Sustainable Cities Collective has re-launched as Smart Cities Dive! Click here to learn more!

Renewable heating: good for the purse and the climate

Heating oil in Germany is currently more expensive than ever before at the beginning of a year. In this harsh winter, households that have already switched to renewable heating are in a financial advantage. In addition, heating systems based on renewable energy sources reduce the greenhouse gas emissions per kilowatt hour by up to 95 percent compared to old conventional heating systems. This can be found in a recent publication of the German Agency for Renewable Energy (AEE, Berlin).

"If we replace, for example, a conventional oil boiler without condensing technology by a modern wood pellet heating system, the average emission of harmful gases is reduced from 376 to 25 grams per kilowatt hour of heat," calculates AEE managing director Jörg Mayer. And even compared to a modern, natural gas powered condensing boiler or a district heating supply (each 250 grams of greenhouse gases per kWh) a solar collector could produce some of the heat demand with only one tenth of the emissions.

ImageThe calculations by the German Öko-Institut come to a similar result: heating systems on the basis of bio-energy, solar thermal energy or geothermal energy are far superior to their fossil competitors in terms of greenhouse gas emissions. This is true even taking into account the supply chain – i.e. the energy used for the production of the fuel and the heating system itself - and even if the auxiliary electricity demand for example of a heat pump is calculated with the emissions of the average German electricity mix with its high share of coal power plants. Still better the balance would turn out, if only electricity from renewable energy sources is used as auxiliary energy for the heating systems.

Currently about 1.4 million solar thermal systems, 390,000 heat pumps and 140,000 wood pellet systems are installed in German households. In 2009, renewable energies covered over one-tenth of the heat consumption in German homes. The heat market is considered a sleeping giant that must be awakened, so that Germany can meet its mandatory climate change targets. By 2020 the share of renewable energy in heating has to be risen to at least 14 percent.

There are two important drivers for a shift to renewable heating systems in private homes in Germany. The regulatory instrument of the Renewable Energies Heating Act establishes mandatory quotas for renewable heat in the new buildings. And the market incentive program promotes the change towards renewable heat and energy efficiency in old buildings. Although both instruments are widely accepted, they are not sufficient to increase the modernization rate of the 18 million heating systems in Germany significantly, believes the AEE. Therefore industry associations are calling for a new, continuous and budget independent incentive system to increase the share of renewable heating.

Renewable heat doesn't only protect the climate it also reduces the consumption-based heating costs. "By switching from fossil to renewable heat, an average household can save up to 600 euros in fuel costs every year," said Mayer.

The full cost comparison of a "heat exchange" away from the old, inefficient gas or oil heating system to efficient heating with renewable sources brings a surprising result: Despite the costly initial investment for the new heating system, over the medium term the change is cheaper than the continued operation of the existing fossil heating. Based on an operating life of 20 years households which change to renewable energy sources may save more than half of their heating costs. Therefore a renewable heating system pays for itself not later than the 13th year of operation.