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 164m swath made by a Vestas Wind Systems venture with Mitsubishi Heavy Industries. A single blade is 80m, 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.
As they got bigger, the units became more efficient, boosting global installations 23 per cent 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 3000 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 per cent 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 4000 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 per cent.
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 last week from the Spanish utility Iberdrola, which will buy 102 turbines valued at as much as US$1.2 billion.
The 80m 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. 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.
The blades for the V164 will be shipped from the Isle of Wight, off the south coast of Britain, where there's a special port facility to supply wind farms.
The turbine is unlikely to ever operate onshore, said Tommerup, the unit's CEO. "It's just too big."
Manufacturers need to be close to the sites of wind parks because their machines typically weigh hundreds of tons. More than 80 per cent of planned offshore wind farms will use turbines larger than 5 megawatts in size, according to Bloomberg New Energy Finance.
All of the 72 turbines in MHI Vestas's firm and unconditional order book will be installed in UK waters - at Dong Energy's Burbo Bank Extension and Walney Phase 1 Extension projects, both in the Irish Sea.
Computers allow the machine to adapt to all conditions. The blades rotate to face the wind and limit downtime. During gales of 12m per second (43 km/h), motors restrict the turbine from spinning too fast. When it gets more violent, the turbine can switch off.
While some rivals aim for a 10 megawatt machine, MHI Vestas says it's focused solely on the 8-megawatt tower for now.
"There needs to be a sizable market for it. Right now, there's no plans for a future turbine. We need to get the volume up so we can get the cost down," said Henrik Baek Joergensen, head of product management.