Upper and lower basin of Limberg II pumped storage plant, Austria, Photo: Voith press image

Upper and lower basin of Limberg II pumped storage plant, Austria, Photo: Voith press image

Energy storage
Key technologies for the energy policy turnaround

Climate change, and the fact that we shall run out of fossil sources of energy, make it necessary to rethink our energy supply systems completely. It will be essential to increase the share of the energy mix contributed by renewables. The main technical challenge here is to harmonize the supply of energy from fluctuating sources with consumer demand, so as to ensure that electricity and heat are provided cost-effectively and in line with actual consumption. With suitable storage facilities energy generation and consumption can be uncoupled from each other timewise; so such facilities can play a central part in the energy system of the future.

Smart Grid and Storage facilities

As part of Smart Grids, storage facilities can help to ensure a reliable energy supply even if an increasing share of fluctuating sources of energy is integrated into grids. Via the strategic process  Smart Grid 2.0 the Federal Ministry for Transport, Innovation and Technology (bmvit) is actively supporting this development in collaboration with the stakeholders from the energy sector, industry and research. The aim is to jointly evaluate the results obtained so far from research and demonstration, and to derive medium-term strategies and concrete plans of action for Austria from these.

Energy generation and consumption can be harmonized in grids by means of options for rescheduling loads and/or changing the rate of supply from generation facilities in response to an external signal (so-called “flexibilities”). Flexibility options including tying in energy storage devices – such as classical pumped-storage power stations or power-to-gas facilities. Batteries in electric-powered vehicles can also serve as storage devices, and help to reschedule loads if they are charged appropriately. The system can also be made more flexible overall by means of active distribution grids (e.g. with controllable substations). Linking the sectors electricity, heat and natural gas together in hybrid networks and systems has considerable potential. Utilizing power-to-heat or power-to-gas technologies can turn heat or natural-gas storage facilities into functional energy storage, making the energy system much more flexible than would be possible purely with electrical load rescheduling.

Economic evaluation

With the study “Stromspeicher 2050” by Vienna University of Technology on behalf of the Climate & Energy Fund, a first-ever analysis was performed of how the demand for electricity storage will develop in the Austrian and German electricity system up to 2030 and 2050 as the share of renewables in power generation increases. A number of scenarios were simulated, leading to a reduction in carbon-dioxide emissions of 76 % to 90 % for the  sectors power generation, space heating, hot water and car traffic. With the aid of HiREPS, a simulation model with hourly resolution developed by the Energy Economics Group at Vienna University of Technology, the technical feasibility of a large proportion of electricity from renewables and the cost-effectiveness of flexibility options have been successfully simulated. The simulations show that expanding storage facilities, plus power-to-heat and managed charging for electric cars, can contribute to integrating a large proportion of electricity from renewables cost-effectively.

Research topics in the field of energy storage range from  developing new materials to experimenting with entirely new storage approaches for fixed and mobile applications. Following we  present various new research projects carried out within the  funding programmes of bmvit and Climate & Energy Fund.

Various technologies are used to store electricity and heat:
> Mechanical devices (flywheel, pumped-storage power station, compressed-air storage facility)
> Chemical systems (accumulators, lithium-ion battery or redox-flow battery, hydrogen)
> Electrical storage systems (capacitor, superconducting magnetic energy storage)
> Thermal storage systems (latent, sensible or thermo-chemical heat storage)