Nasdaq listed Active Power, which sees itself as the leader in battery-free backup power solutions, yesterday announced that it has signed a CoolAir(TM) UPS (Uniterruptable Power System) usage plan agreement withGeorgia State University (GSU).

At the time of posting, the stock is performing well, posting a 14% gain to $3.16 a share. It is also trading much where it did a year ago, before peaking at 5.91 on April 18, 2006. Since then, obviously, it's had a tough time. So the question is, is it now lifting off from these lows in a meaningful way?

The company has been getting some good press for its flywheel technology. People like the green credentials of flywheels. As a UPS source, it is in competition with lead-acid batteries, diesel generators and fuel cells. According to Frost & Sullivan in this same article, the worldwide UPS market is estimated to be worth $6.1 billion in 2006 -  7.1%  growth on the year. Yet flywheels - both static and rotary - will only account for just under $200m of sales.

You can see an overview of the Frost & Sullivan report on flywheels here.

Nasdaq listed GPRE closed up 5.80% today at 36.50.

The company, which is based in Las Vegas, is building a 50 million gallon ethanol plant in Iowa.

Bioenergy watchers might also be interested to trawl through their detailed links page on agricultural data, particularly on corn and ethanol.

London listed Clipper Windpower Plc closed down 10.98% today at 284.43.

Amongst wind companies, Clipper is highly unusual in that it is both a manufacturer at its plant in Iowa and a wind farm developer with 6,000 MW of wind resource rights.

The background to this, according to their annual 2005 accounts is that "When the company was formed in 2001, interest in acquiring wind resource assets in the United States was low" . . . so they did.

This has proved a long-sighted strategy in Britain and Germany, where the number of good wind on land sites have actually become very limited due to planning and resource constraints. This is driving them to look hard at offshore wind power.

However, you do wonder if this is ever going to be a problem in the USA - Clipper's principal market - for a very long time. Growing industries like windpower always specialize and constantly divide effort between emerging specialists.

That's why you wonder how long Clipper's vertically integrated business model will hold into the future.

The Sarbanes Oxley Act has driven yet another US company in to the arms of London's AIM.

According to this newspaper report, Viceroy Acquisition Corp, will list in London next month, eyeing a $200 million fund-raising as it tries to buy its way into the fast-growing U.S. biodiesel market.

Ok, they haven't said that's why they want to list in London, but it's what I consider likely. It has been an incredible turnaround from say 8 years ago, when the whole world wanted to list on NASDAQ. This shift to AIM has been quite pronounced in alternative energy where typically small firms, seeking relatively small amounts of capital, are in no need of onerous and expensive reporting requirements.

It just goes to show . . .

Whenever you raise the entry costs of doing business, you'll always drive some of it somewhere else.

D1 Oils PLC , gaining over 8% on the day to close at 227.75p

It could be that the market is responding positively to news that it is on course to deliver 72,000 tonnes of biodiesel by year-end. Today it was also anticipated that dealings would commence on a 100,000 plus share allotment.

Perhaps the company's renowned volatility will soon start to settle down with more predicatable cash flows like these coming on stream. It has however, been a rollercoaster ride since going public in late 2004, with a high of over 500 and a low of around 150.

That's why this is certainly one company to watch closely.

Chinese Suntech Power has had quite a ride since its IPO last December. The stock went public at $15, tripled to over $45 and has since had quite a fall to the low 20s. Some people think this post-IPO correction may have been overdone - see this recent piece on 21st June - Once-Sizzling Suntech Power Sees Daylight .

If we were to use prejudicial stereotypes, investors are short termists and the Chinese like to take the long view. So what's the Chinese long view on solar that investors might want to know about?

As this piece from March earlier this year explains, the medium term view suggests an enormous solar capacity ramp is under way in China.

"Module capacity of 450 MW will rise to 1200 MW by 2008. The 200 MW of domestic solar cell making capacity will rise to 1200 MW exiting 2008 with the ramp of three large cell makers and as certain wafer suppliers forward integrate. Wafer capacity of 100 MW in 2005 will grow to circa 800 MW by 2008 thanks to the production ramp of domestic polysilicon supply as well as large poly supply contracts beginning in 2008."

And for the long term view, it goes on . . .

"Solar demand in China is expected to increase significantly over the next several years driven by the Chinese renewable energy program enacted in February. Although the government has not communicated the details, the law is expected to generate 500 MW of annual capacity by 2010 ($3.5B USD), 3 GW by 2020, and 60 GW by 2050."

NYSE-listed Suntech closed up on Friday at $26.60

It's a rhetorical question of course. It's also the title of this article here which explores the emerging range of alternative energy investments. Their definitions go a lot wider than here at AEI. We have not and will not cover OTC stocks. And it's a big stretch of the imagination to define Ford and General Motors as green stocks because a tiny fraction of the cars they make are hybrids.

On AEI, you won't find any buy, sell or hold recommendations, but we fully intend to continue exploring the global universe of alternative energy stocks, their underlying technology and encourage you to participate.

This is an emerging industry at the start of a long boom. Rising fuel prices, rising environmental standards and pent-up energy demand are all coalescing to create an enormous wall of money going into alternative energy.

Capital markets will play the critical part in allocating these resources.

That's why green stocks are worth your attention.