One wonders what environmentalist foes of hydraulic fracturing — fracking — for natural gas make of a new Bloomberg Businessweek report.

The vast majority of fracking sites in America are powered by emissions-spewing, noisy diesel engines. Which is why Ron Hyden, who’s seen a lot during his four decades in the oil patch, is eager to show off something new: a fracking machine that uses gravity and electricity generated from solar panels to send sand more quietly into a labyrinth of tubes before ultimately being shot underground to prop open tiny cracks in gas- or oil-bearing rock. The irony of gravity and solar panels being used to help capture fossil fuels isn’t lost on Hyden. “You would’ve never thought we’d give a flip about this,” says Hyden in a Texas twang as he gazes at the solar panels atop his new contraption. But, “we’re big into it.”

The “we” is almost as surprising. Hyden works for Halliburton (HAL), remembered by many for having done the cement job on the BP Macondo deepwater well prior to its 2010 blowout. The $25 billion oil-field giant is the world leader in providing services to companies involved in hydraulic fracturing—the process of breaking up shale by injecting high-pressure sand and chemically infused water to release hydrocarbons.

Halliburton calls its two-year-old solar-powered invention the SandCastle. It has rolled out dozens of SandCastles in the U.S. By replacing diesel engines to move sand from the trailers, Halliburton estimates the devices have saved 950,000 gallons of diesel and reduced carbon dioxide emissions by 20 million pounds in the first nine months of 2012.

Solar panels and fracking? In a project linked to Halliburton? Interesting.