The debate over when utility-scale storage will be needed in Germany is ongoing, but experts agree that once renewable power production exceeds a certain share of the energy mix, it will be essential to keeping the grid stable and ensuring that supply meets demand. Facilities that store power when it is abundant and then act like a power plant, feeding back into the grid in times of scarcity, are not considered commercially viable at present – partly because of the structure of the energy market.
For, example, hydro pumped storage (HPS) facilities traditionally made a profit by generating power to meet high demand at midday, when power prices rose. But because solar power generation peaks during these hours, prices have evened out, undermining their main business model and making it difficult to recoup high investment costs (p. 7).
But utility-scale battery parks can also make money offering other grid services, such as frequency control. This is already happening at the 5MW WEMAG facility in Schwerin and the 1.3 MW BELECTRIC Energy Buffer Unit in Brandenburg.
Power-to-gas and-liquids (P2G or PtG)
Electric power from renewables can be converted into hydrogen through water electrolysis. This means the energy can be stored more easily and used in applications such as fuel cells, to be used in a range of applications, from heating buildings to powering mobility – or converted into high-energy synthetic methane and liquid fuels (power-to-liquids – PPtL) such as methanol, which, like fuel cells, has applications in the transport sector, as well as in the chemicals sector. As an option for storage, hydrogen generated from renewable sources can be added to the gas grid and used in the heating sector while reducing the need for wind energy to be curtailed at times of high generation.
The amount of energy lost in the conversion process is still relatively high. But experts say the development of power-to-gas is likely to rely on transport as its primary application to improve the technology and bring down costs. The greatest potential use of power-to-gas in this sector is in shipping and air travel, where there are currently no other options for low-carbon fuel, as the amount of energy needed excludes the possibility of electric mobility, which requires frequent recharging.
In 2014, the BMWi und BMBF supported the development of hydrogen and fuel cell technology with around 27.2 million euros (p. 12) across 117 projects. The biggest areas of focus for this funding were hydrogen production and solid oxide fuel cell (SOFC) technology.
Converting renewable electricity to heat means it can be more easily stored with lower energy loss. The solutions in this field are often quite low tech – such as insulated water tanks. Combined heat and power (CHP) plants, which utilise the heat created as a by-product of electricity production, have been around since before the 20th century, but are coming back into favour, particularly in Germany, as they make more efficient use of power produced from fossil fuels and biomass. Because they provide heat for local systems – within single buildings, companies or districts – the move away from the centralised energy production makes them relevant once more.
Household energy storage
Electrochemical battery storage solutions designed for private “prosumers” are a growing market in Germany. Lead-acid batteries have been the major technology in this field, but lithium-ion cells, which are more expensive but more compact and can be charged and discharged more frequently, are coming down in price and are now a viable alternative.
An estimated 15,000 German households now use battery storage combined with solar power. Increased competition and economies of scale are driving prices down: according to BSW-Solar, costs fell by 25 percent in 2014. This rapid decline has also been aided by funding from development bank KfW.
While solar companies like SMA are increasingly selling their photovoltaic (PV) units with storage attached, new players are also entering the market – including car companies looking to take advantage of the rapidly growing market as an application for technology developed for electro-mobility. Daimler AG is now taking orders for Mercedes-Benz-branded battery packs for domestic and commercial energy storage.
Meanwhile, American e-mobility leader Tesla recently announced that it was teaming up with Hamburg-based energy company LichtBlicht to offer Powerwall Home Batteries, opting to start the rollout of these domestic storage systems in Germany, where the high number of households produce their own renewable power.
Smart grids and virtual power plants (VPP)
Telsa’s collabration with LichtBlick means Powerwall Home Batteries will do more than just allow households to store their power and use it later. They will have the option of connecting to the energy market via Lichtblick’s SchwarmEnergie system, which means they can also draw power from the grid and sell it back later, potentially earning a profit and helping to keep the grid stable.
SchwarmEnergie is an example of virtual power plant VPP technology, which uses “smart grids” – digital systems that gather information where power is being produced and where it is being consumed – to link up distributed energy storage and production facilities to cooperatively balance out fluctuating generation from renewables and provide other grid services such as frequency and voltage control.
Aside from LichtBlick, other players in Germany’s VPP market include Siemens’ smart grid Decentralized Energy Management System (DEMS), which has been taken up by Germany’s second biggest utility, RWE, and Next Kraftwerke in Cologne, whose Next Pool VPP connects different hundreds of renewable power generation units, so that, for example, biogas can take over when solar or wind power production drops.
Smart grids are a key part of the solution to a decentralised, fluctuating energy supply by providing signals to trigger power production to be ramped up or down or for large power consumers to adjust their load, (in what is known as demand-side management).
Updating the transmission grid
There are also urgent improvements to be made to the transmission grid, which needs to make increased use of more efficient direct current transmission – and be extended to carry power from the windy north of Germany to the county’s industrial south. The latter has faced resistance from those who don’t want huge power lines traversing the German countryside or running through their backyard. Newer technology such as underground cables can help with public acceptance.
Photovoltaic power (PV)
Germany is recognised for having played a key role in developing PV technology, the costs of which have fallen dramatically in recent years. The cost of power from large-scale photovoltaic installations in Germany fell from over 40 ct/kWh in 2005 to 9ct/kWh in 2014. Globally, solar panel prices fell by 75 percent between 2009 and 2014, according to the Earth Policy Institute.
Improvements in efficiency and growing markets continue to push prices lower. In pursuit of evermore efficient PV cells, the biggest focus for public funding of R&D in this sector is crystalline silicon technology, and to a lesser extent, thin-film technology. German PV manufacturers still compete at the top levels of industry, but over the last year Chinese companies have broken German-held records for efficiency in both of these technologies.
Like other renewable power generating technology, wind turbines are well beyond the basic research stage and contribute an ever-growing share of power to Germany’s energy mix. But improvements are being made all the time. Cost reduction remains a major area for development, particularly for offshore wind.
In recent years, taller, more efficient onshore turbines have made it possible to generate wind power in less windy areas – like Bavaria and other regions of southern Germany – that were previously considered unsuitable. Developments such as heated blades and storm control features mean they are more effective in a range of weather conditions and extend the lifespan of the equipment. Turbine manufacturers are also tackling issues such as noise and the “flicker effect” of turbines, which are seen as important to public acceptance. “Bubble curtains” are also being used to protect marine wildlife from the sound impacts of installing offshore wind turbines.
Much of the focus now is on remote monitoring, intelligent control systems for the smooth integration of wind power onto the grid, and making the upkeep and servicing of turbines easier and more efficient – particularly for offshore wind.
Much of the growing public funding for bioenergy R&D comes from the food and agriculture ministry. As well as pursuing new processes to recover energy from biomass, government funding aims to promote better integration of bioenergy into the grid and its use as a complimentary energy source to balance out volatile production from solar and wind energy. Bioenergy production is utilising an increasing range of crops, a broader mix of renewable raw materials – including algae – and by-products from agriculture and forestry. Another key area of research is the use of lignocellulose (plant dry matter) to produce biofuels.
Fossil power technologies
While Germany pushes forward on renewables, other technologies that could reduce emissions from fossil fuel energy generation face broad resistance in Germany and as a result, there is little in the way of R&D in these areas. While not completely banned, fracking is subject to strict limitations, meaning it has scant commercial potential in Germany. Carbon capture and storage (CCS) meanwhile continues to receive limited government support but political controversy has resulted in CCS projects by the major utilities being cancelled.
Despite the phase-out of nuclear power in Germany the government’s German Energy Research Programme spent 138 million euros on nuclear fusion R&D in 2014 (compared to 303 million euros spent on renewables), primarily through the Helmholtz Association and support for the international thermonuclear research reactor (ITER) in France. The government says in its 2015 report on energy research that growing energy demand and the need to reduce carbon emissions mean a range of options must be kept open to secure future energy supply. “Germany has outstanding scientific expertise in the field of nuclear fusion by international comparison,” the report says.