Will the real Renewable Energy Foundation please stand up? This is a question being asked with increasing intensity within the UK's renewable energy sector.

The REF styles itself on its website as "a registered charity promoting sustainable development for the benefit of the public by means of energy conservation and the use of renewable energy", but some prominent voices within the industry have long felt that the charity is little more than a front for anti-wind lobbyists. For example, newspapers that routinely run anti-windfarm stories, such as the Daily Mail and the Telegraph, often turn to REF for helpful statistics and quotes.

The REF's critics believe its name is misleading and they want it to be open and transparent about its real "agenda". The public face adopted by REF today does certainly seem very different to the one it nurtured when it launched in 2004. As this Guardian article shows, the tone used at the launch event was one that was openly hostile to the wind industry. Its then chairman, the broadcaster and vocal anti-wind campaigner Noel Edmonds, and chief executive Campbell Dunford spoke of the "grotesque political push" for a technology that was helping to cause the "industrialisation of the countryside".

In the years since its launch, REF has modified its tone and made a point of regularly stating that it is not "anti-wind". For example, in 2007 there was an exchange of views in this paper between Polly Toynbee and John Constable, REF's director of policy and research, in which Constable said:

We have consistently argued for offshore wind, among other technologies, to be made more attractive, and for a secure role for the renewables sector. Renewables have much to offer in tackling our energy crisis, but undiscerning enthusiasm, and an unwillingness to recognise the problems arising from a defective subsidy system, won't help anyone.

The question of who supports and/or funds REF is also intriguing. First, we have the former chairman Noel Edmonds, who became a high-profile anti-wind campaigner when his north Devon home was threatened by a windfarm development. But he resigned as a director last year due to his "TV commitments", according to REF (see below), who also state that he was never a financial supporter. REF's website also states that Vincent Tchenguiz - the property tycoon who was arrested earlier this year by the Serious Fraud Office and who is now seeking a judicial review into the issuing of the arrest warrant - has been a significant donor.

Then there is the link with David Burnside, the former Ulster Unionist MP, former British Airways press supremo and now public relations consultant. His register of interests from his spell as an MP includes a listing that shows his London-based PR firm David Burnside Associates declaring REF as one of its clients. It also said his firm's clients included an "anti-turbine campaign in Somerset". It turns out, as this Evening Standard article from 2004 shows, that this campaign was Save the Vale Action Group, which was headed by Campbell Dunford, who is now REF's chief executive. The local campaign also later hired the not-insignificant PR services of Porter Novelli. (Incidentally, Ecotricity's plans to erect turbines at Blackmore Vale on the Somerset/Dorset border were seemingly dealt a fatal blow in March.) There are close geographical connections, too: David Burnside Associates is located very close to REF's offices near Charing Cross station in central London.

REF also boasts impressive links to City financiers and energy consultants, as its technical advisory group and list of trustees displays. (Quite what the right-wing historian Niall Ferguson brings to the mix is less clear, though.)

The moderating of REF's tone when discussing windfarms appears to coincide with, what it describes as, a "dialogue" it had with the Charity Commission in 2008 over whether it was violating its charitable status by being too political in its campaigning. I asked the Charity Commission to elaborate. A spokeswoman said:

We received a complaint regarding the Renewable Energy Foundation in April 2008. The complaint related to the charity's campaigning activities and whether or not the Foundation was charitable. We assessed the concerns raised and determined that there was no evidence to suggest that the organisation was not charitable. However, we did provide the charity with advice and guidance regarding its objects and the appropriateness of its activities in accordance with these objects. Following our assessment of the concerns raised we met with representatives of the charity to discuss amending its objects to accurately reflect the charity's activities and purposes. We have not received any recent complaints about the Renewable Energy Foundation and are not currently in contact with the charity.

But the Charity Commission's intervention hasn't appeased the critics, as this recent article published by BusinessGreen displays. Rather, they now wonder whether the moderating of REF's tone might only be further disguising the organisation's real motives.

A spokesman for RenewableUK - formerly known as the British Wind Energy Association - told me:

It would set an unwelcome precedent for a charitable organisation claiming to support renewable energy, to spend time campaigning against what is effectively the chief renewable technology in the UK. It raises issues about the organisation's motives, as well as financial and reputational advantages of being a registered charity. There needs to be a much clearer sense of how REF fulfils its charitable purpose and lives up to its name.

Responding to the news that REF had recently launched a new database at the headquarters of Ernst & Young, Juliet Davenport, CEO of Good Energy, told me:

The problem with the Renewable Energy Foundation is that their name is misleading. It suggests they are in favour of renewables when actually the opposite is true. Although they claim to support small-scale renewable generation, their real agenda is trying to block larger scale windfarms. I'm very surprised that Ernst & Young is allowing itself to be associated with the REF, as Ernst & Young is a pioneer in the renewables sector and has been very supportive of windfarms and renewable energy in the UK.

So, given the confusion and suspicion swirling around REF, I asked it respond to its critics and set the record straight once and for all. Here's how Margareta Stanley, REF's spokeswoman, responded:

How come Ernst & Young hosted your recent launch?

One of their renewables team said could he ever help us and I said if they could ever provide a venue that would be useful. And he said OK. We're very lucky that we have very good relations with all sorts of people in the City and elsewhere. We've held events at Matrix, all sorts.

But there's no formal connection between REF and Ernst & Young? They don't sponsor or fund you?

No.

Why did Noel Edmonds resign last year?

Noel Edmonds was too busy with his television work. He was never a financial supporter. When we launched REF in 2004 we were obviously trying to create a new information body and you want to be in the situation where people know about you as quickly as possible and at the time I believe he wasn't doing any television work. So, by him coming forward and him acting as our figurehead, it allowed us to get media attention for what is essentially quite a dry subject. Having Noel Edmonds host our initial briefing meant that journalists came.

If you look at REF quotes from back then it was clear what your agenda was…

I would totally dispute that. REF was only about putting the research we were doing into the public domain. It's always been about outputting empirical research. Some of our earliest research was on modelling on actual outputs from Denmark. It won the Telford gold medal. We never set out to be anti windfarms. That was how it was perceived externally. We've always, always been about generating data. If you actually look at what we were doing it was producing research.

So, for the record, what is your view on wind turbines?

I couldn't sum up something that would be a soundbite. We have never been anti wind. What I would stand by is that we thought the emphasise of the [government] policy was wrong because of the amount of work wind was being asked to do in the renewables portfolio. It was arguable that you were not going to achieve what you wanted from just focusing on a randomly variable, intermittent generator. And that would be the same if we had a massive investment in, say, [energy from] waste. You'd still have the same problem.

So, is it that you favour a broader mix in the national energy portfolio, or that you object to, say, subsidies?

It's not simple. It's about complexity of the issue and perhaps the over-simplification that comes with policy. Yes, we would definitely advocate a broad mix of generating sources. You would want to do that to maintain a security of supply as much as anything else. There will be a role for wind within that portfolio. We just feel, and have since day one, that the emphasis was wrong. You were asking the technology to do things that it was not ready to do. If someone in, say, America cracked storage tomorrow and found a really cheap way of storing industrial amounts of electricity you could go back to the renewables portfolio and relook at it. But, as we stand today, there are problems. You only have to look at the issues already happening in Scotland who have been using the power produced. We're at 6.5% [of all energy generated in the UK] at the moment, which is relatively small. And it's quite expensive to generate at 6.5%.

Are you for decarbonising the economy and meeting the renewables targets?

Yes.

How do you respond to your critics who say your name is misleading and that your data is almost exclusively used by the anti-wind lobby and media?

It's unfair to say that we're anti-wind. We do research about lots of other things. But people don't tend to call us to discuss our anaerobic digestion research.

I would summarise it by saying that to make good decisions you need good information. I would suggest that REF acts as a critical friend of the renewables sector. If you look at Japan there is a very famous example known as the 'Japanese Solar Tragedy' where a mass investment of subsidy into the solar sector in response to the first oil shock meant there was a big solar roll out. A lot of it was sub-standard. As a consequence, it is arguable that there is less solar in Japan than if that solar subsidy hadn't been there.

What we do is simply generate data. If you are thinking about investing in a wind portfolio in Scotland, you can go onto our website and see the actual generating output of that portfolio by load factor, by rolling load factor on a month-by-month basis, etc. If you were buying a sewage gas portfolio, you could do the same.

One of the things we need more of at the moment is data on actual performance of feed-in tariffs. On our website you can search by postcode to see what it being developed in your area. There's a lot of small-scale solar PV panels in Sheffield, for example. I have no idea why, but it's interesting. We don't, though, have the data on how well they are doing and that is the sort of thing, as REF, we would like. With ROCs you can see that data, but not with FITs.

I'm afraid that the date reflects things that some people don't want to know. I regularly get called by journalists asking how wind performed in the last quarter. I have no problem with giving it to anyone who asks. We are here as a resource. Planners, investors – all sorts of people use our data.

How is REF funded?

We're now funded in two different ways. We knew when we first started up that some of the things we were going to say would be controversial. We could already tell from listening to engineers sitting around the table that some of the ideas being mooted as accepted fact were unlikely to be so when investigated in any serious level. So we decided we wouldn't take financing from government or from companies because we didn't want people to be able to dismiss our work because people said we were funded by, say, Exxon Mobil or someone like that.

Up until 2009 our financing came from private individuals. I think we had two charitable donations that came through the charitable arms of banks. The Golden Bottle Trust, for example.

In 2008/9, we ended up with a situation where our traditional funders, who historically had large property portfolios – Cadogan, Rausing etc [Sigrid Rausing is a prominent anti-windfarm campaigner] – we knew it would be hard to access the funds we needed because of the economic crisis. We were very lucky that they expressed an interest in taking it forward, but just at the point where we wanted to do more research there was a worldwide squeeze happening whilst we waited for charitable status.

Meanwhile, our limited company Renewable Energy Forum was doing vastly exciting things such as processing rent. So we took that and made it a wholly subsidiary company of the foundation. So now any profit it generates finances the charity's work. The income comes from consultancy. Some companies I can't name because they've asked us not to. But some I can. Barclays Capital is one. Calor Gas is one. It's a myriad. But we don't put the list on the record. There are other energy sector companies, though.

Would you consider yourself lobbyists, as some critics claim?

We don't lobby. We sent out a campaign to MPs asking for more information, but it was all checked out by our lawyers [to make sure it didn't contravene our charitable status]. We are allowed to communicate to politicians in the interest of our aims and objectives and we have always made sure that we do so. For example, the document that went out to MPs said that we really should be collecting half-hour generation data and that it should be in the public domain. There's a whole fuzziness there and we think it needs to be clearer and cleaner.

How does REF view the renewables industry in the UK?

We have never criticised the renewables sector in the UK. We were criticising the renewables obligation because it focused on the first technology to market regardless of the intrinsic value of the energy that the technology produced. That was onshore wind. You can't argue that ROCs did anything about innovation in other renewable technologies. The reason that you got this massive flurry of interest in developing onshore wind turbines was because that was the way to make the fastest profit. If you look at the information we put out at the beginning it was criticising the policy.

Did the Charity Commission force you to tone down your hostility to windfarms?

We had a dialogue with the Charity Commission because they very kindly allowed us to expand our articles and memorandum of association. We had started off as an educational charity and we wanted to move the emphasis to research. But if you look at our articles they are broader now than they were before, rather than more limited. They said to us that you seem to be doing more research and you might want to expand your articles. We had a very positive relationship with them. They highlighted to us a potential problem in what we were doing and made suggestions about how we could resolve the issue. We did those things. That's why the wording changed on our website. It was also because we wanted to broaden what we were doing. The legal definition of what was meant by an education changed after we set up and our emphasis needed to be somewhere else. The Charity Commission wrote to us and said you are likely to be infringing if you don't do X,Y, Z so we sent down our lawyers to meet with them. They discussed what we needed to do in our articles and memorandum. They have now given us articles and memorandum that are so broad that we can now do things that we never thought we'd be able to do. We are now education and research.

What is, in your view, the best bet renewables technology?

It depends. Are we talking about the cheapest way to save CO2? The most effective micro renewables?

The highest load factor for a micro renewable would be hydro, but do I think we need to have a huge influx of hydro? Well, then there are other issues. We have a great quote by John Muir on our wall which says: 'You pull on one thing in nature and discover its attached to everything else.' If I said micro-hydro was brilliant, the Salmon and Trout Association would probably get upset with me.

I think the cheapest way to save CO2 at the moment is co-fired biomass. But there is a government limit on how much you can co-fire at somewhere like Drax. There are also arguments about the carbon cycle of biomass. Waste is also obviously very cheap because there is no subsidy paid to it, but would you qualify it as a renewable? I don't know.

Onshore wind is about mid-table on costs, but these things are horribly complicated. Output is one thing, cost is another. It is more expensive to put a turbine at sea. No one would argue with this, but the output is higher.

But by far the most expensive way to generate renewable electricity is solar PV. A lot more expensive than anything else, but that's because of the feed-in tariff. But this will reduce, as the government has indicated.

What's next for REF?

This is a massive year for the energy market: electricity market reform; how the government looks at the cost of carbon. All these things will set the agenda going forward. The biggest problem for people in the renewable sector at the moment is that policy keeps changing. That's not necessarily a bad thing, though. Look at the rest of Europe – lots of policies are being changed. The Treasury is now looking at costs much more closely than it did five years ago.

How can REF influence policy on all this?

We do put some submissions into different consultations. You can see it all on our website. But we're not lobbyists.

Maybe the data used by [anti-windfarm lobbyists and media] is what gets the headlines and that is true. And I have to say, from a personal perspective, I can understand the issues with wind sometimes in locations next to people's houses. But that is a personal perspective. As an organisation, we give the data to both sides of the argument. We are non-discriminatory.

• 5pm update: We have edited the sentence about "close geographical connections". Charlie Methven, New Century Media's managing director, told us: "I would like to clarify that New Century Media neither has, or ever had, anything to do with Renewable Energy Foundation and, indeed, does much work on behalf of renewable energy companies." New Century Media is the parent company of David Burnside Associates.