Plans are being drawn up to build the world's first tidal energy farms off the coast of Scotland as part of an ambitious programme to make the country a leading player in developing and exporting the renewable technology.

ScottishPower is preparing planning applications for three tidal stream farms, two off the coast of Scotland and one off Northern Ireland, which it hopes to develop by 2011. Between them, they will supply enough energy to power up to 40,000 homes.

While tidal stream turbines have been extensively tested, with Scotland already at the cutting edge of developing the emergent technology, ScottishPower's plans mark the first commercial application of the renewable resource which could eventually supply more than one-third of the country's energy needs.

Through its ScottishPower Renewables arm, the company is also planning to build a major manufacturing hub to supply its own tidal farms with underwater turbines and export them, with the creation of up to 7000 jobs.

A decision on the hub's location has yet to be made, although Hammerfest Strom AS, a company set up by ScottishPower Renewables and Norwegian partners Hammerfest StatoilHydro and Hammerfest Energi, is understood to be keen that it is developed in Scotland, where it can draw on the extensive experience of the offshore oil industry. The company hopes the plant will manufacture about 60 turbines a year by 2011.

The turbulent waters around Scotland's coast are among the most potent streams of tidal energy in Europe, with the Pentland Firth between Orkney and Caithness being described by the Scottish Government as the potential "Saudi Arabia of renewable energy".

While the technology has lagged around 10 years behind the development of wind power, experts in renewables say it has even greater potential. Unlike wind-generated power, tidal energy is completely predictable and early testing results have shown it to be reliable.

It is also unlikely to arouse the controversy that windfarms have generated among some environmentalists, as the turbines are located underwater and do not appear to present a problem to fish, which swim faster than the rotation of the turbines' 20-metre blades. They would turn at least 10 metres below the surface to avoid shipping, but trawlers would have to be banned from the vicinity.

ScottishPower Renewables has made plans for tidal stream farms in the Pentland Firth, the Sound of Islay and off the north Antrim coast in Northern Ireland. It aims to submit planning applications to the Scottish Government and Irish Assembly in summer 2009.

Each site will house between five and 20 1MW tidal turbines, depending on the results of seabed surveys, which will take place between now and 2011, and on the granting of planning approval.

The turbines to be used, called Landstrom, have been developed in the Norwegian town of Hammerfest, where a model has been in place for the past four years.

A £6m prototype is due to be tested next year. ScottishPower hopes the cost and output of the devices can be rapidly improved as the technology develops.

ScottishPower has invested more than £1m in Hammerfest AS and estimates the cost of the three tidal stream farms will be more than £100m.

The proposals were welcomed last night by First Minister Alex Salmond, who said the mix of renewable resources in Scotland had the potential to meet the country's energy needs "several times over".

Keith Anderson, director of ScottishPower Renewables, said: "Tidal power is completely renewable, being driven by the gravity of the sun and moon, with no carbon dioxide emissions, plus the added benefit of being entirely predictable."

Scottish Renewables Forum and the British Wind Energy Association also welcomed the plans.

But the announcement is likely to refocus debate on the inadequacies of the National Grid, which is not equipped to handle offshore energy generation effectively.

Both the First Minister and power companies have been lobbying Ofgem, the market regulator, for a better infrastructure to encourage other power companies to commit to renewables.