Ratchaburi Electricity Generating Holding (RATCH) announced yesterday it would buy 6.66 tonnes of carbon credits a year for five years from 25 households in the solar home system at Ban Hau-Ha in Mae Hong Son province. Pandora Production also signed a five-year contract to purchase 7.37 tonnes a year of carbon credits from the Solar Lanterns project at Ban Hau-Ha and Ban Pa-Yoy.