Problem addressed

Unlocking renewable energy for apartments as part of the UK’s transition to net zero carbon has been a huge challenge. Whereas houses can access rooftop solar PV, solar energy for apartments, has previously been infeasible.

Until now, the only way for apartments to install rooftop solar would be to install individual solar systems into each unit – a largely unworkable solution due to cost, footprint and inefficient energy utilisation.

Solution overview

SolShare is the world’s only technology for connecting multiple apartments to a single rooftop solar PV system. This enables apartment residents to finally access the benefits of rooftop solar: reduced electricity bills and lower carbon footprints.

The SolShare technology works with a traditional solar system and enables it to be connected behind-the-meter to multiple flats. It requires no changes to standard metering infrastructure and can be installed on both new builds and existing apartments.

Allume Energy’s SolShare systems are connecting apartment residents in 5 countries, finally providing equitable access to solar.

Furthermore, its ‘dynamic sharing’ algorithm delivers an improved solar utilisation of over 25%. It does this by delivering energy to residents when they are using it throughout the day. Over the course of a prespecified period, normally one month, the algorithm learns when to deliver energy, to whom and at what time, in order to maximise energy delivery and share the solar energy evenly.

SolShare has also recently been accepted as an ‘innovation measure of substantial uplift’ by Ofgem for the latest ECO4 funding initiative. ‘Substantial uplift’ being defined as a technology that is a significant improvement on the closest alternative.

Cost benefit

The SolShare technology saves on space requirements and hardware, given the need to only install one solar system and inverter for the whole building, rather than for each individual apartment. As a result, it saves an estimated 25% in installation costs as compared to a typical solar system.

Typically, apartment residents will save up to 40% on their energy bills and, depending on the size of the system, mitigate between 15-100 tonnes of CO2 from entering the atmosphere each year.

To gain sustainability credits under the new SAP 10 release, a solar system must be connected directly to the apartments; SolShare is the only solution that can feasibly enable this. A SolShare PV system typically adds between 5-15 SAP points to a flat for a total cost of just £2,000-£4,000 per flat. That is for the entire system: panels; inverter; SolShare; installation & labour etc.

The SolShare solution is highly tailorable for the customers’ needs. The kWp capacity associated with each flat can be tailored according to individual needs. For example, they may specify a higher kWp to flats that need a bigger boost in their SAP score to achieve a certain EPC rating. Typically, Allume Energy see between 0.5 – 2.5 kWp specified per flat, which achieves a 15-30% reduction in grid energy usage and consequently CO2 emissions.

The EPC to cost benefit is so attractive, the Social Housing Decarbonisation Fund team of BEIS have stated that even though the SHDF Wave 2 is a fabric first approach, they would accept SolShare solar systems as part of the bids, as long as it is contained within the 50% contributed portion of the bid.

Case study

SolShare is suitable for any low to medium-rise apartment building. Three exemplifying case studies are given below, one from each of our major markets.

Social Housing Providers: A 66 kW SolShare system has been installed on a 44-apartment building owned by a social housing provider. The system is reducing carbon emissions by 93 tonnes per year and saving on electricity bills. Feedback stated “we are hearing from our residents that they don’t need to worry about electricity bills to keep warm in winter, as they have accumulated savings from spring to autumn.”

Property Developers: A 70+ kW SolShare system has been installed on a new build apartment development and connected to 39 of the 50 apartments (the SolShare can be connected to some or all of the apartments depending on requirements). This system is reducing carbon emissions by 115 tonnes per year and is saving each resident 30-40% on their energy bills. The ROI on this system was instant as it was incorporated into the apartment sale price.

Asset Owner & Manager: A 22kW SolShare system has been installed on a landlord owned building. It is connected to 12 apartments and the building’s common light and power. The system is reducing carbon emissions by 27 tonnes per year and saving the residents on their electricity bills.