Darren Arnold lights the burners on a natural gas stove at a testing facility near Portland, Ore. He's using a new, lower-carbon gas mixture for NW Natural, a gas utility that serves 770,000 customers across the region.
"For a cooktop burner, we're looking for a nice blue flame, nice little peaks on the tips of the flame," he says. "So everything looks really good. We'll also check the oven."