Much has been made of the intermittent nature of wind, which cannot produce electricity reliably on demand. However, the cost penalty and grid system challenges of intermittency are often exaggerated. There are ways of compensating for this variability, such as additional capacity from fossil fuel power plants to meet balancing requirements at peak demand, bulk storage of electricity, greater interconnection, and a more diversified mix of renewable sources, as well as measures to manage demand, like smart grids and improved load management.
Sam Fankhauser, carbon economist
And now Gordon Hughes, energy economist, on additional capacity from fossil fuel backup:
Wind power is intermittent and requires backup sources of power – either gas or coal. These backup sources achieve much lower levels of thermal efficiency – defined as the proportion of the energy content of the fuel that is converted into electricity - than conventional power plants using the same fuel which operate all or most of the time. The loss in thermal efficiency is even greater if the backup sources have to run for extended periods as spinning reserve, using fuel but not delivering power to the grid, in order to smooth fluctuations in either demand or supply from wind sources. Hence, the loss in thermal efficiency when plants run as backup sources may outweigh the reduction in the total amount of power generated from fossil fuels when wind generation is added to the system...
Gordon Hughes, energy economist, on bulk storage of electricity:
The only viable, but politically unrealistic, way of storing intermittent power generation is to build pumped storage schemes in every Highland valley. If onshore wind farms and the associated transmission lines are unpopular, how much more resistance would a commitment to build new pumped storage in every suitable valley generate? Most would have to be in Scotland since locations for large reservoirs with a height difference of 100+ metres are scarce in the rest of the UK.
[One should also note Prof Vahrenholt's calculation that pumping Lake Constance to the top of the highest mountain in Germany would provide that country with just ten days' electricity]
Gordon Hughes, energy economist, on load management:
[T]here have been strong reasons to encourage load shifting for more than 30 years and many efforts have been made to promote it. The practical reality is that the gains tend to be small while the costs are relatively high. Claims for the savings made possible by “smart” networks are little more than sales talk that ignores the substantial body of evidence based on actual experience.
I wonder if Professor Fankhauser would like a copy of Professor Hughes' report to read?