Dr Ian Barnes has examined the potential of high efficiency, low emission (HELE) coal-fired power plant to reduce CO2 emissions in a number of major coal using countries: Australia, China, Germany, India, Japan, Poland, Russia, South Africa, South Korea and the USA.
HELE plant upgrades are a ‘no regrets’ option for coal plant owners and operators. A current state-of-the art coal-fired plant operating with a high efficiency ultra-supercritical steam cycle will be more efficient, more reliable, and have a longer life expectancy than its older subcritical counterparts. Most significantly, it would emit almost 20% less CO2 than a subcritical unit operating under similar duty.
Developments in advanced ultra-supercritical (AUSC) steam cycles should continue this trend and a plant operating at 48% efficiency (HHV) would emit up to 28% less CO2 than a subcritical plant, and up to 10% less than a corresponding ultra-supercritical plant.
Dr Barnes calculated the coal fleet profile of each country to meet future electricity demand under three scenarios; continuing with the existing fleet, and retiring and replacing older plant on the basis of a 50 year and 25 year plant life. He quantified the potential impact of HELE upgrades on emissions of CO2 and costs of implementation.
Ian identified a number of trends:
- Countries such as China and India, experiencing a prolonged period of economic growth meaning that additional capacity is needed and that the coal fleet is relatively new, have rising emissions of CO2, but they could be offset by the use of AUSC over ultra-supercritical plant for new build.
- Countries like South Africa, again experiencing a prolonged period of economic growth and so needing additional capacity, but with a more mature coal fleet have rising emissions of CO2, but again they could be offset by the use of AUSC over ultra-supercritical, particularly when older plant is retired and replaced by AUSC units.
- Countries such as Poland and Russia, experiencing a prolonged period of growth and so needing additional capacity, but with an old and relatively inefficient coal fleet see falling levels of CO2 emissions, even with growth in electricity demand.
- Countries like South Korea, with relatively low to moderate levels of growth and an efficient coal fleet do not see significant benefits until 2040 when some older plant is retired.
- As an existing coal fleet evolves to a HELE composition it becomes smaller in respect of the installed capacity. This has potential benefit for the siting and replacement of plant, particularly in countries where planning regulations are demanding and time consuming.
- The greatest gains are seen when plant life is limited to 25 years (evolving practice in China) rather than 40 years or more (common in OECD countries). Policies and incentives to encourage shorter timescale plant renewal would enhance CO2 savings.
- When CCS readiness is considered, in all cases, the 25-year life scenario represents the best option for CCS deployment as all coal fleets transition to a high HELE content quickly and enjoy maximum CO2 abatement as any remaining lower efficiency capacity is retired. This is particularly evident in the Indian case where the effects of a rapidly increasing demand for electricity and attenuated by a combination of HELE and CCS technologies.
- Economics will govern the decision to replace plant unless policies and incentives drive the selection towards HELE technologies.
The IEA Clean Coal Centre will follow up this work with a series of individual country to give a more comprehensive view on regional HELE implementation pathways.
Written by IEA Clean Coal Centre.
Edited by Katie Woodward
Read the article online at: https://www.worldcoal.com/power/01082014/reduce-co2-emissions-by-upgrading-global-coal-fleet-1160/