A new generation of offshore wind and tidal farms could produce �14 billion of electricity every year for Scotland but pose a "significant" threat to wildlife, the fishing industry and islanders' ferries, an official report has warned. The Offshore Valuation Study found the developments have the potential to attract �60 billion of investment north of the Border and to create 20,000 jobs by the end of the decade. With Alex Salmond, the First Minister, ruling out any new nuclear power stations, the report said the wind and tidal farms could eventually generate seven times Scotland's electricity needs. But the planned developments would cost an estimated �180 billion and have a major impact on a species including dolphins, seals, porpoise, wildfowl and other seabirds. They could also have major implications for the future of Scotland's beleaguered fishing industry, with some of the proposals covering spawning areas for white fish, shell fish and nephrons. A draft plan for offshore wind energy also highlights concerns about the farms blocking major shipping lanes, ferry routes to and from Scotland's islands and waters used for leisure activities. Ten new projects are planned for the next decade, with a further 30 earmarked for between 2020 and 2030. The �14 billion figure assumes there will be widespread expansion until 2050, in line with SNP policy. Jim Mather, the Scottish Energy Minister, said: "We must seize these opportunities and will continue to work to make the transition to a low carbon economy a reality." SNP ministers announced a 12-week public consultation on their plans. The study, the first comprehensive economic valuation of Britain's renewable energy potential, found 68 gigawatts (GW) of electricity could be generated in Scottish waters by 2050. This would be worth �14 billion in electricity sales, the equivalent of �2,700 for every Scot. Last year the Crown Estate identified 10 areas where it was prepared to grant commercial leases for offshore wind energy developments that collectively could generate 6.4GW by 2020. But the draft plan states all of the sites "have the potential for significant effects" on marine wildlife, including bottlenose dolphins, porpoise, grey seals, wildfowl and waders. They could also harm the appearance of series of beauty spots � the Solway Firth, Wigtown Bay, Kintyre, Islay and the Argyll Array � without mitigating measures being taken. Seven of the ten sites lie completely or partially in spawning areas for commercially-fished species such as mackerel and plaice, and nursery areas for others such as herring, whiting and cod. However, the most significant effects are predicted at five sites, including Kintyre, where over 800 tons of nephrons are caught annually. Navigation between islands in the north and west of Scotland is also highlighted in the report as a potential problem, with domestic ferries and military exercises potentially hampered. The plan warns that wildlife could be "significantly affected by nearly all" the 30 medium-term proposals, "with more major issues arising from these options when taken together". The fishing industry also faces significant problems, it suggests, with Scottish ministers agreeing to conduct further research "given the importance of this issue". Developers would also have to ensure they do no hamper flight paths, radar coverage and navigational routes, it states, especially in commercial shipping areas such as the Firths of Forth and Tay.