Bishop Hill So long, and Fanks for all the corrections
Jun 25, 2012 Economics Energy: wind More quotes from Sam Fankhauser, carbon economist, and Gordon Hughes, energy economist:
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?
Reader Comments (54)
For anyone interested in some facts about the reserve requirement for wind power, National Grid has been publishing reports (revised after getting feedback from power generators) about how they are going to integrate wind power in the year 2020 under the "Gone Green" scenario: Over the next decade, coal drops from 33% to 14%, wind increases from 5% to 25%. These reports are an interesting source of information, but they didn't risk offending the government by calculating how much the Gone Green plan will reduce CO2 emissions.
http://www.nationalgrid.com/uk/Electricity/Operating+in+2020/
Item 6.30 from the June 2011 Report:
National Grid currently assumes that wind output can decrease by 50% over 4 hours, decreasing to around 30% by 2020. National Grid believes that the forecast wind error will be 10% RMS of wind capacity. Therefore, in order to secure for a 99.7% confidence or 1 in 365 criteria, in 2020 there will be a need to carry operating reserves equivalent to 30% of the forecast wind output four hours ahead of real time.
Note that average wind output is about 30% of wind CAPACITY. 4 hours is probably the amount of time needed to bring a fossil fuel plant online. So, if I understand correctly, 50% of wind power is currently being backed up by fossil fuel plants running in spinning reserve and National Grid is hope to be able to reduce this amount to 30% by better forecasting and drawing on more geographically diverse sources of wind power. Therefore, if all the reserve requirements for wind were met by coal plants, you Brits will be burning almost as much coal to back up your wind power as you will be burning to actually generate electricity.
This analysis also assumes that the thermal efficiency of the standby plant remains constant. Look at this report: http://www.clepair.net/IerlandUdo.html
In Figure 7; at 30% wind penetration, the CO2 output of the fossil plant/kWhr has risen by ~30%!. Remember though that different standby plant is involved so it's not clear cut. However, a summary of the data from different parts of the World is here;:http://www.masterresource.org/2010/02/wind-integration-incremental-emissions-from-back-up-generation-cycling-part-v-calculator-update/#more-7271
I had thought it took 10% wind to increase CO2 above no wind, this report talks of 3%!
Frank your average wind loading of 30% of capacity for the UK is a bit high. Data for the UK over the last 8 years has it hitting 28% only on one year 2009, with 2010 less than 24% An 8 year average looks more like 25% to me.
The main forgotten factor in all these calculations is the fact that the price of carbon generated energy is based on 24/7/350. If you idle a plant, it will still consume coal, but deliver nothing. The extreme situation has been reached in Germany: two gas plants have been idling for the last two years, only producing during 100 h. They will be shut and scrapped, because idling and maintenance and the lack of return on investment due to the sharply reduced income risks to let the owner go broke. The cost will of course, be paid by the bill of the consumer. Fancy Ponzi scheme.....