Energy | 13. December 2010 | posted by Jan Oliver Löfken

Energy question of the week: Complete autonomy - is there a way to total energy self-sufficiency?

Electricity costs rise every year, as do gas and oil prices. Almost all German citizens are obliged to use the services of gas and electric utility companies to keep their homes warm and supplied with power. Is there no way out of this?

More than half of all German citizens live in rented accommodation. For this large group, switching over to autonomous heating and electricity supplies is very difficult, since the initial investment is usually very large. For a rented apartment, building in a fireplace is an option, and a wood fire can contribute to reducing heating expenses.

Energy savings are the key

Owners of apartments or, even better, houses have many more options. However, the first step is always energy saving – high-efficiency electrical appliances and thermal insulation significantly reduce energy consumption. Many technologies are available for independent power generation; the warmth of the ground a few metres below the surface can be used to heat the home using borehole heat exchangers and heat pumps. Rooftop solar cells with a good exposure to sunlight can generate electricity for sale back to the utility company or to meet one's own needs.

If the cost of boring for geothermal heat exchangers is too high, modern wood pellet burners can decouple heating costs from the oil and gas markets. But here too, growing demand for the pellets will inevitably lead to rising prices. For anyone who does not have a large roof area with good exposure to the sun, a fuel cell power station in the basement could be a solution. The first devices of this type are already available and are mostly powered with natural gas. But disconnecting from the electricity company in this case means connecting to the gas company, and they are often just different divisions of the same utility company.

EA house that produces energy

In principle, rebuilding a house to achieve energy savings is more expensive than a new building. After the passive house, which uses very little energy, and the zero-energy house, which uses no external energy when averaged over an entire year, there are already concepts for the positive energy house. This uses solar cells, fuel cells and heat pumps in combination with extensive insulation to produce more energy than it consumes. A prototype, sponsored by the German federal government, has been developed using a lightweight construction concept, and is touring Germany this year. But the expense means that very few builder-owners will be able to build a positive energy house. However, the touring house suggests numerous ideas for reducing energy consumption or even, to some extent, supplying energy independently.

The DLR Energy question of the week in 'The future of energy' Year of Science

The Federal Ministry of Education and Research (BMBF) has given the Year of Science 2010 the motto 'The future of energy'. For this reason the science journalist Jan Oliver Löfken will this year answer a question on the subject of energy in his blog each week. Do you have a question about how our energy supply might look in the future? Or do you want to know, for example, how a wave power plant works and how it can efficiently generate electricity? Then send us your question by email. Science journalist Jan Oliver Löfken will investigate the answers and publish them each week in this blog.

Image: Positive Energy House, Source: BMVBS / Christoph Vohler.


About the author

Energy journalist Jan Oliver Löfken writes among other things, for the Technologie Review, Wissenschaft aktuell, Tagesspiegel, Berliner Zeitung and P.M. Magazin on issues involving energy research and industry. For DLR, he answered the Energy question of the week during the Year of Energy 2010. to authorpage