Power plant performance and cost parametersa	Pulverized coal power plant	Natural gas combined cycle power plant	Integrated coal gasification combined cycle power plant
Reference plant without CCS
Cost of electricity (US$/kWh)	0.043-0.052	0.031-0.050	0.041-0.061
Power plant with capture
Increased fuel requirement (%)	24-40	11-22	14-25
CO2 captured (kg/kWh)	0.82-0.97	0.36-0.41	0.67-0.94
CO2 avoided (kg/kWh)	0.62-0.70	0.30-0.32	0.59-0.73
% CO2 avoided	81-88	83-88	81-91
Power plant with capture and geological storageb
Cost of electricity (US$/kWh)	0.063-0.099	0.043-0.077	0.055-0.091
Cost of CCS (US$/kWh)	0.019-0.047	0.012-0.029	0.010-0.032
% increase in cost of electricity	43-91	37-85	21-78
Mitigation cost (US$/tCO2avoided)	30-71	38-91	14-53
(US$/tCavoided)	110-260	140-330	51-200
Power plant with capture and enhanced oil recoveryc
Cost of electricity (US$/kWh)	0.049-0.081	0.037-0.070	0.040-0.075
Cost of CCS (US$/kWh)	0.005-0.029	0.006-0.022	(-0.005)-0.019
% increase in cost of electricity	12-57	19-63	(-10)-46
Mitigation cost (US$/tCO2avoided)	9-44	19-68	(-7)-31
(US$/tCavoided)	31-160	71-250	(-25)-120

All changes are relative to a similar (reference) plant without CCS. See Table TS.3 for details of assumptions underlying reported cost ranges.

$ ^{b} $ Capture costs based on ranges from Table TS.3; transport costs range from 0-5 US/tCO $ _{2} $ ; geological storage cost ranges from 0.6-8.3 US/tCO $ _{2} $ .

Same capture and transport costs as above; Net storage costs for EOR range from -10 to -16 US$/tCO₂ (based on pre-2003 oil prices of 15-20 US$ per barrel).

Table 3. Estimated cost of CCS compared with Plant without CCS.

### E. TRANSACTION COSTS INCURRED BY FIRMS IN IMPLEMENTING AND OPERATING IN THE EUROPEAN UNION EMISSIONS TRADING SCHEME – INSIGHTS FROM IRELAND

For our purposes, transaction costs can be grouped into three categories: (1) early implementation costs, i.e. costs that were incurred before 1 January 2005; (2) monitoring, reporting, and verification (MRV) costs, i.e. costs that were experienced annually; and (3) trading costs. The first two categories are relevant for all firms in the scheme, whereas the third category is only incurred by firms that participated in the market. Early implementation costs are almost all fixed costs, MRV costs are periodic costs, so the variable costs would be trading costs. All 72 firms (106 installations) were surveyed by mail and asked to document the transaction costs they incurred during the pilot (2005007) period. Twenty seven replied representing 70% of total Irish allowances, and there was then follow up face to face interviews. The key findings were grouped by size; we could not group by sector without running the risk of allowing the identification of individual firms. The average costs per tonne are €0.08 per tonne of $ CO_{2} $ , falling to €0.05 per tonne for large firms, and rising to €2.02 for small firms. This finding validates the decision in the third phase – 2013-2020 – to allow opt out for smaller firms so long as they are required to make ‘equivalent effort.’ The costs of trading in the pilot period were estimated to be of the order €0.06 per tonne, and falling. So there is not case to be made overall that the transaction costs inhibit the development or operation of the market, but there is a case in equity for addressing the high costs for small firms.