SNP MSP Rob Gibson told MSPs "A report from Scottish Renewables in September revealed that the costs of grid connection and transmission to deliver electricity produced from marine renewables in the Marine Energy Park area comprising of sites in the Pentland Firth and Orkney waters, could soar due to new charges from Ofgem under a transmission regime which has yet to be finalised".
Mr Gibson said, in his motion for his member's debate on 19 December 2012, that he understood new charges from Ofgem would result in a transmission regime that will increase costs by 91%.
The SNP MSP for Caithness, Sutherland and Ross told MSPs the estimates for the projected annual connection charges for the Pentland Firth and Orkney Waters area would have increased from £56 million in 2011 to £107 million by 2020.
He said there were "strong concerns" about the "continued discrimination" against the marine renewables sector in Scotland, and in Pentland Firth and Orkney waters in particular, adding the UK regulatory system was "unfit for purpose".
Ofgem were not aiming their transmission regime at the "clean energy potential of the north" but basing it on the Thatcherite model of power stations close to high population consumer bases, the MSP said.
Highlands and Islands Conservative MSP Mary Scanlon said the estimates from Scottish Renewables were "not a true figure" and there was no confirmation or indication of tariffs yet.
Ms Scanlon said she very much regretted these figures were being used as they were "not accurate" and they could scare "investors from our islands".
Environment and Climate Change Minister Paul Wheelhouse said it was a shame the UK coalition government presided over a transmission charging scheme which "punishes most those areas where Europe's greatest renewable energy resources lie."
Mr Wheelhouse said he "should not be too hard" on Energy and Climate Change Secretary Ed Davey as at least he had set up an intergovernmental group to look at solutions to the islands charging regime.
He said high transmission charges to the islands were from the "old energy thinking and outmoded thinking" and added "we need a charging regime that recognises geographical realities".
In closing the debate, the minister congratulated Rob Gibson for his member's debate and said he hoped London was listening.