The Edinburgh-based operation of the £3 billion Green Investment Bank will include key "transactional" or deal-making personnel as well as administrators and asset managers, its chairman has said.

Lord Smith of Kelvin, who was appointed to head the bank's board last month, told the Sunday Herald that, contrary to previous announcements, the market-facing operation of the GIB would not be exclusively based in London.

"I fully intend that part of the transactional team will be based in Edinburgh, not just support functions," Smith said.

"I have discussed this with [Business Secretary] Vince Cable. Of course a lot of these things will happen in London as it's a financial centre, but Scotland is where a lot of the low-carbon hardware is, and it's there the energy majors are based." He added: "If you know anything about my previous career you will know that I don't take things on just to be a 'grande dame' sitting under a brass plate."

Smith hinted that, despite previous announcements, the majority of the staff numbers, initially projected at around 120, might be based in Edinburgh rather than London.

"The original idea was to have about 70 people in London and about 40-50 in Scotland. I am having a look at that. I don't want to be lonely up here."

A search for the bank's chief executive is underway, with an appointment expected in September.

Nathan Goode, a partner with accountants Grant Thornton and unpaid adviser to GIB, has warned that the body's Scottish element risked becoming an isolated "ivory tower" if restricted to head office administration and asset management.

"We have always made the point that Scotland is a great location for developing low-carbon projects, as a high proportion of the UK's low-carbon activity is happening up here and will continue to. We should be prepared to make the case for a real meaningful presence, which means some kind of transaction team up in Scotland.

"Obviously London is a very significant financial centre. But a smaller transactional team up here in Scotland will help to cement the presence of the Green Investment Bank in Scotland and co-locating the chief executive with the transactional team will be to prevent the chief executive being in an ivory tower."

Energy Minister Fergus Ewing said: "Edinburgh is the only location in the UK to bring together both finance and the clean energy industry in a single location. It makes sense to headquarter the Green Investment Bank in Edinburgh, and to locate as many as possible of its functions here. Ministers want to see a strong GIB with a strong identity based in Edinburgh.

"It is important that the new bank establishes a distinct identity within the global investment community, and this will be better achieved in Edinburgh than in the crowded City of London. We must all get to work on the crucially important job of addressing market failures and channelling investment into low-carbon projects to move the sector on to a strong commercial footing."

A Department for Business, Innovation and Skills spokesman said: "The strengths of Edinburgh's financial services sector mean that it offers the greatest opportunity for a green finance cluster to develop outside London, helping the government's goal of rebalancing the UK's economy. The detailed operational decisions including staffing are a matter for the GIB board."

The UK GIB, which is expected to open in September this year, and is intended to provide additional capital for green infrastructure through loans to accelerate private sector investment in the green economy. Edinburgh was chosen out of 19 UK cities as the headquarters of the bank, which will be initially capitalised with £3bn.