Wind led the field with over 1.9 GW of capacity from 458 projects, while solar stood at 528 projects totaling 322 MW.
Commercial-scale on-site power generation grew by 24% (392 projects) last year, the report said, for a total of 2011 projects or 4.7 GW of combined capacity, accounting for 12% of all renewable generation in Great Britain.
The biggest growth was seen in farm-based schemes, with a 74% increase to 347 projects, of which 63% involved wind power.
Manufacturing facilities and commercial premises grew their on-site power by 53%, generating more than £80 million (US$130 million) worth of electricity per year.
Rising energy bills, growing awareness of environmental issues and favourable renewable energy subsidy schemes were cited as factors contributing to the growth.