Dr Gordon Hughes
The Performance of Wind Farms in the United Kingdom and Denmark
1. Onshore wind turbines represent a relatively mature technology, which ought to have achieved a satisfactory level of reliability in operation as plants age. Unfortunately, detailed analysis of the relationship between age and performance gives a rather different picture for both the United Kingdom and Denmark with a significant decline in the average load factor of onshore wind farms adjusted for wind availability as they get older. An even more dramatic decline is observed for offshore wind farms in Denmark, but this may be a reflection of the immaturity of the technology.
2. The study has used data on the monthly output of wind farms in the UK and Denmark reported under regulatory arrangements and schemes for subsidizing renewable energy. Normalized age-performance curves have been estimated using standard statistical techniques which allow for differences between sites and over time in wind resources and other factors.
3. The normalized load factor for UK onshore wind farms declines from a peak of about 24% at age 1 to 15% at age 10 and 11% at age 15. The decline in the normalized load factor for Danish onshore wind farms is slower but still significant with a fall from a peak of 22% to 18% at age 15. On the other hand for offshore wind farms in Denmark the normalized load factor falls from 39% at age 0 to 15% at age 10. The reasons for the observed declines in normalized load factors cannot be fully assessed using the data available but outages due to mechanical breakdowns appear to be a contributory factor.
4. Analysis of site-specific performance reveals that the average normalized load factor of new UK onshore wind farms at age 1 (the peak year of operation) declined significantly from 2000 to 2011. In addition, larger wind farms have systematically worse performance than smaller wind farms. Adjusted for age and wind availability the overall performance of wind farms in the UK has deteriorated markedly since the beginning of the century.
5. These findings have important implications for policy towards wind generation in the UK. First, they suggest that the subsidy regime is extremely generous if investment in new wind farms is profitable despite the decline in performance due to age and over time. Second, meeting the UK Government’s targets for wind generation will require a much higher level of wind capacity – and, thus, capital investment – than current projections imply. Third, the structure of contracts offered to wind generators under the proposed reform of the electricity market should be modified since few wind farms will operate for more than 12–15 years.
Windenergy really really isn’t cost effective by any standard (PDF)
Germany is cutting solar-power subsidies because they are expensive and inefficient.
In the words of the German Association of Physicists, “solar energy cannot replace any additional power plants.” On short, overcast winter days, Germany’s 1.1 million solar-power systems can generate no electricity at all. The country is then forced to import considerable amounts of electricity from nuclear power plants in France and the Czech Republic.
Indeed, despite the massive investment, solar power accounts for only about 0.3 percent of Germany’s total energy. This is one of the key reasons why Germans now pay the second-highest price for electricity in the developed world (exceeded only by Denmark, which aims to be the “world wind-energy champion”). Germans pay three times more than their American counterparts.
Moreover, this sizeable investment does remarkably little to counter global warming. Even with unrealistically generous assumptions, the unimpressive net effect is that solar power reduces Germany’s CO2 emissions by roughly 8 million metric tons—or about 1 percent – for the next 20 years. To put it another way: By the end of the century, Germany’s $130 billion solar panel subsidies will have postponed temperature increases by 23 hours.
Using solar, Germany is paying about $1,000 per ton of CO2 reduced. The current CO2 price in Europe is $8. Germany could have cut 131 times as much CO2 for the same price. Instead, the Germans are wasting more than 99 cents of every euro that they plow into solar panels.
It gets worse: Because Germany is part of the European Union Emissions Trading System, the actual effect of extra solar panels in Germany leads to no CO2 reductions, because total emissions are already capped. Instead, the Germans simply allow other parts of the EU to emit more CO2. Germany’s solar panels have only made it cheaper for Portugal or Greece to use coal.