First: The consumption of electricity must become more flexible

In the old system, to put it simply, we constantly adjust the supply to the demand. When we need a lot of electricity, coal and nuclear power plants have to provide more energy. With Russia’s invasion of Ukraine, the vulnerabilities of the global energy infrastructure have been exposed and it is clear that the oil prices are greatly influenced by global political dynamics, which means the world must transit to clean energy at a greater pace. If a massive amount of electricity is available, e-cars, for example, could receive the signal in a digitized power grid to charge their batteries at that moment to relieve the grid. In times of lull, they could, in turn, give part of the electricity on their batteries to the grid and thus stabilize the supply. The industry also plays a role in this field: companies could ramp up flexible, particularly power-intensive processes in times of high power generation – when electricity prices are low – and throttle them down in shortage when electricity becomes more expensive.

Pilot projects are running: the German Energy Agency cooperates with companies in Bavaria and Baden-Württemberg, for example. In addition, a multi-year model project came to an end in October 2020, which examined in five German regions how intelligent power grids could work on a large scale.

Second: Electricity storage systems are becoming more important

For bridging short periods, rechargeable batteries are the classic option. These are getting bigger and cheaper, and some of them can already store enough electricity to supply 300,000 households with electricity for four hours. However, because they discharge over time – as we know from smartphones lying unused in a drawer – current rechargeable batteries are primarily suitable for bridging a maximum of a few days. For long-term storage, on the other hand, electrolyzers will play an important role: They produce hydrogen, albeit with considerable losses, i.e., a gas that can also be stored for the long term and then, for example, can be converted back into electricity in a power plant instead of fossil natural gas. Hence, energy storage systems will become more important in the near future.

Third: Electricity will be imported and exported significantly more than today within Germany, but also across national borders

Somewhere in Europe, the wind blows, and the sun always shines, while elsewhere, there is a need. The German Weather Service has calculated those cold dark doldrums – defined as a period of 48 hours in which photovoltaic and wind power achieve less than 10 percent of their maximum output – occur on average twice a year in Germany. If you look at the European power grid, the problem is reduced to one incident every five years. Therefore, electricity grids must be expanded to enable the exchange of large amounts of electricity.

For achieving a stable power supply, these different factors must be combined and coordinated. Moreover, many of them are mutually dependent: If, for example, there is no willingness to expand local wind turbines massively, significantly more photovoltaics and thus larger local storage capacities are needed to compensate because solar power generation naturally fluctuates more than wind power. If, on the other hand, offshore wind power in the North Sea is expanded, the transmission grids must be expanded to a considerable extent to transport the electricity across the country.

Whether and by when an utterly renewable power supply will become a reality depends on many unknowns

To sum up, it takes wind and solar energy expansion and a more flexible corset to achieve 100% renewable electricity. How quickly both are implemented depends on many unknowns that are difficult to determine without the colloquial crystal ball: political will and social acceptance, for example, entrepreneurial activity and the speed with which the necessary technologies penetrate the market.

In addition to when the goal would be technically achievable, there is also the question of when it is realistic from today’s perspective – politically, socially, and economically.

Studies on the energy transition examine various hypothetical scenarios in which the various variables are assigned different assumptions. Then we will check when we can reach our goal under the given conditions. Or: You take one year as the target value and check what would have to happen to achieve climate neutrality by that time. The forecasts range from “we can do it by 2035″ to “we can do it by 2050″.

The Wuppertal Institute for Climate, Environment, and Energy has developed a particularly optimistic scenario on behalf of Fridays for Future. Last year, the study examined whether a climate-neutral Germany – and thus a power supply-based 100 percent on green electricity – would be possible as early as 2035. According to the phase-out path from coal-fired power generation negotiated by the so-called coal commission, 2035 is the earliest realistic date for shutting down the last coal-fired power plant.