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Energy Procedía 1 (2009) 4209-4216
Energy Procedía
www.elsevier.com/locate/procedia
GHGT-9
Role for carbon capture and storage in China
Chen Wenying*a, Liu Jiaa, Ma Linweib, D Ulanowskyc and G K Burnardc
a Energy Environment and Economy (3E) Research Institute, Tsinghua University, Beijing 100084, China b Tsinghua-BP Clean Energy Research & Education Center, Tsinghua University, Beijing 100084, China c AEA Energy & Environment, Harwell, Didcot, Oxfordshire, OX11 0QR, United Kingdom
Abstract
Coal is China's primary fuel for power generation and will almost certainly remain so for the foreseeable future. China had an installed power generation capacity of a little over 700GWe in 2007, which is projected to nearly double within the next 20 years. NZEC (Near Zero Emission Coal) is a major Sino-British initiative on carbon capture and storage. One of its key aims is to complete the work required to construct a coal-fired power generation plant in China with CCS. The first phase of NZEC is a feasibility study, due to complete in late 2009, in which options for CCS in China are being explored. As part of the feasibility study, an energy systems analysis using the China MARKAL model is being undertaken to provide a perspective on the energy technologies that may be deployed in China to meet its energy needs. The energy situation in China is being analysed, with a detailed investigation undertaken of the various technologies and fuels employed at present. Based on growth forecasts and national plans for China, predictions will be made of the technologies and fuels that may be deployed to meet its future needs. The role of coal and the various technology options for utilising that coal will be identified. An estimate of the CO2 emissions arising from the utilisation of coal and the potential impact of their release to the atmosphere will be made. The potential for CCS to reduce CO2 emissions to the atmosphere, and the cost and impact of deploying CCS will be examined. In this paper, the authors will provide a progress review of this analysis and present provisional results. © 2009 Elsevier Ltd. All rights reserved.
Key words: Carbon capture and storage, CCS, energy system, China MARKAL model
© 2008 Elsevier Ltd. All rights reserved
* Corresponding author: Email: chenwy@tsinghua.edu.cn; phone: 8610-62772756.
1. Introduction
Coal is China's primary fuel for power generation and will almost certainly remain so for the foreseeable future. At present China's installed capacity of power generation plant totals about 700GWe with over 70% of that based on coal. By 2020, this capacity is projected to nearly double and still be dominated by coal. Although major programmes are in place in China to improve energy efficiency, to increase deployment of renewable energy technologies and to increase the installed capacity of nuclear plant, coal-fired power plant will continue to be built in large numbers for many years to come. An energy systems analysis exercise using the China MARKAL model will be undertaken to provide a perspective on the energy technologies that may be deployed in China to 2050 to meet its energy needs. The model will be used to examine the cost and impact of deploying CCS in China. A projection of energy service demand and a technology assessment are both being undertaken to provide updated input for the model.
doi:10.1016/j.egypro.2009.02.231
The energy service demand projection is focused mainly on high energy-intensive industrial sectors such as iron and steel, cement, ammonia, aluminium and transportation. The main reasons for the selection of these high energy-intensive sectors is that they share around 40% of total final energy consumption in China and most of them are large stationary carbon emission sources, which make them attractive for CO2 capture. Although transportation consumes only 10% of total final energy at present, it is expected to increase markedly in future. Oil import dependency is projected to exceed 60% by 2020. For energy security, the production of liquid synfuels and hydrogen from polygeneration with CO2 capture may well become important. Based on historical data, the relationship between energy service demands and key factors such as GDP, population and industrial structure will be analysed. With China's industrialisation, energy demand has increased dramatically in recent years. It is important to not only look at China's historical trends but also to compare them with trends from selected OECD countries to see what lessons can be learnt. China's future energy service demands will be projected based on the aforementioned analysis and assumptions for future social and economic growth.
The technology assessment will characterise the various technologies in China that use coal at the present time and those advanced technologies that are expected to use coal in the future. Coal-fired power generation technologies, coal gasification and liquefaction technologies will be assessed. Technologies for energy-intensive sectors such as iron and steel, cement, ammonia, aluminium and paper may also be considered. Advanced technologies with CCS will be investigated.
Energy systems analysis modelling, using the China MARKAL energy model, will be used to generate future energy demand up to 2050. Future final energy demand and its mix, primary energy demand and its mix, power generation capacity and output and their mix, as well as carbon emission from 2005 to 2050 will be analysed.
Carbon constraints will then be added to the model; it will be asked to meet the same energy service demands while constrained to limit CO2 emissions to a specified maximum level. The cost of meeting the constraint will be assessed from the marginal carbon cost. Based on the specification, the focus would be on running scenarios that might exclude CCS and those that might include CCS to differing extents, including variations to the take-up of competing technologies. This analysis will provide an indication of the differences in marginal carbon cost. The model will also be used to assess the role of CCS in cutting carbon emissions. This will include indicative costs of abatement and the extent to which CCS could be deployed - constrained, for example, by rate of build or by storage capacity. Although too early in the project schedule for detailed results to be available, a macro analysis for CCS application in China is presented'1-4'.
2. Energy service demand projection
2.1. Methodology and main assumptions
In the study, the Gomperta model is used to project future demand for iron and steel, cement, aluminium and ammonia, and also for car ownership. The Gomperta model is described by the equation:
8-PGDP
I = S- ea
Where I is per capita demand for industrial products, PGDP is the GDP per capita, and S is the saturation level of per capita demand for industrial products. The saturation level is determined based on reviews of related data in OECD countries, especially from the USA. The parameters a and ft are determined based on regression analysis using related Chinese historical data from 1978 to 2006.
For freight and passenger transport (though not for car use), a regression analysis is undertaken on Chinese historical data (1978-2006), but without consideration of saturation. From the analysis, the relationships between transport turnover and GDP or per capita GDP are obtained.
Given basic assumptions for future population and GDP growth, the Gomperta model and linear regression formulae can be used for future energy service demand projection in the industry and transportation sectors. Assumptions used for population and economic growth are displayed in Table 1.
Table 1 Assumption for future population and economic growth
2005 2010 2020 2030 2040 2050
Population (Million) 1308 1370 1454 1483 1483 1440
GDP (Billion US$ 2000) 1926 2970 6411 11481 17830 25151
GDP per capita (US$ 2000) 1473 2168 4409 7742 12023 17466
2.2. Results
2.2.1. Industry sector
When applying the Gomperta model to project future energy service demand, or activity level, for the high energy-intensive sectors, one of the key issues is to determine the saturation level, which is based on a review of related data from OECD countries. The saturation level for steel is chosen as 0.5 tonnes/capita, according to the relationship between per capita steel production and per capita GDP shown in Figure 1. Using a similar approach, the saturation levels for cement, ammonia and aluminium are 1.2t/cap, 0.05 t/cap and 0.015 t/cap, respectively. Figure 2 illustrates the projection results for iron and steel, cement, aluminium and ammonia.
0 5000 10000 15000 20000 25000 30000 35000 Per capita GDP/(US$2000)
Figure 1 Relationship between per capita steel production and per capita GDP 1800 Mt 1500 1200 900 600 300 0
1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050
Figure 2 Gomperta model projection results for the high energy-intensive sectors
The annual growth rate of steel production from 1978 to 2000 was 6.56%, hitting a high of 21.78% from 2000 to 2006 with elasticity of 2.15. Production reached 419Mt in 2006. It is projected that steel production will peak at 742Mt by 2035. While the annual growth rate for cement, aluminum and ammonia in the same period was 11%, 13% and 5%, respectively, it is projected that the production of cement, aluminum and ammonia will peak at 1783Mt, 30Mt, 89Mt by 2035, respectively.
2.2.2. Transportation sector
Figure 3 illustrates projections for transport. In the past 28 years, China's transportation has experienced fast development with annual growth rates of 8.95% and 8.18%, and elasticities of 0.92 and 0.84, for passenger and freight transport, respectively. However, passenger transport per capita was still only 1.46 km in 2006, about one-tenth of that in IEA countries'5'. Total passenger transport is expected increase from 1920 billion p^km (person km) to 20504 billion p^km by 2050 with passenger transport per capita of 17 km, close to the current average level in IEA countries. Freight transport per GDP declined gradually from around 0.6 fkm/US$2000 in 1980 to 0.42 fkm/US$2000 in 2006, similar to the IEA countries' average'5'. It is expected to maintain at around 0.4 t^km/US$2000 for the next 50 years, while the total freight transport will grow from 8895 billion t^km in 2006 to 88675 billion fkm by 2050.
freight transport
100000
80000 ^ pipeline
^ airway
60000 ^ waterway
□ highway
40000 ^ railway
1980 1990 2000 2010 2020 2030 2040 2050
Figure 3 Passenger and freight transport projection results
While car ownership in China was still very low in 2000, with only 0.3 vehicles per 100 people, it grew quickly to reach around 1.4 vehicles per 100 people in 2006. In dealing with car ownership, the Gomperta model estimates the number of private cars will peak at 665 million by 2035, with an assumed saturation rate of 45 vehicles per 100 people. Figure 4 displays the projection results for cars.
ü 400
2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050
Figure 4 Projection for car future
3. Technology assessment
3.1. Coal-based energy conversion technologies in China
Currently, coal is the dominant primary energy provider in China, as illustrated in Figure 5. In 2005, nearly 69% of primary energy consumption in China was satisfied by coal and almost half of the coal was converted into power and heat through combustion. Coal combustion for power generation dominates coal-based energy conversion technologies.
Nuclear Wind Biomass
Crude Oil
Import 0.2 Storage -0.1 1 toiquett' Export 0.52
Unit: 100 million tce
Data source: Statistics Yearbook of China Energy 2006 Figure 5. Energy flowchart of China in 2005
There are a number of environmental and ecological concerns arising from the use of coal, both for power generation and in industry. With its inherently low emissions and the flexibility to co-generate liquid fuels and chemicals, coal gasification is considered by some to offer advantages over coal combustion. Coal liquefaction has also received increased attention in China, driven by energy security worries resulting from a rapidly increasing oil import dependency. Nonetheless, the total production capacity of coal gasification and liquefaction remains very small compared to that of coal combustion technologies.
3.1 Coal combustion technologies in power industry
After 2000, China entered a special economic development stage with rapid industrialization and urbanization, which brought with it a high and continually increasing energy demand, especially for electricity. This electricity demand was mainly satisfied by the construction of coal combustion power plants. Figure 6 provides a breakdown of the total power capacity from 19802007. Between the years 2000 and 2007, the total capacity more than doubled, with an average annual new build capacity of 56.3 GW. In 2007, 77.7% of total capacity was provided by thermal power, 97.44% of which comprised coal-fired power units larger than 100MWe.
Figure 6. China power capacity from 2003-2007
With the twin pressures of energy security and environment protection, the power industry in China endeavours continually to improve the energy efficiency of coal power plants. One of the main solutions adopted is to increase the scale and efficiency of units, while closing down smaller, less efficient units. Efficiency increases are met by the application of more advanced technologies.
Figure 7 shows the thermal power plant mix in China in 2007. Plant efficiencies for the various unit sizes, measured as coal consumption per KWh, are presented, as are the average generation efficiencies for the years 1993 to 2007. Due to there low efficiencies, China is committed to shutting down its smaller units: an estimated 12GW of the smaller, low efficiency units were closed down in 2007.
Thermal Power Mix as of end 2007 Energy efficiency of different size of coal power unit in
China in 2006
Unit Size (MW) Coal consumption of power supply (gce/kWh)
! 500-990MW \ 6 600
/ 0-99MW 1 17% \ 12 550
/ 30% 25 500
50 440
100 410
\~ 100-199MW / 300-390MW / 300 340
\ 9% / 600 299
/ 200-299MW 600 292
1000 285.6
417 . 412 408
44 40-*---•--399
404 ' ----- _380
376 -357
■ Coal Consumptioi of Power Supply (gce/KWh)
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Source: National Bureau of Statistics of China (N1BSC) National Development and Reform Comission (NIDRC), Asian Development Bank (ADB).
Figure 7: Mix of unit scale and energy efficiency of thermal power in China
In Figure 8, the various sizes of coal-fired power plant built over the past four years is demonstrated. Units larger than 300 MW now make up more than half the total capacity of thermal power and the coal consumption per kWh continues to decrease. More recently, the main fleet of coal-fired power plant built comprises units larger than 600MWe.
■IT 60
2007 2006 2005 2004
USC Units: Zouxian. 2 X1000MW
Taizhou. 2 X1000MW
100 200 300
Unit Capacity (MW)
Source: Tsinghua-BP Clean Energy Research & Education Centre. Note: USC, Ultra-supercritical
Figure 8. Size of capacity additions for coal power plant
The main coal combustion technologies for power generation are sub-critical pulverised coal technology (PC), super-critical pulverised coal technology (SC), ultra super critical pulverised coal technology (USC) and circulating fluidized bed (CFB) technology. PC remains the major technology used in existing power plants. Having the advantage of higher energy efficiency and lower emissions, however, new orders for SC and USC are increasing rapidly. A recent survey of the three largest suppliers of steam turbines and boilers in China reveals there are more than 150 SC and USC units larger than 600MW established or on order. Some examples of USC plants are illustrated in Figure 8.
The performances of four operating sub-critical coal-fired power plants are shown in Table 2. The coal consumption per kWh would, of course, have been lower for super-critical plants and even lower for USC plants.
Project unit A B C D
Capacity MW 4*300 2*300 4*300 2*300+2*320
Total investment 100million RMB 59 26 48 51
Coal consumption Kgce/kWh 340 339 355 343
Annual operating time hours 5260 7123 6438 5778
Dust emission t 1240 450 3720 2640
SO2 emission t 24880 10320 27960 13247
NOx emission mg/Nm3 - 234.9 - 260-460
Apart from PC boilers, China also deploys circulating fluidized bed technology (CFB). CFBs offer the advantage of low SO2 emissions but, compared with PC boilers, are much more of a niche technology. Since China began development of CFBs in the early 1980's, however, there has been a lot of success. Many CFB plants now operating in the power industry, with units as large as 300MW deployed. China is currently building a 600MW CFB plant that, if successful, would be the largest CFB plant operating in the world.
3.2 Coal gasification technologies
Of the various coal gasification technologies, entrained flow coal gasification technology appears to have become the technology of choice. Both the fixed bed technology and the fluidized bed technology have developed more slowly in recent years. The main sub-divisions of entrained flow coal gasification technology include the foreign-developed technologies such as those supplied by Shell, GE and GSP, and those technologies developed in China, such as the opposed multi-burner gasification technology and the two-stage oxygen feed gasification technology. With their lower cost and better adaptability to local coal, China's technologies have spread quite rapidly in recent years. The multi-burner gasification technology has been adopted for nearly 29 units, based on information given by the technology supplier.
Besides being used in methanol and ammonia plants, a potential market for coal gasification technologies is in integrated coal gasification combined cycle (IGCC) plant for power generation and poly-generation plant. In 2007, there were more than 10 IGCC and poly-generation projects proposed in China, though many of these have been more recently put on hold. The only one proceeding at present is the GreenGen initiative, ie the 250MW IGCC demonstration plant under construction in Tianjin.
3.3 Coal liquefaction technologies
The main sub-divisions of coal liquefaction are direct coal-to-liquid (DCL), indirect coal-to-liquid (IDCL) and coal to methanol (CM). The first industrial scale DCL plant in China is located in Inner Mongolia, with a coal capacity of 1 Mt/a for the first train and 5 Mt/a in total. There is also a 160kt/a IDCL plant in Inner Mongolia. Commissioning on both plants began in September 2008.
Methanol is an important chemical feedstock and could be used as an alternative liquid fuel to oil. Not only does it offer an alternative vehicle fuel, but it could also be used as a feedstock for dimethylether (DME), methanol-to-olefins (MTO) or methanol-to-propylene (MTP) plants. In 2006, the total consumption of methanol in China was around 8.86 Mt, of which around 65% was produced from coal. About 0.6Mt/a of DME is produced from methanol and some demonstration capacity for MTO/MTP has been planned by the government recently.
4. Macro analysis on CCS application in China
The total power capacity in China is forecast to increase from over 700GW in 2007 to 1500GW by 2020, 2000GW by 2030 and 2500GW by 2050. Over the same period, the share of total power generation capacity provided by coal-fired units is expected to decrease from the present 70+% to 65% by 2020, 60% by 2030 and 50% by 2050. Assume, somewhat optimistically perhaps, that the share of IGCC plants will reach 10%, 30% and 50% by 2020, 2030 and 2050, respectively. Assume also that all the IGCC plants are fitted with capture, then carbon emission reductions will be 357 MtCO2, 1240 MtCO2 and 2188 MtCO2. The additional investment costs are estimated as US$44bn, US$90bn and US$63bn by 2020, 2030 and 2050 respectively. Detailed assumptions and estimation results are shown in Table 4.
Table 4: Macro analysis on CCS application
Year 2020 2030 2050
Total capacity 1500 2000 2500
Share of coal-fired plant 65% 60% 50%
Share of IGCC in coal-fired plants 10% 30% 50%
Investment cost/(US$/kW) 1500 1250 1000
Operation hour 5500 5500 5500
Efficiency 42% 45% 45%
Efficiency loss with capture 25% 20% 10%
Investment cost increased with capture 30% 20% 10%
Capture rate 90% 90% 90%
CO2 emission before capture (MtCO2) 411 1418 2461
CO2 emission after capture (MtCO2) 55 177 273
CO2 emission reduction (MtCO2) 357 1240 2188
Investment cost increase (US$bn) 44 90 63
To achieve the same reductions by 2050 without capture, 1222GW of wind power or 407GW nuclear power would be required to replace coal-fired power plants by 2050, as displayed in Table 5. For the cases examined, the investment costs for wind and nuclear are estimated at US$978bn and US$407bn, respectively, by 2050.
Table 5: Wind power or nuclear power development to achieve the same amount of carbon reduction
Year 2020 2030 2050
Investment cost for wind power (US$/kW) 1000 900 800
Investment cost for nuclear power (US$/kW) 1500 1300 1000
Wind power operation hour (h) 2500 2500 2500
Nuclear power operation hour (h) 7500 7500 7500
New capacity-wind (GW) 186 693 1222
New capacity-nuclear (GW) 62 231 407
Investment cost increase - wind (US$bn) 186 624 978
Investment cost increase - nuclear (US$bn) 93 300 407
5. Concluding remarks
China's economy continues to grow at a rapid rate and, as a consequence, its energy demand is set to increase substantially in the coming decades. With the majority of its primary energy demand, certainly in the medium term, to be met by coal, the prospect of rising atmospheric CO2 concentrations is likely to present China with a major challenge.
Measures need to be taken to move towards a low carbon economy. Though improving energy efficiency and increasing the installed capacity for power generation from renewable energy technologies and nuclear power are important, these alone will not meet the reductions needed to offset the rising concentrations of CO2 in the atmosphere. Only CCS, when applied to the various power generation and industrial technologies that use coal, is capable of meeting the cuts required.
To achieve an insight into the role of CCS in China's energy technology future, it is necessary to estimate the costs and energy penalty associated with the deployment of CCS. This will be accomplished by investigating a selection of emissions scenarios using the Chinese MARKAL model. The information discussed in this paper is based on work recently undertaken in the NZEC project to revisit and to update the underlying data within the model. Using the Gomperta model, future energy demand has been projected for various energy intensive industry sectors as well as the transportation sector. Coal-based energy conversion technologies within China's power sector have been discussed, with evidence demonstrating its year-on-year improvement in average generation efficiency.
A macro-analysis has been presented, looking at the potential contribution to CO2 reductions to 2050 for CCS and comparing the results with those that might be achieved using wind or nuclear. It is clear from this early analysis that CCS offers much promise.
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