SoLa Bristol Project Conclusions

This four year low carbon initiative, addressed the technical constraints that network operators have to manage, as more customers connect photovoltaic cells to the network.

Knowle West, defined as the local council’s SMART City programme were benefitting from the installation of PV panels on the properties owned by the local council.

Mark Dale, Innovation Engineer explains the background, “WPD installed 4.8 KWh battery storage units in properties which were linked to the PV panels.

“These battery units were also connected to the local electricity network which enabled WPD to call on this stored energy at times of peak demand on the electricity network. Customers were paid for this energy at an agreed tariff calculated by the University of Bath.”

All the homes in this project were also fitted with a 24v Direct Current lighting system which was powered directly from the storage batteries.

Working with this defined group in one area enabled detailed monitoring and analysis of the outputs which helped the project partners reach the following conclusions:

Smart Tariffs – although something for Supply companies to consider, this project clearly shows that a domestic time of use tariff that reflects a true cost of generation at peak times is essential for this type of technology to progress.

Direct Current Network – some customers in this trial group were less convinced by the outputs from DC lighting, however they realised the benefit of ‘keeping the lights on’. An unexpected learning was that due to the fact most of the participants were on pre-paid meters, they could still rely on the DC lighting when their meter credit had been used.

Battery Storage – domestic systems of this nature need to be tailored to individual customers demand profiles, a ‘one size fits all’ approach is not the way forward.

Customers – efficient and ongoing stakeholder engagement is essential as is the case with projects of this kind; trial and error is how we learn.

Mark added: “There were clear benefits to the customers on this trial, but the network benefits were harder to define. With a 2KW (4.8KWh) battery feeding in to a 500 kVA substation with a robust urban network supporting it, you would need a large number of participants to make a notable difference.”