With miles and miles of easily accessible coastline, Britain is perhaps better placed than anywhere else in the world to take advantage of offshore wind power. Despite the uptake being slow thus far, UK Energy Minister John Hutton in December set out a grandiose vision of how this vast potential resource would be tapped.

Speaking to a gathering of key European energy industry figures in Berlin, Hutton unveiled plans to open up the entire British coast for the development of wind farms. In launching his Strategic Environmental Assessment of the UK seas, he vowed that every home in Britain would be powered by wind by 2020, with 7,000 new offshore turbines generating 33 GW capacity.

As policy announcements go, this was as well engineered as they come. With climate change dominating news, it was far from surprising that he caught the media's collective eye. His exact proposal went, "The draft plan I'm setting out could allow companies to develop up to 25 GW of offshore wind by 2020, in addition to the 8 GW already planned. If we could manage to achieve this, by 2020 enough electricity could be generated off our shores to power the equivalent of all of the UK's homes."

He noted that the UK is now the number one location for investment in offshore wind in the world, and next year will overtake Denmark as the country with the most offshore wind capacity. On paper, it all sounds very promising.

Britain took its first tentative steps into offshore wind with a first round of development in 2001, which comprised a number of small demonstration projects. The second round, in 2003, resulted in the award of options for leases for larger scale projects in three designated areas. That included the Thames Estuary, the Greater Wash and the North West.

As essential as chimneys and roads

Hutton's latest proposal constitutes the third round, and against such a background, is a mammoth undertaking.

Based on current plans under the first and second leasing rounds, about 8 GW of capacity could be operational by around 2014, including the 1 GW London Array, which is the largest planned offshore wind farm in the world. However, is getting to 33 GW within the six following years to 2020 a tall order?

Hutton expressed confidence during his announcement, saying, "Our trajectory on renewables is beyond question. They are as central to our future low carbon economy as chimneys were to the industrial revolution and road building following the invention of the mass produced car."

Support and delight flooded in from the obvious suspects such as Friends of the Earth, where campaigner Nick Rau described wind power's potential as "enormous"; Green Peace, where executive director John Sauven was happy to brand Hutton's words as a "revolution"; and from the British Wind Energy Association (BWEA), where chief executive Maria McCaffery hailed it as a "decisive step."

In fact, the announcement had been so well timed in the current climate change clamor that even opposition politicians were quick with their approval. His shadow counterpart in the opposition party, Alan Duncan, jumped to tell the BBC that, "I think it's inevitable and a good thing that there will be more offshore wind."

Yes, it seemed that only the most skeptical would dare question Hutton on this one, particularly when there is a European wide target of a 20 percent increase in renewable energy to be met by the same time scale of 2020. There was very little questioning of the figures, even though Hutton himself had defined his proposal as a "major challenge." So do Hutton's bold and ambitious claims stand up to closer scrutiny?

A 60-fold increase

In breaking down exactly what Hutton proposed, Britain has to achieve a 60-fold increase in wind power in just 12 years. So far, the UK government has poured US$1 billion into wind power and has yet to see it deliver even a half-percent of the country's electricity needs. In powering every UK home by wind, he's talking about 25 million households, which currently consume close to 140 GW of electricity. At present, just two percent of Britain's power comes from renewable sources and just 2.2 GW of that is from wind.

On top of that, the 7,000 turbines in Hutton's latest plan equates to a windmill for every two miles (3.2 km) of the country's coast. Developers do not seem ready to fill that huge quota. As it stands right now, wind farm companies have only submitted plans for 8 GW of offshore wind between now and 2014. That's a point not lost on the Royal Academy of Engineering, which has started a new study on the engineering challenges of such "aspirational targets." They are due to report their findings later this year.

Chris Goodall, author of "How to Live a Low-carbon Life," has already pointed out that there will be a clear problem with supply. He highlighted that only a small number of suppliers currently build marine-ready turbines. Among them are Vestas and Siemens, both based in Denmark. Gordon Edge, BWEA economics director, is another who has been vocal on this factor, stating that, "We'd really be struggling from a 'Where can we get the turbines?' point of view."

Shortages in the worldwide supply of offshore wind turbines will persist for several years, says Goodall. However, he does note that new manufacturers could be lured in if they see clear evidence of government support. Even then, it could be the best part of a decade before they have the technology mastered.

Bringing new technology to fruition is inextricably tied to expense, and current figures for offshore wind construction are already extremely high. A figure recently touted by the BWEA puts offshore wind at US$4 million per MW of capacity, double that of its onshore sister schemes.

On the grounds of those figures, the UK government could be staring at an investment of US$128 billion, which is six percent of the country's gross national product. Goodall says this appears to be a high-end estimate, and believes it may be achievable for around US$100 billion. However, this is still a monumental plunge for the government to take.

Beyond the monetary issue lies difficulties in grid connection, the need for substantial back up capacity and the challenge of finding enough skilled people to carry out the installation of 7,000 turbines within 12 years, a big task even for a country with a strong background in offshore efforts within the oil and gas industry.

An optimistic target

Goodall summed up his views on the announcement by saying, "Offshore wind is expensive and still somewhat untried. The government's apparent decision to allow rapid development around a large portion of the UK coast is path-breaking. Most observers think that getting to 33 GW is an extremely optimistic target for 2020. However, industry people think that it may be possible to get as high as 20 GW, probably generating over 15 percent of UK power."

Goodall is not alone in his assessment. Engineering consultant Jim Oswald has analysed the Office of Gas and Electricity Markets figures on renewable energy and believes they are not performing as well as they should because wind speeds vary too much. He said that there can be swings of 100 percent output to 20 percent output within just 20 hours, swings which current turbines and generators are not designed to cope with.

Hutton is undoubtedly aware of all of these hurdles, saying, "The challenge for government and for industry is to turn this potential - for our energy and economy - into a cost-effective reality. This will be a major challenge. The UK has some of the best offshore wind resources in the world, a long history of design, installation and operational expertise in the offshore environment and the skills and manufacturing capability to transfer to the emerging sector."

Whether these resources are enough remains to be seen. With the current international drive for a dramatic slashing of greenhouse gas emissions, Hutton will have had no problem making his 2020 announcement. Only time will tell if it was more about generating headlines than electricity.