International comparison of fossil power efficiency and CO 2 intensity - Update 2014 FINAL REPORT

Transcription

1 International comparison of fossil power efficiency and CO 2 intensity - Update 2014 FINAL REPORT

2 International comparison of fossil power efficiency and CO 2 intensity Update 2014 FINAL REPORT By: Charlotte Hussy, Erik Klaassen, Joris Koornneef and Fabian Wigand Date: 5 September 2014 Project number: CESNL15173 Ecofys 2014 by order of: Mitsubishi Research Institute, Japan ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

3 Summary The purpose of this study is to compare the energy efficiency and CO 2 -intensity of fossil-fired power generation for Australia, China, France, Germany, India, Japan, Nordic countries (Denmark, Finland, Sweden and Norway aggregated), South Korea, United Kingdom and Ireland (aggregated), and the United States. This is done by calculating separate benchmark indicators for the energy efficiency of gas-, oil- and coal-fired power generation. Additionally, an overall benchmark for fossil-fired power generation is determined. The benchmark indicators are based on deviations from average energy efficiencies. For the comparison of CO 2 intensity, Canada and Italy are added as additional countries. Trends in power generation The countries included in the study (excluding Italy and Canada) generated 68% of public fossil-fired power generation worldwide in In the period the share of fossil power used in the public power production mix has increased from 64% to 68%. Total power generation is largest in the China with roughly 4,640 TWh, closely followed by the United States with 4,162 TWh. Japan is the country ranked third with 899 TWh. From the fossil fuels, coal is most frequently used in most countries. Figure 1 shows the breakdown of public power generation per country. 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Other renewables Oil Natural gas Coal Nuclear Hydro Figure 1 Fuel mix for public power generation by source in Note that gas use in the Nordic countries is underestimated as Norwegian power production from natural gas is confidential. Total coal-fired power generation in all countries combined (excluding Canada and Italy) increased from 3,036 to 7,158 TWh (+136%) by the period , with China being the strongest grower, increasing from 442 to 3,697 TWh, fuelled by fast-growing domestic energy demand. ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

4 Efficiency [%] Gas-fired power generation in all countries combined increased from 551 to 1,879 TWh (+241%) in The United States, driven by relative low natural gas prices from 2009 onwards driven by shale gas development, shows the strongest absolute growth from 319 to 954 TWh. Oil-fired power generation played a marginal role by 2011 with only 172 TWh. In 2011, Japan and the United States were the largest oil-fired power producers and generated 86% of all oil-fired power production in the countries of interest. The general trend is that power production from oil has been declining over , although some temporarily peaks can still be observed (e.g. Japan in 2011 doubled power production from oil compared to 2010 mostly likely due to the need for deploying reserve capacity due to the shutdown of nuclear power plants after the Fukushima accident). Generating efficiency Figure 2 shows the energy efficiency per country and fuel source. Because the uncertainty in the efficiency for a single year can be high we show the average efficiencies for the last three years available, : Coal-fired power efficiencies range from 27% (India) to 43% (France). Gas-fired power efficiencies range from 34% (France) to 53% (United Kingdom and Ireland). Oil-fired power generation efficiencies range from 20% (India) to 46% (South Korea). Fossil-fired power efficiencies range from 29% (India) to 45% (United Kingdom and Ireland). The weighted average generating efficiency for all countries together in 2011 is 35% for coal, 48% for natural gas, 40% for oil-fired power generation and 38% for fossil power in general. 60% 50% 40% 30% 20% 10% 0% Coal Gas Oil Fossil Figure 2 Energy efficiency per fuel source (average ). The weighted average efficiency for gas-fired power generation shows a strong increase from 39% to 48% for the considered countries (see Figure 3), caused by a strong increase in modern gas-based capacity: gas-based production more than tripled. ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

5 Efficiency [%] Coal-fired power generation however, doubled in the period , while the weighted average efficiency remained constant at about 34% - 35%. The reason for this is that a large part of the growth in coal-fired power generation takes place in China and India, in which generating efficiencies of coal remained relatively low (despite a significant increase of +7%pts in in China). The majority of coal-fired power plants in China is based on sub-critical steam systems (although this is changing as China is currently the main market in the world for advanced coal-fired power plants). The efficiency that can be achieved by sub-critical units is around 39%. The efficiency that can be achieved by applying best available technology (super-critical units) is as high as 47%. This means that coal-fired power efficiency in China could have been much higher if best practice technology had been used. For India the situation is the same; a large share of coal-fired capacity is built after 1990, of which the majority is based on sub-critical steam systems. 50% 45% Coal 40% 35% Gas Oil Fossil 30% 25% Figure 3 Weighted average energy efficiency for included countries. Figure 4 shows the benchmark for the weighted energy efficiency of fossil-fired power generation. Countries with benchmark indicators above 100% perform better than average and countries below 100% perform worse than the average. As can be seen, in order of performance, the Nordic countries, United Kingdom and Ireland, Japan, Germany, South Korea and the United States all perform better than the benchmark fossil-fired generating efficiency. ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

6 CO 2 intensity [g/kwh] Performance relative to benchmark 120% 110% 100% 90% 80% 70% 60% 50% 40% Coal Gas Oil Fossil Weighted benchmark Figure 4 Benchmark for weighted energy efficiency of fossil-fired power production (100% is average). CO 2 -intensity and reduction potential Figure 5 shows the CO 2 -intensity for fossil-fired power generation for the years per country. The CO 2 intensity for fossil-fired power generation ranges from 547 g/kwh for Italy to 1,174 g/kwh for India on average. This is a difference in emissions of more than 100% per unit of fossilfired power generated. The CO 2 intensity for fossil-fired power generation depends largely on the share of coal in fossil power generation and on the energy efficiency of power production. 1,400 1,200 1, Average Figure 5 CO 2-intensity for fossil-fired power generation. ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

7 CO 2 reduction potential [%] Fossil-fired power generation is a major source of greenhouse gas emissions worldwide and was responsible for approximately 30% of global greenhouse gas emissions in 2005 (UNFCCC, 2008). If the best available technologies 1 would have been applied for all fossil power generation in the countries of this study (including Canada and Italy) in 2010, absolute emissions would have been, on average, 23% lower. Figure 6 shows how much lower CO 2 emissions would be for all individual countries as a share of emissions from fossil-fired power generation. The CO 2 emission reduction potential per country, as a percentage of emissions from public power generation, ranges from 16% for Japan to 43% for India. 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% Figure 6 Relative CO 2 emission reduction potential for fossil power generation by energy efficiency improvement by replacing all fossil public power production by BAT for the corresponding fuel type. 1 I.e. Installations operating according to the present highest existing conversion efficiencies. ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

8 CO 2 reduction potential [Mt CO 2 ] Figure 7 shows the emission reduction potential in absolute amounts. China, United States and India show very high absolute emission reduction potentials of 812, 500 and 338 Mtonne, respectively. This is due to large amounts of coal-fired power generation at relatively low efficiency Figure 7 Absolute CO 2 emission reduction potential for fossil power generation by energy efficiency improvement by replacing all fossil public power production by BAT for the corresponding fuel type. ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

9 Table of contents 1 Introduction Power generation by fossil-fuel sources 1 2 Methodology Energy efficiency of power generation Benchmark for fossil generation efficiency CO 2 intensity power generation Share of renewable and nuclear power generation 13 3 Results Efficiency of coal-, gas- and oil-fired power generation Benchmark based on non-weighted average efficiency Benchmark based on weighted average efficiency CO 2 -intensities Emission reduction potential Renewable and nuclear power production 35 4 Conclusions 54 5 Discussion of uncertainties & recommendations for follow-up work 56 6 References 58 Appendix I: Comparison national statistics 61 Appendix II: Input data 70 Appendix III: IEA Definitions 84 ECOFYS Netherlands B.V. Kanaalweg 15G 3526 KL Utrecht T +31 (0) F +31 (0) E info@ecofys.com I Chamber of Commerce

10 1 Introduction This study is an update of the analysis International comparison of fossil power generation and CO 2 intensity (Ecofys, 2013). This analysis aims to compare fossil-fired power generation efficiency and CO 2 -intensity (coal, oil and gas) for Australia, China (excluding Hong Kong), France, Germany, India, Japan, Nordic countries (Denmark, Finland, Sweden and Norway aggregated), South Korea, United Kingdom and Ireland, and the United States. This selection of countries and regions is based on discussions with the client. United Kingdom and Ireland, and the Nordic countries are aggregated, because of the interconnection between their electricity grids. Although the electricity grids in Europe are highly interconnected, there are a number of markets that operate fairly independently. These are the Nordic market (Denmark, Finland, Sweden and Norway), the Iberian market (Spain and Portugal), Central (Eastern European countries) and United Kingdom and Ireland. The analysis is based on the methodologies described in Phylipsen et al. (1998) and applied in Phylipsen et al. (2003). Only public power plants are taken into account, including public CHP plants. For the latter a correction for the (district) heat supply has been applied. This chapter gives an overview of the fuel mix for power generation for the included countries and of the amount of fossil-fired power generation. The methodology for this study is described in Chapter 2. Chapter 3 gives an overview of the efficiency of fossil-fired power generation by fuel source and addresses the development of the share of renewables in public power generation over time. Chapter 4 gives the conclusions. 1.1 Power generation by fossil-fuel sources Fossil-fired power generation is a major source of greenhouse gas emissions. Worldwide, greenhouse gas emissions from fossil-fired power generation accounted for roughly 30% of total greenhouse gas emissions in 2005 (UNFCCC, 2008). The countries included in the study generate 68% of public fossilfired power generation worldwide in 2011 (IEA, 2013). 1

11 Electricitry production (TWh) 5,000 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1, Other renewables Hydro Nuclear Oil Natural gas Coal 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Other renewables Oil Natural gas Coal Nuclear Hydro Figure 8 Absolute (top) and relative (bottom) public power generation by source in Note that for the Nordic countries there is a small underestimation of power production from natural gas as power produced from natural gas in Norway is confidential. 2

12 In 2011, the total power generation (incl. renewables and nuclear power) was largest in China with roughly 4,640 TWh, exceeding the United States (4,162 TWh) for the first time in history. Japan generated 899 TWh, which is 7% lower than in The share of fossil fuels in the overall fuel mix for electricity generation was almost 70% on average. France, which has a large share of nuclear power (79%) and the Nordic countries with a large share of hydropower (54%) in 2011 are exceptions. When comparing the sources of power generation for Japan, Figure 8 it clearly shows the shutdown of Japan s nuclear power plants following the Fukushima Daiichi accident. In 2010 nuclear power made up 30% of all public power generation (Ecofys, 2013), which declined to 11% in From the fossil fuels, coal is most frequently used in most countries, except for Japan and the United Kingdom and Ireland, in which natural gas is more abundantly used than coal. Australia and China show a very high share of coal in their overall fuel mix for power generation of about four fifths, followed by India with a share of 66% in The share of oil-fired power generation is typically limited; only Japan and the United States have larger amounts, in absolute sense. Figure 9 - Figure 12 show the amount of coal-, gas-, oil- and total fossil-fired power generation respectively in the period , from public power plants and public CHP plants together. 3

13 Electricity generation (TWh) Figure 9 shows that the total coal-fired power generation in all countries increased from 3,036 to 7,158 (+136%) during the period China shows the strongest absolute growth from 442 to 3,697 TWh. The US saw its share of coal-fired power production shrink to the lowest relative level since 1995, mainly driven by national or regional legislation and regulations promoting gas and renewable technologies at the expense of coal-fired generation. The drop in 2009 is caused by a significant drop in natural gas prices due to development of shale gas Australia China France 2500 Germany 2000 India Japan Korea Nordic countries UK + Ireland United States Figure 9 Coal-fired power generation. 4

14 Electricity generation (TWh) Figure 10 indicates that gas-fired power generation in all countries combined increased from 551 to 1,879 in (+241%). The United States shows the strongest absolute growth from 319 to 954 TWh. Between 2009 and 2011, the growth was fuelled by shale gas. In Japan, Gasfired power generation experienced a very steep increase in 2011 (+25% increase in a single year). The UK and Ireland saw a drop in gas-fired power generation because of the relative low prices of coal and CO 2 prices of around 15 Euro per tonne CO 2 under Europe s emission trading scheme (EU ETS) Australia 1000 China France 800 Germany 600 India Japan 400 Korea 200 Nordic countries UK + Ireland United States Figure 10 Gas-fired power generation 5

15 Electricity generation (TWh) Figure 11 shows that oil-fired power generation plays a limited role and its importance has further diminished in the past two decades, especially in the case of the three leading oil-fired power producing countries (USA, Japan and China), although in Japan oil-fired power production doubled again in 2011 post-fukushima. 250 Australia 200 China France 150 Germany India 100 Japan Korea 50 Nordic countries UK + Ireland United States Figure 11 Oil-fired power production. 6

16 Electricity generation (TWh) Figure 12 indicates that the total fossil-fired power generation increased from 4,027 to 9,209 TWh (+129%) in China, US, India and Japan show the strongest absolute growth in this period Australia China France 2500 Germany 2000 India Japan Korea Nordic countries UK + Ireland United States Figure 12 Fossil-fired power production. 7

17 2 Methodology This chapter discusses the methodology used to derive the energy efficiency indicators as well as the input data used to determine the indicators. This study is based on data from IEA Energy Balances edition 2013 (IEA, 2013). The advantage of using IEA Energy Balances is its consistency on a number of points: Energy inputs for power plants are based on net calorific value (NCV) 2 ; The output of the electricity plants is measured as gross production of electricity and heat. This is defined as the electricity production including the auxiliary electricity consumption and losses in transformers at the power station ; A distinction is made between electricity production from industrial power plants and public power plants and public combined heat and power (CHP) plants. In this study we take into account public power plants and public CHP plants. We distinguish three types of fossil fuel sources: (1) coal and coal products, (2) crude oil and petroleum products and (3) natural gas. In the remainder of this report, we will refer to these fuel sources as coal, oil and gas, respectively. For a more extensive definition of public power production and these fuel types, refer to Appendix IV. As a check, IEA statistics on the United States and India are compared to available national statistics (see Appendix I). In some cases energy efficiencies based on IEA are replaced by energy efficiencies calculated from national statistics. This is done when the efficiencies based on national statistics appeared to be more reliable in earlier versions (prior to 2012) of this report. 2.1 Energy efficiency of power generation The formula for calculating the energy efficiency of power generation is: E = (P + H*s) / I. Where: E P H s Energy efficiency of power generation Power production from public power plants and public CHP plants Heat output from public CHP plants Correction factor between heat and electricity, defined as the reduction in electricity production per unit of heat extracted 2 The Net Calorific Value (NCV) or Lower Heating Value (LHV) refers to the quantity of heat liberated by the complete combustion of a unit of fuel when the water produced is assumed to remain as a vapour and the heat is not recovered. 8

18 I Fuel input for public power plants and public CHP plants Heat extraction causes the energy efficiency of electricity generation to decrease although the overall efficiency for heat and electricity production is higher than when the two are generated separately. Therefore, a correction for heat extraction is applied. This correction reflects the amount of electricity production lost per unit of heat extracted from the electricity plant(s). For district heating systems, the substitution factors vary between 0.15 and 0.2. In our analysis we have used a value of It must be noted that when heat is delivered at higher temperatures (e.g. to industrial processes), the substitution factor can be higher. However, at the moment, the amount of high-temperature heat delivered to industry by public utilities is small in most countries. We estimate that the effect on the average efficiency is not more than an increase of 0.5 percent point 3. No corrections are applied for air temperature and cooling method. The efficiency of power plants is influenced by the temperature of the air or cooling water. In general surface water-cooling leads to higher plant efficiency than the use of cooling towers. The cooling methods that can be applied depend on local circumstances, like the availability of abundant surface water and existing regulations. The effect of cooling method on efficiency may be up to 1-2 percent point. Furthermore the efficiency of the power plant is affected by the temperature of the cooling medium. The sensitivity to temperature can be in the order of percent point per degree. [Phylipsen et al, 1998] In order to determine the efficiency for power production for a region, we calculate the weighted average efficiency of the countries included in the region. 2.2 Benchmark for fossil generation efficiency In this analysis we compare the efficiency of fossil-fired power generation across countries and regions. Instead of simply aggregating the efficiencies for different fuel types to a single efficiency indicator, we determine separate benchmark indicators per fuel source. This is because the energy efficiency for natural gas-fired power generation is generally higher than the energy efficiency for coal-fired power generation. In general, choices for fuel types are often outside the realm of the industry and therefore a structural factor. Choices for fuel diversification have in the past often been made at the government level for strategic purposes, e.g. fuel diversification and fuel costs. The most widely used power plants for coal-fired power generation are conventional boiler plants based on the Rankine cycle. Fuel is combusted in a boiler and with the generated heat, pressurized water is heated to steam. The steam drives a turbine and generates electricity. In principle any fuel can be used in this kind of plant. 3 A change of 1 percent point in efficiency here means a change of e.g. 40% to 41%. 9

19 An alternative for the steam cycle is the gas turbine, where combusted gas expands through a turbine and drives a generator. The hot exit gas from the turbine still has significant amounts of energy which can be used to raise steam to drive a steam-turbine and another generator. This combination of gas and steam cycle is called combined cycle gas turbine (CCGT) plant. A CCGT plant is generally fired with natural gas. Also coal firing and biomass firing however is possible by gasification; e.g. in integrated coal gasification combined cycle plants (IGCC). These technologies are not widely used yet. The energy efficiency of a single steam cycle is at most 47%, while the energy efficiency of a combined cycle can be up to 61% (Siemens. 2012). Several possible indicators exist for benchmarking energy efficiency of power generation. One possible indicator is the comparison of individual countries efficiencies to predefined best practice efficiency. The difficulty in this method is the definition of best practice efficiency. Best practice efficiency could e.g. be based on: The best performing country in the world or in a region; The best performing plant in the world or in a region; The best practical efficiency possible, by best available technology (BAT). The best practice efficiency differs yearly, which means that back-casting is required to determine best practice efficiencies for historic years. A different method for benchmarking energy efficiency is the comparison of countries efficiencies against average efficiencies. An advantage of this method is the visibility of a countries performance against average efficiency. In this study we choose to use this indicator. We compare the efficiency of countries and regions to the average efficiency of the selected countries. The average efficiency is calculated per fuel source and per year and can be either weighted or non-weighted. In the first case the weighted-average efficiency represents the overall energy efficiency of the included countries. A disadvantage of this method is that countries with a large installed generating capacity heavily influence the average efficiency while small countries have hardly any influence at all on the average efficiency. On the other hand, when applying nonweighted benchmark indicators, one efficient power plant in a country could influence the average efficiency if absolute power generation in the country is small. In this research we included both methods, to see if this leads to different results. The formula for the non-weighted average efficiency for coal (BC 1 ) is given below as an example. The formulas for oil and gas are similar. 10

20 BC 1 = EC i / n Where: BC 1 EC i n Benchmark efficiency coal (1). This is the average efficiency of coal-fired power generation for the selected countries. Efficiency coal for country or region i (i = 1, n) The number of countries and regions The formula for the weighted average efficiency for coal (BC 2 ) is given below as an example: BC 2 = (PC i + HC i *s)/ IC i Where: BC 2 PC i HC i s IC i Benchmark efficiency coal (2). This is the weighted average efficiency of coal-fired power generation for the selected countries. Coal-fired power production for country or region i (i = 1, n) Heat output for country or region i (i = 1, n) Correction factor between heat and electricity, defined as the reduction in electricity production per unit of heat extracted Fuel input for coal-fired power plants for country or region i (i = 1, n) To determine the performance of a country relative to the benchmark efficiency we divide the efficiency of a country for a certain year by the benchmark efficiency in the same year. The formula of the indicator for the efficiency of coal-fired power is given below as an example: BC i = EC i / BC 1 or BC i = EC i / BC 2 Where: BC i Benchmark indicator of the energy efficiency of coal-fired power generation for country or region i Countries that perform better than average for a certain year show numbers above 100% and vice versa. To come to an overall comparison for fossil-fired power efficiency we calculate the outputweighted average of the three indicators, as is shown in the formula below: BF i = (BC i * PC i + BG i * PG i + BO i * PO i ) / (PC i + PG i + PO i ) Where: BF i, BC i, BG i and BO i Benchmark indicator for the energy efficiency of fossil-fired, coalfired, gas-fired and oil-fired power generation for country or region i 11

21 PC i, PG i and PO i Coal-fired, gas-fired and oil-fired power production for country or region i 2.3 CO 2 intensity power generation In this study we calculate CO 2 emissions intensities per country for the year 2008: Per fossil fuel source (coal, oil, gas); For total fossil power generation and For total power generation. There are several ways of calculating CO 2 -intensities (g CO 2 /kwh) for power generation, depending on the way combined heat and power generation is taken into account. In this study we use the same method as for calculating energy efficiency and correct for heat generation by the correction factor of (see Section 2.1). The formula for calculating CO 2 intensity is: CO 2 -intensity = (1/E i * C i * P i ) / P i Where: i Fuel source 1... n E i Energy efficiency power generation per fuel source (see Section 2.1) C i P i CO 2 emission factor per fuel source (see table below) (tonne CO 2 /TJ) Power production from public power and CHP plants per fuel source (MWh) In the comparison of CO 2 -intensities, Canada and Italy are included as additional countries. The data input for calculating the energy-efficiencies for Canada and Italy are taken from IEA (2011). The table below gives the CO 2 emission factors per fuel source. Table 1 Fossil CO 2 emission factor (IEA, 2005) Fuel type Tonne CO 2/TJ ncv Hard coal 94.6 Lignite Natural gas 56.1 Oil 74.1 Other fuels (biomass, nuclear, etc.) 0 12

22 2.4 Share of renewable and nuclear power generation This report also gives an insight into the development of the share of renewable and nuclear power production in total public power production. For the period , annual developments for all geographical regions as stated above (excluding Canada and Italy) are included. The IEA classifies a number of different energy sources that are used for power production as renewable (see Table 2). Ecofys has mapped (i.e. aggregated) these into various different categories: Bio; Geothermal; Hydro; Solar; Ocean; Waste; Wind. Table 2 Mapping of different renewable energy categories of IEA Renewable energy sources as defined by IEA Industrial waste Municipal waste (renewable) Primary solid biofuels Biogases Bio-gasoline Biodiesels Other liquid biofuels Non-specified primary biofuels and waste Charcoal Hydro Geothermal Solar photovoltaics Solar thermal Tide, wave and ocean Wind Ecofys mapping Waste Waste Bio Bio Bio Bio Bio Bio Bio Hydro Geothermal Solar Solar Ocean Wind Data input for calculating the shares originates from IEA (2013). To be consistent with the rest of this study, only the share in public power production is considered. 13

23 3 Results Table 3 gives an overview of the content of the different sections of Chapter 3. Table 3 What can be found in which section in this chapter Section Content 3.1 Energy efficiencies for coal,- gas- and oil-fired power production, including a simple aggregation of fossil-fired power efficiency 3.2 Results of the benchmark analysis based on non-weighted average efficiencies 3.3 Results of the benchmark analysis, based on weighted average efficiencies 3.4 CO 2 intensities per fuel source and for total power generation per country CO 2 abatement potentials per country when replacing current installed based by best available technology Development of the share of renewable and nuclear power production over the last decade The underlying data for the figures in this chapter can be found in in Appendix II. This section provides, amongst other data, energy efficiency and input data for the analysis in terms of power generation, fuel input, heat output and the resulting benchmark efficiencies. 3.1 Efficiency of coal-, gas- and oil-fired power generation Figure 13 - Figure 15 show the efficiency trend for coal-, gas- and oil-fired power production, respectively, for the period Figure 16 shows the energy efficiency of fossil-fired power generation by the weighted-average efficiency of gas, oil- and coal-fired power generation. 14