This solution consists of utilising the fast and versatile nature of batteries to provide ancillary services to DSO and TSOs. The primary services are frequency balancing, voltage support and congestion manage-ment. The battery types addressed in this flexibility solution are medium size batteries and aggregated small domestic batteries. It is also possible to address adequacy by adjusting charging and discharging to peak in an hourly perspective so the demand curve is more stabilised.
Components & enablers
The following components are required to utilise the flexibility potential of batteries:
- Installed battery banks, either aggregated domestic batteries or larger district batteries.
- Energy consumption / production forecast to predict battery state of charge.
- Algorithm/control system to control and map the available flexibility in the batteries.
- A market solution whereby the user can sell the flexibility the battery provides.
- Change in the current regulatory framework to allow for medium batteries (reduce fees or charging / discharging, reduce minimum power offers in markets, etc.)
State of the art in application and research
Home batteries have recently caught the public’s attention, with products such s Tesla’s Powerwall and similar products from other manufactures. However, the aggregation of these batteries are currently only in the pilot phase. District batteries are not as common, but a number of different pilots are investigating their potential advantages.
Medium-scale battery banks have a large power output compared to their energy capacity relative to other storage technologies. This, combined with their fast reaction time, makes them well suited to provide primary reserve. Simulated primary reserve orders from DSO / TSOs have been tested in the pilot project and, in general, show good results. The ELSA project tested a similar order under actual grid conditions and was able to fulfil the order from the DSO, validating the viability of the solution.
The ability of medium- and small-scale battery banks to deliver secondary and tertiary reserve is limited due to the energy required. However, their fast reaction time enables them to provide ‘virtual inertia’, where the battery acts as a spinning reserve, reacting to small fluctuations in frequency.
Some pilots have tested the batteries’ capability to provide voltage control as they have the ability to control their reactive power consumption. These pilots (ELSA, SENISBLE) have proven that medium-scale banks have the ability to accurately control the phase angle of the energy they provide to the grid.
The technical aspect of the solution is, for the most part, ready. For the solution to mature further, certain economical and legislative barriers must be overcome. New markets have to be established so that the economical potential of ancillary serves offered by batteries can be fully exploited and further development of the existing market rules. Legislative action must be taken to give smaller players get access to this market to realise the full potential of this service. ICT platforms for the optimal control of charging and discharging must be established.
OSMOSE covers how to combine battery storage with flywheel and supercapacitors to provide a combination service of synthetic inertia, frequency balancing and congestion management services in two demonstrators. Furthermore, OSMOSE demonstrates a lithium-ion battery connected at high voltage in DC to provide voltage control services.
COORDINET utilises batteries for congestion, voltage and islanding operation problems at the grid.
CROSSBOW’s objective is to demonstrate a number of different, though complementary, technologies, offering the regional transmission network higher flexibility and robustness through novel energy storage solutions, both distributed and centralised.
EASY-RES aims to develop methodologies to make the converter-interfaced Distributed Renewable Energy Sources / Battery Energy Storage Systems (DRES / BESS) behave like or even better than controllable synchronous generators (SGs) during dynamic and transient events (WP2).
Flexitranstore’s objective is to increase flexibility across the energy industry value chain by integrating BESS, supporting the provision of ancillary services by RES at points such as: the TSO / DSO interface or wind farms and gas turbine plants.
The GIFT project addresses synergies between the electricity, heating, cooling, water and transport networks in the WP5 through storage. Storage for electricity will be provided through batteries and hydrogen, and synergies with the transportation sector will be achieved through the development of V2G solutions (both naval and terrestrial). In addition, there is a synergy between the heating network and the electricity network thanks to innovative energy storage devices that allow heat to be recovered.
The GRIDSOL solution is based on solar firm hybrid power plants. This power plant combines a core of synchronous and non-synchronous generators under a dynamic control system (DOME). The control system of the electricity dispatch is self-regulated and able to provide ancillary grid services because of firm and flexible generation on a single output, tailored to a specific location and relieving pressure on the TSO.
InterFlex investigates the combined implementation of complementary services in dedicated storage assets, with the aim of making the battery a competitive system asset. The combined services cover local grid congestion management, islanding support and customer services such as renewable self-consumption as well as ancillary services.
The overall purpose of NAIDES is to develop a battery technology based on the sodium ion technology for sustainable electrical energy storage (EES) that would result in a radical reduction in cost with respect to the lithium ion technology while ensuring sustainability and performance in terms of safety, cycle life and energy density.
REACT deploys high-capacity and environmental friendly lithium-ion and aluminium-carbon batteries and conventional vented and valve-regulated lead-acid batteries and power-to-gas solutions to form a viable solution that reduces GHG emissions, adapts to energy needs and can be easily replicated across the EU island community.
In SMARTNET, WP2 focuses on the design of market architectures that can foster and leverage the provision of ancillary services by DERs; namely, distributed generation and storage and demand response.
The main objective of TILOS is the development and operation of a prototype battery system based on NaNiCl2 batteries, provided with an optimum, real-environment smart grid control system which can cope with the challenge of supporting multiple tasks. The battery system will support both stand-alone and grid-connected operation, while proving its interoperability with the rest of the micro grid components, such as demand side management aspects and distributed, residential heat storage in the form of domestic hot water. In addition, different operation strategies will be tested to define the optimum system integration.
One of UPGRID’s objectives is the participation of customers, distributed generation and energy storage in network management.
Wisegrid aims to optimise the market deployment of storage systems, manage and balance the network optimally, respond better to changes in demand while simultaneously reducing losses in distribution.
Technology Readiness Level
Although battery technology is capable of addressing all the needs mentioned, the projects research how to address barriers to flexible participation in the power system. However, currently it is not profitable. The batteries’ efficiency and lifetime are insufficient for this purpose. Regulatory and technical barriers prevent batteries from working together with other components in the power system, such as local generation and demand forecasts. Various pilots and demonstrations address potential solutions to these barriers.
Current focus of R&D and research gaps
There is currently a large amount of research being done in the field of battery technology, with research into improving energy density, price, safety, longevity, etc.
Research directly applicable to this solution is research in to how different battery technologies behave when used for grid operation. Especially regarding how the charge / discharge cycle effects the longevity of the battery and what the self-discharge rate is.
 ELSA Pilot 1, 2, 3, 4 [Link]
 INVADE [Link]
 The Smart Grid Battery Storage Project Prottes [Link]
 STORY Pilot 5 [Link]
 NETfficient [Link]
 OSMOSE WP4 [Link]
 SENSIBLE – Nottingham [Link]
 CoordiNet [Link]
 CROSSBOW [Link]
 EASY-RES [Link]
 FLEXITRANSTORE [Link]
 GIFT [Link]
 GRIDSOL [Link]
 InterFlex [Link]
 NAIDES [Link]
 Nobelgrid [Link]
 REACT [Link]
 SMARTNET [Link]
 STORY [Link]
 TILOS [Link]
 UPGRID [Link]
 VINPOWER [Link]
 WINDNODE [Link]
 WiseGRID [Link]