1

LIFE CYCLE MANAGEMENT FOR POWER PLANT OPTIMIZATION

BY LCA CONSOLIDATED EVALUATION SCHEME

Naoki MARUYAMA*, Seizo KATO and Anugerah WIDIYANTO Department of Mechanical Engineering, Mie University

1515 Kamihama-cho, Tsu, Mie 514-8507, Japan * e-mail: naoki@mach.mie-u.ac.jp

ABSTRACT In this paper, the LCA (Life Cycle Assessment)

consolidated evaluation technique of energy systems is described. The integration and evaluation of a variety of environmental load factors of various causes using an identical standard must be taken into account. It is important to measure the various environmental impacts caused by a variety of causes, using the same standard. However, the standard indices for international LCA integration have not yet been determined, and the enactment of ISO14040s as an international standard will take another few years. We are proposing an integrated scheme called the Eco-Load Standardization Scheme (ESS) to express the amount of environmental load from different causes, using an identical standard based on objective data. This “L-R Tolerant Balance Theory,” expresses the maximum tolerance value that the “Loader” (primarily enterprises) can discharge or consume, that balances with the maximum tolerable value by the “Receiver” (primarily ecosystem), integrated and standardized according to the so-called “left and right balancing rule”. This LCA-NETS scheme is applied to different energy systems such as various kinds of power plants and co-generation systems, and the LCA evaluations are discussed for further ecological improvement. A unique result of environmental load consolidation is that it has been found to give a relatively favorable evaluation to coal burning power generation systems (inclusive of costs) as to environmental friendliness.

1. INTRODUCTION The LCA (Life Cycle Assessment) consolidated

evaluation technique of energy systems is described in this paper. The first thing that must be done is to calculate in quantitative values the load of power generation plants on the environment. It is important with LCA that the inventory data (ID) should cover the entire life cycle ‘from the cradle to the grave’ [1,2]. When structuring LCA-ID, down-to-earth, steady data collection and updating are essential. It should be noted that, when discussing environmental problems objectively, it is important to measure the various environmental impacts caused by a variety of causes, using the same standard.

However, the standard indices for international LCA integration have not yet been determined, and the enactment of ISO14040 as an international standard will take another few years.

We are proposing an integrated scheme called the LCA-NETS (Numerical Eco-load Total Standard) to express the amount of environmental load from different causes, using an identical standard based on objective data[3-5]. This “L-R Tolerant Balance Theory,” expresses the maximum tolerance value that the “Loader” (primarily enterprises) can discharge or consume, that balances with the maximum tolerable value by the “Receiver” (primarily ecosystem), integrated and standardized according to the so-called “left and right balancing rule” (details given in subsequent section). This paper describes the method of LCA-NETS used to produce a consolidated evaluation of the environmental load, and the application of this method to a various kinds of power generation systems. A unique result of environmental load consolidation is that it has been found to give a relatively favorable evaluation to coal burning power generation systems (inclusive of costs) as to environmental friendliness.

2. METHODOLOGY 2.1 Environmental Design Methodology for Energy

Systems Owing to the new sensitivity arising towards the

environment, power generation design must respect the environment. The present work aims to elaborate a specific methodology for power plants consisting of a predictive instrument, a management tool, and a series of environmental studies and checks. The design methodology of environmentally conscious products (ECP) or well known as design for environment (DfE) is the methodology usually followed to enhance the environmental performance. The adoption of the DfE in the energy sector is due to the fact that power plants are responsible for pollution referred to various aspects, such as combustion processes, water supplying, waste production, acoustic and electromagnetic emissions. It is necessary to make choices during planning activities, in order to insure economic and energetic efficiency and environmental performance too.

1st International Energy Conversion Engineering Conference17 - 21 August 2003, Portsmouth, Virginia

AIAA 2003-5995

Copyright © 2003 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

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Traditionally, DfE methods consist of a series of rules and principles which able to guarantee environmental compatibility, such as respect of the standards, use of recycling materials, environmental monitoring, adoption of dejecting techniques for pollutant emissions (combustion catalytic, exhaust gas and water depurators, noise, etc.). However, no standard exists for the mentioned rules. In the following, the environmental checklist that should be used in the DfE during the lifecycle;

• Selection of materials with low environmental impact; e.g.: use of non-toxic, non-hazardous materials, use of non-depletive/renewable resources; use of recycled materials; materials with low energy content; etc.

• Materials reduction; e.g.: as reduction in weight, reduction in volume (for transportation), reduction in the number of types of materials (homogeneity), etc.

• Optimization of production technology; e.g.: production technology with low environmental impact, fewer production steps, lower energy consumption, reduction of production waste; etc.

• Optimization of the distribution system; e.g.: simpler packaging, reusable or recyclable packaging materials, re-route, etc.

• Reduction of environmental impact during use; e.g.: decreased energy consumption, use of non-essential items; lower release to the environment (pollutants), etc.

• Optimization of the product life cycle; e.g.: high reliability and endurability, ease of maintenance and repair, modular structure, etc.

• Optimization of the end-of-life management system; e.g.: product & components reusability, recycling of the materials, easier disassembling, etc.

2.2 LCA-NETS method

The consolidated environmental load evaluation method LCA-NETS, developed by our laboratory proposes to consolidate and quantitatively evaluate various environmental loads with different causes using the same standard. The method standardizes the objective indices, for example, various statistical data and regulation values published by such public organizations as the United Nations and the Japanese Government. Table 1 indicates the types of environmental loads that LCA-NETS can handle at present and the basis of standard values for consolidation.

The basic idea of LCA-NETS is as follows. The analysis of an environmental load (for example, global warming due to CO2 emission), is expressed by standardizing on the basis of the L-R Tolerance Balance Theory, which balances the maximum tolerable value that

the Loader (power generation plant emitting CO2 as the result of combustion) can emit (CO2, NOx and SOx) or consume (fossil fuel or natural resources), and the maximum value that the Receiver (primarily people and other ecosystem) affected by the load can tolerate. This approach has the additional feature of allowing a complete quantitative evaluation of the various environmental loads in the new units [NETS].

The L-R Balance Theory defines, first of all, the Maximum Permissible Eco-load Value (MEVi) [NETS] for given environmental load (i) tolerated by the ecosystem on the Receiver side. For example, MEVi for Global Environmental Load (G) that the world population can tolerate is defined as follows:

MEViG = 6.0 x 1011 [NETS] (1)

here, the total population of the world in 1999 is 6.0E+9, assuming that the basic tolerable value for a man is 100 [NETS].

The tolerable value for a person is determined as 100 [NETS], because the tolerance level has reached 100%, and unless some measure is taken, the standard of living we have enjoyed so far cannot be maintained. The superscript G indicates the global scale environmental load, and the subscript i is the environmental load factor class “i”.

When the maximum tolerance value is Pi (kg, kWh, m3, etc.), according to the L-R Tolerance Balance Theory,

iii MEVELMP =⋅ (2)

here, ELMi [NETS/(kg, kWh, m3, etc.)] (Environmental Load Module) is the conversion coefficient connecting Pi [kg, kWh, m3, etc.] and MEVi [NETS], and also refers to the environmental load consolidated basic value for unit

Table 1 Environmental load factors handled by LCA-NETS

Environmental load factors

Number of chemical

Consolidated standardization values

Global Scale 1. Depletion of fossil fuel 4 Proven coal reserve 2. Depletion of natural

resources 42 Proven mineral reserve

3. Global warming 43 GHG emissions, GWP 4. Ozonosphere

destruction 24 Emission of CFCs, ODP

5. Atmospheric pollution Many Environment Agency, WHO regulation values

6. Hydrosphere pollution 28 Environment Agency, WHO regulation values

District scale 7. Acid rain 7 [H+] concentration in

rainwater 8. Waste processing 2 Amount of residuals in the

final disposal 9. Recycling effect Many Factor classified statistical

materials

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emission or unit consumption. As the LCA has to be summarized along all stages of

the life cycle, the total LCs environmental load consolidated value EcL [NETS] is calculated using the following formula.

( )∑=

=n

iii xELMEcL

1

・ (3)

here, xi (kg, kWh, m3, etc.) is the emission consumed amount of the related environmental load factor class “i”.

The procedure is shown in the following for acquiring the maximum emission/consumption amount Pi and the environmental load consolidated standard ELMi, taking the examples such as depletion of fossil fuel, global warming by CO2 and other greenhouse gas emissions, atmospheric pollution and acid rain in which power generation plants are directly and deeply involved.

3. CALCULATION OF Pi AND ELMi 3.1 Depletion of fossil fuel and natural resources

As fossil fuel is a precious resource common to the entire human race, its depletion will certainly impose a global scale environmental load. The difference between the depletion of fossil fuels and the depletion of iron and other minerals is the fact that fossil fuel cannot be recycled.

Table 2 shows classified proved reserves of fuel consumed by commercial power generating stations and the maximum consumable value Pi

FD, and the individual environmental load consolidated standard values ELMi

FD

calculated using formulas (1) and (2). As the table shows, the impact for fossil fuel depletion, as observed from ELMi

FD for the consumption of 1kg of each of the fuels are: coal (1.0) < petroleum (6.9) < natural gas (9.3) < uranium (2.3E+5). The unit calorific value 1kJ calculated from the total calorific value of the proved reserves (Table 2. ELMi

FD lower line) gives coal (1.0) < petroleum (4.3) nearly = natural gas (4.5) < uranium (10).

For Natural Resources Depletion (RD), the basic idea is the same as for fossil fuel depletion. LCA-NETS considers the environmental load due to Natural Resources Depletion for 42 kinds of minerals. When a power generation plant is being considered, the calculations should cover not only materials used in

machinery and buildings such as boilers, turbines, power generators, and transformers, but also materials used in many kinds of machines that manufactured the afore-mentioned machinery and buildings. LCA-NETS has provided inventory data base (IDB) covering these LCs. 3.2 Global warming

The Inter-Governmental Panel on Climate Change (IPCC) report on climatic variations proposed that, if the best scenario S450 for CO2 concentration in the atmosphere is followed, the CO2 concentration can be stabilized at 450 ppmv by 2100[7]. The accumulated emission of CO2 concentration necessary to stabilize the concentration at 450 ppmv is defined as the maximum allowable emission Pi in the Loader side. The maximum allowable emission amount of CO2 from 1900 to 2100 is estimated as 2.31E+15 [kg], after calculating the mass of air in the atmosphere (troposphere up to an altitude 50 km) as 5.45E+18 [kg], and the amount of 0.24E+15 [kg] emitted from 1991 to 1999, the maximum allowable emission amount GW

COP 2 , and the consolidated environmental load standard value GW

COELM 2 can be calculated respectively as follows.

[NETS/kg]109.2 [kg],1007.2 42

152

−×=×= GWCO

GWCO ELMP (4)

As the values indicate, GWCOELM 2 for global warming from

the emission of CO2 is only 1/10 of the same emission/consumption, compared with ELMi

FD for fossil fuel depletion.

To calculate the consolidated environmental load for global warming from greenhouse gases other than CO2, formula (4) multiplied by GWP (Global Warming Potential) for CO2 , namely EMLi

GW =GWPi・ GWCOELM 2 is

used. Table 3 shows the values of six types of greenhouse gases.

3.3 Atmospheric pollution and acid rain

Atmospheric pollution (AP: Air Pollution) imposes a global environmental load. We calculated the maximum allowable emission Pi

AP, as consolidated standard, from the volume of the atmospheric troposphere, using the

Table 2 PFD and ELMFD for the depletion of fossil fuels (1999)

Types of fuel

Proven reserves[6] PiFD ELMiFD

Coal 9.84×1011[ton] 9.84×1014 [kg] 6.1×10-4 [NETS/kg] 2.3×10-8 [NETS/kJ]

Petroleum 1.65×108[m3] 1.42×1014 [kg] 4.2×10-3 [NETS/kg] 1.0×10-7 [NETS/kJ]

Natural gas 1.41×1014[m3] 1.05×1014 [kg] 5.7×10-3 [NETS/kg] 1.1×10-7 [NETS/kJ]

Uranium 4.36×106[ton] 4.36×109 [kg] 1.4×102 [NETS/kg] 2.5×10-7 [NETS/kJ]

Table 3 GWP and ELMiGW for global warming (1999)

Greenhouse gas

GWP [ - ]

ELMiGW [NETS/kg]

CO2 1.0 2.9×10-4 CH4 24.5 7.1×10-3 N2O 320 9.3×10-2 R-11 4000 1.2×100 R-22 1700 4.9×10-1 SF6 24900 7.2×100

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regulation values of WHO and the Environment Agency for the standard for consolidation. The unit environmental load consolidated value ELMi

AP was calculated by equation (2).

The amount of acid rain (RA: Rain Acidification) is estimated from the statistic data for world precipitation (annual average) at 3.25E+14 [m3/year]. However, as acid rain spreads for a radius of 1000 km from the source (0.62 % of the area of the surface of the earth), the precipitation in the affected area is 2.01E+12 [m3/year]. On the other hand, emitted NOx and SOx produce H+

through rain water with the pH determined by the formula pH = -log[H+ ]. If the threshold over which the ecosystem is affected is set at pH ≤ 4, the hydrogen ion concentration in the rainwater [H+][mol/liter] can be determined. When multiplied by the volume of rainwater, this gives 2.01E+11

[mol], which is the maximum tolerable PAR. Table 4 gives Pi

RA and ELMiRA of acid rain containing various chemicals.

When calculating the values for MEViRA, the maximum

tolerable environmental load for the Receiver side, with a population of 1.35E+8 [people](area x population density), was set at MEVi

RA = 1.35E+10 [NETS].

3.4 Ozonosphere depletion, water pollution, waste

disposal, and recycle effect Since it takes about 30 years for CFC gases to

decompose after being released into the atmosphere, presuming that the cause of the present depletion of the ozonosphere is the CFC released before 1970, the accumulative amount of CFC-11 with 1.0 of ODP (Ozone-layer Depletion Potential) released up to 1970 is estimated at 4.61E+6 [ton]. According to scientific data, as the ozonosphere that has already been depleted forms roughly 5% of the total, the total emission amount to deplete the entire ozonosphere is calculated as roughly 9.22E+7 [ton]. Therefore, the allowable emission amount from this moment on, is this amount minus the amount already emitted of 2.02E+7 [ton], namely OD

CFCP 11− =

7.20E+7 [ton]. The consolidated unit environmental load on a global scale is calculated as OD

CFCELM 11− = 8.3

[NETS/kg]. For other CFCs and HCFCs, corrections must be made using ODP values.

WHO, the Environment Agency and others have set

regulation values for the factors that cause water pollution (WP: water pollution). LCA-NETS has consolidated environment loads for 28 chemicals specifically regulated by the Agency. The hydrosphere has been determined down to a continental shelf depth of 200 m (7.4% of the total ocean area) and the amount of water involved has been calculated as 5.34E+6 [km3]. The maximum allowable values for the emission Pi

WP of various chemicals have been calculated by multiplying this by the regulation values, and the environment load consolidated standard ELMi

WP = MEVG /PiWP was obtained

according to equation (2). Environmental load of waste processing (WaP) is a

local problem, as cases differ between one specific country and district and another. In the case of Japan, waste is ultimately disposed of through incineration or landfill. In the case of land fill processing, as the remaining capacity of the disposal area is a basic standard, the maximum tolerable discharge value for industrial waste (IWa) and for general waste (GWa) can be estimated as WaP

IWaP = 2.08E+11 [kg] and WaPGWaP = 1.42E+11

[kg] respectively. As the Receiver side maximum acceptable environmental load for Japan WaP

JapanMEV = 1.26E+10 [NETS], the environmental load consolidated standard values for 1kg of waste are WaP

IWaELM = 6.1E-2

[NETS/kg], and WaPGWaELM = 8.9E-2 [NETS/kg] respectively.

The effect of recycling in LCA-NETS is quantified in minus value of environmental load. The recycling of natural mineral resources (materials) is a particularly important stage as it allows reuse of materials and directly reduces the environmental load.

4. RESULTS AND DISCUSSION Figure 1 shows the energy balance and energy ratio

for each type of power generation plant. The input energy EInput includes the initial equipment energy necessary for power plant equipment and buildings, and the running

Table 4 Pi RA and consolidated value for acid rain

(1999)Chemicals PiRA [ton] ELMiRA [NETS/kg]

NO2 9.26 × 106 1.4 NO 6.04 × 106 2.2 N2O 8.86 × 106 1.5 SO2 1.26 × 107 1.0

76

94

25 26

39

51

35

22

105

119

122

117

114

109

23

104

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LN

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(AC

CS)

0

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E q u i p m e n t E n e r g y

N e t E n e r g y

E n e r g y R a t i o

Ener

gy R

atio

[-]

Ene

rgy

Bala

nce

[ ×10

6 kW

h ]

Figure 1 Energy balance and energy ratio, [1MW, 20 years]

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energy that is consumed by burning fuel and maintenance to operate plants for 20 years as well as on disposal. Operating efficiency has to be taken into consideration for the output energy EOutput. Accordingly, the net energy is defined as ENet = EOutput - E Input. The energy ratio is defined as EEnergy = EOutput/EInput. Figure 1 shows that coal, petroleum and natural gas, and nuclear energy power plants produce a large net energy with an energy ratio as high as 10 to 25. Recent waste-energized systems have large capacity, and, as the fuel is waste, the energy ratio reaches as high as 50. The hydroelectric and geothermal generation plants are operated on a large, commercial scale. However, the power generators that utilize the energy of wind, waves, tide, ocean temperature differences, solar energy, and solar photovoltaic system (PV) have low operating efficiencies and energy densities. Therefore, the energy balance is as low as 1/2 to 1/5 of larger power plants. The energy ratios are as small as around 2.5, thus requiring a long operating term.

Figure 2 shows the lifecycle green house gas emissions for power generation plants. At the point of combustion, coal fired system produce higher greenhouse gas emissions than natural gas. However, over the full life cycle, total emissions from natural gas may be substantially higher than at the point of combustion. This depends on whether the source of gas is high or low in carbon dioxide, the extent of venting and flaring during production, and the extent of losses during transport and distribution. By contrast, 97% of life cycle emissions from coal occur at the point of combustion.

The state-of-the-art of the modern clean coal technologies have 10-20% lower greenhouse gas emissions than conventional pulverized fuel coal-fired power plants (NOx and SOx emissions for clean coal technologies are also significantly lower than the conventional). These technologies include supercritical and ultra-supercritical steam, fluidized bed combustion and a range of coal gasification systems. These significantly increase thermal efficiency. This means less

coal is required to produce a given amount of energy. Co-firing conventional pulverized coal generation with

10% biomass decreases green house gas emissions by approximately 9%. Linking steam from solar thermal technology with the steam cycle of existing coal-fired power plants offers the potential to convert 40% of solar energy into electricity. This compares with 13% for large-scale photovoltaic systems. The estimated capital costs are also much lower than for photovoltaic systems. Moreover, the utilization of by products, for example, if fly ash produced in coal-fired power plants was reused in other industries (e.g. in the production of cement), up to 10% reduction in overall greenhouse emissions could be obtained (i.e. considered as a potential ash credit).

The renewable energy technologies have low total emissions, although all have some emissions associated with certain stages of their life cycle. For example, the production of solar panels is the highest emission point in solar electricity generation. Emissions from photovoltaic systems depend on cell life and the technology used to produce the wafers. It should be noted that the analysis excluded electricity storage.

Life cycle greenhouse gas emissions from hydroelectricity are appreciable, with carbon dioxide and methane being produced from drowned vegetation and organic inflow from the catchments. The analysis concluded that hydro-electricity cannot be automatically assumed to emit less greenhouse gas than the thermal alternatives. Net emissions should be established on a case by case basis.

Table 5 shows the environmental load consolidated fossil fuels standard value ELMi

FE, calculated using LCA-NETS for the combustion of 1kg of each. (FE: Fuel for Fired Plants). The environmental load for fuels decreases in the following order: uranium (7.3E+4), natural gas (3.5), petroleum (2.8), and coal (1.0). (Numbers are ratios to the value of coal taken as 1.0.) The value includes the environmental load factors for all of the processes including mining, transportation, preprocessing, combustion, exhaust gases, environmental processing, and post processing of fossil fuels. For example, when the value for fossil fuel depletion in Table 5 is compared with that in Table 2, the value for coal has increased by 31%, petroleum by 12 %, and natural gas by 16 % respectively.

Table 5 also clarifies that the environmental load of coal as a fuel for power generation plants is 35% that of petroleum, 28% of natural gas, roughly only 1/3. The

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

10% Biomass co-firingConventional coal

NG-Gas turbineNG-Steam turbine

NG-CCOil fired

IGCCFuture IGCC

IG-MCFCIG-SOFC

PhotovoltaicSolarWindWave

GeothermalHydro

Nuclear Potential ash credit Biomass effect Net GHG emissionNuclear

Renewables

Future clean coal

Clean coal

Oil firedNatural gas

Range

Range

Green house gas emissions [kg-CO2 equivalent/kWh]

Range

Range

Figure 2 Green house gas emissions for power technologies

Table 5 ELMiFE [NETS/kg-fuel]

PP Fuel FD RD GW AP&RA Total Coal 8.0×10-4 3.4×10-5 7.2×10-4 6.4×10-4 2.2×10-3

Petroleum 4.7×10-3 4.2×10-5 9.2×10-4 5.6×10-4 6.2×10-3 L N G 6.6×10-3 1.2×10-4 1.0×10-3 5.3×10-5 7.8×10-3

Uranium 1.6×10+2 5.7×10-1 2.9×10-1 2.5×10-1 1.6×10+2

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main reason is that the proven reserves of coal are much more abundant than reserves of others. However, the data shows that coal falls short excellent from the point of view of atmospheric pollution and acid rain, at 115% and 1200%, respectively. It is possible, however, to reduce this environmental load to the level of natural gas by introducing new technologies such as exhaust gas processing and coal gasification.

Figure 3 shows the result of the environmental load calculations for various power generation plants using LCA-NETS. The figure indicates the proportion of the 8 causes of environmental load on all LCA phases. The most significant point is that the environmental load is large for nuclear power generation plants. The plant is a conventional, one-through type in which the fuel is not reprocessed. The main cause for the environmental load is due to the depletion of fossil fuels. However, when it is converted into the reprocessing type, shown next to the one-through type, the fast-breeder, recycling reactor, it becomes clear that the environmental load is reduced markedly and the plant will then be superior to the natural gas firing advanced combined cycle system (LNG-ACCS) plant which is said to be the most environmentally-friendly plant at present. The figure also shows that waste burning generation plants have a large environmental load. This is due to acid rain, namely the strongly acidic gases such as chloride that are emitted when waste is burnt in the plant. It is known that the environmental load for coal fired power plants due to acid rain caused by NOx and SOx is significant. While the environmental load due to fossil fuel depletion for petroleum or natural gas fired power plants is relatively large compared with coal fired power plants.

On the other hand, the environmental load for hydroelectric and geothermal power plants is very small, indicating that they are extremely environmental-friendly power generation systems. The problem is that the power generating capacity of plants that are actually operating is

relatively small. The great prerequisite for their development is that they do not destroy nature. It is clear that electric power generating plants that use soft energy such as wind power and solar batteries cause a significantly smaller environmental load and are friendlier than large-scale thermal power plants. Accordingly, the right equipment for the right application is the best policy for a desirable environmental load.

Figure 4 shows the life cycle costs (generating cost) of various power plant systems, the data was standardized to a generating electricity 1 kWh and a lifetime of 20 years for comparison[8]. The life cycle costs decreases in the order of solar photovoltaic, ocean waves, solar thermal, wind power, tidal energy, oil fired, pressured fluidized bed combustion (PFBC), LNG fired, integrated gasification combined cycle (IGCC), waste fuel, natural gas combined cycle (LNG-CC), nuclear, geothermal, coal fired, and hydropower. Figure 4 also clarifies, the investment cost of photovoltaic is 1010%, 1360%, 390%, 290%, 530%, 420%, 690%, 1070%, 1670%, 1090%, 1170%, 1750%, 1780%, that of hydro, geothermal, wind power, ocean wave, tidal energy, solar thermal, municipal waste, nuclear, coal-fired, PFBC, IGCC, oil, LNG, respectively. However, it is obvious, that fossil fuel power plants, due to rapid depletion of their natural resources, will have less economic merit for their life extensions. This view suggests that power generation systems be fuelled by abundant renewable energy sources, such as flowing water, wind, solar, and to some extent geothermal, in near future, economically.

It was compared a various additional facilities options. For example when installing particulates electrostatic precipitators equipment for coal-fired power plant, 99.5% of particulates and dust could be restrained by the investing with 6% of facilities. About 23% of amount environmental loads become able to be diminished as the result (see Fig. 5). The De-NOx and De-SOx equipment can restrain SOx, NOx by investing

5.3

E-5

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(AC

CS)

Solid Waste Air PollutionWater pollutionOzone LayerGlobal WarmingAcidificationNatural ResourcesFossil fuel

Eco-

Load

[NET

S/kW

h ]

Figure 3 Eco Load values for overall evaluation

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h] Refurbishment Cost

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Fuel Cost

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Figure 4 Life cycle costing of power plant systems

7

23% of the facilities expensed, can improve about 65% of effects on environment as a whole. About 81% of environmental loads can reduce when plant with entire control systems with about 42% increased from original plant capital cost. On the other hand, the net output by the plant falls by doing an environmental controls and the cost of the generation of electricity becomes high. This is because the facilities investment, the operation and repair-maintenance cost become high, and the percentage in the own consumption increases from 7% to 8.8%.

Recently, the next generation coal fired power plant, PFBC and IGCC have been introduced to improve the environmental friendliness of power generation facilities[9-12]. The environmental load of these types of generation plants was calculated using LCA-NETS. Most of the data used for the calculation have been made public at various scientific meetings. For unavailable data, we estimated values from data obtained from existing power plants.

Figure 6 shows the trend of operational years of PFBC-CC (Osaki Unit No.1) and IGCC (experimental unit) when these plants generate 1 kWh and produce environmental load that is converted into total environmental load consolidated value EcL [NETS/kWh]. For comparison, data of the conventional coal fired power generation plant (CF) (Hekinan Unit No. 3) and LNG-CC (Kawasaki Unit No.3) are attached. As the figure shows, the environmental load of IGCC and PFBC in the early period of operation after construction is larger than those of both LNG-CC and the conventional CF. However, the values decrease rapidly with operational years and gradually fall after the 5th year. IGCC gives a somewhat smaller environmental load than PFBC. The environmental load for IGCC becomes smaller than conventional CF after the 5th year and dwindles down further than LNG-CC after

the 17th year. The environmental load for PFBC falls to the same level as conventional CF in 7 years and to the same level as LNG-CC in 20 years. The trend of operational years for the total environmental load verifies that coal gasification for power generation is a promising project.

5. CONCLUDING REMARKS We have conducted a quantitative analysis of the

environmental load produced by various kinds of power plants and co-generation systems using the LCA-NETS approach developed by the author’s laboratory. We also have evaluated the environmental load produced by various types of energy systems in terms of environmental load consolidated values that cover the entire LC phases. The evaluation scheme constructed in this work is found to be an attractive and powerful tool to estimate the cost as well as the LCA environmental loads of power plant systems and to propose the eco-operation of the industrial activity of interest.

REFERENCES [1] Heijungs R. Ed., Environmental Life Cycle Assessment of Products-Guide and Background (English Ed.), Leiden: Centre of Environmental Science, 1992. [2] Steen B. and Ryding S.O., The EPS Enviro-Accouting Method; An Application of Environmental Accounting Principles for Evaluation and Valuation of Environmental Impact in Product Design, report no. B 1080, Goteborg, Swedish Environmental Research Institute (IVL), 1992. [3] Kato S. and Widiyanto A., A Life Cycle Assessment Scheme for Environmental Load of Power Generation Systems with NETS Evaluation Method, In Proc. of the International Joint Power Generation Conference (IJPGC), San Francisco, 1999. [4] Kato S., Kojima Y., Widiyanto A. and Maruyama N., Environmental Impact of Fuel Fired Co-Generation Plants using A Numerically Standardized LCA Scheme, In Proc. of the International Joint Power Generation Conference (IJPGC), Miami Beach, 2000.

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Figure 5 Eco-Load of selected coal power plant options

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Figure 6 Trend in the total eco-load for PFBC and IGCC

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8

[5] Kato S., Maruyama N., Nikai Y., Takai H. and Widiyanto A., Life Cycle Assessment Estimation for Eco-Management of Co-Generation Systems, ASME JERT 2001; Vol. 123 (1): pp. 15-20. [6] Anonymous, 2003, ‘EDMC 2003, Energy and Economic Statistic in Japan, The Energy Data and Modeling Center. [7] Houghton J.T., Callander B.A. and Varney S.K., Climate Change 1992, The Supplementary Report to the IPCC Scientific Assessment. Cambridge University Press, 1992. [8] Widiyanto A., Kato S. and Maruyama N., A LCA/LCC Optimized Selection of Power Plant System With Additional Facilities Options, ASME JERT 2002; Vol. 124 (4): pp. 290-299.

[9] Kaneko S., et al., 1997, Operation Results of the Air Blown Entrained Flow Gasifier, Proc. of International Conference of Engineering 97, Vol. 1, pp. 119-124 [10] Kaneko S., Ohta K., Furuya T., Shinada O. and Hashimoto A., 1999, Design of IGCC Demonstration Plant (in Japanese), Mitsubishi Heavy Industries Technical Reviews, Vol. 36, No. 1, pp. 21-24. [11] Sato S., Ota K., Furuya T., Koyama Y. and Hashimoto A., 2000, Current Status of Research and Development in IGCC Demonstration Plant (in Japanese), Mitsubishi Heavy Industries Technical Review, Vol. 37, No. 1, pp. 25-28. [12] Horiuchi K., 2000, ‘‘Test Operation of Osaki PFBC System (in Japanese), Proc. The 7th Symposium on Power and Energy Technology 2000, JSME, pp. 85-90.