Not a lot of startups tackle the field of geothermal power, which entails tapping into hot rocks deep in the Earth to produce energy and electricity. That’s because it can be an expensive proposition, and can require extensive permits and environmental reports. But a rare startup called AltaRock Energy has recently delivered a promising breakthrough that it says can lead to the commercialization of its next-generation geothermal technology.

AltaRock Energy — which has backing from venture capitalists, as well as Google and Microsoft co-founder Paul Allen’s investment firm — has been working on enhanced (sometimes called engineered) geothermal tech. This technology drills wells deep into the ground, injects them with cold water to fracture the hot rocks, and creates a geothermal source of power where none was naturally occurring. Traditional geothermal systems, in contrast, tap into naturally occurring geothermal reservoirs…

Geothermal power is also the holy grail of clean power because it’s not intermittent like solar or wind power. Geothermal power can produce electricity 24/7 — including at night — while wind power drops off when it isn’t windy, and solar power ends when the sun goes down. Constant power like this is called baseload power, and it’s one of the reasons why coal and natural gas are so widely-used.

AltaRock Energy said that it has reached a milestone at its demonstration site in Bend, Oregon, which it believes is a good sign that it’ll be able to commercialize its enhanced geothermal tech. AltaRock CEO and founder Susan Petty told me that the company has been able to create multiple, stimulated geothermal areas, from a single drilled well. “This has never been done before,” said Petty, who has been involved with geothermal stimulation since the 1970s.

Creating multiple geothermal zones from one well is important, because it means more geothermal power can be produced and the process becomes a lot cheaper in the long run…Being able to create multiple geothermal zones from one well brings down the overall cost of enhanced geothermal by 50 percent, Petty said.

AltaRock is still in the testing and research phase. Now that it’s stimulated multiple geothermal zones at the site, it still needs to run injection tests and test the heat exchange areas. It also needs to drill a production well in the stimulated zones, which could happen by the end of this year or early 2014. Enhanced geothermal sites need at least two wells, one for injecting and one for producing the power.

Go for it. There ain’t hardly anything cleaner than geothermal.

My only experience has been with the naturally occurring systems. I am surprised it’s taken until recently for folks to get round to dispersed boreholes from a single site. It’s been common in oil and natgas drilling for decades.