Grapevine

Boulder, Colorado, voters passed the country's first carbon tax last November. Residents and businesses will be charged based on their electricity use, with the average household paying about $1.50 per month. * Google is putting more than 9,200 solar panels on its Silicon Valley office complex, the largest installation on any U.S. corporate campus. * Travelers making plans on expedia.com and travelocity.com can now buy carbon offsets for their flights, hotels, and rental cars. * The Weather Channel has a new weekly series, The Climate Code, and Web site, climate.weather.com, devoted to global warming. * Reality TV is getting into the green act too: In February, PBS's This Old House began airing a series on an ecofriendly renovation of an Austin home, while actor Leonardo DiCaprio's proposed E-topia would transform an entire town.