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Posts Tagged ‘Renewable energy

Green Light For London Desalination

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Boris Johnson paddling a coracleLondon’s new Mayor, Boris Johnson, has dropped a legal challenge to Thames Water’s proposed £200 million desalination plant in Beckton, East London. The High Court challenge was initiated by his predecessor, Ken Livingstone, on the grounds that the project was inefficient and bad for the environment.

Mr Livingstone said cleaner, cheaper and less wasteful alternatives should be found to avoid the “energy-guzzling and carbon-intensive” way the plant was run. According to Times Online, Boris Johnson withdrew the case after Thames Water “promised to introduce a series of environmentally-friendly measures”.

The plant will use reverse osmosis to remove salt from river water. Osmosis occurs between two solutions of different concentrations or strengths. A very fine membrane separating the solutions allows liquid (but not the dissolved solids) to pass from the weak solution to the strong solution.

Over time, the concentration of the two liquids will balance out but pressurising the stronger solution can stop the flow. If the pressure on the stronger solution is increased further the osmotic process is reversed and the liquid passes from the stronger solution making it more concentrated. This reverse osmosis process can be used to remove water from a saline solution (i.e. brackish water) thus providing a desalination technology.

The first reverse osmosis water treatment plant was built in California and started working in 1965. The nice thing about this technology is that it’s highly scalable, suitable for large projects like Beckton, producing enough water for 400,000 homes, right down to small-scale devices like Red Button Design’s ROSS (‘Innovate or Die‘)

According to Thames Water’s FAQ page, the process will be timed to extract water during the three hours leading up to low tide, minimising the salt content to less than one-third that of seawater. This means that the plant will use approximately half the energy required to treat pure sea water, and around 15% of that used by the most energy-intensive thermal desalination plants.

The plant “will use around 6.3MW a year over a 25-year lifespan”. Hmmm, not sure what that means, someone doesn’t know the difference between a megawatt and a megawatt-hour it seems. More work needed, must try harder. Thames Water have “given a legally binding commitment that 100% of the plant’s energy needs will be met from renewable energy”. Options being considered are wind power, and used cooking fat and oil. Initially, however, the plant will be powered by biodiesel, which raises the old questions, where will the biodiesel come from, and what environmental damage will be caused in producing it? I bet it’ll have some palm oil in it.

Interesting how the word ‘sustainable’ doesn’t show up in Thames Water’s information on the plant, it’s all about ‘renewable’ energy, which is more difficult for the green lobby to take exception to. They’re learning.


Written by Pete Smith

May 13, 2008 at 10:12 am

Pssst! Wanna Buy Some Green Energy?

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Private Walker

The Observer reports that Britain is running out of renewable energy, as a surge in demand from businesses has outstripped the supply of electricity generated from ‘green’ sources. Firms’ interest in reducing their carbon footprint has far exceeded new capacity coming on-stream. This leaves companies which have pledged to become ‘carbon neutral’ with a sizeable headache. EDF is ‘prioritising’ existing customers, Npower says the amount it can supply depends on how much customers can pay, and Good Energy, a renewable-only electricity supplier, is turning away very big orders.

What some might consider a surprising popularity of renewables in the business fraternity is being led by large companies, who are obliged to pay the climate change levy on electricity from fossil fuels. The situation isn’t helped by the snail’s pace of the UK planning system, with wind energy projects which could supply one in six British homes mired in bureaucracy.

So much for the power of the market.

‘Business runs out of green energy supply’

Renewable Energy

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Shares in Renewable Energy Holdings (REH.L) were up today on the news that the green technologies firm has agreed a deal to purchase the Kobylany wind farm site in Poland, which will provide 30 MW of generating capacity with an accompanying off-take infrastructure and transformer station. REH will pay €68,000 per MW of generating capacity, making a total of €2.04m. The agreement allows for an initial lease term of 25 years, with an option to extend for a further 25 years.

The annual lease payment will be €25,000 (plus VAT) with an additional annual payment of €7,000 (plus VAT) for each turbine on the site. It is expected that there will be 15 wind turbines altogether. Construction is expected to start in Spring 2008, financed by REH’s credit facility with Standard Chartered Bank. Good to see the credit squeeze doesn’t apply for renewable projects.

REH is active in wind, wave and biomass. The company owns the CETO wave energy technology, which it is developing in co-operation with Carnegie Corporation.

Written by Pete Smith

December 10, 2007 at 12:47 pm