Monitoring Energy Efficiency in W.A.G.E.S/Utilities for reducing cost Dipl.-Hyd. Oliver Seifert, Endress + Hauser Flowtec AG, CH-4153 Reinach BL 1. Introduction Our customers in all industries are coming more and more under pressure to measure the

cost of their utilities:

- Water

- Air

- Gas (e.g. Natural Gas, other gases or fuels)

- Electricity and

- Steam

It is interesting to confirm that this trend is independent of the industry. We can see it in small

breweries and in big chemical parks.

These utilities are the life-blood of the industry: they are crucial in order to manufacture.

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Fig. 1: The Production Process in Industry. The utilities/W.A.G.E.S. play a vital role in order

to convert raw materials into products during the manufacturing process.

One important driver for this pressure is the ever increasing cost of energy. The cost of

natural gas for industrial applications has more than tripled within the last ten years and the

price for electricity in Europe has risen by 30% within the previous 4 years.

Another driver are certifications according to EMAS and the ISO 14000 series that force

customers to measure the energy streams using calibrated technology.

The utilities have frequently been neglected in the past, however, they are coming more and

more into focus. The cost drivers for all industries are:

- Capital Cost

- Labour Cost

- Raw Material Cost and

- Energy Cost.

Of these, Energy Costs are the only point can readily be influenced.

Many companies still only measure natural gas and electricity only at the custody transfer

point. Using these few measurements, however, important parameters like specific energy

consumptions are determined that give important indications such as how much energy does

it take to make a tonne of product? These measurements are typically only taken on a

monthly or sometimes even on a yearly basis. Investing a relatively small amount of money

in comparative terms it is possible to set up energy monitoring systems that measure the

consumption of each respective utility close to the point of use every 15 or 30 minuntes.

These measurements can then be used to build meaningful relations between energy

consumption and the factors driving it that enable the customer to

- Gain transparency over their energy consumption

- Identify and justify energy reduction projects (Where is most energy consumed?

Which changes are possible?)

- Detect poor performance earlier (are the boiler’s heating surfaces fouling?)

- Provide support for decision making (Should the contract with the provider of

electricity be changed?)

- Report performance automically (Which Energy Accountability Centre/shift etc. is

performing best? Did exceptions occur?)

- Audit historical operations

- Provide evidence of success (Did promises made by a manufacturer of energy

efficient equipment come true? Calculation of Return on Investment ROI)

- Provide support for energy budgeting and management accounting

- Provide the energy data to other systems (e.g. exisiting SCADA)

- Reduce their energy consumption

2. What is Energy Management?

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DataCollection

Energy Analyses

Energy Reporting

Optimize

Controlling ofEnergy Data

Transparency of Consumption

Customer

Fig. 2: The Energy Management Cycle. It consists of data collection, data analyses,

communication of the results (reporting) and „taking the action“ to reduce the energy

consumption based on the findings. The first three steps of „Energy Management“ are called

„Energy Monitoring“.

2.1 Data Collection

Energy Management can be seen as a cyclic operation. Data collection is the bases of all

energy monitoring, energy management and therefore energy savings.The energy

consumption is measured and converted to appropriate units. For most of the utilities, these

conversions require close scrutiny and understanding:

- the conversion from volumetric units (e.g. natural gas measured by turbines, steam

measured by DP devices or vortex meters) to corrected volume, mass or energy

often is done in a wrong way resulting in errors in the range of typically 10…30%

- many devices are mis-installed resulting in similar error ranges and

- if the basis is wrong, the analysis will be wrong and all action taken will be at best

misleading.

The simplest way of data collection remains, even today, paper and pencil and it is amazing

to see how many people in the industry still have to walk around the factory and find certain

meters on a monthly basis to take the readings. Modern recorders as stand-alone devices or

so-called „software recorders“ are able to record data in typically 15 or 30 minutes intervals.

If these intervals are not sufficient, even a data collection every 100ms is possible but this is

more common in Process Control.

Most modern systems of data collection are even able to collect the data of up to 30 devices

using bus communication and pass the data on using „Field Gates“.

Manual reading of electricitymeters

Semi-automatic collection usingUSB stick

Automatic data collection usingFieldGate FXA520 HART

Fig. 3: Types of Data Collection ranging from manual, semi-automatic e.g. using a recorder

to automatic data collection using FieldGates

2.2 Data Analysis

If the Data collection is the basis of it all, data analysis is the heart as it helps to convert the

pure measurements of energy signals into meaningful data.

A first basic analysis consists in looking at the 15-min or 30-min data profiles:

- What is the base-load of the application? Why is energy still consumed without

production? How can this base-load be reduced?

- What is the typical maximum load during productive hours? How can the maximum

load be reduced? (This is important e.g. for electricity contracts)

- What is the typical load distribution? How can a more uniform load-distribution be

obtained? For this purpose, different policies of load-management are available (e.g.

peak-clipping)

A more powerful analysis consists in putting energy consumptions in relation to a driving

factor. Examples are:

- how much heating energy is consumed compared to how cold the weather is (so-

called degree days)

- how much energy is consumed to make a tonne of product

- how much electricity is consumed in order to light a building compared to the hours of

day-light.

Once we have associated an energy consumptions with a relevant drivers, they are

generally called „Specific Energy Consumptions“ SEC.

Controlling such a factor now enables the user to control a individual process should it be found to drift over time, i.e. the process is becoming more inefficient. Possible causes of such a drift could be:

- the amount of leakage in a compressed air grid is growing due to lack of effective

maintenance

- the specific energy consumption for making steam is rising due to ineffective

maintenance of steam traps (steam traps fail open in case of a failure)

- the specific energy consumption for heating a building rises due to fouling of the

surfaces of heat-exchangers

Generally, comparing the energy consumption with a driver will reveal a linear relationship. In

certain applications this linear relationship also shows an intercept that does not equal zero.

If no actions are taken, the trend will be as follows:

- the intercept grows (examples: increasing leakage in a compressed air application or

failing steam traps)

- the slope of the linear relationship grows (loss of efficiency e.g. because of fouling

heat-exchangers)

Customers, however, should strive to

- reduce the intercept and

- reduce the slope of the linear relationship.

The linear relationship can be used as a target for the future. If, for example in the past it

took 4 GJ of energy to make a tonne of steam then we can expect this same value for the

future unless we take actions to improve efficiency.

We can now compare the real energy consumption to the expected one and record the

differences. If this difference exceeds a predetermined value, a warning will could generated.

Fig. 4: The Control Graph for controlling deviations from a pre-set target. If the control limits

are exceeded, an alarm can be generated.

We can also take these differences and total them up over time in the so-called CUSUM

(cumulated sums) chart.

Fig. 5: The CUSUM chart. It acts as a totalizer and can reveal savings achieved.

This chart acts like a bank-account; if the process becomes less efficient, the CUSUM trend

will diverge from the zero line as in Fig.5 where the process has become more efficient. In

our example an economizer was installed improving a steam boiler’s efficiency. Compared to

the systems former performance an investment into the economizer saved the company

1100 MWh of energy over 15 weeks. Therefore, the CUSUM gives a direct indication of the

Return on Investment for Energy Savings Measures.

Performing the Analyses will enable customers to ask and answer at least the following

questions:

- Where is the energy in general going? How many emissions are created?

- Which energy accountability centers are consuming most energy? Which areas are

working the most efficient and why?

- Why are certain shifts more efficient than other?

- Which machines/boilers/motors etc. are most efficient? Can you switch from the

current main boiler to a more efficient boiler?

- Why was the specific energy consumption stable for months but started drifting

recently? (e.g. fouling of boilers)

- Is energy consumed during non-productive hours? Can this amount be reduced in the

future?

- When do peak loads occur and how can they be avoided?

- Is currently the most economic tariff purchased or are there cheaper alternatives?

- Where is the biggest potential for investing into more environmental friendly

technologies?

- Are changes in performance observable? Are boilers fouling?

- Do exceptions from predefined target values occur?

2.3 Communication/Reporting

Recipients of Energy reports can be separated into different hierarchies: from operations

personnel to top management and in different areas of a company

(production/operation/engineering, controlling, energy and eco management).

Management

ControllingOperation/Maintenance/Engineering

Environmental andEcological Manager

Fig. 7: Typical recipients of Energy reporting

The reports must provide information to enable the user to act. Operational staff needs to

know when a problem has occurred as quickly as possible and know what they should do

about it. Senior management, on the other hand, need summary information to know that

procedures and systems are working well. In order to design reports, it is important to

understand who needs what and why.

Reports to senior managment might include

- a summary of last year’s costs, broken down into EACs (energy accountable centers)

- a summary of the current year’s performance on a monthly basis

o against budget

o against the previous year

o against targets

- a note of the savings (or losses) achieved to date and how they were achieved

- a note of additional savings opportunities and what actions are ongoing to address

them

A new report to management should be issued each month and be available in time for

board meetings.

Operations management will be responsible for operating processes and plant efficiency.

They will need to know on a shift, daily, weekly or monthly basis (depending on the nature of

the process and the level of energy use) what energy has been used and how this compares

with various targets. The information will be used to

- measure and manage the effectiveness of operations personnel and process plant

and systems

- identify problem areas quickly

- provide a basis for performance reporting (to executives)

Operations personnel need to know when a problem has occurred and what needs to be

done to rectify it. This information needs to be provided in a timely manner, which might

mean within a few minutes of the event for a major energy-using process, or within a day or a

week.

Engineers associated with operations will need reports similar to those for operations

personnel. Engineers may typically be involved with problems where there is more time to

act (compared with process operators), for example, cleaning heat exchangers, solving a

control problem or removing air from a refrigeration condenser.

Engineers who are not directly in operations but who provide support will need more detailed

historical information. Typically, these individuals will be involved in analysing historical

performance, developing targets and modelling. They will require access to the plant data

historian and will use analysis tools, ranging from commonly available spreadsheet software

to advanced data mining and similar software.

Engineers that are involved in projects will need supporting data, for example, levels of

energy use, process operating conditions, etc. They will also need access to the raw data in

the historian and access to analysis tools.

The accounts department may be interested in actual energy usages and costs to compare

with budgets. They will need information that is broken down by department so that costs can

be allocated to related activities. Accurate costing of operations and the cost of producing

goods can improve decisions regarding product pricing, for example, and the allocation of

resources.

Energy and environmental managers will need summary data that identifies the performance

achieved and trends, much like executives and operations managers require. Like engineers,

they may require more detailed information for specific analysis.

The environmental department may want energy consumption expressed as equivalent CO2

emissions, and the energy reports may need to be integrated into environmental reports that

are more general. Summary information may be required for annual energy and

environmental reporting and may be needed more frequently by regulatory bodies.

The energy manager may be involved in energy purchasing as well as efficiency. He may

need information about the profile of energy use (using a half-hourly graph, for example),

peak usage, night-time usage, etc. The energy manager will also need access to the raw

data in order to allow evaluation of purchasing options and checking of bills.

We can see from this broad variety of requirements that modern Energy Management

Information Systems have to be very flexible in creating effective reports.

2.4 Taking Action

Results of implementing Energy Monitoring Informations Systems in the UK indicate that,

when properly implemeted, such a system can save 5 to 15 percent of annual energy costs.

As an initial approximation, 8 percent appears to be a reasonable estimate. [1]

Implementing an Energy Management Information System and taking the action based on

the outcome of this tool alone will result typically in 8 percent savings. Most experience

regarding this tooling can be found in the UK based on the local “Carbon Trust”.

Further savings can be achieved by spending capital cost e.g. for more efficient burners and

boilers, economizers etc.

Savings Strategies in Energy Management typically fall into the four following categories:

• Eliminate. Generally, one should question if certain processes or sections of a

plant are really required or if they could be replaced. A simple example:

eliminating dead legs of a plant.

• Combine. CHP is a well-known “combine” process: generation of heat and

electricity are combined. Another example is the use of off-heat created by air

compressors e.g. for pre-heating factory air. Oliver I am not sure about this, do

you mean hot air conditioning for offices?

• Change equipment, person, place, or sequence. Equipment changes can offer

substantial energy savings as the newer equipment may be more energy efficient.

Changing persons, place, or sequences can offer energy savings as the person

may be more skillful, the place more appropriate, and the sequence better in

terms of energy consumption. For example, bringing rework back to the person

with the skill and to the place with the correct equipment can save energy.

• Improve. Most energy management work today involves improvement in how

energy is used in the process because the capital expenditure required is often

minimized. Examples include reducing excess air for combustion to a minimum,

reducing temperatures to the minimum required. Improvement does sometimes

require large amounts of capital. For example, insulation improvements can be

expensive, but energy savings can be large, and there can be improved product

quality.

2.5 Energy Monitoring Solutions

Modern recorders already offer solutions for monitoring boilers or compressed air grids. They

are not only able to monitor flow or other parameters, they can also be used for calculating

and visualizing energy, emissions, specific energy consumption, efficiencies etc. Alarms can

be initiated in case violations of pre-defined values occur.

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Fig. 6: Energy Monitoring solution of a boiler using a recorder. Energy, efficiency (fuel to

steam), emissions and specific energy consumption are calculated in the recorder.

For monitoring the energy consumption of a complete company and multi-site companies

Energy Monitoring Software solutions are the solution of choice. As an example, existing

mains meters and electricity meters provide their information through a pulsed output to the

system. For multivariable flowmeters a bus like the HART protocol is used to make use of the

wealth of information available from these devices. These data are then passed through

FieldGates to the company’s Ethernet and are collected every 15 to 30 minutes through a

data collection software. This software creates .csv files that then are made available to an

existing SCADA and to the Energy Monitoring Software. This software will then visualize the

data, analyze them and automatically create reports. Targets as explained above can be

defined, deviations from the targets identified and return on investment of energy savings

measures calculated. The software should be web-based to enable the customer accessing

his data globally from any computer. Additionally, web-based solutions are ideal for multi-site

companies.

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FXZ520Module

4x Pulse

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ExistingVisualization/SCADA

Energy MonitoringSoftware

ExistingProduction data

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Client server

Software for ½ hourly datacollection

FieldgateFXA520RS485

HART-Multiplexer

RS485FieldgateFXA520

PLCField ControllerSFC173

EneryManagerRMx621

Memograph M

Fig. 7: Set-up of a typical full-blown Energy Monitoring Information System. Data are

collected from existing meters or electricity meters with pulsed output and multivariable

flowmeters using HART communication or from recorders and flow computers. This data

collection typically is done every 15 to 30 minutes. The data is visualized, analyzed and

reported by the Energy Monitoring Software.

These solutions enable the customer to

- gain transparency over their energy consumption and emissions

- identify potential areas of savings

- follow indicators like specific energy consumption

- save time through the automatic data collection, data analysis and creation of reports

- reduce energy consumption and therefore emissions typically by 5 to 15 % (according

to the British Carbon Trust and the Canadian CIPEC)

Literature [1] Office of Energy Efficiency of Natural Resources Canada: Energy management

information systems: achieving improved energy efficiency: a handbook for managers,

engineers and operational staff.