Integration of district heating with existing combined cycle gas turbines in North Dublin

Abstract

There is potential in Ireland for the development o f existing large scale CCGT by conversion to CHP. A district heating network developed for North Dublin would provide this opportunity for CCGT generating stations. Connecting two CCGT plants currently optimized for electricity production to a district heating network would require the plants to be converted to allow a Combined Heat and Power mode. It would make use o f the themial energy produced during electricity production and increase the plant efficiency, while significantly reducing the energy required to run condenser cooling fans. It would also reduce the carbon intensity o f the energy generated, as the use o f the waste heat would increase the total energy with no increase in the greenhouse gas emissions from the combustion process. Use o f waste heat increases efficiency, avoids emissions and helps enhance the quality o f the environment. The pipe network for North Dublin would circulate hot water in an underground, preinsulated pipe system with supply and return lines. Flow temperatures would be in the range o f 80 - 95°C with return temperatures o f 60 - 65°C. The biggest cost o f district heating is the investment required to establish a pipe network. However such a scheme would service the local area for m any decades and would allow flexibility by using alternative heat sources if required.