Electricity supply

Electricity can be produced from the widest variety of energy sources. Bituminous coal and lignite, natural gas and nuclear power (uranium) are particularly significant for electricity production in Europe today, as are renewable wind power, water power and photovoltaic systems. The environmental effects connected with production differ greatly. Figure 1 gives an overview of the greenhouse gases emitted per generated kilowatt hour. Electricity from bituminous coal is by far the most CO2-intensive. Electricity production from renewable energies places only a slight burden on the climate Although nuclear power is connected with very low greenhouse gas emissions, it brings other unsolved problems (e.g. final storage).

FIG. 1: Specific CO2 emissions from different power station types (IFEU 2017)

In Germany today, almost half of electricity is generated by burning fossil fuels, which means that the average environmental effect of electricity in Germany is around 595g CO2 equivalent per kWh of generated electricity. Political provisions (primarily the Renewable Energies Act) have led to greater expansion of renewable electricity generation in recent years. Despite a range of amendments to the REA, a further significant expansion can also be expected in the coming years. The prospect of long-term cost increases for CO2 emissions through emission trading also makes a contribution here. Current electricity market models assume that renewables will generate more than half of German electricity, even if no further political measures are implemented beyond those already decided.

Integration of renewable energies

However, electricity production from renewable energies fluctuates greatly, for example depending on meteorological conditions. For further expansion, solutions must be found to better integrate renewable electricity into the mains power network. Alongside the expansion of storage capacities for electricity, there are attempts to adjust energy consumption in line with its generation.

By controlling the retrieval of electricity from the mains, vehicles can be absorbers during peak generation periods of fluctuating renewable energies – the term for this is "controlled" or "intelligent" charging. With its plans for a high proportion of wind power, this could stabilise the mains power network especially in Germany and create the prerequisites for a more intensive expansion of renewable energies.

Conversely, refuelling vehicles after the last journey (i.e. without controlled charging) can lead to an increasing load on the mains power network at particular times of the day, which in some cases can overload the local infrastructure.

Further information on the influence of charging strategy on the environmental assessment