Nottinghamshire County Council is using a new system that allows the size of an installed solar array to exceed the grid allowance.

The 32kW array at Hagg Farm was installed in September as part of the council plan to reduce emissions and energy bills and will generate 25,000kWh a year.

As the system was installed in a rural area with only overhead lines, there is a 7kW energy export grid limit. Regardless of how much power is consumed on site, the array would have been limited to 7kW, instead of 32kW without a new control system to manage the generation and grid import. This barrier to renewable energy generation with existing grid infrastructure is a growing problem for those wishing to install solar.

The array is fitted on the roof of the Education Centre in the Peak district. The install took less than two weeks with a team of five working on slate roof tiles that are more than a century old.

The Export Power Control system limits increasing problem can be used with any size of array with many inverters, and was created by installer EvoEnergy and manufacturer of monitoring systems, Moody Automation.

“As the Grid becomes increasingly congested with renewable systems, the issue of managing diversified power generation across the network isn’t going away,” said Tim Hickman, technical manager for EvoEnergy.

“There was no ‘off the shelf’ solution to the export limit problem at Hagg Farm so our technical team had to develop something new to meet the needs of this project and others where we’re faced with similar limitations.”

The new control system ensures that the 7kW of exported power is not breached for more than a few seconds. “It’s an inventive answer to what is becoming a common requirement of the electricity network operators,” said Hickman.

Phil Keynes, energy team manager for Nottinghamshire County Council, said: “We were really pleased that EvoEnergy found a solution which enabled this installation to go ahead successfully. The centre was very keen to have PV as a showcase for renewable energy technologies.”

Evo Energy also commissioned a display that informs young people about the energy savings to improve their understanding of sustainability, said Phil Baker, head of Hagg Farm,

Keynes added that the Hagg Farm installation is part of Nottinghamshire Council’s £1.8million investment programme in solar panels, which is also part of a wider programme of investment in renewable energy and energy efficiency.