Germany's Experience: How Effective Are Renewables, Really?

The Principle

Our Earth is a gigantic heater. The core of our planet, 6,000 kilometers below the surface, is several thousand degrees Celsius -- an inheritance from the time when the Earth came into being. In addition, radioactive processes maintain that temperature. One can tap into that energy by drilling deep into the Earth's crust. In some places, one must drill up to five kilometers deep, but in others, the heat is much closer to the surface.

The Market

Geothermal power plays but a niche role in Germany's energy mix with just a 0.2 percent share of the renewable energies market and 2.4 percent of the heating market.

But the advantages are huge. The heat from deep within our planet can be used around the clock and, in theory, could fulfil Germany's entire energy needs. But the problem lies with the technology. In Germany, one has to drill hundreds, or even thousands, of meters down to access geothermal energy -- which drives costs up.

Other countries have an easier time of it. Iceland, for example, covers most of its energy needs with geothermal energy.

The Potential

In theory, the potential is endless. But the problem is the costs. As long as the drilling technology remains as expensive as it is today, geothermal will not play a major role in Germany's energy mix.

In addition, geothermal drillings are risky. They can occasionally cause minor earthquakes and, should the ground settle, nearby buildings are endangered. In the southern German town of Staufen, for example, the effects can be seen, with numerous buildings having cracked in recent years following geothermal drillings. In Wiesbaden, by contrast, water flowed out of the ground for days as a result of another geothermal project. "That doesn't have to be the case everywhere," says Bardt, "but the uncertainty remains."