Catch the wave
Innovator Andrew Mill on harnessing the ocean for energy.
Andrew Mill is Managing Director of the European Marine Energy Center in Stromness, Scotland. Engineers bring their experimental marine energy devices to the center and anchor them on the sea floor near EMEC to test their performance. Producer Marc Airhart interviewed Mill in September, 2004.
Airhart: So, can you give me an overview of what marine energy is?
Mill: Marine energy in the renewable sense is very much looking at trying to extract the energy from the waves and the tidal currents that are in the seas. Different parts of the world have different resources in this area. Predominantly it’s those parts of the world where the winds are very strong, because wind is what generates the waves and in the eastern seaboard of the European continent, we have a very, very strong wave regime that comes from the storms that generate the waves out in the Atlantic. They come in very strong over a long period of time coming into the shore. Ocean waves contain a huge amount of energy and what we’re trying to do now is look at how to harness that energy.
It’s quite a challenge because the marine environment itself is very hostile to man in the sense that it’s not an area that we normally try to work in. The offshore oil and gas industry has for some years in the North Sea and out in the Atlantic begun to work in this environment. So, we’re now seeing technologies coming through that can cater with the extremes of the waves.
With the tidal current, that’s a different matter. That’s not generated by the wind. That’s generated by a combination of the moon’s gravity and our own gravity here on Earth and that moves large bodies of water past different parts of the land mass. So we have large transitions of water from the Pacific into the Indian ocean, from the Pacific to the Atlantic, from the Atlantic to the North Sea, and so on. So this creates a large volume of water moving in some cases very rapidly. And round the British coastline, we have water that can be moving anything up to about 3 and a half meters per second [or about 600 miles per hour] and when you look at the very large volumes involved, that’s a very high energy density that we can tap into.
Airhart: Tell me a little about the European Marine Energy Center.
Mill: So, what we’ve done is to build a facility on the coast of Scotland right at the very top, a small island group just off the north of Scotland called the Orkney islands. It has a very strong wave regime coming in from the Atlantic. And there we’ve built four test berths out in the Atlantic. We have high voltage cables and we bring the power onto shore and then from shore into the national grid system so that it can feed electricity in to where the load centers are. And what we’re doing there is just starting the assessment of devices that have made it to prototype stage and to full scale demonstration phase. And we’re going to, over the next few years, start to look at verification of the data, look at how good they perform. And a very important part of that is whether they can survive the extremes of waves. So, survivability is one of the things that we’re also looking to get some measure of by putting on instrumentation that can measure the forces, the strains and stresses that are experienced by the device while it’s generating electricity.
Airhart: What’s your background?
Mill: Well, yes, a very interesting question. I started off as an electrical engineer. Graduated from Strathclyde University in Scotland and then went into a part of Rolls Royce where we were building small hydroelectric projects world wide. I’ve always been involved in renewable energy and then the energy scene. I came through that and eventually found myself in the utilities and looked at new forms of generation and then eventually into this job.
Now I don’t see myself quite so much as an engineer, much more as a businessman trying to look at what’s needed to build an industry.
Airhart: Can you describe the test berths at the EMEC?
Mill: Well I think it’s difficult to generalize too much in that area because some devices are tethered to the sea bed – so this is sort of large clump weights and an anchor system with heavy lines and chains that they would come lay down on the sea bed and moor to in order to keep the device in position. Others are looking to pile into the seabed and basically anchor the system on a solid foundation and then there are whole stacks of different sorts of categories in between that go from semi–permanent through to permanent structures.
Right now we’re looking at something in excess of thirty devices that are coming through. Now not all of them will make it beyond the test berths because they won’t be commercially viable. But we’re going to see different requirements for the test berths. So, what we’ve done is section off an area of the sea to provide that mooring facility. And then we’ve got underwater cables which are very heavy armored cables that run out into these test berths and then when someone comes to use a test berth, they put down their anchor system to lift our test bed up and connect to a flexible cable, an umbilical cable onto it, which will act to take the power from the device down into our grid network system.
So, there’s quite a lot of work going on in terms of the seabed laying out the cables. So we do have a lot of support required from work boats, divers and as I say a lot of the offshore technology that’s been developed for the oil and gas industry is now seeing this as perhaps another area for opportunity to use the skills that have been learned in the marine environment over the last 30 years in that industry and bring it to a new industry.
Airhart: Why do you do this work?
Mill: I think in Europe we begin to see some of the effects of climate change. We’ve seen some extreme events this year in the UK with some major flooding in the south of England and some landslides in the north of Scotland that have taken out both roads and railway lines. So, we’re seeing some extreme events and I think we’re convinced that this is a pattern that is certainly being influenced by carbon dioxide levels in the atmosphere created by our industry. So we are very, very interested in looking at how we can reduce carbon dioxide emissions and looking at renewable energy as one of those.
My background has always been in areas such as hydroelectric energy generation. So, I’ve always been in this kind of area of non–polluting technologies. And it’s really taking that interest and realizing that it could make a difference. And what we’re trying to do is bring devices through quickly so they can make a meaningful contribution.
The U.K. has committed to a 10 percent target of all of our energy to come from renewables by the year 2010. Currently, we’re at about 3 percent and the majority of that is hydroelectric and a little bit of it is wind. So by 2010, we’re probably looking at wind being the main contributor other than hydro to meeting that 2010 target. We’ve got a 2020 aspiration, which is to do 20 percent of our generation from renewables. And by 2020, I want to see those marine devices beginning to make some contribution to that. And then obviously over the longer term that will carry on. And interestingly enough, while Europe has been looking at trying to set these limits and it’s really been driven by our commitment we made to Kyoto as a government. In fact, the government on behalf of the UK was to set targets to reduce our carbon dioxide emissions by 60 percent. What we’re seeing is that the UK government has set some fairly ambitious targets as I say going forward. Scotland has doubled those figures. We’re looking for 40 percent of our generation to come from renewable sources by 2020 and getting energy from the sea is going to be a major factor in us meeting those targets.
There’s nothing more certain than the fact that we will eventually run out of oil and gas. Now whether it’s 10 years, 20 years, 50 years, we can all argue about what date that might be, but we are certainly going to see a reduction in carbon based fuels being available to us.
We’re also seeing now that those oil and gas resources are very volatile to price changes that come from stability and political terms. So we’ve got this resource, so why shouldn’t we use it to help stabilize our energy mix and also use it to confront climate change? There are a number of different factors that make it imperative to try to capture some of these renewable resources.
I think it’s probably going to be 10 years though before we see any significant number of these devices in the water and making a significant contribution – but you have to start somewhere.
Airhart: What’s the most exciting part of this work to you?
Mill: I think that’s fairly easy. I think just to see that you are making a difference in the world, that you are genuinely perhaps helping a technology come to fruition that may make a difference in the generations to come.
It’s not going to be in my generation that’s going to get the benefits of it. But my children and their children will see the benefits of renewable energy and it’s that knowledge that we’re doing something to make a difference that gives me a buzz. And every day we go down there, see a device in the water, see the wave characteristics and achieve another step on in the development and testing of the device. That’s a great kick. And it’s really just that – it’s the feeling that you’re making a difference.
Airhart: Dr. Mill, thank you so much for speaking with Earth & Sky.
