Even before Congress passed vital legislation extending tax credits to the industry last week, investment in clean energy companies had been growing at a sharp pace.

Renewable energy companies with ties to Nevada have said investment has increased in the past year as the industry gains a higher profile and political candidates express support for growth in the sector.

Reno-based wind spire company Mariah Power just reached a fundraising goal with enough investment dollars to spur major growth.

The consumer-scale wind spire manufacturer is launching a more powerful product, opening a manufacturing plant in Michigan and is moving forward with research and development on spires to power parking-lot lights, streetlights and a residential rooftop model, founder and Chief Executive Mike Hess said.

Ausra, a California-based solar developer with a factory in Las Vegas, recently secured $60.6 million in its latest round of equity financing.

Wellspring of green ideas: The entryway to the Origen Experience at the Las Vegas Springs Preserve. The 180–acre Preserve serves as a prototype for businesses to integrate principles of sustainability. STEVE MARCUS / STAFF PHOTOGRAPHER

The money will fund the company's research and product development and commercial activities, including the completion of a 5-megawatt solar thermal power project near Bakersfield, Calif., and a ramping up of manufacturing activity in the Nevada factory.

The sector has been successful for a variety of reasons from growing concern about the nation's energy future to the influx of highly inventive entrepreneurs forsaking Internet-based businesses for something more stable.

"The overhang of talent once the dot-com music stopped playing - a huge amount of talent - was looking for the next vision and career area and a lot of that moved into clean tech space," said Mark Donohue, the clean technology entrepreneur-in-residence at Babson College and an expert on clean energy investment.

The scenario is playing not just on a local stage, but nationally and internationally as well.

Venture capital investment in the sector has increased by more than 30 percent to about $1.65 billion. At the same time, overall venture capital investment is down at least 5 percent.

Ernst & Young reported last week it would invest at least $270 billion in the next decade to fight climate change.

Solar home: Ausra's solar panel factory is shown near Las Vegas Boulevard South. The solar developer recently secured financing to fund further research and product development. STAFF FILE PHOTO

As most American renewable energy companies are privately held startups, this could be the best indicator of the sector's potential.

At the same time, the world's larger international clean energy developers are also doing well.

While the Dow Jones industrial average and Standard & Poor's index have nose dived over the past year, indexes of publicly traded clean energy companies have continued to increase dramatically.

The Jefferies Global Clean Technology Composite Index is up 19 percent this year compared with last year. And the Cleantech Venture Network announced last week an record investment in clean technology companies in the third quarter with $2.6 billion of investment in 158 green technology companies in the network, breaking the previous record of $2.2 billion in the second quarter.

Investment in clean technology companies listed in Cleantech rose 37 percent compared with the same period a year ago.

The London Alternative Investment Market, which also has listings for several clean energy and technology companies, is also up compared with last year.

This points to a trend that backs up anecdotal information provided by Nevada clean energy businesses - as the rest of the economy tanks, investors of all types are putting a good portion of their money into clean technology and renewable energy.

"The financial performance has been significantly better (for clean technology)," Donohue said. "That's logical because people see the argument for energy security, see the argument for public policy to continue to enhance these industries. There's already a lot of good business momentum in these sectors, so it's logical that it would do better than the general stock market. And I think we'll see even more support for that and investment as we come closer to the election."

The one-year extension of wind energy development tax incentives and the eight-year extension for all other types of renewable energy development will spur further growth in renewable energy, experts said.

The expiration of the credits at the end of 2008 was considered a major hurdle to further clean energy development in the United States. Industry associations reported investors were leery of putting large pots of money into an industry with unresolved financial issues. Some utility-scale wind developers and almost all solar developers depend on the tax credits to trim the cost of construction so their power is competitively priced.

Now that the incentives have been signed into law, the renewable energy industry foresees increased investment on a massive scale in the next decade. The sector has the capacity to generate more than 400,000 jobs in key industries such as manufacturing and construction.

In terms of total solar energy generation, the country already trails behind smaller countries such as Japan and Germany, which have far smaller solar energy capacity. However, the U.S. is considered the most attractive country in the world for future renewable energy development, according to a 2007 Ernst & Young Renewable Energy Group report.

Nevada alone has enough solar energy capacity to power the entire nation, according to Energy Department research.

The industry does not, however, exist in a vacuum.

As financial markets around the globe worsen and more lenders go into bankruptcy, it may be more difficult for renewable developers to get the loans they need to build their projects.

Lending to renewable energy projects has historically been considered something of a no-brainer to creditors, renewable energy insiders said.

Renewables projects such as solar and wind arrays generally get long-term loans - often from multiple sources - for a specific project. And before they seek capital, they generally have significant investment in place, the permit process completed and a guaranteed income source from long-term energy contracts with regional and local utilities.

Acciona's Nevada Solar One array in Boulder City, for example, expects to pay back its loan within 20 years. The array has a life span of at least 40 years, meaning it can still guarantee a return to investors after its bills are paid.

But as the credit market continues to tighten, some in the industry worry that the lack of capital could slow industry growth.

"All ships rise and fall with the tides," Donohue said. "Clearly as we have declining liquidity, declining investment, declining purchase across most industries, an industry as broad-based as renewable energy is going to have to experience some contraction in its growth rate. Maybe not its overall growth, but the rate of growth could be slowed by the global contraction."