Posted by Barry Brook on 8 August 2009
If renewable or nuclear energy is going to be successful in decarbonising our electricity supply (and, ultimately, all energy use), it needs to hit a couple of fundamental benchmarks:
(i) its life cycle energy inputs must be low compared to its ‘clean energy’ output; and
(ii) it must be able to displace fossil fuels — with elimination of carbon emissions from stationary energy being the first major objective.
Regarding life cycle emissions from nuclear power, I’ve already touched on the issue, but will be exploring this in more detail in the future. But this post is about wind.
To tackle this topic, I profile a recent analysis circulated by retired engineer Peter Lang, called “Cost and Quantity of Greenhouse Gas Emissions Avoided by Wind Generation“. Peter has 40 years experience on a wide range of energy projects throughout the world, including managing energy R&D and providing policy advice for government and opposition. His experience includes: coal, oil, gas, hydro, geothermal, nuclear power plants and nuclear waste disposal (6.5 years managing a component of the Canadian Nuclear Fuel Waste Management Program). Click on the title of the paper to download the 14 page PDF.
Okay, so what does he say? Let’s start with the bottom line and then work back:
1. Wind power does not avoid significant amounts of greenhouse gas emissions.
2. Wind power is a very high cost way to avoid greenhouse gas emissions.
3. Wind power, even with high capacity penetration, can not make a significant contribution to reducing greenhouse gas emissions.
Strong statements, to be sure. Here’s the justification.
Peter looks at the issues of variability and back-up generation. Energy storage in the form of batteries is dismissed as uneconomic for the amount of energy required. For hydro, he says:
“We have insufficient hydro resources to provide peak power let alone provide back-up for wind power. Hydro energy has high value for providing peak power and for providing rapid and controllable responses to changes in electricity demand across the network. So our very limited hydro resource is used to generate this high value power.”
Pumped hydro is obviously an alternative route, if you are willing to accept the energy conversion losses in going from electricity from wind turbines to mechanical energy (pumps) to potential energy (water stored in the dam) to kinetic energy (falling water to turn the turbines) and back to electrical energy. But let’s focus for now on the most touted (and widely used) form of back up for wind: natural gas (that is, fossil methane) using open cycle gas turbines (OCGT).