The government has spent 20 times more subsidising the coal industry over the past six years than it has put into marine energy, new figures show.

Ministers have given away £52.8m of a £60m coal investment aid scheme to extend operations at a range of mines around Britain, including Daw Mill in Warwickshire where energy minister Mike O’Brien is the local MP. This contrasts with the £2.3m handed out from a £50m pot created under the Marine Renewables Deployment Fund, which started in 2004 just 12 months after the launch of the latest coal scheme.

“At a time when we need to deliver a major expansion in renewable energy, it’s astonishing to find that less than 5% of the investment promised to give Britain a lead in marine energy has actually been made,” said Greg Clark, shadow energy and climate change secretary.

“It is little wonder that Britain punches way below its weight on renewables – we have the third-lowest contribution from renewable energy in Europe, despite some of the best resources.”

The Observer revealed last month that ministers had spent almost nothing out of the Marine Renewables Deployment Fund, with potential users complaining the conditions attached to grants were so onerous that they could not gain access.

The amount of cash handed out under the coal aid scheme was recently revealed in parliament and the Conservatives say that all of it – bar one grant – has been spent in Labour constituencies.

The government has sought to make up lost ground, with money being promised in the recent energy white paper to various tidal and other schemes. More than £20m has been earmarked for a new Marine Renewables Proving Fund with a further £9.5m going to develop a Wave Hub off Cornwall and £8m for a European Marine Energy Centre in Orkney.

But the Tories argue that ministerial promises mean very little. “It is easy to talk about support for renewables but what we need is action,” said a spokeswoman. The opposition says it would use the money from the Marine Renewables Deployment Fund to establish a network of large-scale marine energy parks to be run on a commercial basis.

When the coal subsidies were launched in 2003 by the then trade and industry secretary, Patricia Hewitt, the main emphasis was on job retention.

Last night a spokesman for the Department of Energy and Climate Change said it was not helpful to compare two completely different technologies – coal having been in development for generations, and marine very much cutting edge.

He added: “We want to be a global leader in wave and tidal energy, that’s why we announced £60m of low carbon investment funding in the budget. That included £22m to help pre-commercial testing of marine technology, which should enable access to the Marine Renewables Deployment Fund.”

Fishermen near an oil rig on the edge of Lake Albert in western Uganda, where 700m barrels of oil have been discovered Photograph: Xan Rice

The world’s biggest oil companies – including BP and Shell as well as state-owned operations from China – are trying to muscle their way into the world’s largest new oil region: Uganda.

Tullow Oil, the relatively small British-based firm at the centre of the huge energy strikes in Lake Albert, says it plans to hand over part of the oil riches in return for financial help to build pipelines and other vital infrastructure.

Excitement over the Ngara wells increased when Tullow reported it had encountered further shows of oil and was more convinced than ever about the enormous prospects in the region.

But the company also announced an 83% slump in first-half profits to £21.4m and a 16% drop in its existing production from the North Sea and elsewhere, while needing billions of pounds to bring oil out of the ground and refine it in Uganda.

“It is not every day you find a new oil province similar in size to the central Graben region of the North Sea. Practically all the oil majors and some national oil corporations have been on our doorstep seeking to pre-empt a competitive [sales] process”, said Angus McCoss, Tullow’s exploration director.

Tullow plans to sell part of its 100% stake in Block 2, one of three blocks which cover the Ugandan side of Lake Albert, in the next 12 months, it said, but only through a public offer and not via a bi- lateral deal with one other company.

Among the possible partners is Eni of Italy which has already been tipped as a potential buyer of the whole Tullow company although the British firm said it was clearly not for sale.

Tullow shares fell 4% to 1052p on profit-taking following a period where euphoria around the Uganda exploration success has driven the value of the stock up by nearly a third in value since early July.

McCoss said 700m barrels of recoverable reserves had already been proved up but the latest oil shows put the company on the way to proving that there was a further 1.5bn waiting to be exploited.

Tullow said Eni, which has a 43% stake in pipeline builder Saipem, would be a suitable partner as would Chinese companies and others but insisted there was currently no favoured partner in mind.

Tullow said its Ngassa-2 well in Block 2 found signs of oil at two intervals in the reservoir being tested.

“The pressures in these intervals are higher than normal, which may indicate that they are associated with significant oil columns,” it added.

Investment bank Citigroup said in a research note that the results of the latest well would pave the way for a part sale of the block as it makes clear how much it is worth.

The Ugandan government has made clear to Tullow that it would like the company to refine the oil in the area so that the relatively impoverished country could gain as much added value from the energy as possible.

The African country is also acutely aware that many developing countries have found oil riches can be curse as well as cure with charities warning it can bring corruption and wealth only for the political elite. Nigeria is often held up as an example of this.

Philip Maxwell, chairman of the Islay Energy Trust, by the Sound of Islay where the ScottishPower turbines will be sited. Photograph: Murdo MacLeod/Murdo MacLeod

ScottishPower is planning a tidal energy project that will supply all the electricity for one of Scotland‘s most famous islands, the Guardian can reveal.

The company is close to signing a supply contract with Diageo, the drinks group, to provide electricity from the project to eight distilleries and maltings on Islay – including the makers of the renowned Laphroaig and Lagavulin whiskies.

The 10MW tidal project, one of the world’s largest, will provide enough electricity for Islay’s 3,500 inhabitants for 23 hours a day.

ScottishPower will submit a planning application in the next couple of months and expects the ten 30-metre underwater turbines to be operational in 2011. The turbines will cost about £50m to install.

The tidal waters in the Sound of Islay, the channel dividing Islay from the Jura, move at up to three metres a second.

Energy companies and representatives from the Scottish government will publish on Wednesday a “marine energy roadmap” outlining how to reach the target of generating up to 2GW (2,000MW) of electricity from tidal and wave power by 2020. It will call for more grants and revenue support to enable developers to build commercial scale demonstration projects, such as the Islay installation, over the next two years.

The renewable energy industry admits the techniques to generate electricity from marine energy are in their infancy. Morna Cannon, from Scottish Renewables, said: “This makes it very hard to pin down the costs of the technology at the moment.”

Alan Mortimer, head of renewables at ScottishPower, admitted tidal energy is more expensive than offshore wind, which costs up to £3m for each megawatt built and itself is only barely economic. Tidal developers earn more subsidies under the Renewable Obligation Scheme than offshore wind, but only once schemes are operational.

Marine energy developers such as Martin Wright, managing director of start-up company MCT, complain that few investors want to risk their money. But the Islay project has heavyweight backers. ScottishPower is owned by Spanish group Iberdrola and has teamed up with Norwegian oil firm StatoilHydro to develop and finance the project.

There is also strong support on the island, although it is by no means universal. Kevin Sutherland, manager of the Islay group of Diageo distilleries, works at the Caol Ila distillery, which overlooks the Sound. The distillery, like the rest of the island, gets the majority of its electricity from the Hunterston nuclear reactor on the mainland. But the reactor is being decommissioned in 2016 and the distillery suffers frequent power cuts in stormy weather when pylons are blown over.

When the tidal project is built, the distilleries on the island will enjoy a much more secure electricity supply, confounding critics of renewable energy – primarily wind power – who say it is intermittent and unreliable.

One of the biggest obstacles for renewables in Britain has been planning permission. Onshore wind applications are frequently rejected because locals object to the visual impact. Because the Islay generators will be on the seabed, no one can see them and the Scottish government will have the final say on planning.

Operating underwater brings its own problems, says Cannon from Scottish Renewables. George J Gillies is a local fisherman who fishes for crab and lobster at either end of the channel in winter. He complains that his lobster nets could get tangled in the turbines and says the project threatens the livelihood of eight local fishing families. But he seems resigned: “If it’s going to generate money, it will get the go-ahead.”

The Islay Energy Trust, a community organisation chaired by Philip Maxwell, has been helping to lobby local politicians and opponents of the project. In return, it will receive a small slice of the revenue to fund community projects on the island, such as a swimming pool