In the short term, Germany will need not much storage. Based on statistics for actual power generation from the first half of 2012, energy expert Bernard Chabot has estimated (PDF) that a combined future output of 46 gigawatts of wind and 52 gigawatts of PV (the current targets) would generally not peak above 55 gigawatts, meaning that this level of generating capacity – which Germany is only a few years away from – would not require a lot of power to be stored because almost all of the electricity generated could be consumed.
In 2013, researchers at Fraunhofer ISE found that Germany could still consume 99 percent of its fluctuating wind and solar power without storage if around 62 gigawatts of wind and just over 75 gigawatts of solar were installed – along with the current 20 gigawatts of must-run capacity. Here, “must-run” indicates the level that Germany’s conventional fleet cannot drop below. But if the must-run level is reduced to 5 gigawatts, then Germany could have nearly 100 gigawatts of wind power and around 120 gigawatts of solar installed and still managed to consume 99 percent of this electricity without storage.
At power consumption levels ranging from 40-80 gigawatts, Germany will therefore still need nearly a full 80 gigawatts of dispatchable capacity even if these goals are met. The problem is that an increasing amount of this dispatchable capacity will be idled almost all the time, making such systems unprofitable. One solution proposed is capacity payments and the creation of a strategic reserve – but it is unclear what policy will be implemented and what the details will be. In 2015, the German government rejected the idea of a capacity market.
In addition, a number of flexibility options are developed, ranging from demand side management in energy-intensive companies, flexible biogas plants, smart customer solutions to new, innovative power-to-heat options, which use surplus wind and solar electricity to feed district heating systems. These flexibility options will create a new market of energy service companies.