ST. LOUIS (AP) — AmerenUE's Pure Power program is under scrutiny by the Missouri Public Service Commission.

Regulators say the utility's customers don't know what they're getting when they agree to pay extra to support renewable energy development.

The St. Louis Post-Dispatch reported Tuesday that PSC staff are concerned that many of the 6,000 AmerenUE customers who are paying an extra monthly fee don't know how little of it actually supports green energy.

PSC says that less than half is spent on renewable energy certificates. The rest goes to a San Francisco-based administrator's marketing, administration or profits.

The group says that at least 75 percent of the renewable energy certificates will be purchased from wind projects and at least half will be in Missouri and Illinois.