The CleanTech-10 is a basket of stock-market-listed companies in the green energy spectrum from wave, solar and wind power to exchanges trading carbon emissions and trading permits. Set up after Alistair Darling's so-called Budget for the Green Economy, these 10 stocks are a bellwether for the clean technology sector.

CLEANTECH-10 -- HOW STANDARD'S INDEX IS FARING

Climate Exchange

--Market cap: £400 million

--What do they do? Operator of emissions trading exchanges

--Where have the shares been? Floated at 100p in September 2003, the stock tripled in three years, took off in 2007 and eventually peaked above £20 last year. Crashed during the financial crisis to a low of 430p in February but has since rallied again to trade at 880p

--Latest news: trading on European Climate Exchange has tripled in a year and US market set to open up after Barack Obama's carbon legislation

Clipper Windpower

--Market cap: £155 million

--What do they do? Manufacturer of wind turbines

--Where have the shares been? Soared fivefold to a high of 915p in the summer of 2007 from its float in September 2005. Crashed to a low of 63p in January this year before rallying to the current 119 1/2p

Latest news: revenues soared to £450 million after it sold 238 turbines but losses widened to £195 million after wide-scale repairs of faulty blades and gearboxes

Ceres Power

--Market cap: £130 million

--What do they do? Fuel cell developer to allow homes to generate own energy

--Where have the shares been? Floated on AIM in November 2004 at 120p. Hit a high of 380p in the summer of 2007 but fell to a low of 58p six months ago. Now trading at 193p, exactly where they were a year ago

--Latest news: says trials of its boilers with venture partner British Gas have been successful and on the road to residential market launch in 2011

Novera Energy

--Market cap: £65 million

--What do they do? Operator of UK wind farms and hydroelectric power stations

--Where have the shares been? Having floated at 53p in the summer of 2005, peaked at 96p in the spring of 2008. The shares dived last autumn and have fallen further this year to trade at 38p

--Latest news: admitted the sunny dry weather in the UK this year is good for neither its wind turbines nor its reservoir-based hydro plants

Ramco Energy

--Market cap: £45 million

--What did they do? Oil minnow-turned-offshore wind farm developer

--Where have the shares been? Joined the old USM market in 1984.