Coastal energy: the waves
Wave power, using offshore devices (there are onshore ones, but their total output would be small) could, in practical terms, give us about 14% of our electricity. Just as with tidal power, a wide range of weird and wonderful technology has been developed, like the Edinburgh Duck, the Pelamis‘ Seasnake, the Osprey and the Swedish Floating Wave Power Vessel.

The Osprey sits on a large base on the sea bed, and therefore shares some of the wind turbine’s impacts on it, but the other three, and most wave power technology, is either free-floating or simply tethered to the sea bed. It has been suggested that marine life might even benefit from wave power plants by, for example, providing artificial reef conditions underwater and new ‘hauling out space’ for seals. But negative impacts could include changes to food supplies, and changed erosion patterns, caused by reduction in wave energy levels, and – as with wind – disturbance during maintenance and electromagnetic interference from cables. Again, the consensus is that the overall impacts will not be great enough to justify preventing development.

To try to conclude
Oil, gas, nuclear and coal all have some enormous advantages: they are here; we know (more or less) how much of them we can have in the future, and at (more or less) what price; we know, (more or less) what environmental damage they cause, and, (more or less), how this can be avoided or cleaned up.

Tidal, wind and wave power, on the other hand, are not here yet in any quantity; we do not yet know how much of them we can have, or at what price; we think that their environmental impacts are usually tolerable, but we have said that about other technology in the past. We know that they cause ecological damage to the shore or to offshore waters, but we have decided to press on. We hope the damage will not be serious, relative to the large amounts of energy they might offer at some time in the future, and we know that by going ahead we are avoiding other problems associated with conventional energy, especially climate change.

The government has said that it will act to monitor and minimize the impact of wind, tidal and wave power: perhaps we should check occasionally with the Marine Conservation Society whether they agree that the new energy lunch being consumed by the coastline is as near free as we can make it?

Further Reading
For readers who might like to read further about renewable energy, I can (genuinely without obvious bias) strongly recommend two of the textbooks of the OU course on which I teach: Energy Systems and Sustainability, power for a sustainable future, G. Boyle et al eds, OUP & OU [ISBN 0199261792], and Renewable Energy, power for a sustainable future, G. Boyle ed, OUP & OU [ISBN 0199261784].

Also:
Elphick J., ed.Coastline: Britain’s Threatened Heritage. London: Kingfisher, 1987
Border Wind Offshore Wind Energy: Building a New Industry for Britain, Greenpeace, 1998

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