The Scotsman can reveal that an Australian company is already preparing a serious bid for the huge tidal farm that it says will power one million homes.
Atlantis Resources wants to be the first to take advantage of an imminent decision by the Crown Estate, which owns the seabed, to invite firms to build in the powerful seas off the north coast.
But as Alex Salmond, the First Minister, pins his hopes on tidal power answering Scotland's energy crisis and providing a huge boost to the economy, an expert has warned that politicians are "living on a different planet" if they think the technology will provide the answers.
Dr Tony Trapp, whose company built one of the first tidal devices, told The Scotsman the issue of renewable energy was based on "faith not science". He said four companies in the UK that had tried to develop tidal energy had still not achieved any output.
"It has completely conned the politicians from all parties and the worst people who are being conned are in Scotland," he said. "They've been conned hugely."
Such doubts will not deter Timothy Cornelius, the chief executive of Atlantis Resources, or ScottishPower Renewables, which plans to install up to 20 tidal turbines off the north coast, or about 90 other renewables firms across the world that are expected to be interested.
Such a level of interest means Mr Salmond's aspirations for Scotland to lead the way in the development of tidal technology and to become the green capital of Europe could become a reality.
The Pentland Firth has some of the strongest currents in the world because of the funnelling of tidal flows through a narrow strait. This produces fearsome tidal currents of up to 30km an hour, as well as rips and whirlpools.
"It really is the Saudi Arabia of marine energy, so it's a natural focus for us,'' Mr Cornelius said.
"The north of Scotland is one of the best places in the world where people could possibly want to develop marine technology. It provides everything you could possibly want. There's no better place in the world, in my opinion."
However, he said there were still constraints, in particular the lack of grid access that makes it is difficult for renewables firms to transmit electricity across the country.
Neil Kermode, the managing director of the European Marine Energy Centre, set up close to the Pentland Firth where renewables firms can test prototype devices, said it was crucial Scotland grasped the opportunities of tidal technology, and he believed it was "entirely feasible" for Scotland to lead the way.
"There's no doubt at all about it," he said. "The only thing that worries me is the UK does have a habit of getting to these technological points and then blinking and stepping away from the big challenges."
If Atlantis goes ahead with its 500-turbine project, it will be larger than any other planned anywhere in the world. The next biggest is a proposed scheme in South Korea by Lunar Energy, a British tidal power company, and Korean Midland Power Company, involving 300 tidal turbines, which the firms hope to install by 2015.
But Dr Trapp, after spending 6 million developing a prototype turbine, came to the conclusion there was little potential in tidal energy..
Dr Trapp, the managing director of Engineering Business, believes the few sites that are suitable, with tidal flows that are strong enough, are too far from urban areas, which is where the electricity is needed.
"If you exploited all the tidal energy resource in the UK and the Channel Islands, you might be able to get two gigawatts," he said. "The overall conclusion is it's silly. It's not a sensible use of intellect or financial resources."
He even disagrees over one of the aspects of tidal stream devices often put forward as their key strength – predictability.
The tides follow the same pattern each day, unlike the wind, which blows at varying strengths. But Dr Trapp said that when his company monitored the output of its Stingray device, at Yell Sound off Shetland, it discovered that the output varied day by day.
"What that led me to think was that actually this is quite widely affected by the weather, the wind and the wave environment, and it's not as reliable as we thought," he said.
He said that of four firms in the UK that were trying to develop tidal devices at the beginning of the decade, none had yet provided any output. "The trouble is, it isn't the solution. Tide and wave are trivial in the world energy picture," he said.
Dr Trapp suggested politicians, including Mr Salmond, had been "conned" into believing in renewables.
"These guys are just living on a different planet. They don't question the science. There's this huge religion going on which is to do with renewables which doesn't in any way reflect reality," he said.
Scottish Renewables, the trade body, estimates that the marine green energy industry could employ tens of thousands of people in Scotland by the end of the next decade.
Jason Ormiston, its chief executive, emphasised that the industry was still in its early days, and the construction of a 500-turbine project such as that proposed by Atlantis was still a long way off.
"The industry obviously speculates an awful lot," he said. "Clearly, they will start off relatively small and then get bigger.
"The technology is proven. There's a risk with any new industry like this, but if you speak to the majority of people, there's a consensus that these machines can generate electricity in these environments."
Jim Mather, the energy minister, said: "By maximising every opportunity, we will make Scotland a world leader in marine renewables. We have ambitions to make Scotland the green energy capital of Europe.
"And Scotland's seas can provide 25 per cent of Europe's tidal power and 10 per cent of wave power. Backed by significant government support, developers are investing millions in the testing and deployment of wave and tidal devices to harness that potential."
Pentland Firth's 'epic power is the future'
HIDDEN deep beneath the waves an army of turbines rotate unseen, generating green energy just from the pull of the Sun and the Moon.
This may sound like science fiction but many experts predict it could be a reality in the Pentland Firth within a decade.
The Crown Estate, which owns the seabed, has estimated more than 700 mega watts could be installed by 2020 – the equivalent of about 400 tidal devices.
However, First Minister Alex Salmond has previously said he thinks there is ultimately potential for up to 30 times that amount in the Pentland Firth, the stretch of sea between Orkney and Caithness.
It is this water, with its extremely powerful tides, that gives Scotland its reputation as having the best tidal resources in Europe, with 80 per cent of the UK potential. It has been calculated that at least a third of Scotland's energy demand could be met by tidal renewables.
Atlantis Resources, which has been developing tidal devices for a decade, has built two turbine types, Nureus and Solon.
Nureus is suitable for shallow water up to 25 metres deep and has been generating electricity in a test site in Australia for two years. It uses aquafoils to capture momentum from the flow of water, to drive a massive chain, which generates electricity.
Solon is a deep-water turbine suitable for installation in some of the world's fastest waters, in depths of at least 40 metres.
They are both tidal stream devices, differing from the tidal barrage schemes, such as the proposed Severn Barrage.
Tidal barrages block in water at high tide, before releasing it through flood gates to harvest the energy. In contrast, tidal stream devices do not require any blocking of waterways, and are believed to have fewer environmental impacts as a result.
Initially, Atlantis Resources, backed by US financial giant Morgan Stanley, is expected to lodge plans with the Crown Estate for about 15 tidal turbines capable of generating 30 megawatts.
Timothy Cornelius, chief executive, hopes these will be installed by 2011, and will be used to power a computer data centre near Castle of Mey in Caithness.
This, he hopes, will lead to a far larger tidal farm, of 500 turbines. "The reality is that, if there's the political will to assist developers like us, the technology is now in a state where people are willing to make this industry a real reality," he said.
"We are incredibly confident in our technology. We have built and tested many large-scale turbines to get where we are." Close to the Pentland Firth in the Fall of Warness off the island of Eday in Orkney, is the European Marine Energy Centre (EMEC), a first-of-its-kind facility where prototype devices can be tested.
In May, Irish company OpenHydro, which had been testing its prototype at EMEC, became the first company to success-fully connect a tidal device to the UK grid.
Neil Kermode, managing director at the EMEC, thinks that by 2020 the Pentland Firth could be teeming with tidal energy devices. "By then we will have worked out how to do this in a way that's cost-effective and we will look back in wonder at the time we hadn't bothered to access it," he said.
"There's an epic amount of power in there and I think our grandchildren will ask why we hadn't used it earlier."