A £500,000 investment into an innovative new roof for a Portland stone factory is set to save thousands of pounds a year on its electricity bills.

The 800 solar photovoltaic (PV) panels on the Albion Stone building are the largest solar project in which The Crown Estate has invested.

The Crown Estate lets the factory to the island mine operator and manufacturer.

The solar panels are expected to generate more than 150,000 kilowatts of electricity per year – the equivalent to the annual consumption of 50 houses – and will reduce Albion Stone’s carbon footprint by 80 tonnes per year.

In addition to Albion Stone’s electricity savings available to, the solar panels will also generate a return for the Crown Estate, which pays its entire revenue surplus to HM Treasury.

Electricity generated from the installation will be sold to Albion Stone at a reduced rate, with any surplus fed in to the National Grid.

The installation is particularly innovative – instead of the panels being built on to the existing roof, the installation provider replaced the entire roof with an Energy Roof.

The Energy Roof, installed by Solarcentury, will generate electricity for 25 years and requires little maintenance.

Alan Laidlaw, head of new business development for The Crown Estate’s rural estate, said: “Our investment at Portland represents a significant first step into solar energy for us.

“We welcome a joint investment approach to renewable energy, which works both for us and our tenants, by protecting their businesses from volatile energy markets, and at the same time cutting carbon emissions from our estate.”

The Crown Estate was keen that the installation should not result in any loss of business for Albion Stone, and organised the installation to allow the factory to continue to operate.

Michael Poultney, managing director of Albion Stone, said “Albion Stone has been pleased to support The Crown Estate’s solar panel project at our stone production factory, which further reinforces the continuing reduction in the carbon footprint for our Portland Stone.”