Individually a home delivering energy to the grid from a PV system or storage battery is a small player with minimal impact on the system. But aggregate numbers of homes and then the impact can become significant, potentially able to unbalance the grid but equally able to provide support to the grid.
There has been some testing of the role of electric vehicles to provide stored energy to the grid. [Engerati-Nissan Begins LEAF to Home Grid Demand Response Testing] In the US Advanced Microgrid Systems has pioneered the concept of developing fleets of ‘hybrid electric buildings’ using large buildings, with projects at various stages of development for Southern California Edison among others. [Engerati-Gridding Buildings For Storage] But so far little testing has been done on the role of home batteries in supporting the grid. However, with their costs dropping, they are becoming increasingly attractive to homeowners and the numbers are quickly growing to the level where aggregation may become viable.
In order to evaluate the potential for home batteries Dutch utility Eneco has launched a new service named CrowdNett, in partnership with Tesla, SolarEdge and the Swiss startup Ampard. Taking its name from the charging or discharging of a network of batteries at a specified time, CrowdNett will develop a network of such systems to provide reserve capacity (frequency containment reserve) to the national grid operator, TenneT.
“Home batteries already form a part of [our renewables] solutions, but using these batteries for grid balancing purposes offers even more advantages,” comments Dirk-Jan Middelkoop, manager Innovation at Eneco. “Grid operators will be able to replace backup capacity provided by physical power plants by capacity provided by a 'virtual power plant'.”
Currently TenneT, like other European national grid operators, purchases its required additional capacity mainly from gas and coal fired power plants.
Home energy systems
The first phase of CrowdNett aims to achieve a network of 400 home battery systems. This will correspond to up to 1MW of reserve capacity.
Tesla will provide its Powerwall batteries. SolarEdge is a leader in solar energy inverters and Ampard provides the battery energy management system, which is used to control the home batteries remotely. The solution comprises a software algorithm which commands the battery-inverter combination based on the state of grid. The solution contains grid frequency measurement. Aggregation is done using a control centre, which continually monitors all the individual units.
Last year, Ampard demonstrated the supply of reserve capacity to the grid operator in its home country, Swissgrid, by means of a network of home batteries.
Middelkoop says that homes with PV or those planning to install PV are being targetted for CrowdNett, in order also to promote that technology. Participants can purchase the Powerwall battery and SolarEdge inverter as well as the interface and installation at a more than 35% discount on the standard price. With an investment of €4,500, in addition to the other benefits of owning a home energy system, they can look forward to a guaranteed €450 per year for at least 5 years from their participation – as long as they share their battery with Eneco.
“This results in the world's best and most sustainable business case for home batteries,” comments Middelkoop on the benefits, which include increasing the sustainability of Eneco’s energy supply.
Battery storage aggregation
Middelkoop says the solution has been tested both in the lab and with several installations in the field.
The next step is to put in place the 400 systems, which is planned by Q1 of 2017.
It is also intended to introduce the initiative in Belgium, for which preparations are well under way. Thereafter in 2017, the intention is to expand the availability more widely in Europe.
Under its new forward strategy Eneco has committed to “transforming from an energy supplier into a service provider and a platform for the coordination of the supply of and demand for sustainable energy at the local level.” CrowdNett is an example of the innovative new products and services that its customers can look forward to and that can support the emergence of the prosumer in the energy market.