PGE tests biomass process for Boardman

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Arundo donax

Portland General Electric has teamed with researchers from Washington and Oregon to study how a fast-growing grass could serve as fuel for the utility’s controversial coal-fired power plant in Boardman, if the plant were converted to biomass.

It's one of a handful of possibilities facing the 585-megawatt capacity plant, which burns 2.5 million tons of coal annually and produces enough electricity to power 250,000 homes. The plant is responsible for 15 percent of power production for customers of PGE, but has been under fire for pollution.

The Oregon Department of Environmental Quality is poised to mandate new emission controls at the plant, but PGE is aiming to reduce the cost of compliance — and future uncertainty about the cost of carbon regulation related to coal burning — by closing the plant or converting it to other uses over the next 10 to 30 years.

Even while PGE and the DEQ are sniping over the details of the plan to stop burning coal at Boardman, officials from PGE are working closely with scientists at Oregon and Washington state universities grow test crops of a fast-growing cane grass called Arundo Donax which could meet future fuel needs for a biomass plant.

Jaisen Mody, a general manager of generation projects at PGE, unveiled elements of the research during a talk Monday at the second annual conference of Oregon BEST (Oregon Built Environment & Sustainable Technologies Center), a state-funded initiative aimed at spurring economic growth in renewable energy and green building sectors.

Speaking to approximately 100 researchers, government employees, students and nonprofit personnel, Mody disclosed that PGE has been working with scientists to grow sample crops of Arundo Donax. The goal is to study its viability as a fuel source and probe how much electricity the grass could produce if it were torrified — or roasted like coffee — into a charcoal-like substance that would burn inside a revamped Boardman plant.

Arundo Donax grows rapidly, as much as one foot per week. It can be harvested twice each growing season and requires approximately the same amounts of water and fertilizer that are used on alfalfa crops, Mody said.

Converting the Boardman power plant to burn torrified Arundo Donax would create the first 100-percent torrified biomass power plant in the world. It would require significant changes to the existing plant, Mody said, including a $200 million investment in emission controls.

He said it was too soon to say whether biomass would prove financially viable but general analysis shows it appears to compare favorably to a natural gas combustion turbine or a wind plant with a natural gas "chaser" to fill gaps in production.

Burning biomass at Boardman would also allow the power plant to remain a baseload plant, he said, meaning that it could still provide a constant and dependable power supply without coal, unlike wind or solar farms.

"The fact that Boardman has land, sunlight and water makes this a doable solution," said Mody.

Biomass is far from a done deal, however. Still required is another 10 years of study of whether Arundo Donax could supply the steady stream of fuel a biomass power plant would require, and whether torrified biomass would burn as predicted.

PGE has done enough study of the idea, however, to know that converting the Boardman plant to torrified biomass would cost between $350 and $450 million, in addition to the $200 million for pollution controls. Also known is that the utility would need between 75,000 to 114,000 acres to grow Arundo Donax in the Boardman area and that the land could be available without displacing food crops.

Mody said the utility would likely need an additional 60 workers to staff a biomass plant (the Boardman plant currently employs 110 workers year-round and another 225 seasonally). Approximately 400 trucks may also be required to deliver crops, though rail is also being considered.

Portland General Electric spokesman Steve Corson said it's too soon to say whether biomass will pull ahead of other options still being considered to replace capacity for power generation at the Boardman plant, including additional wind and solar development.

"We really have not begun the process of fully evaluating potential replacements," he said, adding the utility is still actively involved in clarifying near-term rules for operating the Boardman plant as a coal-fired facility.

In the interim, however, Corson said, PGE has "a responsibility to explore all of the technologies that could be used."

Those possibilities include renewable energy in part because the state of Oregon is requiring utilities to derive 20 percent of electricity from renewable sources by 2020, and 25 percent by 2025.

Should the biomass idea pull ahead, the idea would face scrutiny from the Oregon Public Utility Commission. The commission is tasked with pushing utilities to generate power through the most affordable means and in ways that pose the least risk to ratepayers.

Lee van der Voo, lvdvoo*at*gmail.com, is a freelance writer for Sustainable Business Oregon.