Business Green: Despite the onset of recession, 2008 proved to be a bumper year for green energy tariffs in the US as utilities saw sales to businesses and consumers climb about 20 per cent. According to new figures from the Department of Energy’s National Renewable Energy Laboratory (NREL), more than 850 US energy companies now offer green tariffs to more than 600,000 customers. Together they sold five billion kilowatt-hours through green power programs last year, an increase of about 20 per cent on …