Wind turbine manufacturers are drawing up plans for new super-sized machines as Europe increases its investment in renewable energy.
Danish company Vestas, which has opened a factory in Scotland, confirmed it is working on plans for a new turbine which will improve on the 2MW version it produces at present.
Tom Petersen, managing director of Vestas Celtic, would not reveal how much capacity the new turbine will offer, but outlined the main areas of development work. ‘We market a 2MW turbine. There are larger ones on the drawing board but I’d rather not discuss that. Our company has placed a lot of emphasis on the core of the turbine. A problem is that wind can go from zero load to 100% load in one second.’
It can take up to four years to develop a new gearbox, said Petersen, and Vestas is working closely with its suppliers on making improvements.
‘Variable speed systems are key. The larger turbines get, the more specialist parts have to be. Research and development is certainly increasing in the area of the control of electricity output using electronics. But we have tried to keep things simple while making some modifications.’
The generating capacity of a typical wind turbine has increased during the past 20 years from a few kW to a few MW. For many years, the cost of technology meant it was uneconomic to build a wind turbine of a capacity less than about 400kW. But the larger the turbine, the better return it will deliver on the investment.
Dr Jack Noakes, wind turbine expert at the UK energy research company Renewable Energy Systems, which is responsible for developing the world’s largest windfarm, in Texas, expects the industry to continue developing huge structures for capturing the energy in wind.
‘There is no theoretical limit in terms of machine design, but you can get into transport problems with huge blades. The blades are now the biggest technical barrier,’ he said.
Some turbines sited out to sea already use blades of more than 50m in length and they are likely to get bigger. The giant blades are used to take advantage of the sea’s higher wind speeds and to make the turbines cost effective.
These developments have seen the cost of wind power fall dramatically over the past five years — leading to a growth in the number of windfarms in Europe. Chris Gooding, spokesman for environment group Solar Energy Alliance, said business views wind power as an attractive investment.
‘A 1.5MW turbine can be put in place for £1.5m and a return can be gained in four years. That’s very quick for the energy industry. And the larger theturbine, the more economic it becomes,’ he said.
The Crown Estates has granted licences to 18 companies to build windfarms on sites off the UK coast. Leases have been granted for 13 seabed tracts, each roughly 10km2. The windfarms will be around 10km from the shore and each will contain up to 30 turbines — with the potential for a total of 400 turbines.
The combined sites could generate 1,000-1,500MW of power, enough to supply one million households for a year, or about 1% of the UK’s energy needs.
Despite the government’s leasing of land and seabed to stimulate investment in windfarms, local planning laws are already frustrating progress.
Tom Petersen of Vestas Celtic said other European countries have offered more encouragement to the industry than the UK.
‘In Germany, every county had to find a location for a certain amount of generating capacity. In Denmark, local planning is coordinated with the national wish. The planning system in the UK is the most annoying obstacle. There is a huge difference between the government and local planners.’