Counting carbon, pounds and pence

Mark Lynas and Chris Goodal recently presented data in the Guardian which demonstrates that wind is displacing output from Combined Cycle Gas Turbines, MW-hr for MW-hr. Such quantitative analysis is to be welcomed and certainly adds to the debate. We clearly need to deal in numbers with units rather than simply words.

It can be seen from the data presented that as wind output rises, the production share of efficient Combined Cycle Gas Turbines (with emissions of order 350 kg CO2 per MW-hr) indeed falls. However, the production share of coal (with emissions of order 900 kg CO2 per MW-hr) remains unchanged. At present, wind is therefore displacing relatively clean and efficient gas, rather than base-load coal, which is our largest source of carbon. 

To evaluate the merit of energy technologies, we firstly need to remember that low cost energy drives our economy and underpins the historically unprecedented prosperity we now enjoy. In choosing a future energy mix we therefore firstly need to ensure that it is low cost (£/MW-hr), and then that it efficiently displaces carbon dioxide (£/tonne CO2). We need our investments to be productive and to work hard for us.