This project examines the feasibility of natural gas combined cycle (NGCC) plants equipped with post-combustion carbon capture and storage (CCS) as a source of firm low-carbon electricity.  

Representative NGCC plant scales are evaluated, and an MEA-based capture system with geological storage is integrated into the analysis. Mass and energy balances quantify efficiency impacts, fuel requirements, and parasitic energy use. A discounted-cash-flow model estimates electricity costs and the cost of CO₂ avoided, with sensitivity to carbon pricing.

Results show that CCS significantly lowers emissions but reduces net efficiency. Under supportive carbon price trajectories and with suitable storage resources, NGCC with CCS can act as a credible option for reliable low-carbon power in a decarbonizing grid.

Specific aims:

• Quantify efficiency penalty, parasitic load, and CO₂ reduction from 90% capture.

• Estimate CAPEX, OPEX, LCOE, and cost of CO₂ avoided for both plant sizes.

• Assess how BC’s carbon price path affects the competitiveness of NGCC+CCS vs. unabated NGCC.

We model two natural-gas combined-cycle plants (100 MW and 1,000 MW, 58% net HHV efficiency) and integrate a 30 wt% MEA post-combustion capture system designed for 90% CO₂ removal with compression to pipeline pressure. Steady-state mass and energy balances quantify flue-gas flow, a reboiler duty of 3.5 GJ/tCO₂, steam extraction impacts, and electrical loads for compression and auxiliaries, yielding net power and efficiency with CCS.

A discounted cash-flow model with a 20-year life, 8% discount rate, 2.5 CAD/GJ fuel price, and representative CAPEX/OPEX converts these technical results into levelized cost of electricity and cost of CO₂ avoided, which are then evaluated across a range of carbon prices up to 170 CAD/tCO₂.

Integrating post-combustion CCS into NGCC plants lowers net efficiency but delivers deep emissions cuts. In both 100 MW and 1,000 MW cases, adding Carbon Capture reduces output due to steam extraction and extra electrical loads (Table 1).

Capital cost results show CCS is strongly CAPEX-intensive, especially at small scale. For a 1,000 MW unit, total overnight cost rises into the multi-billion-dollar range, with the capture island and compression accounting for more than half of total CAPEX. The 100 MW plant looks even less favourable per kilowatt, highlighting that CCS is best suited to large units or shared hub developments rather than small stand-alone projects (Chart 1).

Chart 1. Capital cost breakdown for a standalone 1,000 MW NGCC and Carbon Capture System addition (90% capture).

In LCOE (Levelized Cost of Energy) terms, CCS clearly raises generation costs when there is no carbon price. As carbon prices increase, however, unabated NGCC becomes progressively more expensive as its full emissions are taxed, while CCS plants pay only on residual CO₂ (Chart 2).