For wind and solar facilities, it does not matter when electricity will be used, but rather whether the wind is blowing or the sun shining. As a result, electricity from renewable sources is often generated at times when it is not needed. Conversely, there may be no electricity just as demand is at a peak.
The goal for 2050: 80 percent of electricity from renewables
- Under the German federal government’s energy policy, the proportion of electricity generated from renewable sources is to increase to 80 percent by 2050.
- The government expects renewables’ share of gross energy consumption to reach 19.6 percent by 2020.
- It also sees as much as half the country’s electricity demand being met from renewable sources by 2030. (http://bit.ly/ZNAv7W)
Electricity storage has an important part to play, as it allows power supplied from strongly intermittent sources to be better integrated into the grid. The energy can be stored in large batteries and then drawn down when needed.
Renewables have already become an established part of the energy mix
Renewables already play a major role in electricity generation, currently accounting for over 23 percent of Germany’s gross power consumption. According to the German federal government, a total of some 135 billion kilowatt hours out of a total consumption of 586 billion kilowatt hours were generated from renewable sources in 2012. (http://bit.ly/ZNAv7W)
Germany needs – and is providing support for – electricity storage
“We need market-based solutions and incentives for storage that are transparent, practicable, and affordable,” says Peter Altmaier, Germany’s Federal Environment Minister. One step in this direction has already been taken: since May 1, a subsidy program run by Germany’s Federal Ministry for the Environment (BMU) and KfW Bankengruppe bank has been providing support for systems that combine decentralized stationary battery storage with photovoltaics facilities that are connected to the electricity grid. (http://bit.ly/17WxKVo)
“Germany needs electricity storage.” That is the opinion of Stephan Kohler, chief executive of dena, the German energy agency. This agency is developing markets for energy efficiency and renewable energy in collaboration with players from politics, business, and society. Its shareholders are the Federal Republic of Germany, KfW Bankengruppe, Allianz SE, Deutsche Bank AG, and DZ BANK AG. (http://bit.ly/10VOmVa)
Storage in the home
Battery storage systems designed to store electricity generated by decentralized photovoltaic units in households are already available in the market. They make it possible for households to use 60 to 70 percent of the power they generate. At the same time, they ease stresses on the low-voltage distribution grid by storing power at times of peak production and making power available at times of peak demand. The systems have a capacity of 5 to 10 kWh. (http://bit.ly/10ORVgr, see page 49)
Study: electricity storage systems relieve power grids
As Germany moves to alternative forms of energy in a process known as the “Energiewende,” one of the challenges it faces is that many solar cells simultaneously generate power whenever the sun shines. Wind power poses a similar problem. At these times, power grids have problems in transporting the produced power to the end consumer and come up against their capacity limits. The imminent overloading can be avoided by the use of storage solutions at the point of power generation. Battery storage systems – in combination, say, with a photovoltaic system – can do a lot to relieve power grids and expand the availability of solar power, while at the same time reducing the cost to consumers of the Energiewende. These are the key findings of the 2013 storage study conducted by the Fraunhofer Institute for Solar Energy Systems ISE on behalf of the German Solar Industry Association.
Decentralized solar batteries store power generated during the day to make it available at a later time. According to the study, this smooths peaks in supply. As a result, battery storage systems increase the ability of existing power grids to accept electricity by up to 66 percent. “Grid bottlenecks are one of the biggest challenges posed by the Energiewende. The positive effect on the power grid of decentralized photovoltaic battery systems cannot be stressed enough,” says Dr. Christof Wittwer, head of the Smart Grids department at Fraunhofer ISE and a co-author of the 2013 storage study.
(Study: http://bit.ly/11ra06E; Press release: http://bit.ly/12saxc3)
Huge commercial potential for electricity storage
A DB Research study entitled “Modern electricity storage systems – indispensable building blocks for the Energiewende” states that by 2040 at the latest there will be a regular need to store 40 TWh of electricity generated in times of temporary oversupply. It goes on to say that it will be necessary to store electricity for several weeks and months. Over the next two decades alone, the total capital investment required for new energy storage facilities in Germany amounts to some 30 billion euros.
Various studies suggest that a major global market for storage technologies will develop in the coming years and decades – and this is borne out by current developments. According to “Building blocks for sustainable energy supply”, a study prepared by the Öko-Institut institute for applied ecology and commissioned by Robert Bosch GmbH, the potential global market for electricity storage is likely to grow to between 9 and 31 GW by 2020. (http://bit.ly/10ORVgr, see page 45)
Storage as an element of smart grids
The flow of electricity through the power grid is set to be improved by what are known as smart grids. Of the many important features that smart grids usher in, three stand out in the German government’s view as central to ensuring a stable supply of electricity: more flexibility in load management; control of the output of electricity generation facilities; and an expansion of storage capacity. (http://bit.ly/ZKTgsU)
Adjustment of the regulatory framework
In short, battery storage systems stand to make a real difference in the Energiewende. But a market for them will not develop in the absence of suitable regulations. The wider future market for renewable energy and storage needs to be designed to allow the cost of investments in storage systems to be recouped via payments that reflect the benefit they bring to the overall system, while removing existing barriers to their use. Otherwise competition between technologies will not be fair.