THE UK government's review of feed in tariff (FIT) energy payments is estimated to have stalled £100 million of hydropower investment in Scotland.

The British Hydro Association claims dozens of small and medium-scale developments have been halted and left in limbo since the Department of Energy and Climate Change announced a review of the FIT process last year.

While changes to payments for solar schemes have already been announced, no date has been set for a consultation into the hydro sector where Scotland is thought to hold up to 90% of the UK's resource.

At the moment, hydro projects can get up to 21p per kilowatt hour generated through the FIT scheme.

David Williams, chief executive of the British Hydro Association, said: "If the tariff isn't too badly affected then hopefully these schemes which have been stopped will go ahead.

"But if it does get knocked down then some of them could fall by the wayside. We are just hoping and praying the review doesn't hit the hydro tariff adversely."

Scottish Renewables said the uncertainty meant several of its members had been unable to complete projects.

Joss Blamire, policy manager, said: "It is unacceptable the industry has been left waiting for the Government to launch a comprehensive review of the feed-in-tariff.

"These delays aren't just holding up significant investment but also delaying much-needed jobs.

"With 90% of the UK's hydropower resource, these continued delays mean Scotland risks missing opportunities to generate clean electricity; create local jobs; attract investment; support the supply chain; tackle climate change; and help us meet our 2020 renewable energy targets.

"Companies across Scotland, both large and small, are being affected by the delays and we must ensure that any future reviews are carried out in a much more transparent way that gives increased certainty to the industry."

The three megawatt Cia Aig site, at the eastern end of Loch Arkaig north of Fort William, could generate enough power for 1500 homes.

However the potential for there to be a reduction in FIT for hydro has seen the multimillion-pound project, backed by RWE Npower, unable to progress to the construction phase.

Another example is the £638,000 Bunavoneader scheme, by the North Harris Trust, which had its bank funding put on hold in the middle of last year due to the concerns.

The 100 kilowatt river scheme has the potential to generate £100,000 a year, which would be used for regeneration projects.

David Wake, energy development officer at North Harris Trust, said: "It is terribly frustrating.

"We had a provisional offer of a loan of more than £500,000 back in the spring [of 2011]. We took a few months to build the mezzanine finance, then the bank said they were not going to be doing anything else due to the feed-in tariff review.

"The bank now won't even do the provisional credit checks on the organisation until the FIT review comes out and we don't know when that will be."

A spokeswoman for DECC confirmed there was no date set for the next part of the pricing strategy to be unveiled.

She said: "We will publish a second part of our comprehensive review as soon as possible.

"We understand people are concerned about the uncertainty."