One of the great financial quandaries in the age of global warming is how to go green profitably. It is a question that hangs over the commanding heights of all developed economy, from decarbonising energy markets to forcing car manufacturers to accept tough emissions standards. And there have been indications of sympathy within government for private sector concerns about the cost of environmental levies, following claims last year that David Cameron had described them as "green crap".

Nonetheless, the CEO of the UK government-backed Green Investment Bank (Gib) is optimistic – if Whitehall will let the shackles off. Shaun Kingsbury says he could raise up to £60bn to fund low carbon energy infrastructure, from windfarms to wave power, if the restrictions on his ability to borrow in the capital markets were lifted.

The prediction comes just days before Gib will report a financial loss but the bank has already helped raise £4.8bn for windfarms and other projects during its first 18 months. The institution has spent only £1.3bn of its £3.8bn seed capital but says project developers have been able to raise £3 from the private sector for every £1 provided by Gib.

"We will eventually need more capital. It may come in as debt or equity. There are all sorts of different flavours of capital that we could access. I would like to have somewhere between £10bn and £15bn," says the former Shell executive, who quit the oil business for a career in private equity and the low carbon sector.

If the same fundraising multiplier seen in the first transactions was repeated from a base of around £15bn, then Gib would be able to kickstart £60bn-worth of investments. That is more than half of the £100bn often talked about as being needed to modernise Britain's crumbling energy infrastructure.

Green Investment Bank boss Shaun Kingsbury says project developers have been able to raise £3 from the private sector for every £1 provided by GIB.

The bank will officially unveil its first full set of financial figures on Wednesday, with a deficit reflecting the cash injections it has made in schemes that have yet to launch. "We will produce a loss this year because we are not producing income. But if we did nothing else in the way of investments we would expect to be profitable in two years time," says Kingsbury.

Gib has a goal of investing profitably in wind, biomass and other green energy schemes that would otherwise not find funding from the private sector because they are considered too risky, or take too long to develop and pay back the investment.

The first 28 projects have been funded by it alongside global investment banks such as Goldman Sachs, JP Morgan and Deutsche Bank as well as operators such as Dong Energy, Balfour Beatty and RWE.

Gib has contributed through taking an equity stake or providing project financing and says it had helped create 3,000 jobs so far.

Kingsbury is particularly proud of the large investments made this year in windfarms such as the £241m Gib put into Westermost Rough off the coast of Yorkshire and the £220m for a 10% stake in Gwynt y Mor, the biggest offshore field under construction in Europe. The Rough scheme will see the deployment of 6MW-sized turbines, almost double the size of their predecessors.

This is an important step in reducing costs of offshore wind construction and power generation, he says, while other Gib-supported projects include generating power from refuse and energy efficiency initiatives including ones for the NHS.

The bank, which is overseen by the business secretary, Vince Cable, claimed to be the first of its kind in the world but has already organised a summit for similar organisations established in the US, Australia and the Middle East.

Kingsbury says there is huge scope for the pioneering bank to grow more extensively but accepts this will only happen after a successful track record has been carefully established.

"We will need to move into profit in the next two to three years time. We are well on track and if all the projects were built today we would be profitable. My job is to build a profitable and green business. We are not [environmental] activists. We are investors and we are there to make a return on this green market."

Kingsbury is happy to look ahead to a time when the bank may be able to bring in a private sector asset manager to create a larger capital base using private money- something that is currently outside of Gib's remit.

"We are not cash constrained at the moment and there has been a good deal of debate around should the bank borrow … At the moment we are 100% public owned. I hope to move to a position of raising private capital and eventually we have some government capital and some private capital and we are publicly and privately owned – some kind of mixed model."

Kingsbury says he is pleased with the fast progress made by Gib but admits it could have been faster if the external investment environment had been easier. He clearly does not want to bite the ministerial hand that feeds but admits changes introduced as part of the government's electricity market reform policy – such as contracts that underwrite the price of renewable and nuclear-generated power – has had a dampening effect on the market.

"It is the unintended consequence of making a positive regulatory change. You would expect people to say, 'Well let me see what this looks like before I make a big commitment.' That's very rational. In another year we will know.

"We have in our pipeline investment opportunities north of £4bn of sensible projects with sensible co-investors, well thought through. If we typically put up 25% of the capital that shows we have £20bn of live opportunities in the pipeline. There is a lot of stuff out there and we expect it to really pick up in the next year now the process (EMR) is reaching a conclusion."

Gib has 50 staff in a London office but a further 43 at its formal headquarters in Edinburgh, leaving it in an awkward position should the Scotland vote for independence in September's referendum.

Kingsbury is an open and articulate ambassador for the bank. He is happy to discuss his salary – £325,000 plus performance related bonuses – and any other subjects. But he has only two words to say on any aspect of the Scottish independent debate: "No comment".