Further developments of OGI’s in-house software have been completed to allow calculations of heat abstraction from a series of boreholes which are within the influence of each other. Within the UK there is rarely much space to position heat abstraction boreholes and so placing boreholes within the influence of each other is inevitable. OGI’s software enables the position of the individual boreholes within the collector field to be optimised to maximise heat generation from the ground.