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It examines only existing technologies – wind turbines with both fixed and floating foundations, wave machines, tidal range and tidal stream devices – and the contribution they can make by 2050.

It accepts the usual constraints on offshore renewables: maximum water depths, the need to avoid dense shipping lanes and other obstacles, the various technical limits. Having applied these constraints, it finds that the practical resource for offshore renewables in the UK is 2,130 terawatt hours per year. This is six times our current electricity demand.

Were we to use only 29% of the total resource, the UK would become a net electricity exporter. We would be generating energy equivalent to 1bn barrels of oil a year, which roughly corresponds to the average amount of North Sea oil and gas the UK has been producing over the past four decades.

The report estimates that this industry would directly employ 145,000 people and produce annual revenues of £62bn. The construction effort would be roughly similar to building the North Sea oil and gas infrastructure: eminently plausible, in other words, if propelled by strong government policy.”

Jul 8th 2009
From The Economist print edition
Solar electricity may be about to attract real money

A meeting on July 13th might get the ball rolling. Munich Re, the world’s largest reinsurance company, has invited 20 large companies (including Siemens, Germany’s engineering giant; power suppliers RWE and E.ON; and Deutsche Bank, Germany’s biggest) to join it in forming a consortium called Desertec. If all goes well, this will eventually build a legion of solar power stations in Africa and Arabia, and connect them to Europe.

…

The power stations in question will be “solar thermal”, rather than the better known sort relying on photovoltaic solar cells.

…

If the scheme were implemented in full, it would involve spending €400 billion ($560 billion) at today’s prices, over the next 40 years, building enough solar power stations to satisfy 15% of European demand in 2050—together with most of North Africa’s and Arabia’s—and about 20 trans-Mediterranean HVDC cables which, unlike conventional AC power lines, can transmit power over long distances and through water without significant losses.

Rather than showing one monolithic 600x600km block, it shows 65 ‘blobs’ each with an area of 1500km^2 and 1/3 full of solar power facilities. Each would produce 10 GW of output, and the set of 65 could produce 16 kWh per day for one billion people (Europeans today use about 125 kWh per day, so you would need a lot more efficiency, lower living standards, or more blobs per person).

True, but I think the caveat about extrapolating from a single facility is the most important thing. Let’s build a few 10km by 10km solar farms, then start estimating how much 600x600km facilities would cost.

Posted by Francois Cellier on April 25, 2009

Recently a debate has arisen here at ETH Zurich centering on the question whether the envisaged “2000 Watt Society” is inevitable. Why shouldn’t we be allowed to use more energy? Wouldn’t it be more important to limit greenhouse gas emissions? A report about the new energy strategy of ETH Zurich was published in the Oil Drum in May 2008.

In this presentation, we discuss whether the 2000 Watt Society is at all sustainable, and if so, what it will take to keep energy supply at that level after the end of ample and cheap fossil fuels. What are the implications of energy deprivation to our society? Can we stave off famine? How can we maximize our chances of getting through the emerging world-wide crisis relatively unscathed? What are the pitfalls in designing and implementing a strategy that helps us achieve these goals? How much time have we got left?

In cities that already have overhead wires for trolley buses, why not trolley taxis? Although that might force cabbies to drive in an un-erratic fashion, ruining the entire purpose of taxis.

That being said, it does seem likely that moving to an economy based entirely on renewable energy will cost trillions, and involve facilities the size of medium-sized countries.