For more than a year, the commission has pushed PacifiCorp to better protect its customers from unnecessary rate increases.

Despite such measures, Pacific Power, PacifiCorp’s Oregon subsidiary, raised its rates more than any other major utility in the region.

Records show that PP raised energy bills by 61% since 2006.

Last year, PP got 78% of its electricity from coal power and spent more than $US2 million on ageing power plants.

The commission alleges the money was spent on unnecessary modifications that were not in line with the regulations of the clean energy act.

The commission also alleges that 25% of those funds were derived from increased electricity bills.

It was also claimed that a further $2million was spent on power plants in Utah and Wyoming.

The commission accuses PacifiCorp of committing Oregon, unbeknown customers, to ageing coal plants by spending more money on them, reaping a nearly guaranteed rate of return on the spending, and forwarding the profits to owner Warren Buffett, who reported a record $19 billion in profits last year.

Last week, the commissioners vigorously questioned PacifiCorp’s transparency, with Commissioner John Savage saying: “We really don’t want any more surprises in terms of already-launched construction.”