While we're nearing 100,000 plug-in electric cars on U.S. roads, they're not evenly distributed--and the largest group of them is in California.

This has led to occasional congestion at charging stations, and now it turns out that happens at workplaces too.

Venture-funded startup Nest Labs, a media darling for its high-design smart thermostat, is headquartered in Palo Alto, California--the heart of Silicon Valley.

The company had installed an electric car charger in January, partnering with the ChargePoint network to do so, as part of an initiative to help its 200 employees make their commutes in a greener fashion.

But within a month, Nest found that during the workday, its charging station was being used to recharge various plug-in cars essentially 100 percent of the time.

As Nest's founder and VP of engineering Matt Rogers explains, the company parking lot includes four Nissan Leafs, a Chevrolet Volt, a Ford Focus Electric, a Ford Fusion Energi plug-in hybrid, and--inevitably in Silicon Valley--a Tesla Model S.

As Rogers noted Friday in a cheerful blog post peppered with photos, Nest quickly realized it needed more chargers--and so it tripled its capacity, installing an additional pair of ChargePoint stations.

Since January, Nest calculates that its employees who commute in electric cars have saved 374 gallons of gasoline and prevented 7,000 pounds (3,200 kg) of carbon dioxide being emitted into the atmosphere.

(Rogers didn't note whether that number nets out the carbon profile of extracting, refining, and transporting the fuel required to generate the electricity to charge the cars--and it's a weekend, so we're too lazy to do the math ourselves.)

Nest also counts two biodiesel-fueled cars in its parking lot as well as innumerable Toyota Prius hybrids.

About one in ten Nest employees bike to work, either from home or from mass transit, and a few simply walk.

That makes Nest likely one of the greener employers in the spread-out Bay Area suburbs, although perhaps less so than some companies in downtown San Francisco who may see half or more of their employees walk, bike, or take public transport.

If your employer isn't quite as progressive as Nest just yet, by the way, here's our guide on how to get your workplace to install charging stations.


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