Assessment of energy and economic benefits arising from syngas storage in IGCC power plants

• The option of syngas storage in small size coal gasification power plants is proposed.
• IGCC power plants with syngas storage and peaking gas turbines are analysed.
• Syngas storage enhances operational flexibility of IGCC plants and allows load modulation.
• Syngas storage reduces conversion efficiency and increases energy production cost.
• Peaking energy production costs can be competitive in the electrical market.

This paper aims to evaluate the energy and economic performance of IGCC power plants equipped with a syngas storage section. Syngas storage enhances operational flexibility of IGCC power plants as a portion of the produced syngas can be stored during periods of low energy demand and used to increase power output during periods of peaking demand, when the produced electrical energy is most valuable and prices are highest.The results of the study show that IGCC systems with syngas storage require a more powerful prime mover and a larger coal gasification section in comparison to base-load IGCC power plants. In the field of duty-cycles of more likely interest (peaking periods of 2–7 h/day and base/peak power outputs ranging from 0.5 to 0.8), the coal gasification section needs to be enlarged by 5–50% and a fraction from 4% to 30% of the produced syngas needs to be stored. Syngas storage in IGCC power plants leads to a penalty in the overall conversion efficiency (by about 1–6 percentage points in the field of duty-cycles of more practical interest) and higher energy production costs (by about 5–20%) with respect to base-load IGCC power plants.