Alternative Tides

"Not only will atomic power be released, but someday we will harness the rise and fall of the tides and imprison the rays of the sun.” Thomas Alva Edison (1847-1931)

Thomas Edison was a man truly ahead of his times, an absolute visionary; like Donald Rumsfield, only different. (Must i provide a reference for that? if you need one, then probably you’re better off reading this instead.) My own brain apparatus being a fine example of low functionality – especially by comparison - i marvel considerably more than Edison ever would at what’s happening in the world of renewable energy technologies. Thus, on the heels of my little foray into algal fuels, news about the first tidal power station feeding into the UK’s electricity grid naturally caught my attention and fired up the old Amaze-O-Meter again.

Located off the coast of Northern Ireland, this single underwater turbine will be generating 1.2MW of power by the time it reaches full capacity in a few months, which translates into enough electricity for approximately 80 households (depending on the number of appliances and energy-efficient measures employed). The technology employs the same principles as those found in wind power and achieves the same results, using the currents of both neap and ebb tides in the same way that wind turbines use air flow. Marine Current Turbines, which designed the SeaGen device, offers this short animated look at the technology. As noted on their site, one of its important features is that the whole apparatus can be raised above the surface for maintenance, eliminating the substantial expenses involved in underwater repairs, etc.

Apparently this is just the beginning of a major push to bring the contribution of tidal power up to 20% in the UK, while Scotland projects supplying 25% of Europe’s total marine-based energy through a combination of wave and tidal power stations. Given that the Scots have already surpassed their 2010 goal of 18% renewable, it seems reasonable to place confidence in their projections as well as determination to meet them. The Orkney project will be the world’s largest marine energy undertaking to date, and is scheduled to begin installation of its complex array of wave and tidal energy devices this year at a cost of £13 million (compare this to $13 billion – £6.5 billion – for one nuclear plant). The Scots are collaborating on this project with Hammerfest Strøm of Norway, who, in 2003, were the first to connect a tidal power generator to the public grid network.

Elsewhere, turbines similar to SeaGen and designed by the Canadian company, Blue Energy, will be employed in that company’s joint project with the Philippine government:

The Dalupiri Ocean Power Plant will utilize 274 ocean-class Davis Turbines, each generating from 7MW to 14 MW. However, the $2.8 billion project is just the first phase of a much larger proposed Build Own Operate Transfer (BOOT) project to be transferred to the Philippines after 25 years. Used to generate large scale renewable energy, the San Bernardino passage could help the Philippines to become a net exporter of electrical power.

That, to me, is pretty amazing. South Korea is also catching this renewables wave in a joint venture between Lunar Energy, a British tidal power company, and Korean Midland Power Company. The Wando Hoenggan project will be the world’s largest tidal wave generation “plant” and is anticipated to supply electricity for about a quarter of a million households. The turbine design is completely different, the advantage apparently being that seabed ducts will not interfere with safe passage of ships at the surface

Photo from Times.UK

Looking for critiques of these systems, what i found were a range of position papers and articles decrying the environmental impacts of tidal barrages. These are essentially dam networks constructed in coastal areas that allowed the operators to surge water (and thus, create current) at will. Problems are then more or less the same as what we’ve seen in standard hydro dams: impacts on wildlife, marine creatures, local hydrology and so forth. This analysis of such a system in northern Canada looks at some of these issues, though largely in the context of public-private investment and not clearly concluding that the problems are insurmountable.

In the non-tidal wave marine energy sector, progress is also being made from both technological and application standpoints. Portugal has a small wave farm of 3 units generating a total of 2.5MW 5 km off the coast at Aguçadoura, with plans for expansion in the works. According to folks at the British-based renewable energy center, wave energy entrapment is currently less advanced than its tidal counterpart, but more diverse in approach; clearly an area of development with many groovy innovations yet to come.

In all likelihood, this blog will continue to betray my own ignorance about renewables as i continue to survey what’s happening in the alternative energy sector. As Santayana once noted, “The tide of evolution carries everything before it, thoughts no less than bodies, and persons no less than nations.” Like anyone trying to escape those feelings of despair that wash over us when W justifies the destruction of Alaska for oil drilling or Sarkozy applauds Gulf emirs for signing on to nuclear power, i find that i can subvert my fatalism by reading about non-nonsense alternatives to the dominant paradigm. When it comes down to it, that’s pretty much the best that atheism has to offer. Not necessarily belief in science, but belief in the future - and free will to make the most of it.