Often derided as a blot on rural landscapes, wind turbines got bigger and stronger than ever anyway. The next generation are even larger and designed to withstand an Arctic battering. 

The granddaddy of them all is a machine with rotors that cut a 164 meter (538 foot) swath made by a Vestas Wind Systems venture with Mitsubishi Heavy Industries. A single blade is 80 meters, about the entire wingspan of an Airbus A380 jumbo jet. In the intensely competitive wind turbine business, it’s rare for executives to allow a close-up look of what they’re developing, lest they tip off rivals. Vestas allowed Bloomberg News to visit and photograph the prototype units this month.

As they got bigger, the units became more efficient, boosting global installations 23 percent last year to a record 63.5 gigawatts, which at full tilt would be about as much as what flows from 63 nuclear reactors. Wind is now the most installed form of low-carbon energy. While few people outside the industry noticed, the trend lifted shares and profit of manufacturers from their crash during the financial crisis. Vestas is due to report its fifth consecutive increase in quarterly profit on Friday, overcoming a slump that forced it to cut 3,000 jobs since 2011.

Even the plunge in crude prices since  2014 has failed to derail industry growth.

“The doubling of turbine size this decade will allow wind farms in 2020 to use half the number of turbines compared to 2010,” said Tom Harries, an industry analyst at Bloomberg New Energy Finance. “This means fewer foundations, less cabling and simpler installation -- all key in slashing costs for the industry.”

The average turbine installed in Europe was 4.1 megawatts last year, 28 percent larger than in 2010, according to the London-based researcher, which expects 6.8 megawatts to be the norm by 2020. Harries said Siemens has hinted it’s working on a 10 megawatt turbine.

Standing in northern Denmark, where fjords cut through flat farmland, MHI Vestas Offshore Wind has erected the world's most powerful turbine. The turbine produces 8 megawatts of power, enough for about 4,000 homes. It could challenge the lead in offshore wind accrued by Siemens, which has almost two-thirds of installed capacity, according to BNEF. MHI Vestas is in second place, with 19 percent.

A Siemens spokesman said a 7-megawatt turbine the company is working on has a “track record of reliability” that will reduce costs for customers. It won its biggest contract for the machine on Wednesday from the Spanish utility Iberdrola, which will buy 102 turbines valued at as much as 825 million pounds ($1.2 billion).

The 80-meter blades of the MHI Vestas V164 make the machine almost as high as the Times Square Tower in New York, and are so large that they were “a nightmare” to transport on narrow country roads, Jens Tommerup, chief executive officer of the venture, said in an interview. This prototype is built for use offshore and has been tested on land since January 2014 at the wind turbine field in Osterlid, managed by the Technical University of Denmark. The goal is to spot faults before they enter service.

David Fuller's view

As with all technologies, windmills are becoming more efficient, which is obviously very good in terms of the energy produced.  Aesthetically, I do not like them.  They remind me of the invasion machines from H.G. Wells memorable science fiction novel: The War of The Worlds, first serialised in 1897.  If you live within earshot of a windmill the effects can be very disturbing.  Nevertheless, we will see more of them around the globe because their technology is improving and they are helping us to inch closer to a world in which our energy is mainly of the renewable variety.