The concept for the so-called Dyson-Harrop satellite begins with a long metal wire loop pointed at the sun. This wire is charged to generate a cylindrical magnetic field that snags the electrons that make up half the solar wind. These electrons get funnelled into a metal spherical receiver to produce a current, which generates the wire’s magnetic field – making the system self-sustaining.

Any current not needed for the magnetic field powers an infrared laser trained on satellite dishes back on Earth, designed to collect the energy. Air is transparent to infrared so Earth’s atmosphere won’t suck up energy from the beam before it reaches the ground.

Back on the satellite, the current has been drained of its electrical energy by the laser – the electrons fall onto a ring-shaped sail, where incoming sunlight can re-energise them enough to keep the satellite in orbit around the sun.

A relatively small Dyson-Harrop satellite using a 1-centimetre-wide copper wire 300 metres long, a receiver 2 metres wide and a sail 10 metres in diameter, sitting at roughly the same distance from the sun as the Earth, could generate 1.7 megawatts of power – enough for about 1000 family homes in the US.

A satellite with the same-sized receiver at the same distance from the sun but with a 1-kilometre-long wire and a sail 8400 kilometres wide could generate roughly 1 billion billion gigawatts (10²⁷ watts) of power, “which is actually 100 billion times the power humanity currently requires”, says researcher Brooks Harrop, a physicist at Washington State University in Pullman who designed the satellite.

Since the satellites are made up mostly of copper, they would be relatively easy to construct. “This satellite is actually something that we can build, using modern technology and delivery methods,” Harrop says.

Satellites laden with solar panels that can beam their energy down 24 hours a day have been discussed for decades. California agreed last December to a deal involving the sale of space-based solar power. Solar panels cost more per pound than the copper making up the Dyson-Harrop satellites, so according to Harrop, “the cost of a solar wind power satellite project should be lower than a comparative solar panel project”.

So far so good, but there is one major drawback. To draw significant amounts of power Dyson-Harrop satellites rely on the constant solar wind found high above the ecliptic – the plane defined by the Earth’s orbit around the sun. Consequently, the satellite would lie tens of millions of kilometres from the Earth. Over those distances, even a sharp laser beam would spread to thousands of kilometres wide by the time it reached Earth.

“Two megawatts spread across areas that large are meaningless, less than moonlight,” says John Mankins, president of consultancy firm Artemis Innovation which specialises in space solar power. To beam power from a Dyson-Harrop satellite to Earth, one “would require stupendously huge optics, such as a virtually perfect lens between maybe 10 to 100 kilometres across,” he says.

He also points out that the wire could burn out due to the huge current coursing through it, although he has not performed the calculations to gauge the probability of that occurring. But he does say that a smaller version of this “clever and interesting” satellite could help power some space missions. “I could imagine uses for this idea outside of the plane of the ecliptic, such as helping generate power for something like the Ulysses spacecraft, which went around the poles of the sun.”

Source: http://www.newscientist.com/article/dn19497-outofthisworld-proposal-for-solar-wind-power.html?DCMP=OTC-rss&nsref=online-news

The UK is determined to get out of the “dunce corner” on renewables, Energy Secretary Chris Huhne said today as he officially opened the world’s largest offshore wind farm off the UK coast.

The 100-turbine Thanet wind farm off the coast of Kent will produce enough electricity to supply the equivalent of more than 200,000 homes a year, and brings the UK’s total power from onshore and offshore wind to more than 5GW – enough to power all the homes in Scotland.

At a ceremony at sea to mark the launch of the new site, Mr Huhne said offshore wind was a key part of meeting the country’s commitments to boost renewables, and the Government was focused on moving from the “frankly atrocious record” on green energy it had inherited. Currently the UK sources just 3% of all its energy from renewables, against a target of 15% by 2020, and is 25th in the league table of 27 EU countries on action on green power. Offshore wind power was part of ensuring secure, cheap energy supplies in the future, as well as providing jobs, Mr Huhne said.

But concerns were raised about the proportion of jobs created by the offshore wind industry going to British workers, and whether incentives such as £60 million promised for ports development to support the supply chain would survive the forthcoming Government spending review.

About 30% of the 3,500 jobs generated by the manufacture, construction and installation of the wind farm owned by Swedish company Vattenfall went to UK employees.

Mr Huhne said the ports funding was subject to the comprehensive spending review but said it would be foolish not to encourage in every way possible investment in the supply chain, to ensure as much as possible of the manufacture and skills for offshore wind were based in the UK.

“We need to make sure we have both the supply chain and the skills, and we will do what we can to make sure we are as attractive as we can be to investors,” he said.

“We do have an awful lot of wind and wave and tidal power and we are determined to have a supply chain to match.”

While he said the opening of the Thanet wind farm and the reaching of the 5GW was a landmark for the UK, Mr Huhne said the country had a long way to go, and could easily encourage the industry to deliver 10 times as much wind energy by 2020.

The Energy Secretary’s comments came as new research published by Vestas, which made the turbines for the Thanet wind farm, suggested that the UK offshore wind industry could directly provide as many as 34,000 permanent skilled jobs, and another 24,000 jobs in the wider economy.

The tens of thousands of jobs would come from operations and maintenance of wind farms and would be in addition to the temporary construction jobs from installing the energy plants.

But Vestas, which was at the centre of controversy when it closed its onshore turbine factory on the Isle of Wight with the loss of 600 jobs last year, said uncertainties over financial support, local skills shortages and inadequate grid and port infrastructure was putting thousands of the potential jobs at risk.

The company called for clarification on financial support, and targets agreed between Government and industry for 2020 and beyond. And there should be decisions over which ports will receive funding from the £60 million pledged for developing harbour areas to accommodate new wind farm construction.

Vestas Offshore president Anders Soe-Jensen said: “We need more qualified people to come into this industry, if this industry is going to take off.”The wind turbines will be there, we can handle that, but we need to get them erected and maintained, so we need people to come into the industry in high level jobs.” And he said: “To build up the entire supply chain will require some assistance from the Government.”

But Oystein Loseth, chief executive of Vattenfall, said the UK was the best country in the world to be installing, building and operating offshore wind. “This project would not have been possible without the British Government’s active support and its commitment to renewable energy,” he added.

And Maria McCaffery, chief executive of wind industry body RenewableUK, said: “Today’s 5GW announcement and the news on September 6 that wind supplied 10% of all electricity to consumers serves to highlight just how mainstream this energy source has become.” She said that each gigawatt of power that was installed was taking less and less time to construct, and with the right Government policies in place, the industry expected to be installing between 3GW and 4GW a year when the next major round of wind farms begin construction.

Original source: http://www.independent.co.uk/environment/green-living/worlds-largest-wind-farm-opens-off-kent-2087352.html