At the end of the non-technical portion of his book, David MacKay estimates what it would take to renewably power the United Kingdom, switching forever away from unsustainable fossil fuels. With one possible approach, he reckons that it would require the following:
- 52 onshore wind farms: 5200 km2
- 29 offshore wind farms: 2900 km2
- Pumped storage: 15 facilities similar to Dinorwig
- Photovoltaic farms: 1000 km2
- Solar hot water panels: 1 m2 of roof-mounted panel per person. (60 km2 total)
- Waste incinerators: 100 new 30 MW incinerators
- Heat pumps: 210 GW of thermal energy pumped
- Wave farms – 2500 Pelamis, 130 km of sea
- Severn barrage: 550 km2
- Tidal lagoons: 800 km2
- Tidal stream: 15 000 turbines – 2000 km2
- Nuclear power: 40 stations
- Clean coal: 8 GW
- Concentrating solar power in deserts: 2700 km2
- Land in Europe for 1600 km of HVDC power lines: 1200 km2
- 2000 km of HVDC power lines
- Biofuels: 30 000 km2
- Wood/Miscanthus: 31 000 km2
In total, this adds up to about 300 gigawatts (GW) of energy for transport, heating, buildings, and everything else. What this suggests is that, if you want to maintain population density at levels similar to now along with per capita energy use, you need to turn entire densely populated countries into energy factories even with nuclear and ‘clean coal.’ While he doesn’t estimate costs for the last two, his ballpark estimate for building all the rest are about £870 billion. That number may well be an overestimate, since the costs for many of the technologies are extrapolated from a few pilot facilities.
That may seem like a staggering amount of money and land. On the money side, however, it must be borne in mind that the UK is currently spending £75 billion per year on imported energy. That means the whole conversion would cost as much as about twelve years of continued fossil fuel use, at prices similar to now. The land use change may be a far bigger barrier. Making the UK into a renewably-powered country requires devoting a considerable portion of its total land area to that purpose. That’s a lot of spoiled views and local resistance to overcome.
He offers five other energy plans for the UK, based on different balances of technology. He also has energy plans for Europe, North America, and the world as a whole. To make the figures add up, they all require either nuclear, massive solar farms in the desert (600 by 600km), or both.
Countries are going to need to make some hard choices about population size, energy use, and the maintenance of land for agriculture, wildlife, and human enjoyment.
Massive solar farms to be built in the Sahara were among the top news last night on European TV. Apparently, major energy providers want to collaborate on some big projects. What are your thoughts on that?
MacKay discusses that option, as well.
It looks pretty good, compared to the alternatives. Build huge concentrating solar harms and high voltage direct current connection lines. Add to that wind energy, geothermal, hydro, etc. Perhaps nuclear as a bridging technology.
That’s the closest thing we have to an all-renewable plan that could give everyone alive enough energy to live at a first world standard of living (though more efficiently than people in first world countries presently do).
It certainly makes sense to put the solar farms where the sun is, rather than in sunny wales. That said, I get chills at the idea of oil companies buying up an area the size of Germany. The U.S. is certainly better off, having its own desert.
It is mind boggling to me, to think of solar power as hundreds of times greater en masse than hydro power. But, I suppose that’s because hydro power is already mechanical, it’s very easy to intuit its force – whereas the Sun’s energy is more abstract.
How does the author project the cost of these 600 by 600km solar farms?
And just to point out something about algae – this is the scale I thought it would have to be grown on. And even if it extracts less energy than the photo voltaic cells, it could still be deemed worthwhile because what it produces could fly airplanes.
He estimates that solar farms would cost £190bn per 1000 square kilometres, though that is based on a single 10MW facility in Germany (Solarpark in Bavaria).
At that price, each 600 x 600km square would cost £68.4 trillion (US$111 trillion, C$125 trillion), since they would have an area of 360,000 square kilometres. By comparison, world GDP is about US$54 trillion. Each square could give 1 billion people the average European’s consumption of 125 kWh/d. North American consumption is twice that.
Of course, it is absurd to scale up from a single German facility to unprecedented giant desert solar farms.
I think you are using the cost figure for solar PV – not concentrating solar.
This page cites a cost for concentrating solar thermal at £340 billion for 2,700 square kilometres, in the desert. That estimate is also based on a single facility: Solúcar.
At that price, 360,000 square kilometre blocks would cost about £45 trillion each (US$74 trillion , C$83 trillion).
As you say, to provide a European level of energy to everyone on Earth would require about seven of them.
It is mind boggling to me, to think of solar power as hundreds of times greater en masse than hydro power. But, I suppose that’s because hydro power is already mechanical, it’s very easy to intuit its force – whereas the Sun’s energy is more abstract.
Hydro power is solar power. It is the sun that causes water from oceans, lakes, rivers, soils, etc to evaporate in the first place. Without that energy input, it would never get the gravitational potential energy that dams convert into kinetic and then electrical energy.
And just to point out something about algae – this is the scale I thought it would have to be grown on. And even if it extracts less energy than the photo voltaic cells, it could still be deemed worthwhile because what it produces could fly airplanes.
MacKay estimates that cheap solar cells could get about 10 watts per square metre – 20 times better than the best energy crops, when they are just turning sunlight into carbohydrates (which could then be processed into fuels). That being said, some source of liquid fuels will probably be required for aircraft for a long time, whether it is expensive remaining fossil fuel oil, synthetic oil from biomass, or something else.
If all of our energy was electric, we’d need less of it due to the relative efficiencies of electric motors versus combustion engines. I would think the difference would be quite significant, too.
The solar farms MacKay describes would produce 125 kWh/d per person. That is about equal to current European usage (including transport fuels), but half of current usage in North America.
I just mean that from this website a barrel of oil is good for about 6.4 gigajoules of energy or 1800kw/h. But with gas cars being only maybe 20%-25% efficient (a guess), and say an electric vehicle being maybe 70% efficient (another guess) you’d need less overall energy to maintain current levels of transport, if transport were electric.
There is no doubt that we could have similar lifestyles while using significantly less energy.
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.
This thread also considers the logistics of oil replacement.
“you’d need less overall energy to maintain current levels of transport, if transport were electric.”
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.
Is the 2000 Watt Society Sustainable in Switzerland?
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?
I think you are using the cost figure for solar PV – not concentrating solar.
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.
Here is a better figure on desert solar than the one linked before.
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).
Solar power and the Sahara desert
The start of something big?
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.
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The power stations in question will be “solar thermal”, rather than the better known sort relying on photovoltaic solar cells.
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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.
“Whenever you suggest that renewables could one day supply a large proportion of our electricity, scores of people jump up to denounce it as a pipedream, a fantasy, a dangerous delusion. They insist that the energy resources don’t exist; that the technologies are inefficient; that they can’t be accommodated on the grid; that the variability of supply will cause constant blackouts.
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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.”
Most of the world’s (at present puny) tidal power comes from barrages across estuaries. Yet long-mooted plans to wall up the River Severn, Britain’s longest, have foundered because of high costs and worries about wildlife. Instead, scientists are focusing on two newer technologies, both of which could soon be tested in commercial schemes. This puts the country “completely at the forefront” of tidal technology, says Gareth Potter of Swansea University.
The first sort is found in the Pentland Firth, the fast-flowing strait between Orkney and the Scottish mainland. This year Atlantis Resources, a marine-power firm, plans to start installing turbines on the seabed—it hopes to plug in 260 by 2020, each about 18 metres in diameter. That would create an underwater power plant with about the same oomph as a small gas-fired station. Researchers at Oxford University think the Pentland Firth could one day generate more than 40% of Scotland’s power, if it were packed with similar gizmos.