A quick A-Z of the switch to renewable energy in Germany


Biogas is obtained from energy crops like rapeseed and maize, manure and other organic waste. The substances are fermented by micro-organisms in a biogas plant without any light or oxygen. Methane gas is produced, which can then be burned in a gas engine. Many combined heat and power (CHP) units rely on this to generate electricity and heat.


It is precisely in winter, when people turn up the heating and consume particularly large amounts of electricity, that the sun and wind tend to provide only low levels of energy. It was for this reason that the grid operators had to activate the cold reserve for ten days in February 2012. In Germany the cold reserve is composed of five coal-fired plants that have actually been closed down but can, when necessary, be started up again relatively quickly.


Dispatchers are people who work for grid operators and ensure that every region in Germany receives enough electricity. As there needs to be a constant balance between the supply of and demand for electricity in the grid, the dispatchers measure how much electricity is being consumed every quarter of an hour. If demand is greater than supply, the dispatchers choose which power plants to bring online. They have to give preference to plants that generate electricity from renewable energy sources.


Every power plant has an efficiency level indicating the percentage of the energy obtained from coal, gas, sun or wind that it has actually converted into useable electricity by the end of the process. During the electricity generation process, a proportion of the energy is lost, for example through heat and friction. The higher the efficiency level, the more efficient the power plant’s use of primary energy.


Electric current is the movement of electrically charged particles that jump back and forth between the atoms of conducting materials, such as water. The atoms capture some particles and release others, producing a chain reaction. We use the kinetic energy of the charged particles as electricity.


This ordinance sets out the minimum requirements building owners must fulfil to make their flats, offices and factories more energy efficient. This includes installing sufficient insulation and modernising the heating and ventilation systems used inside buildings.


Unlike gold, coal or oil, electricity cannot be stored and must be used at once. If suppliers produce more electricity than they need, they offer the surplus to buyers at the European Energy Exchange in Leipzig. If they produce too little, they can purchase electricity there. The exchange is intended to regulate prices by matching supply with demand. Trading takes place online, where energy providers and traders from all across Europe can deal in the derivatives market (up to six years in advance) and the spot market for the following day. Only wholesale traders are permitted to take part.


In comparison to conventional energy sources, it is still relatively expensive to generate electricity from renewables. Renewable energy plant operators would actually have to demand higher prices for their electricity – which would prevent them from being competitive – were it not for feed-in tariffs paid by the Federal Government to balance out the additional costs.


Grid operators or, more precisely, transmission grid operators, are responsible for ensuring that electricity flows across Germany from the energy provider into the big transmission routes. They also make sure that electricity is constantly available in the German grid and that the grid remains stable. In Germany there are four operators managing the 380-kilovolt grid: Amprion, TransnetBW, TenneT TSO and 50Hertz Transmission.


This surcharge, stipulated by the Renewable Energy Sources Act (EEG), is added as a premium to electricity prices. It shifts the cost of promoting renewable energy to private and commercial energy consumers. The surcharge’s value is determined each year by the four grid operators in Germany. For 2013 they have decided to raise the surcharge from 3.6 to 5.3 cents.