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World's First Lagoon Power Plants Unveiled In UK
AmiMoJo writes Plans to generate electricity from the world's first series of tidal lagoons have been unveiled in the UK. The six lagoons — four in Wales and one each in Somerset and Cumbria — will capture incoming and outgoing tides behind giant sea walls, and use the weight of the water to power turbines. The series of six lagoons could generate 8% of the UK's electricity for an investment of £12bn. Tidal Lagoon Power wants £168 per MWh hour for electricity in Swansea, reducing to £90-£95 per MWh for power from a second, more efficient lagoon in Cardiff. The £90 figure compares favorably with the £92.50 price for power from the planned Hinkley nuclear station, especially as the lagoon is designed to last 120 years — at a much lower risk than nuclear. Unlike power from the sun and wind, tidal power is predictable. Turbines capture energy from two incoming and two outgoing tides a day, and are expected to be active for an average of 14 hours a day. Friends of the Earth Cymru, said the group is broadly in favor of the Swansea lagoon.
http://en.wikipedia.org/wiki/Tidal_barrage suggests fish mortality is quite high with this method. Considering estuaries are typically fish breeding grounds, If the alternative wasn't nuclear I'd say it wasn't worth the risk to an already depleted ecosystem.
This is a horrible, horrible idea. It will reek havoc with the existing natural tidal currents and completely change the ecosystems and natural patterns present in this tidal lagoons. Many of these species are already under heavy pressure from human activities and this could be the nail in the coffin, so to speak. Do these idiots even think before they plan these things? It's like they put ecological destruction primary in their considerations and then power production secondary. Hopefully these can be easily taken out with a boat and a proper load of high explosives.
I have some detailed knowledge of this project which has been in planning and is approaching potential planning approval in the next few months. Clearly this news announcement is a late push by their PR function.
I have seen the predicted costs of the Swansea bay development rise from £600M to £1000M in the space of two years, hence the exorbitant guaranteed MWh price the developers are seeking. Bear in mind that the functional generating equipment has a design lifespan of around 30 years therefore in the lagoon's predicted lifespan this kit would need to be changed out in it's entirety multiple times, accruing further major operating costs. But no matter, the end user will pay by virtue of the mechanism set up by the UK government.
As its generation is governed by the tides a large proportion of the time it's effective output will be out of the premium workday window and effectively wasted generation.
The further claim that newer lagoon developments would require lower guaranteed MWh price closer to nukes by virtue of improved efficiency is quite frankly nonsense.
No matter how you look at these, they represent very poor value for money for the consumer.
Hmm, 14 hour uptime per 24 hours and change. Which means up for seven hours, down for 5.3 (or so) hours, up for seven hours, down for 5.3 (or so) hours.
First off, you can't shut down a coal power plant and restart it in only five hours. And it will operate at considerably (for values of "considerably" that vary from 10% to 30%) reduced efficiency for some hours after startup
Secondly, pollution from coal plants are 30%-50% (or so, depending on type of pollutant) higher during the 24 (or so) hours immediately after startup.
Which means that you're basically reducing efficiency of your coal plant in exchange for getting more pollution out of it.
In other words, that won't work.
"I do not agree with what you say, but I will defend to the death your right to say it"
Nothing wrong with a little tidal power but just looking at the geography it will never be a significant source of power.
Another problem is the cost. The prices listed in the summary are very expensive electricity ... and those are the lowball figures used to get the project approved, not the "real" numbers. Offshore wind would be cheaper, and have far less environmental impact.
As an traditional power plant engineer, offshore wind costs seem staggeringly high to me. A 90m (300ft) tall tower in the middle of the ocean supporting a nacelle that weighs about 520 metric tons (1.15 million pounds) doesn't come cheap. Have you seen rate sheets for the cranes that are needed to assemble these turbines? On land, they average in the tens to hundreds of thousands of dollars per day.
At sea, with the need for a large vessel and all the crew that a large vessel requires to keep it operating, the cost is staggering. I spent a couple weeks aboard the Tolteca, a Mexican heavy-lift ship with a 2000 ton crane and a crew of about 250. Even using labor from the developing world, the costs are astronomical. We invoiced them millions of dollars of work and they didn't even blink. An offshore supply boat rents out (in good oil-boom times, maybe not right now) for hundreds of thousands of dollars per day. A heavy crane ship is probably in the millions per day. That's just for erecting the wind turbine, which is probably at least a 24 hour lift. You also need specialized vessels to lay high voltage cable across the sea floor. Adding "marine" or "offshore" to the name of anything is an excellent way to multiply the cost by at least 3.
Even those who arrange and design shrubberies are under considerable economic stress at this period in history.