Energy-efficiency company Comverge is getting less picky about whether the hardware it works with is an electric vehicle or an air conditioner.

The company today is expected to announce that the latest version of its software can work with the OnStar vehicle communications system and wireless thermostats that control air conditioners from Carrier.

Comverge's specialty is demand response, where its software can turn down power use at multiple locations during peak times. Lowering energy use on the grid is an effective way for utilities to meet energy demand without having to turn on costly and polluting peak-time power plants. Consumers who sign on for utility demand response programs get some sort of rebate or lower electricity rate.

Right now, much of Comverge's residential business is based around air conditioner controllers, small devices that can connect to Comverge's data centers and control an air conditioner. To lighten the load on the grid at peak times, a controller cycles the air conditioner compressor to raise the temperature one or two degrees, explained Comverge CEO R. Blake Young. Pool pumps are another commonly controlled device.

The latest version of its IntelliSource software can work with Zigbee-compatible wireless thermostats, which work with Carrier air conditioners. Similarly, the company will show at the DistribuTech utility conference that its software can tie into the OnStar system for managing when an electric vehicle is charged. The Chevy Volt is one car that will use OnStar to get utility rate information and let consumers manage charge times.

The software has also been enhanced to better tie into utilities' back-end software systems. For example, it has better tools for verifying and measuring demand-side power reductions.

Grid operators and utilities are increasingly using demand response as a way to plan for grid capacity. Rather than build new power plants to add generation as overall demand grows, utilities contract with demand-response providers and reduce demand when needed.

"This past year we saw more events over more consecutive days than we've seen over the history of the programs we've run," Blake said. "The peaks are happening more often for longer periods of time, so we've become a very critical part of the entire energy mix."

Comverge manages thousands of megawatts now, with about 60 percent in the residential area, but last year saw rapid growth in the commercial and industrial area, Blake said.