Investments and acquisitions in clean energy companies will top $100 billion this year, according to New Energy Finance data, as quoted by Clean Edge. New Energy Finance also reports that venture capital given to clean energy companies was up 167 percent in 2006 over the prior year.

Based on the conferences I've attended many of the investors who were behind the Internet revolution of the late 90's are moving their money into renewable energy and alternative fuels. While some of the innovations (eg. fuel cells) are more risky propositions and may not live up to the hype, this investing gold rush is much more grounded in reality than the web run-up of last decade.

Last time around we had companies such as Pets.com and Kozmo telling us that people were going to stop shopping in the physical world and purchase goods from their desktops, and that ecommerce was going to create substantially more demand for known commodities. As we know, to a great extent that didn't happen.

But energy is a different beast as economists, governments and financial analysts all agree that demand is going to increase at a relatively steady rate based on population growth and the increasing wealth of developing nations. So the companies that are developing solar cells or ethanol don't need to create new markets for their products; they only need a share of the expected growth. Nearly all of the predictions say that the demand for fuel and electricity will outstrip today's primary resources of coal, petroleum and natural gas, so something will need to fill the void.

We don't know for sure today which company that is developing an algae to turn biomass into fuel or wind turbine technology will hit it big, but we do know that if the technology can generate energy at a comparable cost, then there will be a market for it.