With a statewide utility-environmental agreement and new state legislation to phase out coal in play, Portland General Electric (PGE) engineers are exploring the possibility of converting the state’s lone remaining coal-fired electric generation plant to burn wood waste biomass.

The company is considering wood waste over natural gas because converting a coal plant to burn wood is likely to be more efficient than converting it to gas.

Last January the state’s two major electric utilities and a coalition of environmental groups agreed to phase out coal-fired generation between 2030 and 2035, leaving out any mention of the future role for natural gas in the power mix, although its use still could expand (see Daily GPI, Jan. 14). More recently, a new 440 MW natural gas-fired generation plant was opened this summer by PGE near its Boardman coal-fired plant in eastern Oregon (see Daily GPI, Aug. 4).

Last March, the Oregon legislature passed SB 1547, eliminating essentially all use of coal-fired electricity by 2030 while expanding goals for renewable energy, efficiency and electric-based transportation in the state by 2040 (see Daily GPI, March 3). PGE’s Boardman plant was already scheduled to shut down at the end of 2020.

In anticipation of the coal plant closure, PGE hopes by the end of the year to complete a daylong test at Boardman, producing power with wood waste to test the feasibility of creating what would be the nation’s largest biomass-fired generation plant. PGE earlier conducted a co-firing test burn at Boardman in November last year that included some coal, which won’t be used in the upcoming test.

“We have made no decision on this and view it very much as a ‘research’ project,” a PGE spokesperson told NGIon Tuesday, noting that converting Boardman to natural gas would be feasible, but the resulting plant would be far less efficient than the new Carty gas-fired plant it has already built adjacent to Boardman.

“If the research [on biomass] proves that it is feasible, we can gather more information on the economics and what would be required for emissions controls, and then put it in our resource management process and compare it with alternatives.” A biomass conversion includes the advantages of using Boardman’s remaining useful equipment life (it was opened in 1980), and it can provide a dispatchable renewable power which is unique since more renewables like wind and solar are variable, the spokesperson said.

“We have often been asked about a gas conversion at Boardman, which would be technically feasible, but it would not be an efficient use of gas. You’re better off just building a new gas-fired plant.”

Earlier this month, an Oregon-based company, HM3, unveiled technology that could help convert coal-fired power plants globally to biomass boosted by a technology called torrefaction, which essentially roasts forest waste wood or other organic matter (removing moisture from it) into an energy-dense form that can be applied to a coal-fired plant with minimal modification. It allows the biomass to be condensed into pellets that are used in the generation plant just like coal.

At a grand opening of its $4 million Troutdale, OR, demonstration plant, HM3 said told local news media that it had “cracked the code” on torrefaction, a concept that got a lot of attention early this decade but has been set back as companies have struggled to produce fuel consistently and economically in test-scale ventures.

HM3 said New Energy Development has licensed its technology for use in a torrefaction plant proposed to be built in Oregon. The site for the plant, which could begin operations in 2018, has not been determined, however.

In the meantime, environmentalists and climate change advocates are urging lawmakers to be wary of the biomass projects, contending they are not clean, particularly in terms of their potential carbon emissions.

U.S. Sen. Ron Wyden (D-OR) toured the demonstration torrefaction plant, telling local news media that the state has a chance “to show the country and even the world how to do biomass right.” At the same time, environmental groups are urging Wyden and the rest of the U.S. Senate to strike a provision in pending energy legislation that would classify biomass as “carbon neutral.”