The World’s First Commercial Wave Power Station in the Isle of Islay, Scotland
The world’s first commercial wave power station commenced operation in 2000 on the Scottish Isle of Islay and has now been steadily producing up to 500kW of power for more than a decade. Its simple reliable design provides a means of providing local power to sea coast communities around the world.
- Islay: a history of marine energy ‘firsts’
- The LIMPET 500 wave power station
- How the LIMPET wave power station works
- Is the LIMPET just a gimmick?
- The potential for wave and tidal power
Islay: a history of marine energy ‘firsts’
The Isle of Islay, off the coast of Scotland, hit the headlines recently with the announcement that the world’s largest tidal power array (essentially a ‘wind farm’ on the sea bed) is to be built in the narrow straight between Islay and the neighbouring island of Jura as what is expected to be a test of this new technology for a much larger array planned for Scotland’s Pentland Firth. However this is by no means Islay’s first record for the use of green marine energy: the island is the home of the first wave power plant, the LIMPET 500 and the first to use marine energy for public transport. A group of Scottish scientists is now seeking to put together a consortium to make the island into the world’s first ‘hydrogen economy’ by using the wave power electricity to produce hydrogen for fuel cells to power vehicles and appliances.
The LIMPET 500 wave power station
The power station was designed and built by Wavegen and researchers from Queen’s University, Belfast in Northern Ireland, with financial backing from the European Union. Its unusual name is an acronym for Land-Installed Marine-Powered Energy Transformer rather than the fact that it appears to cling to the cliffs like a limpet, but the name is apposite nonetheless. It feeds 500 kilowatts of power into the island’s electricity grid. It is the result of a 10-year research project conducted on the island, where the research team built an initial pilot plant generating 75 kW of electricity.
How the LIMPET wave power station works
The design of the LIMPET is essentially very simple, making it eminently duplicatable. It consists of a collection chamber connected via a duct to a turbine to produce electricity.
A sloping reinforced concrete shell with an internal chamber is built into the rock face on the shoreline with an inlet large enough to allow seawater to enter and leave the chamber freely. As waves enter the chamber through the inlet, the air in the chamber is compressed and escapes, under pressure, through a duct or ‘blow-hole’ leading to the turbine. The air drives the turbine’s blades, generating electricity.
As the seawater in the chamber recedes, air is drawn back down the duct, again driving the turbine’s blades. The turbine itself is specially designed always to turn in the same direction regardless of the direction of the airflow. This type of turbine is called a ‘Wells Turbine’, named after its designer, Professor Alan Wells of Queen’s University, Belfast.
The next wave causes the cycle to repeat, keeping the turbine blades moving in what is termed an ‘oscillating water column’ generating system.
Is the LIMPET just a gimmick?
The LIMPET 500 station has been operating steadily for over a decade, providing a reliable source of electricity to the Isle of Islay. It has provided good amortization of its initial cost and proposals are now underway to utilize what becomes, post-amortization, a virtually ‘free’ source of power for the island. And that is the nub of the matter: sea-edge wave power generating stations can also be hooked into the national grid but should be regarded as local sources of power.
At 500kW the output from the power station may seem modest in comparison to huge coal and nuclear plants but the individual stations can be hooked together as modules to boost output. The generating technology can be incorporated into existing proposals for improvements to sea defences, harbour walls and breakwaters, offsetting much of the infrastructure cost and leaving just the turbine to be financed.
The potential for wave and tidal power
Wavegen’s research indicates that even at just the present level marine energy development, sea-edge wave power installations are viable sources of power on any coastline with wave-creating prevailing winds in the Earth’s temperate zones between the fortieth and sixtieth parallels. The use of renewable energies frees us from previous power generation constraints such as fuel costs and transport, power distribution over enormous distances, pollution considerations and expensive decontamination and decommissioning costs.
Just like photovoltaic and wind power, marine energy from wave or tidal power is not restricted to just one area of the globe or just one part of a country but is available on the spot, for local use, through whatever combination of power-generating modules the local community requires. The power generated can be sold at retail prices rather than the significantly lower wholesale prices to the national grid network, thereby amortizing costs much sooner while still providing a cheap source of electricity to the local community. Days with low wave energy can be offset by storage of excess production from other days and, if necessary, with power from the grid. We now have the chance to think outside the blinkered box for our power supplies.
Scotland, with one quarter of the potential tidal and one-tenth of the potential wave energy in Europe continues to be at the forefront of technological development in the marine energy field. Islay’s wave power station will soon be joined by a seabed tidal power array in the Sound of Islay and the planned development in the Pentland Firth.
BBC News: How it works: wave power station
Herald Scotland: World’s largest tidal farm highlights green ambition
Herald Scotland: Electric bus destined for island roads