|Looking For The Next Wave - part 1|
|Written by david brunnen|
|Sunday, 29 June 2008 09:48|
In this short series David Brunnen sets off on a personal voyage to explore the future of marine energy generation. In Part 1 he sets the scene with a back-story of clues from his marginal experience of green marine energy.
Thirty years ago, when our children were still very small, our sailing holidays were extremely modest adventures.
Barely six miles out of Portsmouth we would drift towards St Helen’s Fort off the Isle of Wight, sneak into Bembridge harbour and ghost our way, usually on a falling tide, as far inland as possible to a tiny marina at Brading Haven.
Heroic voyage complete, the kids were then free to roam, to row the dinghy and to wander around the faded ruins of what had once been, before the harbour silted up, a bustling port with a rail head and a strong local economy.
Every parent on holiday values the idea of children ending the day so tired that they’ll drop off to sleep without protest. This place had no shortage of long walks perfectly suited to the cause. One of best was the path along the dyke of what for 400 years had been the catch-pool that powered the tidal mill.
The old mill had long since been converted to a home. The mill-stones were now nothing more than garden ornaments; relics too heavy to throw away but of uncertain artistic value. Most of the tide gates along the path were hopelessly beyond repair but, being solidly engineered exemplars of their day, you could still see how they worked. The mill pool itself was massive and would still flood on every tide. At the ebb you could sit at the gates and sense the power of that pressure as it wasted away – no longer put to any useful purpose.
These days we demand our power to be available at the flick of switch. We value constancy. We prefer not to be reliant on the naturally variable elements. The notion of working the tides survives only amongst boat owners with engines as unreliable as the one that ensured that we used the sails, and the paddles, a bit of rudder waggling, and a lot of cheerful singing, to make it home.
But times change and in these days of rising fuel costs and worries about pollution there is a renewed focus on renewable energy. We are once again aware of the need to harness the massive forces of ocean currents, wild waves and turbulent tides.
If the tide-pool at Bembridge symbolises the 1st generation of marine energy then I suppose the exemplars of the 2nd generation looked beyond the tidal-hydro barrage on the river Rance near St Malo and, in my youth, were typified by designs from modern pioneers such as Prof.Steven Salter and his intriguing bobbing ducks. It was difficult to get research grants for such ‘alternatives’ in days when enthusiasm for nuclear technology was brimming over and it was assumed that infinite supplies of clean energy would be lighting up our lives for little or no cost.
Nowadays, whether we consciously admit it or not, most of us realise that new technologies rarely deliver against their promises until their 4th or 5th generation. One has only to survey the 3rd generation of mobile phones (and their current race to develop a fourth generation ‘get-well plan’) to understand the cyclical process of over-hyping the prospects in order to gain development traction - a process invariably followed by a slow sinking slide towards reality.
Wind power has been suffering the same adolescent angst. Now, again just like mobile phones, the bottleneck to seriously-scaled off-shore wind-farm progress is understood to be ‘the backhaul’ – the way that generators of power (or urgent chatter) in out-of-the-way places can get connected to the main-stream.
All this has been valuable learning for the proponents of marine energy – especially for energy that can be generated in places where, unlike that old mill at Bembridge, it has no local use. So where in the world, I wondered, should we look for the 3rd, 4th or possibly the 5th, generations of technologies that could harness sea-power? What might this next wave look like ?
Future episodes of 'Looking for the Next Wave' will consider the prospects for marine energy generation and review a range of designs that are at various stages of development.