We knew that Khosla Ventures and Kleiner Perkins Caufield & Byers were major backers of Ausra Inc., the Palo Alto, Calif.-based developer of solar-thermal power generation systems. But the company will disclose Monday, along with the launch of its Web site, that Khosla and Kleiner Perkins have invested more than $40 million in Ausra’s first round of financing, giving the two VCs roughly half ownership in the company. On top of that, both Vinod Khosla and Ray Lane sit on Ausra’s board, indicating the two VCs are quite intent on guiding the young company toward success.

Ausra, founded by Dr. David Mills (who has spent the past three decades in Australia), got its big break last summer. It’s a great story, really. After years of trying to attract serious interest in his technology in Australia, Mills says he was getting ready to throw in the towel and retire. Then, last fall, he got an offer to go meet Vinod Khosla, followed by the folks at Kleiner Perkins, in October. “We clicked really well,” recalls Mills. By February, Ausra got its first funding and by March the company relocated its headquarters to California and started hiring like crazy. Since relocating, Ausra’s workforce has ballooned from six to nearly 70, and hiring continues. “It’s probably the most exciting time in my career,” Mills, 60, told me in an interview. “Better late than never.”

Ausra aims to offer an emission-free replacement to coal-fired electricity in the United States (California, Texas, Florida, etc..), China and other suitable geographies. Rather than using solar PV, the company uses its own low-cost solar concentrating technology to create steam from water that generates electricity after it passes through high-efficiency turbines. “We are currently building a 30 MW power plant, and are in the process of scaling up to 2,000 MW over the next three years — enough power for two million homes,” the company states in a new job listing on Craigslist.

Mills says the timing is perfect. “There are far more coal plants being cancelled these days than are being ordered, and the interest in our technology exactly coincides with this downturn in coal markets,” he says, adding that his solar-thermal systems are quite competitive with coal, and the economics are expected to improve. “The whole picture is now changing very, very rapidly. You’ll be seeing 10 cents per kilowatt-hour bandied around here, but that will drop very rapidly over the next few years.”

Mills cited many fascinating figures and details about what Ausra is working on, including plans for heat storage, but I’m going to reserve those tidbits for a larger profile I’m working on — so stay tuned.