Financial implications on power generation costs resulting from the parasitic effect of CO2 capture using liquid scrubbing technology from power station flue gases

Four power generation options covering the spectrum of methods of fossil fuel power generation were used as the base cases to determine the resultant increase in base case levelized generating costs resulting from CO2 capture from the flue gas of a 500 MW(e) power station by liquid scrubbing technology. Suitable liquid scrubbing technology for CO2 capture was investigated only for end of pipe treatment, after upstream FGD (where applicable), for each of the options of a 500 MW(e) power station from coal and natural gas at a coastal site in the Netherlands. The three coal options were based on pulverised fuel, IGCC, and coal combustion in a mixture of oxygen and recycle gas respectively, whilst the natural gas option was based on a sulphur free NGCC. Only commercially proven liquid scrubbing technology screened in economic and technical terms. Inhibited MEA (monoethanolamine) was the most acceptable for the conventional pulverised coal fired power station, the IGCC coal fired power station and the NGCC plant. Selexol(R) was the most suitable for combustion of coal in the recycle mixture. In all cases pre treatment was necessary to remove traces of NOX and/or SO2 which otherwise would cause solvent degradation. As a consequence of CO2 capture, drastic reductions of both acid gases and particulates occur. The reduction in overall generating efficiency over the four options ranged from 2.4 to 13.5 per cent export of 500 MW(e) after CO2 capture and regeneration. Investment costs increases substantially by between 52 to 108 per cent in terms of $/kW(SO). Over the range of options the resultant levalised base case generating costs increased from 22 to 108 per cent. The conventional PF coal power station showed an increase from 53.4 to 80.38 mills/kWh(SO), and the natural gas (sulphur free) NGCC plant showed an increase from 32 to 50.24 mills/kWh(SO). In the case of the non conventional combustion of coal in recycle gas the cast increased from 83 to 101 mills/kWh(SO). Because the base case selected for the coal based IGCC plant required CO2 to be captured al almost atmospheric conditions, rather than at higher pressure, the costs were seriously distorted and are not readily comparable with the other options. The nett parasitic effect was not only to substantially increase investment costs but also to substantially increase the basic cost of electricity irrespective of the type of fuel and method of power generation. The balance between a CO2 tax and CO2 capture cannot be inferred without taking into cognisance the additional cost of CO2 disposal.