It is a top priority of European Energy Policy to have secure and cost-effective energy for European citizens and enterprises. The internal energy market should play an important role in the achievement of the EU's targets by providing the necessary cost signals. These targets aim to obtain greater decarbonisation, increased deployment of renewables, better affordability and greater energy efficiency, which will ultimately deliver progress towards all the objectives of the Energy Union and boost the clean energy transition by modernising our economy.1
The energy system in Europe has a great degree of complexity, partially due to its historical national focus and more recently due to the rapid changes in demand and supply patterns. This applies to the gas, heat and the electricity grids. Recently the large-scale deployment of variable renewables generation has created challenges especially for the operation of the European electricity system. The power generation mix has changed with unprecedented speed and therefore new solutions for the electricity system need to be considered. The role of forward looking energy policy plays a crucial role in enabling the needed solutions.
Investments in storage, both for Security of Supply and grid flexibility, have been challenged by increasing levels of risk in energy infrastructure related investments, resulting in sub-optimal level of investments in flexibility from system point of view. We need a market framework that supports and incentives flexibility in existing and new generation assets and other flexibility mechanisms.
Storage can contribute to a much more effective use of today's existing grid infrastructure, at all voltage levels. A more flexible grid will contribute to making the most efficient use of the existing infrastructure, reducing the peak load in the main transmission and distribution lines. This will have a positive effect on the capacity needs of the interconnections, where even the interconnection target (10% by 2020 and 15% by 2030) could be insufficient for the needed flexibility.
The generation technology mix and the location and size of these generation capacities determine the grid flexibility needs. Many storage technologies are scalable and geographically rather independent, making storage a prime solution in the evolving energy system, accommodating the changing generation and consumption mix.
The optimal location of storage is determined by economic, technical, physical, public acceptance and political variables. It is now the moment to reflect on how to optimise the EU level energy system with an urgent implementation of flexibility solutions to enable more renewables and less curtailment. Small and medium scale batteries can be installed quickly, and represent a fast solution at customer or even distribution grid level. Other technologies could provide optimal solutions as a function of the specific grid needs.
While cables sometimes face criticism, local storage benefits from high public acceptance. In some cases storage can provide temporary solutions, until cables are operational. Hybridisation of several technologies seems to be a new trend in many local projects in order to ensure clean, secure and affordable electricity, heating and cooling.
Significant progress has been made in Power-to-Gas for large scale storage, in Power-to-Heat for demand response, in battery systems at grid and home level and other hybrid systems on islands and remote areas. Power-to-Gas technologies are developing very quickly, providing a possibility to link the electricity grid to other energy grids and uses, like transport and industrial feedstock. This should provide additional opportunities for integration of higher shares of variable RES. Further progress is required on all technology fronts, as we need a mix of all technologies for all sizes and all locations.
The trend towards more decentralised electricity generation and self-consumption has been triggered by the ongoing energy transition. The benefits of distributed generation are can be better seen when there is higher levels of self-consumption and when energy storage is a significant part of the distributed system. Also the coupling the distributed system with smart grids provides additional value to distributed generation.
The role of thermal storage should also be considered in distributed systems. Existing storage of heat, in the form of hot water boilers and the thermal mass of buildings, is in some circumstances of both economic interest and can be quickly installed for usage. Also a more efficient use of waste heat, especially low-temperature heat, could further contribute overall energy efficiency targets.
In general we can see that energy storage can be a bridge from centralised to distributed generation, which is another path worth to explore further.
The recent geopolitical developments have increased the focus on energy security in the energy system. Energy Security can be understood in two ways, as security of electricity supply and as security of energy supply. In both of these cases, storage options have strong attributes to contribute to increased levels of security.
The security of electricity supply relates to grid stability and power generation capacity. A number of factors have reduced the quantity of spare capacity in the grid; increased load on transmission lines, increased variability in generation and slowly decreasing amounts of conventional generation capacity. These factors, if not adapted to, can result in lower safety margins and increases the risk of black-outs. Energy storage can support reducing these risks while supporting at the same time integration of RES and the transition to a low carbon economy.
The geopolitical frictions have underlined the need to strengthen the European security of energy supply. Using the available renewable and other domestic energy resources would mitigate the risks related to energy supply. Large-scale energy storage, both for electricity and gas, has a key role to play. Today gas storage can buffer and store the available energy resources, providing gas, electricity or heat security of supply over months. It is expected that energy storage technologies related to the use of electricity, such as chemical storage (allowing days and weeks of storing capacity), could play a growing role in relation to security of energy supply as well.
Storage can also improve the system Energy Efficiency - being one of the cornerstones in the Energy Union - and contribute to an optimal design of the European energy system at affordable costs. As a conclusion, energy storage allows for energy efficient use of existing assets, including conventional and renewable power generation, and can provide energy efficiency benefits at both the grid and at consumer level.
© European Union, 2017
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1. Clean Energy for All Europeans – unlocking Europe's growth potential- http://europa.eu/rapid/press-release_IP-16-4009_en.htm