Renewable energy development and the integration of various different sources of energy present our current energy infrastructures with new challenges if we are to ensure long-term, efficient and flexible energy supply that also meets demands.
The German electricity grid is currently tuned to large-scale power plants which, as central power generation systems, run non-stop in base load operation and offer hardly any scope for flexible or customised control.
The challenge for the future supply of energy is to cover energy needs, which change during the course of the day, with fluctuating renewable sources of energy. For this reason, existing grids and energy storage capacities must be expanded to safeguard energy distribution, compensate for peaks in demand and to stabilise the power grid by balancing out fluctuations in production and demand.

Many storage technologies are well-known and have been used in Germany for a long time. In fact, these are mostly methods of converting electrical energy into other forms of energy, which can be converted back again as and when necessary. Pumped storage and compressed air storage power plants, storage batteries and hydrogen provide various possibilities for storing energy.

Renewable energy and nuclear power are structurally completely different. Nuclear power plants constantly run in base load operation and always supply the same amount of energy, regardless of fluctuations in demand. A flexible, customised, efficient combination of nuclear power and variable types of energy production is therefore almost an impossibility. Renewable energy sources are subject to natural, weather-induced fluctuations and they are not statically available at all times and in every location.
The integration of various types of energy from renewable sources requires that existing utility grids be adapted. A high share of inflexible nuclear power plants in total energy production prevents the development of renewable energy. The longer nuclear power plants remain in operation, the longer they will compete to feed into the grid, to the detriment of renewable energy sources: even now, at times when high volumes of energy are produced from renewable sources, some electricity is not fed into the grid in order not to jeopardise its stability. Environmentally-friendly energy is forfeited because electricity generated by ecologically harmful, large-scale power plants are given priority.
Although the generators of electricity from renewable sources are compensated for such losses, these costs are carried by consumers through the cost of electricity and not by the operators of the nuclear power plants.

The sun and wind are environmentally-friendly, natural sources of energy that are available in almost unlimited quantities. Generating electricity from solar and wind energy is subject to natural fluctuations during the course of a day or year. Electricity generated from PV plants is known as peak load power: its peak, i.e. when output is at its highest, is around midday. This corresponds to the time of the day when most power is required. The wind and sun compensate for one another as sources of energy both seasonally and during the course of the day. Combining different sources of energy ensures that renewable energy will provide reliable electricity supply: for example, combined heat and power (CHP) plants can be used to generate electricity from biogas in the evening or during calm weather conditions. Biogas is controllable and is a source of energy that is constantly available. It can also be stored without problems and can be used at short notice to cover electricity needs at peak load times. In addition, the heat produced from converting biogas into electricity can be used in local and district heating supply systems. Geothermal energy, i.e. using heat from the earth, can also be used to cover the base load. Hydro-electric power stations and pumped storage power plants complete the energy mix from renewable sources of energy.

The future of climate-friendly, sustainable energy supply lies in a power plant park, which produces energy efficiently in a decentralised manner, and that is able to adjust to the current needs.
The foundation for this is a “smart grid”, which gathers and provides cross-grid information on current energy consumption at a given time. This information can be used for consumption control (demand side management), where energy-consuming appliances may be centrally turned on or switched off.
At times when a considerable amount of energy is produced from the sun or wind, washing machines could be left to run or electric vehicles supplied with electricity at battery charging stations, for example. On the other hand, electricity from electric vehicles may be fed back into the grid with the help of a smart grid, or a decentralised plant such as a thermal biomass power station may be connected for energy production.
An efficient supply of energy that meets requirements within a smart grid requires weather data to be as precise as possible, in order to calculate exact yield forecasts. The meteorological data available already provide very precise forecasts for up to three days which enable direct reactions to be made to fluctuations in energy production. This contributes to system stability and to independence from conventionally produced energy.