PROCEEDINGS OF ECOS 2016 - THE 29TH INTERNATIONAL CONFERENCE ON

EFFICIENCY, COST, OPTIMIZATION, SIMULATION AND ENVIRONMENTAL IMPACT OF ENERGY SYSTEMS

JUNE 19-23, 2016, PORTOROŽ, SLOVENIA

LCA study of the Fuel Cell based UPS in manufacturing and operational phase

Mitja Mori a, Grega Štern b

a University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, SI-1000 Ljubljana, Slovenia,

mitja.mori@fs.uni-lj.si bMiktra d.o.o. Gortina 142, 2366 Muta, stern.grega@gmail.com

Abstract:

Environmental impacts of a 3 kW UPS system based on PEM fuel cell are evaluated in manufacturing and operating stage at operational locations representing renewable (Norway) vs. fossil fuel (Morocco) based energy mix. The LCA method was applied; numerical models were set up using PE International Gabi 6 software; CML 2001 method was used for evaluating environmental impacts through environmental indicators. Numerical model consists of detailed model of manufacturing of 3 kW UPS with all mass and energy balances in manufacturing stage. In addition operation stage was compared with manufacturing stage in terms of environmental impacts. The scope of the study was cradle-to-end of utilization with functional unit of 1 kWh of produced uninterruptible electricity. Hydrogen in both end-locations is produced with different methods (electrolysis, EU hydrogen pipeline and steam reforming), so the influence of hydrogen production method (utilization phase) could be evaluated in comparison with manufacturing phase. Results show that electrolysis in Norway has the lowest and electrolysis in Morocco the highest environmental impact in almost all criteria in utilization phase. In manufacturing phase main impacts come from manufacturing of fuel cell stack, battery, auxiliary components and cabinet production. UPS’s GW till the end of utilization phase is 278 g of CO2 eq. per 1 kWh of uninterruptible electricity if operated in Norway, 416 g with hydrogen from EU H2 pipeline, 1,042 g with gas reforming and 4,390 g with electrolysis in Morocco putting hydrogen production method as a main source of environmental phase. Energy return of investment is 15.1 % in Morocco up to 21.9 % in EU hydrogen pipeline. If H2 is produced with electrolysis, the energy mix in Norway is more favourable from Morocco, where 91 % of electricity is produced from fossil fuels. Manufacturing phase has small environmental impact in comparison with operational phase and transport is almost negligible concerning environmental impacts.

Keywords:

Life cycle assessment, hydrogen technologies, polymer exchange membrane, uninterruptible power supply, hydrogen production, operational phase.

1. Introduction

The use of modern telecommunication services is based on telecommunications grids with different

base stations, transmitters, and other important infrastructure. For reliable operation without grid

break downs, electrical energy is needed all the time, without interference. Because of the complexity

of electrical grid system, the probability of the electricity cut outs is not negligible. In these cases the

reliable uninterruptible power supply systems (UPS) are needed to ensure undisturbed operation, [1].

Conventional UPS systems consist in most cases from battery stacks. In the cases of longer cut-outs,

UPS systems on the basis of internal combustion engine (ICE) are added to battery stack UPS system,

[2]. In the case of telecommunication services the most frequently used UPS system is on the basis

of lead battery stacks that are charged in normal operation of telecommunication system, but provide

electricity in cases of cut-outs, [2]. The main limit of latter systems is when long term cut-out occurs.

Main reason is limited stored energy in battery stacks, while their effectiveness is also affected by

operational conditions i.e. extreme temperatures, many charges/discharges cycles, etc., [3]. The life

time of lead battery based UPS system is estimated to 5 years and even in this period the capacity and

efficiency of charge/discharge cycle can be drastically lowered, [4]. This is not the case within UPS

systems on the basis of hydrogen technologies (HT-UPS). HT-UPS systems use fuel cells for

electricity generation and are limited mostly with fuel (hydrogen) availability. At normal operation

are able to operate without maintenance 10 years and more, [5]. In contrary to ICE-UPS systems they

have almost no moving parts that lowers the maintenance costs and emits no noise during operation.

In addition, the conversion of chemical energy in electricity occurs based on effective electrochemical

processes. The energy efficiency remains almost constant at wide operational temperatures (from

- 40°C to 80°C). The very important issue is that operation with HT-UPS releases less harmful

emissions for environment and for people’s health into earth’s atmosphere, soil and water than

operation with ICE UPS systems that use fossil fuel as fuel. Apart from their evidently decreasing

reserves, fossil fuels, which account for more than 80 % of today’s total primary energy supply, pose

also other problems, [6].

A life cycle assessment (LCA) that is the methodology used in the current study is a standardised

technique to determine the environmental impacts associated with all stages of a product’s life. It can

also serve to improve a product’s environmental profile, compare it to incumbent technology, make

environmental labels and declarations, etc. LCA of hydrogen production technologies and assembly

has been carried out by several authors, [7], [8], [9], [10], [11] and [12]. Hydrogen technologies in

UPS applications have been evaluated without assessing their environmental performance in [13],

[14], [15], [16] and [17]. Contrary to that the current paper evaluates environmental impacts of HT-

UPS system based on polymer membrane fuel cell in its manufacturing and operating stage at two

different operating locations. Operation in Norway and Morocco is evaluated for 10 years or 10,000h

of operation time with onsite hydrogen production with three different production technologies. The

study emphasis the contribution of manufacturing and operational phase to overall environmental

impact and the importance of hydrogen production method.

2. Hydrogen Based Uninterruptible Power Supply Systems Advantage of hydrogen based UPS systems (HT-UPS) is mainly the reliable operation in extreme

conditions. In addition HT-UPS systems are considered feasible to be integrated into advanced energy

supply systems on large scale, [18], [19], [20] and [21]. The three subsystems: hydrogen production

system, hydrogen storage tank and fuel cell have the ability to convert electric energy into hydrogen

based chemical energy, store it, and convert it back into electricity when needed. If hydrogen is

produced from renewable energy sources (RES), such a system emits very small amounts of CO2 in

its operational phase. However, in other stages of its life cycle: raw materials production,

manufacturing, transport and decomposition, it is expected to have certain environmental impact.

Fig. 1. Introduction of hydrogen technologies to current energy grid, [18].

In Fig. 1 the advanced energy system is shown where redundant electrical energy is converted to

hydrogen fuel with electrolysis. With HT-UPS system the conversion back to electricity is possible

when needed. With that the future challenge of RES integration in conventional electricity grid is

feasible. In addition to that operating of big energy systems (i.e. fossil fuel based power plant) out of

the region of high efficiency could be omitted. The use of hydrogen technologies enable fast reacting

and adaptable advanced energy systems that are additionally economically justified and

environmentally sounder. Fuel cells have great potential also in transport applications, that only

upgrade future advanced energy system, [22], [23].

Fig. 2. Left: fuel cell and developed balance of plant components; Right: FluMaBack UPS system,

[5].

The 3 kW HT-UPS system from Electro Power Systems from Torino that is the main objective of

LCA study is shown in Fig. 2. Main components included in the study air blower, external heat

exchanger, hydrogen recirculation blower, PEM fuel cell stack, air humidifier, control and regulation

system, main cabinet and lead batteries are manufactured in different locations across Europe and

therefore have to be transported to the assembly site in Torino. In the study all components were

modelled according to detailed manufacturer’s data and numerical models for all balance of plant

components were set up. In table 1 general data of HT-UPS is presented.

Table 1. Basic data of 3 kW FluMaBack HT-UPS system, [5]

FluMaBack 3kW

Dimensions / Weight 100 x 100 x 150 / 300 kg

Electrical power 3 kW

Fuel cell PEM fuel cell

Electrolyte Nafion™

Efficiency 0.5

Rated voltage output 24 V

Rated el. current output 125 A

Temperature range up to 65 °C

Lifetime 10,000 h

Fuel Hydrogen, 99.99 % purity

Fuel consumption (at 3 kW ) 0.0883334 kg/ kWh

3. Life Cycle Assessment Life cycle assessment (LCA) method that was used in the current paper is the most comprehensive

method for evaluating the environmental impact of the product in all its life cycle stages. The LCA

is a compilation and evaluation of material and energy inputs and outputs, and potential

environmental impacts of a product during its lifetime. It consists of four stages: the definition of the

goal and scope, the life cycle inventory analysis, which is the construction of the product’s life cycle

model where all relevant mass and energy flows are quantified; the life cycle impact assessment

which is the evaluation of the environmental relevance of these flows; and finally the interpretation

of results, [24], [25].

3.1. Numerical model of 3 kW HT-UPS, Goal, Scope and Functional Unit

3.1.1. The goal and the scope of the study

The goal and scope define the exact questions that the analysis will try to answer, and set its spatial,

temporal, and technological boundaries. The product’s function is defined and quantified by the

functional unit – which in the case of this study is 1 kWh of produced uninterrupted electricity. The

goal of the study was to determine environmental impacts of the 3kW UPS and evaluate those impacts

in manufacturing and operational phase at two end operation sites. The study is physically limited to

UPS system, while hydrogen production facility manufacturing process was not included in LCA

numerical model. The system’s physical boundaries include the all UPS’s subsystems.

Geographically system is assumed to be installed in northern Africa (Marrakesh, Morocco) or

northern Europe (Oslo, Norway). Transport via railway, cargo ship and truck has been included in

the numerical models. Operation phase is considered for 10 000 h in approximately 10 years’ time.

In the model the maintenance of the system is excluded since it has to operate mainly without

maintenance for 10 000 h. The type of analysis was cradle-to-end of utilization, covering raw

materials production, energy requirements for manufacturing process and assembly of parts, the

system’s transport from manufacturing site to operation site, and its operation (hydrogen from

different production methods). Not enough data was available to properly model the system’s end-

of-life phase (reuse, recycling and disposal of parts).

3.1.2 LCA Numerical model

Numerical model is shown in fig. 3 with all material and energy inputs. A top-to-bottom principle

was used to model the system, sequentially dividing it into smaller segments in order to reach the

most detailed description of the system’s design and function: one main integrating process, seven

manufacturing processes (FC, air blower, hydrogen blower, external heat exchanger, humidifier,

battery stack, additional components), nine transport processes (transport of components to assembly

place and transport of HT-UPS to end-operating sites), four operation processes (4 different hydrogen

production methods).

Fig. 3. The numerical LCA model of 3 kW UPS system with boundaries.

Model was set up on four layers with plan nesting technique in Gabi 6 software. In fig. 4 the part of

numerical model is presented that shows the main phases of the study and in the manufacturing phase

the detailed LCA model of just rotor part of the air blower. All parts in manufacturing phase were

modelled according to detailed manufacturer’s data presented in public document, [5].

Fig. 4. The numerical LCA model set up in Gabi 6.

manufacturing transport operation

Steel billet

Gasoline

Stainless steel

Brass

Aluminium ingot mix

Plastic bonded ferrite

Electrical steel

SI Electricity mix

Thermoplastic

Materials

Data used in the model were generic secondary data from PE International database that include raw

material production, electric energy mixes in the manufacturing phase, hydrogen production, type

Euro 4 cargo trucks, ship and railway transport in the transport phase, water, hydrogen and oxygen

in the operation phase.

3.2. Life Cycle Inventory Analysis

In the LCIA step, all input and output flows are translated into contribution to the chosen

environmental impact categories (e.g. global warming). In the study all virgin material mass flows in

BoP components manufacturing process are included as well as emissions during the phases of

materials extraction, manufacturing, transport and operation. Data consist of primary data gathered

on the basis of manufacturers' masses of materials as inputs in manufacturing process of BoP

components. Secondary data are used in all cases where primary data are not available. In this case

reference studies and generic databases are used, [26].

3.2.1. Manufacturing phase

In manufacturing phase data was provided for all components and parts by manufacturers in detail.

Components and parts were manufactured across Europe, so mass and energy balance was taken for

the specific manufacturing location and component/part. All components were transported to Torino,

where assembly was done.

Table 2. Summarizing data of LCIA for 3kW HT-UPS system

mass unit

External heat exchanger 23.0 kg

Air Blower (details in table 3) 2.210 kg

rotor 0.282 kg

stator 0.483 kg

impellers 0.152 kg

return channels 0.139 kg

housing, electronics, other 1.153 kg

Hydrogen Blower 1.890 kg

rotor 0.241 kg

stator 0.325 kg

impellers 0.048 kg

covers, volute, housing, motor protection 1.186 kg

screws, nuts, small parts 0.014 kg

electronics 0.075 kg

EPS UPS Assembly, Turin 165.130 kg

cabinet 141.500 kg

compressors, fans, pumps 1.500 kg

DC/DC converter 8.180 kg

control panel 1.400 kg

cables 4,000 kg

cooling fan 5,000 kg

pressure regulator 0.550 kg

Valves-Fittings-Piping 3.000 kg

Air humidifier 1.975 kg

PEM 3 kW Fuel Cell 28.000 kg

Lead battery stack 60.800 kg

All detailed data are presented in public available study from European funded project FluMaBack1,

[5]. In table 2 mass of all components or/and processes are presented for one HT-UPS system. All

parts and BoP components are broke down up to virgin materials in next level as a results of data

assembly of manufacturers. As an example in table 3 detailed LCI for air blower is presented with all

virgin materials and process energy inputs. Energy input required for each component/part is

measured in manufacturers’ production process. For all components presented in table 2 detailed data

are available in public available document of European project FluMaBack, [5].

Table 3. LCI table of air blower manufacturing process

Material Quantity Unit

Vir

gin

ma

teri

al

aluminium 950.2 g

electrical steel 460.1 g

electronic board 250 g

PA66 223.24 g

carbon steel 141.6 g

copper 78.75 g

plastic bonded ferrite 47 g

stainless steel 38.11 g

brass 17.3 g

gasoline 1.5 g

solvent 1.168 g

glue 0.64 g

paper 0.1365 g

Electricity Slovenia grid mix 1.690125 kWh

3.2.2. Operation and hydrogen production

One of the goals in the study was comparison of the manufacturing and operation phase of HT-UPS

system. Manufacturing of hydrogen production facility was not included in the numerical model, but

nevertheless the main impact comes from hydrogen production process that was in the scope of the

study. The basic scenario of hydrogen production was hydrogen production with electrolysis on-site.

Since the production facility was not in the scope of the study, the main contributor to environmental

impact is electrical energy mix in the country. In the case of Morocco, the energy mix consist of

electricity produced: 43% from coal, 24% from oil, 23% natural gas, 7% hydro and 2% of wind

power. In contrary on Norway 95 % of energy mix consist of energy from hydro power. Since

statistical data from 2008 shows that hydrogen production worldwide was 49% from natural gas, 29%

from liquid hydrocarbons, 18% from coal and just 4 % with electrolysis, additional hydrogen

production processes are included for comparison: steam reforming from natural gas and EU pipeline

with steam cracking as a by-product in oil-refinery, [26], [27].

Table 4. LCI table of hydrogen production

H2 production method

Energy input (for 1 kg H2)

Mass (for 1 kg of H2) Remarks

Electrolysis (NO) 52.5 kWh 9 kg of water Share of RES (hydro): 95 %

Electrolysis (MA) 52.5 kWh 9 kg of water Share of RES (hydro + wind): 9 %

Natural gas (EU) * * (natural gas) * secondary data form generic

databases, [26, 27]Napaka! Vira

sklicevanja ni bilo mogoče najti. EU pipeline (EU) * * (long chain hydro carbons)

1 Fluid Management Component Improvement for Back Up Fuel Cell Systems, www.flumaback.eu

In table 4 energy input and mass of the water required for electrolysis and the source of generic data

for hydrogen production are presented. In the case of electrolysis the theoretical case was used.

3.2.3. Life Cycle Impact Assessment

In the life cycle interpretation step, attention was paid to determine whether the methods, models and

data are consistent with the goals of the analysis. To ensure the credibility and comparability of such

analyses, standardisation documents have to be taken into account. Since 1997, ISO standards 14040

and 14044 have covered terminology, methods and procedures, environmental declarations, resource

management, measurements, audits, [24]. The results were analysed in terms of chosen environmental

indicators, and major contributors to environmental impacts were identified.

Global warming (GW), abiotic depletion (AD), ozone depletion (OD), acidification (A),

eutrophication (E), photochemical ozone creation (POC), and human toxicity (HT) were calculated

as environmental impact indicators, [28], according to the CML2001 methodology, [29].

4. Results and discussion In first part of discussion the comparison of manufacturing and operational phase is discussed in terms

of environmental indicators. In second part different operation strategies regarding hydrogen

production are compared.

4.1. Manufacturing Phase of UPS

In manufacturing process the main impacts come from manufacturing of fuel cell, battery and the

cabinet. Environmental impact is high due to the high mass of steel used in the case of cabinet. In the

case of fuel cell and battery in contrary high energy consumption (local electricity energy mix) during

manufacturing process is very important parameter. Transport of all components to assembly site in

Torino represents just 1 % of total GW (Figure 5).

Fig. 5. Global warming in kg CO2-eq. for manufacturing process (total of 2157 kg of CO2-eq.)

In table 5 relative contributions of environmental impacts of BoP components in manufacturing stage

are presented for all environmental impact criteria. Significant environmental impact in general

comes from manufacturing of the fuel cell, battery, auxiliary components (assembly process in

Torino) and air blower. Main cabinet has high GW and A because of high energy consumption of the

local energy mix, linked to big mass of used steel. The lowest impact have humidifier and external

climate because of low masses of material and optimized manufacturing technology that means low

energy consumption.

77,7; 4%

26,2; 2%

495,0; 28%

8,0; 0%

98,2; 6%

353,4; 20%

462,8; 26%

229,9; 13%

11,0; 1%

air blower

H2 blower

battery

humidifier

external climate

fuel cell stack

cabinet

auxiliary components

transport - manufacturing

Table 5: Contribution of impacts of single BoP components to manufacturing phase total impact

AD A E GW HT OD POC

air blower 18.1 % 4.4 % 24.4 % 3.5 % 17.0 % 0.1 % 4.4 %

H2 blower 2.8 % 1.1 % 3.8 % 1.2 % 4.5 % 0.0 % 1.1 %

battery 23.7 % 23.3 % 5.7 % 23.0 % 2.5 % 0.0 % 21.1 %

humidifier 0.0 % 0.2 % 0.1 % 0.4 % 0.4 % 0.0 % 0.3 %

external climate

0.1 % 2.8 % 0.7 % 4.4 % 6.6 % 0.0 % 3.8 %

fuel cell stack 19.5 % 43.0 % 10.7 % 35.9 % 20.8 % 99.5 % 31.4 %

cabinet 0.0 % 14.0 % 4.3 % 21.4 % 3.1 % 0.0 % 26.1 %

auxiliary components

35.8 % 11.3 % 50.3 % 10.2 % 45.1 % 0.3 11.7 %

Total – absolute value

0.177 kg

SO2 eq.

12.2 kg

SO2 eq.

3.40 kg

PO4 eq.

2157 kg

CO2 eq.

1766 kg

DCB eq.

0.0046 kg

R11 eq.

0.89g kg

Eth. eq.

Human toxicity (HT) is highest in the case of auxiliary components and fuel cell due to hazardous

materials used in electronics of auxiliary components and platinum used in fuel cell.

4.2. Operating phase of HT-UPS system with hydrogen from electrolysis

In tables 6 and 7 relative contributions of all phases are presented: manufacturing, transport and

operation. In operation phase four scenarios of hydrogen production process are used and two

operation location (Morocco and Norway). Basic scenario is hydrogen production with electrolysis

with Morocco and Norway energy mixes (table 6 and table 7).

Table 6. Contribution of manufacturing, transport to Morocco and operation of 10.000h in total

impacts

MOROCCO AD A E GW HT OD POC

transport utilization site 0.0% 0.0% 0.1% 0.0% 0.0% 0.0% 0.3%

operational 10.000 h 1.6% 97.4% 92.1% 98.6% 77.3% 0.0% 57.3%

Manufacturing 98.4% 2.6% 7.9% 1.4% 22.7% 100.0% 42.5%

In the case of Morocco operational phase is the most influential because of fossil fuel based energy

mix. In abiotic depletion (AD) and ozone depletion (OD) manufacturing phase is influential because

of Nafion® membrane manufacturing process that used in as virgin material PEM fuel cells

membranes. In Norway the most influential phase is manufacturing phase in most impact categories

since most electricity for electrolysis is produced with hydro power.

Table 7. Contribution of manufacturing, transport to Norway and operation of 10.000 h in total

impacts

NORWAY AD A E GW HT OD POC

transport to utilization site 0% 1% 1% 0% 0% 0,00% 0%

operational 10.000 h 9% 36% 30% 82% 6% 0.01% 49%

manufacturing 91% 63% 69% 18% 94% 99.99% 54%

4.2. Operating phase with additional hydrogen production methods

From results in tables 6 and 7 is evident that operating phase is very or the most influential therefore

some additional research was done just for hydrogen production. In table 8 environmental impacts of

hydrogen production for 30.000 kWh uninterruptible electricity are presented for all four H2

production methods.

Electrolysis in Morocco is by far the worst case regarding environmental impacts. Acidification (A)

in figure 6 partly generalize most environmental indicators of CML2001. Just three the most

frequently used are presented in figures 6 to figure 8.

Table 8. Environmental impacts in operating phase for different hydrogen production methods for

30,000 kWh uninterruptible electricity.

AD, kg Sb

eq. A, kg SO2

eq. E, kg PO4

eq. GW, kg CO2 eq.

HT, kg DCB eq.

OD

kg R11 eq.

POC, kg Eth. eq.

Electrolysis (NO)

1.64·10-2 7.75 1.23 6.123 134 1.62·10-7 0.69

Electrolysis (MA)

2.66·10-3 795.42 50.45 129.511 11.705 2.33·10-7 46.30

Natural gas (EU)

2.16·10-3 16.27 1.60 29.101 50 2.72·10-8 3.42

EU pipeline (EU)

3.02·10-3 30.52 2.76 10.298 676 4.10·10-7 5.91

The best choice for hydrogen production from environmental point of view is electrolysis in Norway

where 95 % of hydro energy is used in electricity production mix. Intensive hydro energy is closely

linked with extensive land use that is the reason for the highest abiotic depletion (AD) of all H2

production methods. Natural gas steam reforming is currently the most frequently used hydrogen

production in the world and it is the best production method directly from fossil fuels regarding

environmental impacts criteria, [30]. Impacts in the case of steam reforming are in general 2 to 3

times higher than in the case of Norway electrolysis, except for ozone depletion presented in figure 8.

Fig. 6. Acidification in operating phase in kg SO2 eq.

8

795

16 31

0

100

200

300

400

500

600

700

800

900

Electrolysis (NO) Electrolysis (MA) Natural gas EU pipeline

A,

kg

SO

2 e

q.

EU pipeline hydrogen represents the future idea of hydrogen pipeline in the Europe that is mainly

produced with steam cracking as a by-product in the process. Environmental impacts are up to 5 times

higher than environmental impacts with electrolysis in countries with RES hydro energy mix

(Norway). In addition the hydrogen from steam reforming and steam cracking needs additional

cleaning that is linked with more energy consumption and environmental impacts.

Fig. 7. Global warming (GW) in operating phase in kg CO2 eq.

Fig. 8. Ozone depletion in operating phase in kg R11 eq.

6,123

129,511

29,101

10,298

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

Electrolysis (NO) Electrolysis (MA) Natural gas EU pipeline

GW

, k

g C

O2

eq

.

1.62E-07

2.33E-07

2.72E-08

4.10E-07

0.00E+00

5.00E-08

1.00E-07

1.50E-07

2.00E-07

2.50E-07

3.00E-07

3.50E-07

4.00E-07

4.50E-07

Electrolysis (NO) Electrolysis (MA) Natural gas EU pipeline

OD

[k

g R

11

eq

.]

4.3. Energy efficiency, energy and mass balances

In the case of energy systems, mass and energy balances are of great importance. In the study in

addition to energy efficiency, energy return on investment (EROI) value was added. It represents the

ratio between produced energy and all input energy, [31]:

energyinputtotal

energyproducedEROI , (1)

In the case of energy systems produced (useful) energy represents electricity or/and heat produced in

operating phase. In special systems as HT-UPS systems heat is treated as a loss and is not useful

(produced energy, eq. 1) part of energy. Total input energy represents all energy flows in form of

material and fuel extraction in manufacturing, transport and operation phase. In figure 9 shares of

input energy for electrolysis case is presented. In the case of HT-UPS system the manufacturing of

hydrogen production infrastructure is not included.

Fig. 9. Input energy share in all considered phases of HT-UPS life cycle system for the electrolysis

case.

It can be seen that 94 % of all energy input is needed in operational phase as consequence of hydrogen

production (electrolysis). Manufacturing phase of HT-UPS system represents just a minor part of

energy input i.e. 6.6 % in the case of EU hydrogen pipeline. Within manufacturing phase, 60 % of

energy input is due to battery stack and fuel cell stack manufacturing process. The reason for that is

because of big virgin material masses (lead, etc.) and/or energy input in manufacturing process

(electricity from energy mix). Significant amount of energy is required for external heat exchanger

manufacturing, while in the case of air blower and hydrogen blower the main energy input is due to

virgin material extraction process. A significant input energy is needed for cabinet manufacturing

because of big masses of steel. But the energy input in the case of transport is almost negligible.

Material

extraction

3.388%

Manufacturing

2.383%

Transport

0.149%

Operating

(electroliysis)

94.080%

Fig. 10. Energy input required in manufacturing phase of HT-UPS system.

Eq. 2 represent EROI in the case of system manufacturing in Torino and operating of 10 years

(30,000 kWh) in Norway with hydrogen produced with electrolysis. Results of all EROI are presented

in table 9.

151.0, inputs

useful

selctrolysiNOW

WEROI (2)

Table 9: Input energy flows and calculated EROI.

Hydrogen production

Input energy, kWh Useful energy, kWh

EROI Manufacturing Transport Operation

Electrolysis (NO)

8.5·103

220 1.89·105

3.0·104

0.151

Electrolysis (MA) 145 4.25·105 0.069

Natural gas (EU) 45 1.43·105 0.198

EU pipeline (EU) 45 1.29·105 0.219

Overall energy efficiency of energy conversion from electricity to hydrogen with electrolysis and

back to electricity with HT-UPS is 0.255 (eq. 3). For the calculation hydrogen consumption of

0.0883 kgH2/kWhe (measurements of manufacturer) and theoretical electricity consumption of

52.5 kWh/kgH2 (Wel,input in eq. 3) for electrolysis is used. That means that during considered life time

139,125 kWh electricity is needed for hydrogen production with electrolysis regardless of location.

For EROI the energy input in operation phase is even higher than just theoretical required electricity

input for electrolysis and amounts 189,000 kWh for Norway and 425,000 kWh for Morocco. That is

because all energy inputs are considered from fossil fuel extraction to process energy required for

electricity generation, etc. In addition, because energy mix for electrolysis is different for both

operating locations, the input energy in operating phase is typically different.

22 ,HiH

useful

UPSHTHm

W

(3)

inputel

Hs

iselectrolysW

H

,

, 2 (4)

1087

167

2370

4520

384

1228

8282

50327

6590

5020

62 22461

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

Externalheat

exchanger

Humidifier Batery stack Fuel cellstack

Hydrogenblower

Air blower Othr. BoP(EPS)

Ene

rgy

inp

ut

in k

Wh

Virgin material extraction Manufacturing

255.0 UPSHTiselectrolys (5)

Theoretical efficiency of electrolysis, electrolysis, is 75 % and is higher that efficiency of natural gas

steam reforming and steam cracking that amounts from 65 % to 75 %, [32]. Nevertheless EROI of

electrolysis for both locations is lower than in the case of gas steam reforming and EU pipe line

because of lower energy input in operational phase. But there is no energy input considered for

cleaning the hydrogen in the case of gas steam reforming and steam cracking production method that

would lower EROI.

5. Conclusions A hydrogen technology based UPS system’s environmental impacts were analysed with LCA method

in its manufacturing and operational phase. Hydrogen for operational phase was produced with three

different technologies: electrolysis, EU steam reforming, EU pipe line – steam cracking. In the case

of electrolysis for two geographical locations: Norway and Morocco. Study shows that the main

environmental impacts come from operational phase and that hydrogen production method is the key

for making HT-UPS system environmentally acceptable. Results show:

Operational phase has the major environmental impact and in the case of electrolysis in

Morocco that represents more than 90 % of all environmental load.

In manufacturing phase the biggest share of environmental impacts comes from

manufacturing of battery and fuel cell stack.

The production of hydrogen with electrolysis in Norway has the lowest environmental impact

of all four methods due to favourable energy mix that includes 95 % of hydro power.

Energy and mass balances were introduced for all phases for production of 30,000 kWh electricity

with HT-UPS. It was found out that in the case of electrolysis 139,125 kWh is needed for hydrogen

production with electrolysis that represents 94 % of all required energy input in manufacturing and

operational phase. Energy return on investment (EROI) introduced in the study shows that hydrogen

from natural gas and EU pipeline has higher values of EROI because there is less energy conversions

from primary fuel to useful energy (electricity), which are linked with additional energy inputs that

lower EROI.

Regarding the intensive R & D efforts in hydrogen technologies production and operation energy

efficiencies are expected to improve in the future. That will lower environmental impacts of HT-UPS

systems, but as presented in the study the major contributor will be hydrogen production method.

Therefore, awareness is needed in the case of hydrogen technologies implementation in existing

power production systems, so it could play a key role in lowering of overall environmental impacts

in the future.

Acknowledgments The work has been accomplished within EU funded project FluMaBack (abbreviation for Fluid

Management component improvement for Back up fuel cell systems). Grant agreement nº: 301782.

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