Green River Star -

Adding carbon-capture systems to existing coal-fired power plants in Wyoming could cost the average residential ratepayer an additional $100 per month, according to Black Hills Corp’s initial filings to the Wyoming Public Service Commission.

The retrofit costs alone could range from $400 million to $1 billion for each coal unit, according to PacifiCorp, which operates as Rocky Mountain Power in Wyoming. Adding carbon capture utilization and storage technologies would also significantly reduce electrical generation efficiency at the coal plants, further ramping up the expense for ratepayer...