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In principle no one seems to have anything against renewable energy. In practice, however, people keep repeating that there are three practical obstacles: it is not affordable, the technologies are not mature yet, and we lack the area required to generate the energy. And because of this we need fossil fuels and nuclear power....

Time will take care of two of these objections. The technologies are getting better all the time and the more they are deployed the bigger the economy of scale, leading to lowers costs. But the available area won’t increase much. Will this be the bottleneck?


The British scientist David MacKay has written a very good book: "Sustainable Energy – without the hot air". The book has its own website and there you can even download the book for free.

MacKay''s argument is simple: renewable energies require too much area because they have low energy density. For example, wind energy has only 2W/m2, biomass even less: 0.5 W/m2. Solar energy has the highest energy density but still reaches only 5-20W/m2.

At the same time Europe is very densely populated: The European Union has a density of 115 people per square kilometre. We would take a very large area for renewable energy. People would have to live among wind turbines and solar panels.

And that, he thinks, is not possible. There is very little acceptance for the necessary infrastructure: Wind farms are ugly, noisy and a blot on the landscape; solar panels on rooftops disfigure our historic buildings, rubbish incineration poses health risks, etc.

MacKay conclusion: Although we theoretically have the area we needed, in his opinion we won’t be able to use it to produce renewable energies. We must therefore use other people’s area (for example, producing solar energy in a desert in Africa and bringing it to Europe) or nuclear power. Or both.

But the area available for renewable energy keeps growing, particularly in Germany. According to a report by the Federal Ministry for the Environment, the share of renewable energy in energy mix has doubled since 2000 to 9.5%.

However one reads in the same report that the “long-term viable and sustainable potential” of renewable energy share in Germany will reach only about 60% in the year 2050! Why? Too expensive? Not enough area? Unfortunately the reason is not given.

Others are more optimistic. For example, the Agency for Renewable Energies, which is supported, among others, by the Federal Ministry for the Environment, recently published the “Germany Renewable Energy Atlas 2020”. The atlas shows that Germany will need a relatively small area to raise the share of renewable energy to 28% of the energy mix by the year 2020. The German government goal is only 18%.

My question is: How do you go from 28% to 100%? Is it possible? Is there enough area? Do we really need to sleep under wind turbines? Can you calculate it?

The answer follows. Stay tuned.


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