The Edinburgh Duck
Scotland’s lost wave-power opportunity, a victim of foul play?
Have you ever watched mega waves crash against Lewis’ west coast? Or braved a queasy ferry journey across the Pentland Firth?
The phenomenal power of Scotland’s waves surges around 790 islands and over 11,000 miles of coastline – a vast and largely untapped resource of wave and tidal energy.
Today Scotland’s abundant renewable potential has been recognised, attracting world-class research. Shetland Tidal Array and Hywind Scotland’s floating offshorewind farm are the first of their kind on Earth. And in 2014 Wave Energy Scotland was formed to ensure the country’s pioneering role in developing marine energy.
Yet wave-power innovations aren’t new – back in the 70s one Scot’s clever invention kickstarted the wave-power revolution we know today.
Edinburgh engineer makes waves
Born in South Africa, Stephen Salter was a Scottish academic, engineer, and esteemed professor of engineering design at the University of Edinburgh. Salter was a leading voice in marine cloud brightening — a technique that reflects incoming sunbeams to mitigate global warming.
His pioneering inventions like the world’s first multi-directional wave tank earned him many honours including induction into the Scottish Engineering Hall of Fame and an MBE for services to engineering.
Yet Salter is most famous for inventing the Edinburgh duck (also known as Salter’s duck or the nodding duck). The Edinburgh duck was a 300-tonne floating canister capable of generating energy by its duck-like bobbing motion on the waves. In tests, Salter found that on rough water the Edinburgh duck could convert 90% of wave motion into energy. This dropped to 50% in calmer water.
In the final design, each duck had four internal gyroscopes that moved back and forth when waves rocked the pear-shaped duck over. This movement created hydraulic energy that could be transferred to a turbine or generator. Salter’s idea was to link 20 - 30 ducks together. 250 miles of offshore ducks could generate 20 - 40 Gigawatts of energy.
Today engineers still regard Salter’s duck as the most efficient wave power generator. Unfortunately, the duck never made it out to sea.
Salter’s duck dead in the water.
You’d think that a device capable of harnessing up to 90% of the tidal power perpetually crashing upon the Scottish coast would be music to the UK government’s ears. This was the early 1970s when the Organisation of Arab Petroleum Exporting Countries enforced an embargo that led to the oil crisis.
Salter developed the Edinburgh duck as an answer to the oil shortage. However, a misplaced decimal point left his invention dead in the water. Only now are cries of sabotage being taken seriously.
Salter and his colleagues developed the duck at the University of Edinburgh. The project required funding and help came from an unlikely source. At that time all renewable energy research was facilitated by the United Kingdom Atomic Energy Authority (UKAEA) whose Department of Energy staff – responsible for funding and assessing renewable energy — were recruited from the nuclear, coal, and gas sector.
After toiling on their invention for eight years, Professor Salter and his team felt confident that the Edinburgh duck was a sustainable way of producing energy. The government made the somewhat questionable move of asking the Atomic Energy Authority to assess the duck’s viability. To Salter and his team’s utter disbelief, the Edinburgh duck was deemed uneconomic. Funding was withdrawn and the project collapsed.
Salter suspected his green-energy device posed a threat to the ‘off the shelf’ nuclear power favoured by policy makers. He wasn’t alone. Clive Grove-Palmer, head of Project Duck, was a fierce advocate for the efficiency and cost-effectiveness of Salter’s design. His enthusiasm for the project came despite his previous role as a government engineer who supported nuclear energy.
When the government held secret talks about the future of the Edinburgh duck, Grove-Palmer wasn’t invited. At the same talks, government officials deemed the project uneconomical and closed the programme – just when the duck was ready to be tested at sea.
Grove-Palmer resigned, refusing to “write the obituary of waver power”. In 1987 Salter had to break up his team of bright engineers when funding dried up. Reflecting on the project in an interview his despair is palpable:
“Our programme was in the hands of the UK nuclear agency. Our reports and numbers were deliberately altered. They wanted us to fail. The official who did most damage to us was then put in charge of public relations for the Dounreay nuclear reactor. And because the UK had good wave resources the world was told that if we can’t do it nobody can.”
Only years later did it emerge that a rogue decimal point in the report damning the duck’s costliness had falsely inflated the cost by ten times. Innocent mistake or deliberate sabotage?
The future of renewables in Scotland
Whether or not foul play was afoot, the UK government squandered its chance to become a world leader in renewable energy in favour of short-sighted commercial gains. Decades on however, the intensifying climate crisis and increased demand for green energy has seen Scotland emerge as the biggest contender for master of the waves with two of the world’s biggest offshore wind farms.
The colossal power of the sea has long been recognised in Scottish folklore – the Cailleach, a fearsome hag-goddess, was said to have created the awe-inspiring Corryvreckan whirlpool by washing her plaid in the waves. Salter saw the massive potential in Scotland’s wild energy too:
“The average 3-meter high Atlantic wave with a period of about 10 metres from crest to crest has a power of about 90 Kilowatts per meter width — enough electricity for 180 UK residents.”
Wild weather and monster waves go hand in hand. Scotland’s stormy seas already create the perfect conditions for daredevil surfers — why not a source of renewable energy too?
Whether you place faith in ancient wisdom or modern ingenuity, there is untapped –possibly limitless – potential surging around Scotland’s coasts. If given a fair chance, wave power could mean an abundant source of cleaner, cheaper energy and a chance to create a more sustainable future.