Searaser – One Step Closer to Affordable Wave Power?

Welcome guest poster,  Mathias Aarre Maehlum.

The team behind Searaser, a device that converts wave energy into useful electricity, claims it will generate electricity even cheaper than fossil fuels and coal. Are their claims rooted in reality, or is this just another hype within renewable energy? Let’s take a look closer at this technology.

What is Wave Power?

Wave power can be defined as the transport of energy as a result of wave on the ocean surface. There are two contributors to wave power: Ocean currents and the tide (rise and fall of ocean levels caused by the gravitational fields of the Moon and the Sun). The worldwide potential of wave power is estimated to be around 2 TW!

How Does a Searaser Work?

A Searaser acts almost as a “bicycle pump” and is used to pump water from the ocean to higher levels, thereby converting wave energy into potential energy, which we can use much in the same way as we do hydroelectricity.

Water that is higher than a reference height (higher potential energy), can be converted into kinetic energy (motion) by dropping it downhill through pipes. The next step in the process is to convert the kinetic energy into electricity, which easily can be done with a turbine and generator. This is a well-established technology with high efficiency rates – we’ve been doing it for decades.

I hope it is clear that the Searasers themselves does not generate electricity, but only elevate the water. A Searaser consists of the following main components:  Two buoys that are attached to a piston.

The idea is quite simple.   As waves come in, the upper piston is forced upwards by buoyancy since it is floating on the water surface. As the wave passes, gravity pulls the same piston back down. This is how the device got its analogy “bicycle pump.”

The Benefits of Searaser

Generating electricity with the help of Searasers is obviously green – there are no climate gas emissions involved, at least not after construction and installation. The ocean water that is elevated has to return to the sea for us to generate electricity, it is therefore also a renewable source of energy. This is also true for other technologies that harness wave energy.

So what is so special with Searaser?

Simple design and cheap components pushes the energy prices for the end users down. I have to admit that I haven’t seen anything else in wave power comparable to Searasers when it comes to simplicity.

Additionally, electricity generation is happening well above the water surface in the generators. In other words, the effects of corrosion on electrical components are negligible, which further helps bringing costs down.

One of the problems with today’s ways of harnessing renewable sources is that they are highly unpredictable. Wind and solar power are fluctuating sources of electricity and we have to do reach significant technological breakthroughs before we reach affordable efficiency rates with energy storage – the solution to stability and the base load demand. Searasers has the advantage that pumped water hydro is well established.

Downsides

One would expect that the there’s a whole range of downsides with the Searaser-technology, as it usually is with ways of harnessing energy. Hydroelectricity has long been blamed for disrupting the ecosystem by altering the natural flow of rivers. Wind turbines are infamous for killing birds. However, this is not the case with Searasers nor any other wave power device.

It is clear that some people could have issues with aesthetic of the scenery where Searasers would be located, but this would be nowhere close to the same issues with coal power plants or onshore wind-farms for that matter. Searasers are not expected be a threat to the ecosystem in the sea either.

It all boils down to if Ecotricity, the company behind the Searaser technology, is able to make the Searasers cost-competitive. The end user energy prices has be on par with conventional sources of energy such as coal power, fossil fuels and nuclear.

How far is Searaser from Commercial Launch?

Searaser 1200, which is the current model, has through extensive testing showed to be able to generate as much as 932 kW under ideal conditions. A flow of power of this amount would be sufficient to provide electricity for 17, 000 homes.

Taking normal conditions into account, it would require 11,000 Searasers to cover the UK’s entire domestic power demand. Ecotricity aims to have them on the market already in 2014.

Already back in 1890, the first attempts to use wave power were conducted in San Francisco. In the last decade or so, hundreds of so-called revolutionizing ideas have been patented, most of which has been discarded and only a few reaching the final testing stages.

I think the Searasers holds a lot of promise. This is a fresh approach to harnessing wave power and numbers look good. However, if the Searaser-technology actually will pan out not can only be speculated in.

The data from this article has been taken from a slideshow that was given by the inventors in Dartmouth Wave Energy Ltd.

Bio of the Author:

Mathias is currently doing a masters degree in energy and environmental engineering at NTNU in Norway. He is also a writer at EnergyInformative, a site dedicated to inform about renewable energy sources (wind, solar and geothermal) and energy conservation/efficiency.

Editor’s note:  Thank you Mathias for such an interesting article.

Join the Conversation:

• What are your thoughts about this wave technology?
• Do you think it is scalable option for many countries?
• Do you feel that this type of technology will be disruptive to the ocean ecosystems?

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