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The five pillars of renewable energies in Germany are: biomass (biodiesel, vegetable oil, bioethanol, biogas, wood pellets, wood chips, etc.), wind energy (onshore & offshore), solar energy (open fields and rooftops), geothermal and hydropower.

According to the Agency for Renewable Energies, the share of renewable energy will cover 28% of the energy consumption (electricity, heat, transport) in Germany in 2020. How much area will this take? And how much land would be needed to go from 28% to 100%?

 

In 2020 renewable energy will account for 28% of total final energy consumption. To achieve this goal, the following areas will be needed

1. Biomass
3.7 million ha (ha=hectares)
(= 22% of the total farming area)
131% growth compared to 2008

2. Wind energy (onshore)
270,000 ha
59% growth compared to 2008

3. Solar Energy
10,500 ha open field photovoltaic
518% growth compared to 2008

37,000 ha rooftop photovoltaic and solar thermal
(= 16% of available area)
537% growth compared to 2008

4. Geothermal
960 000 ha (subterranean land use)
643% growth compared to 2008

5. Hydropower
Not specified


Biomass only
How will the area for biomass grow from 9% (1.6 million ha) in 2010 to 22% (3.7 million ha) in 2020?

Today 60% of all agricultural land in Germany is used to produce feeding stuff (10.2 million ha) and only 27% (4.5 million ha) to produce food! I personally hope that less animal feeding stuff will be produced and that the area for food production will remain the same. Eating less meat would do us all good! So the area for feeding stuff would go down to 47% or 8,4 million ha.

Couldn’t we go even further? Instead of cutting down the area for feeding stuff to only 47%, what about going further down to 30%? That would mean eating half as much meat in 2050 as we do today.

This way the total area for biomass could go up to 6.7 million ha. But biomass has a very low energy density: 0.5 W/m2, remember? Therefore this area would be enough to raise the share of renewable energy only to 40% of the total energy mix. To get to 100% we need to add some wind to the equation!

Biomass + wind energy
Let''s assume that, of the area that we want to take up for biomass (6.7 million ha), only half would be well suited for the production of wind energy. These 3.35 million ha could then close the gap and increase the share of renewable energy from 40% to 100%.

Advantage: You can generate both biomass and wind energy using the same area.

Disadvantage: We would then have an area almost as large as the German state of North Rhine-Westphalia full of windmills! That’s about the size of the US state of Maryland and bigger than Wales (2.2 million hectares).

Would solar be better than wind?

Biomass + solar energy
If we do not want the windmills, we should then try solar. It has the highest energy density (5-20W/m2 for photovoltaic) and therefore needs much less space.

If we would first use up all suitable rooftops (approximately 235,000 ha), we would need “only” about 1 million hectares of open land for solar farms. This would correspond to about 50% of the area of the German state of Hesse! That’s bigger than the US state of Delaware.

Biomass + wind energy + solar energy
The best solution is a mix of biomass, wind energy, and solar energy. Even in Germany there are large relatively unpopulated windy areas that could take some windmills without negatively affecting the tourism industry. The solar farms are not that visible from far away.

Conclusion
Yes, the required areas are huge – we should not pretend otherwise – but they are available to meet 100% of our energy needs from renewable energy only. These areas are already being used for agriculture and buildings at this moment. Instead of producing foodstuff to feed animals we would be producing renewable energy.

Whether it makes economic sense to do so is another question. There is still one other option. Europe can cooperate with neighbouring countries with lots of sunshine and low population density: the desert countries in northern Africa. The United States and Australia can use their own deserts.

Following soon: solar thermal power plants!. Stay tuned.

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