It’s a dimmer switch that potentially could save megawatts of power. HID Laboratories, a Silicon Valley startup armed with technology from Oak Ridge, Tennessee, has developed a digital ballast for controlling high intensity discharge (HID) lights, the bright bulbs that illuminate stadiums, streets, industrial and big box retailers. American River Ventures, out of the Sacramento region, recently invested in the firm. Overall, HID’s digital ballast can cut the power consumed by an HID light by 40 percent or more, said CEO Antonio Espinosa. Lighting consumes 22 percent of the power generated in the U.S. and the majority of the juice of that total goes to more than 100 million HID sockets in the country. Thus, if used universally, you're talking a big whack in electricity consumption. VCs have been putting money into energy efficient lighting for the last several years, but mostly into companies that produce bulbs. Companies with complimentary technologies have received less attention, but some, such as Nuventix (air-cooler for LEDs) and Intematix (designer phosphors) have emerged. Digital ballasts effectively exploit the inefficiencies of magnetic ballasts, hoary devices devised decades ago, by finely controlling voltage and current. A ballast effectively delivers power to the bulb so that the bulb’s internal gases get excited and create light. With the digital ballast, administrators can dim HID lights to save on power consumption, something that isn’t possible with HID lights hooked up to conventional magnetic ballasts. Humans don’t notice a difference in illumination if a HID light is cranked down by ten percent. Thus, in a brownout scenario, a utility or facilities manager could turn down HID lights, cut power bills and avoid a crisis without bothering anyone, said Espinosa. Digital ballasts also can flip lights on rapidly. An HID hooked up to a conventional ballast takes about eight minutes or longer to warm up. Thus, HIDs can be turned off and on via motion sensors to cut power. Facilities managers can also use lower wattage bulbs. Ultimately, a digital ballast can also allow HID to better compete against solid state lighting like LEDs. “You can use a 320 watt bulb instead of a 450 watt bulb,??? he said. Maintenance costs go down as well because the digital ballast lets administrators predict and schedule replacements. The company has shown the technology to several large lighting manufacturers and will begin beta tests in the fourth quarter. Manufacturing and commercial shipment could begin in the first quarter of next year. The company will primarily aim its initial product for lamps holding 200 to 450 watt light sources. HID Labs makes the entire ballast. Competitor Metrolight, which last year received funds from Virgin Fuels and Gemini Israel Funds, is pursuing an OEM strategy. Espinosa says the company will likely announce a round of funding in the relatively near future. The inventors initially approached Bill Fenwick about the idea. He was mildly interested. But on a subsequent night flight, he noticed how much electric light there is at night, most of it wasted. He called them back.