Investments in start-ups specializing in areas like conservation technology and alternative energy are on the rise. Companies are also developing other clean technologies that include water and gas purification, waste recycling and energy storage. Venture capitalists are betting on these tools and specifically "nanotechnology," which has the potential to reduce the need for scarce materials and to henceforth reduce pollution.

"Nanotechnology has variously been described as a transformative technology, an enabling technology and the next technological revolution," says Judith Lightfeather of the NanoTechnology Group. "Even accounting for a certain level of hype, a heady combination of high-level investment, rapid scientific progress and exponentially increasing commercialization, nanotechnology will have a fundamental impact on society over the coming decades."

Solar led the investment drive within public markets during 2006. Of the $10.3 billion raised, it took in $4.4 billion. That's more than double the level of financing it raised in 2005. After solar, bio-fuels raised $2.5 billion, which is more than 10 times the money invested in the sector in 2005, says Clean Energy. Wind technologies were next, raising $1.2 billion in 2006, which is about the same as the year before.

The federal government has promised to ante up $3.7 billion to encourage research and development in the nanotechnology sector through 2008. Non-profit organizations are also participating.

Plextronics, for example, just received $750,000 from Pennsylvania-based Sustainable Energy Fund to develop organic solar cells. Organic solar cells use extremely thin layers of plastic semiconductors, instead of silicon, to absorb light and create electricity. The semiconductors can be printed like inks resulting in a much lower cost of production.

Nanotechnology permits scientists to rearrange atoms and to build matter from the ground up, allowing a substance to be rearranged with atomic precision. Chemical structures that are not disallowed by the laws of physics can be rebuilt. So, scientists can create new building blocks that produce materials with the exact properties they desire, which are generally smaller, stronger and lighter than current technologies.

Public Eye

According to Pradeep Haldar, head of the nanotech center at the University of Albany in New York State, nanotechnology can be viewed along two lines: evolutionary science and revolutionary science. The former already exists but scientists are trying to understand it better and enhance performance. The latter is 10-20 years out. It's about building devices from the ground up one atom at a time -- something that could create a monumental impact on mankind and on the energy world in particular.

The vision: Solar cells that turn sunlight into electricity could become more efficient and diminish the global need for carbon-based fuels that are thought to cause global warming. And filter systems could be built so that they capture even the smallest particles that might escape into the atmosphere, which has far-reaching implications for refineries or power plants.

Nanotechnology-based lighting advances, meantime, could begin reducing energy consumption by more than 10 percent worldwide. That reflects a total consumer savings of several billions per year and a corresponding reduction of 200 million tons of carbon emissions, says the National Science Foundation.

The goal now is to make such science workable. Medical applications are considered by many to be the first nanotechnologies that will surface in the market. But energy- and environmental-related technologies are not far behind.

California-based Nanosolar, which raised $75 million in 2006, will begin building a printing plant in the San Francisco area that it says could produce 200 million solar cells a year that would generate 430 megawatts. Similarly, Hydrogen Solar, a British company, says that it is working on fuel cells that can convert sunlight to hydrogen power and store the energy -- all with nanotechnology.

Along those lines, a company called Ener1 out of Ft. Lauderdale plans to manufacture high-rate lithium batteries for use in hybrid vehicles. The market for such cars is only expected to increase and Ener1 believes it can mass-produce the batteries to power these automobiles on a cost competitive basis -- all of which helps ease the dependence on foreign oil supplies while helping to cleanse the air.

The science is in the public eye. And, like anything with such high-hopes attached, there's a lot of overestimation and grandiose claims that have yet to be substantiated. But, nanotechnology offers some unprecedented goals and particularly in the areas of solar and wind power as well as fuel cells and energy efficiency. The research is ongoing and certain areas appear ripe for commercialization and ones in which investors are willing to place bets.