A County Durham family firm has sold its wind farm business in a deal reported to be worth between £500m and $1bn.

Durham based Banks Group has agreed a deal to sell its renewable energy division – Banks Renewables – to global asset manager Brookfield. The company launched the renewables business in 2006, and has grown it to become one of the UK’s leading independent owners and operators of onshore wind.

Its other businesses, which include Banks Property, Banks Homes, Banks Mining, Banks Transport and Banks Plant Solutions, will continue to operate as normal.

The renewables business currently has 11 onshore wind farms across the North East, Yorkshire, the North West and Scotland, and earlier this year it completed the construction of its 100th wind turbine as part of the development of the new Kype Extension Wind Farm in South Lanarkshire. The company also strives to play its part within the community and, so far, around £3.5m has been distributed from community benefits funds linked to its wind farms, which provide funding for voluntary groups, environmental projects and good causes in their respective locations.

No value for the deal has been released by either Banks Group or Brookfield, but reports have put it at between £500m and $1bn (£828m).

Founder and chairman of the Banks Group, Harry Banks, welcomed the deal, saying: “I believe that Brookfield’s established position in the renewables industry and the strong cultural fit that exists between both businesses will lead to this acquisition being to the benefit of all parties involved.

“The greater resources of Brookfield will enable the fuller development of opportunities which Banks Renewables are introducing. It will be good for Banks Renewables’ employees and their career prospects, and it will be good for Brookfield because they are acquiring a renewables business with a proven track record and a capability to take the business forward.

“This is also good news for other Banks Group businesses and their employees, who will continue to develop our existing businesses in land, property, mining and in developing our new regional housebuilding business, Banks Homes.”

Sebastian Perl, vice president at Brookfield, added: “The United Kingdom is a high-quality location for renewable energy development and we are delighted to have made a further commitment to this market. We have a track record of being long-term owners of renewable energy businesses around the world and we see great potential to continue the great work that Banks Renewables has already achieved.”