Windpower

Wind power is not all hot air Wind power is the fastest growing of the renewable energies; not surprising given that it is widely available and easily integrated into the grid. Wind is created by uneven heating of the Earth by the Sun. Most of the wind is at high altitudes. Research by Stanford University in California estimated that 72 terrawatts (TW) of the earth’s wind energy could be commercially viable, which is four times the amount of electricity currently consumed around the world. Wind turbines, which are used to generate the electricity, can be sited onshore or offshore, where the wind blows harder but it is much more expensive to set up the turbines in the sea.

Setting up wind power generating capacity is not a quick business. It can take two years to assess the wind resource on a site and analyse the best place for the turbines. An average wind speed of 14mph is required to convert wind energy into electricity but if the wind gets too strong the turbines shut down for safety reasons. As the technology has developed costs have come down. Commercial wind power got going in the 1980s and since then the size of wind turbines has grown and costs have fallen by more than 90%.

The UK has the eighth largest wind power capacity in the world. It has 5.7GW of capacity installed and the electricity produced in the second quarter of 2011 was 131% higher than the same period in 2010. This was enough to supply 1.3m homes according to trade association RenewableUK. The rise in wind power helped to partly offset the 21% decline in gas-fired generation as gas prices increased.

According to BP’s latest energy review wind energy used in power generation grew 22.7% in 2010, compared to overall renewables growth of 15.5%. There was nearly 200GW of wind capacity installed at the end of 2010. While the rise of wind power began in developed countries, emerging markets are catching up. Two-thirds of that growth in wind power came in China and the US, even though the increase in capacity in the US was less than half of the previous year at 5.1GW. China has overtaken the US in terms of total installed capacity, although Europe as a whole accounts for 44% of capacity. Europe has used incentives, such as feed-in tariffs, in order to encourage investment in wind and other renewable power. Over the past decade, wind power capacity has grown by an average of 27% a year.

Wind supplied 1.6% of total electricity generated last year. The World Wind Energy Association (WWEA) says that 18.4GW was installed in the first half of 2011, including 8GW in China, and predicts that 43.9GW will be installed during 2011 as a whole. Three new countries, Venezuela, Honduras, and Ethiopia, installed wind power capacity for the first time. There are 86 countries using wind power.  The WWEA believes that capacity could hit 240GW by the end of this year.  Investment is increasing in India, which needs a slightly different technology to Europe because the wind speed tends to be lower. General Electric has developed a turbine, with a higher hub height and larger rotor diameter. By 2030, 15% of Indian power needs are expected to come from wind.

Brazil is another country that is keen on wind power. Brazil’s latest A-3 energy auction, effectively a competitive tender open to different types of power generation, was held in the middle of August. Wind energy represented 39% of the 2.7GW of capacity that was approved to participate in the auction and 44 projects totalling 1.07GW were successful, 70% of the 1.53GW contracted. The average price was just under R$100/Mwh (or less than US$63/£38). That price was lower than expected and 23% below the previous average wind price in the 2010 auction. This shows that wind power is able to compete with natural gas projects, the majority of which were not successful in the auction.

Two natural gas projects and four biomass projects make up the rest of the successful generating projects. Mauricio Tolmasquim, President of Empresa de Pesquisa Energética (EPE) argues that wind power equipment manufacturers starting up in Brazil has increased competition because they need to sell their turbines. Tolmasquim also argues that the reverse auction model in Brazil is good because it helps to "stimulate efficiency and innovation". He believes that the European model is flawed because feed-in tariffs do not force developers to think about how to keep costs as low as possible.

While emerging markets are keen to get in on the act, Europe still leads the way. Wind energy is expected to reach 560GW of installed capacity by 2020, with nearly one-third of that in Europe equating to around 13% of European electricity supply.