By Dave Collins, Synergetics
4 September 2012 – Letter: Nice piece of work by Bruce Precious reported in The Fifth Estate. In my opinion, the Melbourne Energy Institute’s combined cycle gas turbine (CCGT) with energy efficiency proposal, reported at Beyond Zero Emissions, is far superior to the trigen system.
There are technical innovations that will improve the efficiency trigen system, such as low loss energy transfer systems but even so the other benefits of CCGT would dominate trigen.
As noted by the Institute, remotely located CCGT with grid distribution has similar operational greenhouse gas emissions to trigen, but with much lower urban air quality impacts.
Although not explored by the Institute, CCGT has many other benefits compared to trigen including: lower capital and operational costs, much lower technical simplicity, lower embodied energy, lower maintenance costs, improved reliability and less administrative overheads.
Another benefit of remotely located CCGT with grid distribution is that it is a much better fit to back-up large scale PV solar and other renewable power sources, which are likely to become dominant in 10 to 20 years.
CCGT can be used intermittently when renewable supplies are low, whereas in contrast the benefits of trigen are only realised if it is continuously running and hence available and generating much higher net greenhouse gas emissions than renewable with CCGT backup.
See:
- The Fifth Estate, Sydney’s chiller trigen plans hit a road block
- Melbourne Energy Institute’s CCGT proposal
- how low loss energy transfer systems at Infoscience
Dave Collins is executive director of the Melbourne office of Synergetics