MSm3

gas and would cost 1200-1300 million NOK [OedoN]. The gas power plant issupposed to produce 6.4 TWh electricity and 1 TWh heat every year. Thismeans that a gas power plant at Byneset has to be bigger than the one plannedat Skogn. The solution to the energy issue means that Byneset aluminum plantimports gas from outside the region. A pipeline from Tjellbergodden to Trond-heim would have to be about 100 km. When it comes to getting the gas toByneset, it could also be transported by boat or truck. Due to assumed costsand the amount of gas needed, this project will focus on importing gas bypipeline.

The arguments against building a gas power plant is that it contributes to theglobal warming through CO2 emissions. That is only true if you dont clean thegas. However, when cleaning the gas, the plants efficiency decrease. When the

4.1 Energy 29

Figure 4.1: Gas pipe from Tjelbergodden to Byneset.

alternative is importing coal based power, gas power plants with CO2-capture,is by far the better alternative from a global perspective [Sve06].

4.1.6 Coal power plant

The third alternative is to produce energy from low-cost coal and utilize CO2-capturing. If this approach is taken, the energy price will be approximately 8.0re/kWh [Sve06]. This way the energy will be much cheaper, leading to muchhigher profits. It will produce a lot more CO2 than the gas alternative, andthe matter is then a question of profits and politics: Profits will be higher, butthere will still be some environmental issues that might oppose a coal powerplant. For instance there are emissions related to transportation of coal. Suchindirect emissions may oppose a goal for operating as environmental friendly aspossible.

4.1.7 Conclusion on energy technology

There is sufficient energy available when piping gas from Tjelbergodden. Dueto availability and costs, gas seems to be the most realistic source of energy toprovide the required amount of power.

By building a gas power plant beside the aluminium plant and running it our-selves, there is no longer need for a long term agreement for power, only fora long term agreement for gas. This kind of agreement is not affected by theEU-directive. Furthermore it might be easier to get a reasonable price on gas,which is something we have in abundance, rather than an agreement on a rea-sonable price for electric power, which is scarce. The price of gas, however

4.2 Environmental Evaluation 30

does influence the profit. The cost is estimated to be about 3 billion NOK forthe power plant facility, while the piping will cost about 1.3 billion NOK. Themaintenance of the piping, is estimated to be approximately 40 million NOK ayear. When considering building and running the power plant ourselves thesecosts along with the running costs will have to be weighed against the cost ofbuying energy produced on site in a similar way by a third party.

When considering building a gas power plant, it is assumed that the price onelectricity out of gas is no more than 18 re/kWh. The melting and holdingfurnaces in the casthouse use liquid natural gas as well as the anode bakingfurnaces. The price of liquid natural gas is 30 re/kWh [Skj06]. The Statisticsof Norway (SSB) further supports this. In 2004 the energy price for aluminiumproduction was 18.6 re/kWh [oN04]. Energy prices are going up, however, bybuying the gas and producing the energy ourselves, we can most likely avoidthis increase in price. Hence we shall assume 18 re/kWh.

The energy alternative that is chosen, is to bring gas from Tjelbergodden toByneset by piping. A gas power plant have to be built on Byneset and be runby the plant.

Treatment of CO2 have to be taken into account when calculating the runningcost of the gas power plant.

Due to the political landscape and the assumed indirect emissions when it comesto a coal power plant, the coal power alternative have to be investigated furtherby the contractors who want to build the plant. This have to be a question ofprofits and politics.

4.2 Environmental Evaluation

Historically the aluminum production has been highly pollutive, and had agreat impact on the local surroundings. The area around the old plants weresuffering. By using the state of the art technology, aiming for zero emissions,the production hardly pollute at all.

4.2.1 Emissions

The main emissions from an aluminum plant are fluorides, dust, sulfur dioxideand PAH. In addition there is as mentioned in Chapter4.1 the CO2 issue whenusing natural gas or importing electricity as the power source.

Using the technology chosen in Chapter 2, the emission from the plant willfulfill the requirements given by the Statens Forusensingstilsyn (SFT). Thetechnology used at Nye Sunndal is similar to the technology that will be usedat Byneset. When comparing emission from Sunndal 1 (the old Sderberg line)and Sunndal 4 (the new line), the improvements are significant: PAH emissionto air is approximately zero in Su 4, the emission of fluorides to the air has gone

4.2 Environmental Evaluation 31

Table 4.1: Development in Reduction cell emissions [Paw99]Emissions (kg/1000kg Al) 1948 1999Fluoride (F) 30

4.3 Waste heat 32

4.3 Waste heat

The waste energy can be used to produce either heat (in the form of warmwater) or power.

4.3.1 Hot water and power

After cleaning the gases in the dry scrubbers, the clean gas can be passedthrough a heat exchanger. In the heat exchanger, the heat in the gases heatsup the water. The water can then be distributed.

To be able to produce power, you need hot gas. By combustion, you get twoproducts: Electricity and gas with a lower temperature. The remaining gas stillhas to be cleaned, so it can still be used to produce warm water as describedearlier.

Power production from the raw gas out of the pots is under development [Ski06],and might be ready for commercial use just in time for the building of theByneset plant. By using this technology, you make use of the gas when thetemperature is at its highest. In stage one, the production of power takesplace, and stage two is the same as described earlier.

In addition to the waste heat from the aluminum production, there will be wastehot water from the gas power plant and the combustion plant. This water shouldbe distributed together with the warm water from the dry scrubbers.

4.3.2 Smelter heat losses

In the previous chapters the processes involved and the main technical data ofthe plant has been outlined giving the reader an impression of the dimensionsof this huge primary aluminum plant. One of the byproducts when producingaluminum is waste heat.

Only about 20 % [GK93] of the heat generated during the electrolysis processin the smelter is actually used for the aluminium production.

50 % heat loss More than 50 % of the 13 kWh consumed to produce one kgaluminium in modern high ampere cells is heat loss [Ber06b].

For a smelter of the described size this heat loss amounts to a total of

13 MWh/ton Al 50 % 600 000 ton/year = 3 900 000 MWh/yearThis 3.9 TWh is heat with the temperature of approximately 300 - 500 C,which corresponds to a medium sized power plant(Skogn project 6.4 TWh).The magnitude of this number makes it evident that the waste heat utilizationis of very high interest.

4.3 Waste heat 33

Figure 4.3: Typical heat loss of a prebake cell

The Figure 4.3 [Hau91] shows the heat loss distribution for a typical prebakecell. There are two waste energy fluxes that are of major interest:

Energy in the fumes Energy leaving the cell over the side walls

4.3.3 Sidewall heat flux recovery

Frozen side ledge There is no material that stands the corrosive attackof liquid cryolite over an extended period of time. In order to increase thethermal resistance of the side lining a cryolite layer (ledge) is frozen to thesidewall refractory.

The heat loss over the sidewall is essential; it has to ensure a temperaturegradient that allows the cryolite bath to freeze onto the sidewall refractorythereby protecting the sidelining of the cathode cell against excessive erosion.A too thin layer increases the erosion of the side lining and may increase therisk for cell failure known as side wall tap-out.

Carefully designed cathode linings and pot room ventilation systems ensure asufficient enough ledge in actual smelter project, but these designs do not utilizethe enormous amounts of waste energy.

4.3 Waste heat 34

Energy recovery over heat exchange systems in sidelining Pipes castinto the sidelining of the reduction cells capture the heat emitted by the elec-trolysis process and carry it to a generator located in the basement below thecell. There generators will convert the sidewall-waste-heat to electric energy.Experiments carried though by Hydro Aluminium showed promising results.About 50 % of the energy that is usually loss as heat over the sidewalls, couldbe captured in the heat exchange system and feet to generators. Assuming a40-45 % efficiency of the common generator converting heat to electricity, anoverall utilisation of 7 to 8 % of waste heat could be achieved [Ber06b]. Overall0.455kWh/kg Al can be recovered using this technology. When building theplant at Byneset an energy recovery system that captures heat emitted overthe sidewalls should be taken into consideration.

Varying current loads. There is en even larger potential in an energy re-covery system using the sidewall heat exchange system. Autonomous generatorand heat exchanger systems for each cell provide additional advantages. Thepipe system with variable cooling-fluid flow can be used to fine-tune the heatbalance of the cells, making it possible to vary the current load of each cellindividually with out freezing or overheating the cells.

The changing power consumption profiles during a year or even during theday result in periodical shortage. Power suppliers aim for evening out thisconsumption peak and try to increase the power consumption in periods withlow demand due to economical reasons.

Dynamic current load in modern smelters. During high-price-periodthe cells equipped with heat recovery systems can be operated with reducedcurrent to save energy without causing the electrolysis process come to a stop.Variable cell heat balance would allow low energy consumption which will helpsaving money during period with high power prices and would allow increasingproductivity in periods when cheap energy is available.

4.3.4 Heat loss over pot room roof

As mentioned in the previous chapter the two potrooms will have an area ofapproximately 100.000 m2 each (an area the corresponds to approximately 13football fields). A significant amount of energy leaves the pot room in form ofwaste heat over the enormous roof area.

Vision of a green aluminum plant in the near future. The energyemitted over the roof surface could be utilization by placing greenhouses on topof the pothouses. The heat emitted can be used to grow plant, vegetables forsale and algae that can convert emissions and thereby help binding and reducingCO2 and other compounds emitted.

4.4 Waste combustion 35

4.4 Waste combustion

Due to the increase in social awareness of pollution, a non-polluting smeltershould be a strategic goal for the plant. The domestic industry are likely to beintroduced to economical policy tools in the future and therefore it would beintentionally to act pro active. To remove waste and climate gases, the solutioncould be to build an combustion plant at the site.

4.4.1 Combustion

With an incinerator at the Byneset plant site the spent potlining and othercombustible waste can be combusted rather than being transported to Langyain the Oslofjord. This combustion incinerator can take care of spend potliningof Norway, Island and even Europe. The benefits of such a solution is that greatamount hazardous wastes can be converted to heat and less harmful compounds.CO2-capturing technology as described in the following section can be utilizedto reduce the harmfule effect of combustion product even more. Chapter 5

Importing waste would gain both other aluminum plants and give econom-ical gain to the plant at Byneset. By doing so, the plant at Byneset wouldearn money by selling power or heat and save the atmosphere from additionalCO2-emissions.

4.4.2 CO2-capturing technologies

As a result of the Kyoto agreement, Norway has agreed not to exceed more thanone percent of the 1990- level of national CO2 emissions [Mil97]. This meansthat the CO2 emitting industry have to buy quotas if they do not remove theirown CO2 emissions [Sel05].

Due to the decision regarding building a gas power plant, the problems due tothe CO2 emissions emerging from the processing of electricity have to be solved.The environmental interest organization Bellona have concluded that buildinga gas power plant with CO2 capturing would be a preferable way of producingpower. They suggest to use the CO2 captured for enhanced oil recovery. Theenhanced oil recovery is a method that allows the captured CO2 to producemore oil and gas by pumping the CO2 back in the reservoir [Sel05]. There arethree main groups of technology for capturing CO2.

1. Post combustion scrubbing

2. Pre combustion decarbonization (Hydrogen)

3. Oxyfuel


Figure 4.4: Capture technologies 4.4

Post combusting Scrubbing Post-combustion technologies capture CO2from flue gases by chemical processes [Bre05]. The process uses amines in thewater to scrub the flue gas [Buc05].

Advantages [oSG06b]:

Captures generally higher CO2 concentrations than for post-combustioncapture

There is no need for powerful solvent Higher driving force for CO2 separation

Disadvantages:

Fuel processing is needed Partial oxidation Shift conversion of fuel gas to H2 and CO2 Involve more radical change in power plants design


Pre combustion Decarbonization Natural gas is converted to hydrogenand CO2 in a reformer. The CO2 is compressed for storage and the hydrogenis mixed with air for combustion, emitting only nitrogen and water [oSG06a].

Advantage:

[Eur]

It uses techniques that are already in wide application The yield is much higher concentrations of CO2 than are present in con-ventional fuel gases, and at higher pressure.

Capture of the CO2 is more energy efficient and thus potentially cheaper. Hydrogen is produced.

Oxyfuel Oxygen is separated from air and then burned with hydrocarbonsto produce an exhaust with a high concentration of CO2 for storage [oSG06a].

Advantage [Buc05]:

Simple and low energy demanding separation of CO2 Extremely low emissions

Disadvantage:

The technology is yet not sufficiently mature.

4.4.3 Costs

When it comes to the costs of an cleaning plant, one can imagine three importantfactors:

Investment costs in the cleaning facility Investment costs in infrastructure for transportation and capture Running cost attached to cleaning and capture

According to the World Energy Council, the cost of carbon capture storagelies between US$50 to US$100 per ton of CO2. By this the council impliesthat costs for electricity production increases by between 25 to 100 percent[Bre05]. For an aluminum plant, an increase in the energy price by 25 to 100percent would mean a significant higher production cost. Gasstek and AkerKvrner have calculated that the investment cost in a cleaning plant (Aminefacility) would be about 470 million NOK. The running cost of the cleaningfacility would be about 180 NOK per ton CO2. This means that the prices onremoval of the climate gas approaches the expected price on CO2 quotas [Sel05].Current price on CO2 quotas is in the EU is US$ 40 per ton. During 2008, thisprice is expected to be US$100 [Nor06]. This would give further incentives toinvest in a cleaning plant. Such investment makes it even more attractive when


(previous) oil and energy minister Torhild Widvey has stated that there will begovernmental subsidies to cleaning and transportation of CO2 from prospectivegas power plants [Sel05].

4.4.4 Solution

If CO2 capture technology is installed, this would be the first of a kind inNorway, as for the rest of the world. If there is built an infrastructural systemfor piping CO2 back to the reservoirs, this could give incentives to take careof other industries CO2 emissions. It can be imagined that the economicalgain from this can be determined by future CO2 quota prices. For instance,the combustion incinerator at Heimdal may be interested in dealing with theirCO2 emissions instead of buying quotas, this could state a win-win situationfor both actors. As mentioned there is also the possibility to import and burnwaste containing CO2 or spent potlining from foreign aluminum producers.

In addition to generating heat for the central heating system, a combustionincinerator with CO2 capturing could use the captured gas to allow for produc-ing more oil and gas from the gas reservoir. Trond Giske (the Norwegian laborparty) states that when using CO2 capturing technology, the actor can sell itsemissions back to the oil industry. In that sense, CO2 becomes a resource ratherthan an emission [Lan05].

Figure 4.5: An option for geological storage of CO2 [W.W02]

One can imagine that as the gas is being sent by pipe from Haltenbanken toTjelbergodden and from Tjellbergodden to Byneset, it can be the case thatcaptured CO2 is sent back by pipes the same route as the gas is collected.

Figure from: Bellona, Presenation, Case: Tjeldbergodden gasskraftverk med oguten CO2 handtering, 24.08.2004.


Figure 4.6: Piping CO2 capture to Halten

4.4.5 Symbiosis and CO2 capture

Good planning when introducing a CO2 capture technology in the productionof aluminum can lead to effective solutions. To find the most effective way ofplant design, it can be imagined that processes emitting CO2 have to be placedon the same cite to increase the capture density.

A one cite placement of CO2-intensive facilities like anode plant combustionpower plant, waste incinerator and smelter would also lead to a more energyeffective solution as a result of using waste heat more concentrated to the centralheating system (This will be described in section 2.3. Also gas emissions can beused more effectively when putting them back to the electricity systems enteringthe turbine.

Capturing CO2 makes otherwise dirty energy productions cleaner. This meansthat for instance coal power can be used as a energy source at the cite (insteadof gas). In such a case, it would also be a point to use cheap coal containingmore carbon since this would be more cost effective.


Figure 4.7: Symbioses CO2 capture.

4.4.6 Conclusion on CO2 capturing

Norways obligations to the Kyoto agreement are most likely to affect Nor-wegian industry by use of economical policy instruments. These costs giveincentives to invest in a cleaning facility. However, an investment in a cleaningfacility are likely to give income as a result of four principles:

1. Sell services like capturing other industries CO2 emissions.

2. Sell the captured emissions back to the oil industry for enhanced oil re-covery

3. More production of hot water to the central heating system

4. Governmental subsidies

In addition, being the first industry to make use of CO2 capture, this could givethe industry a positive environmental profile that could be used in marketingstrategies.

4.5 Local aspects 41

4.5 Local aspects

There is a bird reservoir at Gaulosen by the river outlet at Gaula into theTronheimsfjord [Gau06], that has to be taken into consideration. By usingthe new technology and with keeping the emission within the limits, the plantshould cause no harm to the birds.

Neighbors might be worried about living close to a plant, but when visitingaluminum plants in 2006, even the ones who use old technology; they have niceand green surroundings. In the summertime the plants even have to employpeople to take care of the green areas.

4.6 Global aspect

Emission requirements are very strict in Norway compared to other energyrich countries. This means that producing energy in Norway is better for theglobal environment than producing aluminum in a country with less pollutionregulations.

4.7 Conclusion

The energy alternative that seems to be the most realistic to provide for thepower that is needed to produce aluminium at Byneset, is to bring gas fromTjelbergodden to Byneset by piping and to produce electricity at a gas powerplant at site. Due to requirements to energy prices, the gas power plant shouldbe built and run by the aluminum plant.

In running a gas power plant, the problems due to the CO2 emissions emergingfrom the processing of gas to electricity have to be solved. Since the worldconcerns on climate gases and global warming are increasing, proactive actionsshould be considered to limit the concerns and to limit the global warming dueto primary aluminum activity. In fulfilling governmental and public claims tolimit the CO2 emissions, CO2 capturing is needed on site.

Chapter 5

Localization

5.1 Description

Byneset is a area at the outskirts of Trondheim (Mid Norway). It consist mainlyof farm land but have also some dense areas of densely populated area.

When placing the aluminium plant at Byneset, this localization have to beshown as plausible in terms of geographical features, governmental willingnessand social demands.

5.2 Requirements 43

5.2 Requirements

The following requirements apply when setting out to build a plant at Byneset:

1. Availability of energy

2. Availability of technology/knowledge

3. Availability of personnel

4. Availability of raw materials

5. Access to the market

6. Support by the government

Reguleringsplan Konsekvensutredning Byggetillatelse7. Support in the local community

8. Support by the media

9. Seawater - harbor and scrubbing

10. Infrastructure

5.3 Fulfilling the requirements

5.3.1 Energy

Since an aluminum plant requires a lot of energy, the energy situation in MidNorway has been evaluated. All available information are pointing in the direc-tion of a need for more energy. To fulfill the requirement of energy, it may bethat a new power facility have to be built. This discussion is done in Section4.1.

5.3.2 Raw materials

Due to raw material prices, it would be advantageous to have owner interestin the raw material production. It seems essential to have good contacts andassets within the market.

5.3.3 Reaching the world market

By building at Byneset, the location gives direct access to seawater and therewill be a port where freighters can dock. Thus the world market can be reached.Required materials like fuel grade coal for power plant and household wast andspent pot lining from aluminium smelters over the world can be shipped easily

5.3 Fulfilling the requirements 44

to the cite. Aluminium products on the other hand can be shipped to supplythe emerging markets.

5.3.4 Public support

The plant will bring many well paid jobs to the Trondheim area, but that doesnot mean that it will be wished welcome by everyone. When it comes to supportby the government, local community and media, this is a political campaign,and whether or not the locals in Trondheim are susceptible to the idea of ahuge plant at Byneset is anybodys guess. In this project there has been noresearch on this. That would be the next step before going public with the idea.Hence, for further argumentation it is assumed that there will be support forthe project.

5.3.5 Infrastructure

In addition to being in close contact to Trondheim city, the area has as shownin the Figure 5 infrastructure build out in terms of roads. This meaning thatno large cost are necessary to emerge from requirements of road transport.

Energy is expected to be provided by discussion in Chapter 4.

5.3.6 Employment

Due to the plant design in Section 2.3, there will be a great demand for aworking force. A facility producing 600 000 tpy of aluminum is in need of 620potroom workers (Calculations based on [Mil97]). In addition there is a needfor workers in other functions as mentioned earlier. It is assumed that the plantwill need about 840 employees to run. The average wage is expected to be about352 500 NOK a year [oN06].

The largest share of employment in running the plant is expected to affectthe local community. Several hundreds of workplaces may disappear whenSderberg production in Hyanger and Ardal is closed. (The resolution leadsto 285 persons in Ardal, 130 in Sunndal, 70 in Hyanger, 285 in Karmy and 45persons in Oslo) [Tid03]. It will be of great interest to take care of redundantand competent personnel from Sderberg lines that are closing. Relocationis possible based on the existing living center in Trondheim. In addition theNTNU and SINTEF environment is expected to supply some working forcewithin research and development.

In addition to the workplaces at the plant, one can imagine that both theconstruction phase and the operational phase of the plant create workplacesand economic growth in other sectors. To the Norwegian business activities, theByneset project demands activities that can be important regarding business inthe region. Due to the discussion about the market need for primary aluminum

5.4 Advantages 45

production, the project will not give any pressure problems to other Norwegianaluminium industry. This means that other domestic aluminium working spaceswill not be negatively affected by the Byneset plant.

5.4 Advantages

There are several advantages both regional and national, if building an alu-minum plant at Byneset. Some of these factors are discussed in the followingsections.

5.4.1 Research and development

Trondheim is considered to be the capital of technology in Norway. Both NTNUand SINTEF are situated there, along with a multitude of other research insti-tutions. This makes a powerful foundation of technology and knowledge. Thecompany that would consider to build an aluminum plant at Byneset wouldprobably benefit from collaboration with these research institutions in terms oftechnological and economical improvements. The means of technology transferfrom Byneset Plant is expected to stimulate technology within the aluminiumsector. An economic effect of such a spin-off can be technology transfer such aspatenting and technology licensing.

However, if Hydro is the actor that wants to build the aluminum plant, they willhave a luxury problem: They can choose whether to have one or two researchand development centers for primary aluminium. One possibility is to haveone in Ardal and one at Byneset, and have them working together, or theycan choose to have just one of them. It is important to take into account thatif Hydro wants to build the plant at Byneset, this would probably affect theresearch at the research department at Ardal. This effect does not necessarymean closing down the Ardal department, it could also be a positive stimulation.

The importance of research and development can be analyzed in different ways.An objective could be to reduce the cost and increase the quality of the indi-vidual processes. As an example, this could be an improvement in anodes andcathodes . Also technical solutions due to automation control system will leadto reducing worker costs. Smelting research is concentrating on improving theenergy efficiency of the Hall-Heroult process [SHD00] as mentioned in chapter2. Research and development will provide for breakthroughs in lowering costsfor aluminum production and boasting productivity. Moreover, although earn-ing additional money on technology patenting and licensing is not the a goalor driving force for technology innovation, a good improvement in technologywill no doubt attract interests of other producers and therefore provides you apotential profit by transferring them.

5.4 Advantages 46

5.4.2 Spin-offs and related effects

National and regional spin-offs are valuable when arguing for putting the alu-minum plant in Norway and Mid Norway. The decision to build or not to builda aluminum plant at Byneset is not only a matter of corporate economics, butalso a political question. Politically, it is easier to argument for a plant whenregional and national spin-offs are accounted for.

When it comes to the regional effects, the regional deliverance to the Byneset-project is expected to have the greatest impact on the construction business inthe building phase. In addition there will be some services like consulting andproject management. There will also be some effects on transportation, tradein goods, hotels, restaurants and others. The building of the new Sunndal plantgives an idea of what spin-offs one can expect. At Sunndal the service businesshad increased activity during the construction of the plant [Sch06].

Most likely the case is that the project will give valuable commissions for thebusiness activity and stimulate the employment and expertise in different sec-tors. For instance there will be a need for activities in retail-, service-, andconstruction sector purchased by people in Trondheim as a receiving commu-nity. In addition new settlers will give valuable tax money to the municipality.

When it comes to national spin offs, the fact that products are exported inaddition to more domestic activities, will influence national value added on theGross National Product. Due to imports of raw materials, it is difficult to statethe national trade balance, but it is expected that the trade balance is positiveas a result of the refinement of goods.

5.4.3 Waste heat

The heat has two main energy carriers; water and air. Whether it is possibleto make use of it, both with regards to the economy and the technology arebased on a combination of two things: The temperature and the quality of theenergy. The higher the exergy content the energy has, the easier it is to makeus of it. 1

5.4.4 Distribution

The hot water is distributed by pipelines to buildings that have a water basedheating system. The users are all kinds of buildings, from homes to factories.Byneset has one advantage here: Trondheim already has a water heating system,and it is powered by the combustion furnaces at Heimdal. The energy sourceat Heimdal is household waste. The pipelines from Heimdal cover the areafrom Heggstadmyra to Ila, both which are close to Byneset. In addition to

1Electricity has an energy content of 100 %, while water at zero degrees Celsius has about0 % energy content.

5.5 Further advantages 47

distributing the water locally at Byneset, the rest should be connected to thepipelines at either Ila or Heggstadmyra.

5.4.5 Economical support

Enova has a program in which they contribute economically to projects in Nor-way that saves energy 2 [Eno06]. This support is supposed to be on the marginof what is profitable for the concessionaire of the project. When the new Sun-ndal plant was built, Sunndal Energy and Hydro Aluminum Sunndal decided touse some of the process gas from the dry scrubbers to produce hot water. Thishot water is distributed to households and other buildings, for heating. Thisparticular project received economical support from Enova, and the economicsupport was about 10 % of the investment costs [Eno06] and [Gje06].

5.5 Further advantages

The location by the sea provide seawater needed for scrubbing and place forharbor facility. The scrubbers need seawater to clean the gases, as describedearlier chapter 2.3. There is none existing harbor facilities at the site, but thecoast is suitable for a big ship harbor.

5.6 Conclusion

As seen in this chapter, Byneset fulfill the requirements needed which makeit suitable for a greenfield aluminum smelter. Such a facility will create bothworkplaces and tax money in the region, as well as an increase in the Norwegianexports. Having a goal of being the capital of technology in Norway, it shouldbe in Trondheims interest to support such a project. Furthermore, Norway asa nation is in need of growth in its industry, and this will be a fine addition.

2In reality saving energy here means using energy with lower exergy content, where youbefore used energy of a higher exergy content

Chapter 6

Economical Considerations

In this chap

future aluminium plant at byneset

Documents