Which is cheaper to produce energy

Generate electricity yourself : Turn your back on the electricity supplier

Six percent of consumers already produce their own electricity, according to a new Emnid survey commissioned by the Federal Association of Consumer Centers (VZBV). 41 percent would also like to do that, but shy away from spending on technology.

Generate electricity yourself: what are the options?

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It can be assumed that many of the millions of German citizens who have bought roof-top solar systems, geothermal probes or micro-CHP systems in recent years were not driven solely by the thought of future generations: according to surveys, some are motivated by the rising energy prices of basic suppliers, others the desire for a completely energy self-sufficient life. The latter - that is already revealed here - is theoretically possible for a single household, but technically and economically extremely demanding.

It looks different in connection with neighbors. Today, from Saxony-Anhalt to the Upper Black Forest, there are more and more, mostly small communities and districts that generate their own electricity. This does not necessarily mean that they could cut their electricity or district heating lines to the established supplier (these villages also exist). Rather, it means that the places theoretically produce more electricity generated from renewable sources than they consume themselves - but are dependent on "imports" at some times of the day.

For example, a combined heat and power (CHP) system or biogas system fed with liquefied gas produces enough heat for the local indoor swimming pool or a mast operation and, together with the solar systems and the community wind farm, provides enough electricity on an annual average to also supply the neighboring community .

The majority of households that generate their own electricity do not use the energy for themselves, but feed it into the local power grid and collect the feed-in tariff for each kilowatt-hour fed in. According to the Renewable Energy Sources Act (EEG), the rates for photovoltaic systems are guaranteed for 20 years from connection. That shouldn't change for the time being.

Considerations by the Federal Environment Minister to subsequently cap the guaranteed funding in order to reduce the costs of the energy transition, the Chancellor had given such a clear rejection in the whale fight that it would be open whale fraud should it come to that. A corresponding law would hardly have existed in court.

The most common solution for those who generate their own electricity is to install a photovoltaic system (PV system). This includes the solar panels on the roof and an inverter that converts the direct current produced into household and grid-standard alternating current. Anyone who is not directly dependent on the return on the feed-in tariff - currently around 15 cents per kilowatt hour fed in for small roof systems with 10 kilowatt peak (kWp) lines - can keep the electricity in the house. He has to buy correspondingly less expensive household electricity (currently around 25 cents). One solution is to feed a heat pump with the currently unused electricity from the PV system. It draws the energy from the outside air or the floor and distributes it in the house, for example as heating, hot water or cooling. To do this, however, it needs electricity, which is best drawn from a PV system.

With this combination of investments there is money from the state

With the combination of a PV system and a heat pump, at least a conventional new building can easily be upgraded to KfW Standard 55 (efficiency house) or even Standard 40 (passive house). The number indicates how much energy is consumed in percent compared to the "standard house" according to the Energy Saving Ordinance (EnEV). Building owners and renovators can secure repayment grants of up to 50,000 euros through the KfW repayment subsidy.

Homeowners who invest in renewable heat receive a grant of several thousand euros. The federal government is currently promoting the said heat pumps, biomass systems (pellet heating) but also solar thermal collectors that convert solar heat directly from the roof into heat. The Federal Office of Economics and Export Control (Bafa), which is responsible for the payment and which gained fame in connection with the legendary car scrapping bonus, offers an overview of the subsidies for renewable heat.

Electricity storage solutions for the home are on the rise. For a long time they were considered too big, too heavy and hardly affordable. But because of falling manufacturer prices and increased user-friendliness, they are increasingly in demand with private households who want to generate their own electricity. This means that solar power can then be used at night, regardless of whether it is for the washing machine or the electric car that may be up for sale.

In addition, after a long tussle within the coalition, storage facilities are now being funded. KfW has launched the 275 loan program (“Speicher”). In addition, up to 100 percent of the net investment costs can be deducted from tax, provided the storage system meets certain technical criteria.

The reason is that experts and governments see private storage as a key to overcoming the problems surrounding the energy transition: every kilowatt hour of electricity consumed locally does not have to be remunerated by the consumer community, so it is easy on everyone's wallet. In addition, self-consumption increases the stability of the local electricity distribution network.

There are conventional lead batteries or more expensive and smaller lithium-ion batteries. So-called redox flow batteries are on the rise. They should have a similar energy density as lead batteries, but be more durable. And in terms of price, they should soon beat lithium-ion batteries significantly. A problem with all storage systems is that they are usually not yet able to communicate intelligently with the power grid operator and thus only contribute to a limited extent to relieving the grid.

Generate electricity yourself from the basement and balcony at home

There is also a lot of movement on the market for systems for environmentally friendly heat production. "It is estimated that only around a quarter of the heating systems in German cellars are state-of-the-art," explains Philipp Vohrer, managing director of the Renewable Energy Agency. In Germany, a good half of the final energy consumption would be used for heating. Renewable energies currently only contribute a good ten percent to the heat supply.

Well-engineered technologies are available to increase this share of renewables, ”says Vohrer. This included wood heating and heat pumps for geothermal and environmental heat as well as solar collectors. The large selection of different technologies for using renewable heat can be adapted to individual needs, he says. Vohrer's Agency for Renewable Energies offers an online configurator that provides initial information about heating systems that suit your house. The tool is aimed at home builders and modernizers alike.

A more conventional solution for combined heat and power generation at home is also offered by small combined heat and power plants that work on the principle of combined heat and power: mini or micro CHP systems, previously only designed for apartment blocks or industrial plants, are now even suitable for the small use in one to two family houses and are characterized by high efficiency. Especially those who have an above-average heat requirement, for example to heat a pool, can generate their own electricity in this way and thus save a lot of energy costs.

The gas industry and equipment manufacturers are promoting these technologies. Many of them, including the Berliner Gasag, fell on the market with their first devices - also because promised subsidy programs did not come. But now these micro-CHP systems are also gaining market share. New devices impress with their high levels of efficiency.

How you can generate electricity yourself in a rented apartment

Up until now, tenants have had a hard time actively participating in the energy transition or in generating electricity at all: roofs, basements, where systems can be installed, belong to the owner. But there are devices on the market: Well established, but more of an ecological gimmick than a cost-saving principle, are mobile “solar chargers” from various manufacturers for charging cell phones, cameras and tablet PCs. Nevertheless, they relieve the conscience, considering how often these devices have to be charged.

Somewhat more serious, but definitely not the culmination of engineering, are solar modules for the balcony: mini PV systems. They are around 80 by 160 centimeters in size, weigh just under 20 kilograms and generate a peak power of just under 200 watts. That is not enough to feed a vacuum cleaner or even a stove top, but to charge batteries. The models can even be plugged into the socket so that they feed the electricity into the circuit of the house - and thus reduce the electricity bill (for all tenants in the house).

However, these mini-systems can “outsmart” fuses and circuit breakers in the house's electrical circuit and thus themselves become a safety risk, ie they can burn through lines elsewhere. Therefore, the home owner and an installation company should always be consulted before connecting a mini PV system to the socket.

But if you consider what has happened on the market for private electricity producers in the past five years alone, it should not be long before useful devices come onto the market that even ordinary tenants can use to get away from their electricity supplier say goodbye and generate its own electricity.

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