We pick up our look at wind power through the ages in October 1973, when the Organization of Arab Petroleum Exporting Countries announced an oil embargo against the United States and its allies in retaliation for US support of Israel during the Yom Kippur War. Combined with declining US oil production, this triggered a renewed interest in non-petroleum energy sources.
Much of the development of wind turbines in the late 20th Century took place in the US and Denmark. From 1975, NASA began managing a US government programme to develop utility-scale wind turbines. While none of the resulting turbines ever made it to mass production, the programme set a number of new records and developed new technologies for multi-megawatt turbines that are still used today, such as partial-span pitch control, steel tube towers, composite blade materials, and variable-speed generators. The WTS-4 wind turbine set a new record for generation of four megawatts – a record it held for over 20 years. As oil prices declined again in the 1980s, interest in wind turbines dropped off as it became clear they could not compete against cheap fossil fuels.
Denmark made its own breakthrough in 1978 when teachers and students at the Tvind school built the world’s first multi-megawatt wind turbine. Despite its creators being dismissed as amateurs, the wind turbine worked and could deliver up to two megawatts of electricity. It featured a novel wing design, pitch-controlled wings, three blades, and a tubular tower.
By the turn of the 21st Century, concerns about energy security and global warming led again to a renewed interest in wind power. While wind power was never going to fuel an internal combustion engine, it did have the potential to compete on a cost basis with natural gas for electricity generation. Interest later intensified as oil prices steadily increased from 2003 onwards.
Modern wind turbines have developed largely incrementally, with most of them resembling the Tvind turbine of 1978. Increases in scale are a common theme in the quest to improve economic feasibility, with the Burbo Bank windfarm in the Liverpool Bay currently hosting the world’s largest wind turbines at 195m high.
The evolving wind-power industry has presented challenges for lubricant manufacturers like Shell and Mobil. Wind turbines operate in diverse weather conditions, both onshore and offshore, so typical industrial lubricants are not always suitable. Since Mobil, the maker of the anti-wear hydraulic oil Mobil DTE 24, introduced the first synthetic oil in 1998, there has been a noticeable shift towards specially formulated synthetic lubricants.