Feasibility studies and analysis

Elaborate studies were and still are conducted in Belgium with regards to the technical and economic feasibility of neighbourhood batteries in our low and medium voltage grid. The effective first implementation was missing.

However, in-field experience is key to gain understanding in the effective behaviour and interaction with the surrounding system(s) and additionally initiate the needed changes in the enabling framework. Hence the goal was set: in 2014, Th!nk E included the actual implementation of a neighbourhood battery in a proposal for the H2020 EU-project STORY. In spring 2018,  the works to implement Belgium’s first neighbourhood battery on a weak electricity line were kicked off!

The first challenge was the selection of a location.

Current legislation on building permits does not include a neighbourhood battery. It is difficult to explain the societal value of neighbourhood batteries when the experts on building permits have not yet been confronted with electricity markets, quality of electricity and curtailment of small scale PVs. Hence, it took several months of discussion with the local and Flemish government.  When a piece of land was for sale on the demonstration site in Oud Heverlee, it seemed the ideal opportunity: the first notarial act that mentioned a neighbourhood battery was a fact!

The next hurdle was the permit itself.

Was anything special needed or not? Can it be considered a part of the grid infrastructure? Is it public or private? Workshops with local, regional and Flemish governmental servants were organized to conclude that only an environmental notification was needed: no building permissions, no restrictions with regards to the duration of the asset being installed on site.

Challenge number 3 was the electrical connection.

Also on the side of the DSO, there was no precedent. However, treating a neighbourhood battery as a normal connection would neglect the potential added value it could bring. Therefore, the main focus was on restricting potential actions with unintended impact on the one hand, and encouraging a grid-supporting behaviour on the other hand. Important is that the electricity line was already used to a maximum of its capacity. Saturated electricity lines are characterized by voltage variations. As the capacity of the line is not sufficient to supply simultaneous energy to all consumers, the voltage will drop below the standard 230 V. The other way around, in a street with a high percentage of solar panels, the voltage can rise to 240V and beyond. Hence voltage variations could be used as a good indication of the actual load or injection on the line. The battery is to compensate for low voltages with discharging and for high voltages with charging. The DSO therefore developed a clear and logical addendum to the connection contract, emphasizing the need for grid-support in the operation of the neighbourhood battery.

The last obstacle is in the electricity price.

A standard connection with over 10 kW injection power has a separate supply and injection tariff. The former includes the energy price and all charges and taxes, for instance societal and  denuclearisation contributions. The latter only includes what the electricity supplier is willing to pay for the energy that is injected in the grid. In practice, this implies that around 30 cents are to be paid for every kWh that the battery takes from the grid, while only about 4 cents are received for every kWh injected back in the grid. Services to the grid are not yet remunerated, even though the European Clean Energy Package gives more than just a hint towards establishing such schemes. However, for local grids that are well-sized and congestion is not an issue, there is little value of a neighbourhood battery.

Also, in relation to the business case, the project shows that cable replacements are still a less expensive option. However, despite focusing on local weaknesses and especially on issues that occur at high temporal resolution, having multiple neighbourhood batteries acting in a coordinated manner could also generate benefits for the medium and even high voltage grid, therefore justifying the penetration of decentralised and centralised batteries.

Th!nk E worked on the design of the enabling framework and went through each of the above 4 aspects, discussing the need and potential design of a tariffing structure with the regulator.

Together with the project partner ABB and integrators Imtech and Enervalis, Th!nk E managed to get the battery up and running in early 2020.

We would be happy to apply the expertise gained in this implementation in your next innovation challenge. Do you want to understand how we can help you on neighbourhood batteries? Contact us!

Contact us! Mail to info@think-e.be