(AP) — Nebraska’s largest utility is offering customers the chance to pay more to support renewable energy, but the money won’t be earmarked for green power and the utility doesn’t plan to change where it gets its electricity.

The Nebraska Public Power District announced the voluntary program Wednesday. Starting next year, customers will be able to buy renewable energy in blocks of 100 kilowatt hours for $1.80 per month.

Utility customers who sign up will have to pay the green energy surcharge on top of their regular bill, but the source of their electricity won’t change and NPPD doesn’t plan to use the fee money to invest in more renewable power.

Ken Winston, the Nebraska Sierra Club’s policy advocate, says he’d prefer to see NPPD invest in more renewable energy.