Wednesday, 22 April 2015

Making Waves

Deputy Steve Luce @DeputySteveLuce on Twitter:

Travelling to Alderney today with @MurrayNorton to discuss CI Renewable energy...hoping for some electrifying discussion....‪#‎workingtogether

Rob Duhamel talked a lot about renewable energy, but I don’t recall him every going to Alderney. It’s good that Steve Luce is going to see what is happening, because this kind of renewable energy could well be part of Jersey’s future as well.

The three main kinds of renewable energy sources available for Jersey are:

Solar – needs light, sunlight is best, but in fact any light can generate electricity, as people with watches or calculators powered by light will testify. This is the photoelectric effect which uses the property that some metals emit electrons when light shines upon them.

Light can eject electrons even if its intensity is low, a fact explained by Einstein in a paper published in 1905, and for which he received the Nobel Prize for Science in 1921. C.P. Snow attributes this to the theory of relativity (special and general) being relatively too new for the Nobel committee at the time.

The advantage of solar power is that it requires relatively little maintenance, as it has no moving parts.

Wind power – which is dependent on the fickle nature of the weather. That’s the main drawback, as well as the fact that it has moving parts, which are likely to wear out.

Wave power – the tides and currents follow pretty regular patterns, so tidal power systems are much more ideal as they can supply a much more regular power than wind. They do have parts that can wear out, and cabling is needed undersea to carry the power, so the technology has tended to lag behind wind turbines, which are relatively easy to throw up and connect into existing land systems.

Regarding Alderney, in June 2014, Michael Lewis, project managerof development projects, OpenHydro, stated that:

“OpenHydro and Alderney Renewable Energy (ARE) have recently formed Race Tidal Ltd to do just that. Together, these two companies intend to harness the energy in the waters around Alderney in order to generate enough electricity to power 150,000 homes. The formation of Race Tidal is the first step in a complex and challenging process to develop a 300 MW tidal energy array. This will be one of the largest tidal energy arrays in the world when it is constructed in 2020.”

The engineer also throws in a fascinating nugget of history:

"Taking advantage of the energy stored in the tides is certainly not a new concept. In fact, there is evidence that tidal barrage-style mills were in operation as far back as Roman times. These mills made use of the tide by trapping water in reservoirs when the tide was high, and then allowing the water to exit through waterwheels as the tide went out. The waterwheels provided the mechanical power to mill grain.”

The difference is that the new system uses “in stream” tidal power generation. It is explained as follows:

“These turbines are located in the tidal flow, where they extract energy from the flow of water associated with the tides. This resolves many of the environmental issues associated with barrage generation, as there is minimal impact on the flows around the turbines and there is no requirement for significant civil works like dams or reservoirs. In the case of the OpenHydro technology, no infrastructure is visible above the surface of the water.”

How is the project planned?

The first thing to do is to put down “acoustic doppler current profilers” around Alderney – these are tidal flow measuring devices which look at the waves and turbulence and build up a picture of what is going on beneath the surface. The data collected can - with modern technology - feed into 3D models to see where it is best to site turbines.

The seabed will also be checked by surveys which use multi-beam echo sounders, side scan sonar and magnetometer. This means that a picture can be built up of the underwater depth of the sea floor (which is termed “bathymetry” and the geological characteristics of the area can also be noted. It will also look for the presence of any metallic objects on or under the seabed, such as cables, shipwrecks or unexploded ordinance!

And over a two year period there will also be a baseline assessment of the marine environment, looking at marine life on the seabed, the abundance of seabirds above, different kinds of fish and mammals in the waters, and general marine traffic through the area. Any sites of archeological interest will also be noted. It is important to make sure that there is minimal environmental impact resulting from the project..

The power generated would be far in excess of that needed for Alderney, and most of the electricity will go to the South of England and France via an interconnector link.

This is, of necessity, a long term project, not an instant one set up overnight, and OpenHydro is also working on two other similar projects in Northern Ireland and Scotland. But it is important to lay secure groundwork, as Michael Lewis says:

“In an environment such as the Alderney Race, preparation is absolutely integral to the overall success of the project. In devoting time and resources to the development phase, we can harness the unique conditions that the Alderney Race provides and in doing so provide renewable energy that is silent, invisible and predictable, for generations to come.”

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