PHOENIX -- State utility regulators are defending their decision to let a utility generate electricity from burning garbage and calling it a "renewable resource.''
In filings Wednesday, the attorney for the Arizona Corporation Commission urged the state Supreme Court to reject arguments by the Sierra Club that a trash-burning incinerator does not qualify for the same legal status as solar and wind. Wesley Van Cleve said even the federal government considers biogenic trash -- waste from plant sources -- to be renewable.
More to the point, Van Cleve said the commission had a good reason for approving the plan.
"The objective of the renewable energy rules is to achieve resource diversity in generation facilities in order to protect the public from fluctuations in fuel prices and to promote system reliability,'' he wrote.
"Obviously, resource diversity is promoted by including a variety of technologies,'' Van Cleve continued. "The commission's rules expressly recognize this goal.''
What the Supreme Court ultimately rules will determine the fate of a proposal by Mohave Electric Cooperative to meet part of its renewable energy mandate through power generated from a proposed plant near Surprise. But it also would affect the ability of other utilities to propose incineration of trash to meet their own mandates.
Commission regulations require all utilities to obtain at least 15 percent of their power from renewable resources by 2025. And that has been defined in rules as technology that displaces "conventional energy resources'' like natural gas, coal, oil and uranium.
And, in recognizing the higher cost of alternatives, commissioners agreed to let utilities impose a surcharge on customers.
The Surprise trash-burning plant is being proposed by a company called Reclamation Power Group. The company needed it to quality as "renewable'' power in order to charge Mohave the rates to justify the cost of the power plant and for Mohave to be able to charge more to its 39,000 customers.
Commissioners approved the request four years ago on a 3-2 party-line vote, with Republicans in support.
In challenging the decision, the Sierra Club contends the commission's own rules do not allow trash incineration to be considered a renewable energy resource.
Van Cleve, in his court filings Wednesday, acknowledged the rules designate specific technologies as "renewable energy resources.
Those include solar, wind and combustion-based technologies that burn biomass, biogas or methane from landfills. But he argued that's not an absolute limit.
"Because the (renewable energy) rules promote the diversification of generation resources, they are not designed to be static,'' he wrote. Van Cleve said the rules specifically allow for pilot programs and waivers so the commission "may evaluate the efficacy of different technologies on an experimental basis.''
He said Mohave Electric applied for the designation as renewable as an experimental program.
Plans are for the facility to accept about 500 tons of trash per day, about a quarter of which would be recycled. The balance would be incinerated to generate electricity.
Van Cleve said one reason the commission likes this proposal is the plant would be what's known as "baseload power,'' meaning it would provide continuous energy to meet a given region's needs. By contrast, he said, many common renewable resources are intermittent, generating power only when the sun shines or the wind blows.
Commission spokeswoman Angie Holdsworth said the agency also does not believe there will be any public risk from the incinerator. She said things like plastics will be recycled and keep them out of the plant and the state Department of Environmental Quality will monitor pollutants.
The merits of the project aside, Van Cleve urged the high court to recognize that the commission is established through the Arizona Constitution and has specific authority. He said the renewable energy rules "clearly fall within the commissions ratemaking jurisdiction'' and should be upheld by the justices.