As a pioneer in the development of solar-thermal power, Craig Tyner is gratified to see the technology he's spent decades of his life working on finally getting hot.

Tyner, a former chairman of the International Energy Agency's solar-thermal working group and Sandia National Laboratories solar-thermal researcher, was named senior vice president of engineering for solar-thermal startup eSolar Inc. earlier this month.

The idea of using the heat of the sun to generate electricity has been around a long time. But it's only recently that the combined factors of rising energy costs, increasing concern about global warming and what Tyner called "incremental" improvements in solar-thermal technology have put the industry in the spotlight.

Pasadena, Calif.-based eSolar has certainly shared that spotlight, in June announcing a deal to build 245 megawatts of concentrating solar-thermal plants for Southern California Edison by 2011 and in April landing a $130 million investment from, IdeaLab, Oak Investment Partners and other investors (see California to Get More Solar-Thermal, Funding Roundup: Solar-Thermal Heats Up Despite Cool VC Climate, Google Heats Up eSolar with $10M and Q&A: Bill Gross Puts a Shine on Solar).

ESolar plans to produce electricity using fields of mirrors that direct sunlight toward a water tower to make steam, which it then converts into electricity.

In an interview with Greentech Media in April, Bill Gross, CEO of Idealab, said eSolar's advantage is that its power plants will be completely prefabricated, removing the need for construction and extensive labor at the site. He also said using many small, flat mirrors instead of large, curved mirrors will reduce the cost.

Not that other solar-thermal companies haven't been raking in the cash and contracts as well.

Oakland, Calif.-based BrightSource Energy Inc. in May landed $115 million, one month after it announced it would provide up to 900 megawatts to Pacific Gas and Electric Co. And Palo Alto, Calif.-based Ausra Inc. in November announced a 177-megawatt deal with PG&E, two months after securing a $40 million investment, and in June opened a factory for the components of its solar facilities in Las Vegas.

And Phoenix-based Stirling Engine Systems, which employs a different technology using the sun's heat to power an electricity-generating engine, in April raised $100 million from Dublin firm NTR and is planning to build 1.7 gigawatts of solar farms, starting with a 300-megawatt plant in El Centro, Calif., for San Diego Gas & Electric.

So what has made solar-thermal so attractive to investors and utilities lately - and what does Tyner believe puts his new employer at a competitive advantage? We talked to Tyner this week to get his thoughts on the past, present and future of the solar-thermal industry.

Q: You've been involved in solar-thermal technology development since the 1980s. Why has it taken until now for the technology to gain wider acceptance?

A: What I think has happened in the past few years is a confluence of both the need for more energy - solar power doesn't generate fuels, but it does address the rest of the market for electricity - and the emphasis for green and clean technologies that address the need to fight global warming. ... On the other side of the coin are the changes in technology that have brought the cost down. I don't think I'd characterize it as any major breakthroughs, but the technology has evolved.

Q: How do you think eSolar can differentiate itself from others in the solar-thermal space in terms of technology?

A: The ability to be able to calibrate and control our mirror systems. That allows us to use very cost-effective implementations of our mirrors and the drivers that control them. ... [The modular nature of our power plants also is] a significant element of the cost.

Q: How quickly will eSolar be able to commercialize this technology?

A: We are building our first commercial demonstration plant in the Southern California area - the plant's going up as we speak. We have a smaller test facility where initial elements of the system are tested out. This shows us how quickly we can build these things from the component parts, and the speed at which our systems are going in has met our expectations and shows the cost effectiveness of the technology.

Q: How cheap do you think solar-thermal has to get to compete against fossil fuel-generated power, and when might that happen?

A: Costs, I think, have typically been in the range of 15 cents per kilowatt-hour and up - mostly up. As they come down from that range, they become effective in markets that have some sort of green incentives. Our approach at eSolar is we want to be able to compete in the long term with conventional sources of energy, coal and natural gas. We believe right now we're competitive in any market that has green incentives, and in a handful of years, we'll be competitive without those incentives.

Q: Do you think that solar-thermal is as suited as photovoltaic solar for distributed generation, and what do you make of arguments that utility-scale solar power should take a back seat to putting traditional photovoltaic solar panels on rooftops?

A: There are a number of perspectives to that debate. Certainly distributed power has its advantages, but it also has its disadvantages, one of which is maintenance of the systems.... If you put a PV system on somebody's roof, if it's not working tomorrow, very likely nobody will know. The ability to maintain and monitor those systems is difficult.

[Also, compared to coal-fired or nuclear power plants], a 100-megawatt solar-thermal system may look fairly distributed. I think solar-thermal is situated such that it can meet demand from any perspective, from 40-megawatt distributed systems, if you will, to multi-hundred-megawatt plants where that meets our customers' needs.

Q: ESolar has set a goal of building 1 gigawatt of generation capacity. What's the timeline for the company to reach that goal?

A: I really can't give you the specifics on that... but solar-thermal has to be deliverable on those scales to be effective. Solar-thermal has the ability to generate not just gigawatts, but hundreds of gigawatts, and make a very measureable dent - perhaps as much as 50 percent - in the nation's electricity needs.... If we're going to have an impact, we have to do it on that scale.

Q: Beyond generating large amounts of electricity, what other longer-range goals do you and eSolar have for using solar-thermal technology to meet the world's need for renewable energy?

A: ESolar is looking at the potential for broader markets -- for example, solar-generated fuels. That's a long way down the road.... You can use electricity for electrolysis to make hydrogen from water, but you can do that with any sources of electricity. But because solar-thermal generates very high temperatures, we may be able to split water through various thermal-chemical processes... to drive chemical reactions that can produce fuel. If you can make hydrogen, you can probably split carbon dioxide, and make something called syngas - and from syngas, you can make methanol, you can make other (liquid) fuels.

That will require advanced technologies that we're beginning to look at, and others have been looking at. It's a long way away.... [But] we actually have some work ongoing. We're doing work in high-temperature systems that can ultimately go in that direction. ... In the end, to address that second half of our energy problems - that being fuels for transportation - you have to be in that market. That's a good way down the road for everybody, but I think that's part of the potential for solar-thermal.