Seneca’s biomass plant fails first pollution test

Posted by Trish Riley, September 30, 2011

A new wood-burning electricity plant just north of Eugene has flunked a small part of its initial pollution control test — and consequently, its owner has paid the Lane Regional Air Protection Agency a $9,856 fine.

The problems are related to emissions of particulate and nitrogen oxide from the so-called “biomass” plant off Highway 99.

Seneca Sustainable Energy General Manager Richard Re says the problem is most likely an anomaly in the testing and not a true breach of air pollution limits.

“It’s extremely frustrating,” Re said Monday. “We did the first set of tests and expected everything would turn out fine.”

The emissions pose no threat to human health, air agency Director Merlyn Hough said Monday.

The agency set up a timeline for the company to conduct a more sophisticated test that could prove the initial results were false and that the pollution control equipment is working as required.

The company must submit its testing plan on Wednesday, conduct the test by Oct. 12 and report results to the air agency within 45 days. If the results show that the plant is in fact violating emissions limits, the company has three months to submit an action plan and to pursue reasonable technological controls.

The pollution problem is likely to arouse the critics of the plant, including the Eugene-based Oregon Toxics Alliance, which argued the plant would degrade the air.

“It’s been controversial throughout,” Hough said, adding there have been no complaints since the plant went online in February.

“There hasn’t been concerns about visual emissions; in fact, it appears to the person driving by as a very clean operation.”

The Oregon Toxics Alliance could not be reached for comment late Monday afternoon.

The $50 million biomass power plant burns mill waste and logging residue to create 19.5 to 20 megawatts of power, enough to keep the lights on in more than 13,000 homes. It takes about 30 truckloads of biomass daily to power the plant.

To build the “cleanest renewable biomass energy plant in the United States,” Seneca installed about $11.5 million in pollution controls, Re said.

One of the pollution devices, a selective noncatalytic reduction, or SNCR device, appears to be the cause of the current problem, Re said.

The SNCR is meant to clean nitrogen oxides from the plant’s emissions. The release of nitrogen oxides is of concern to air regulators because the gases react with hydrocarbons in the presence of sunlight to form ozone, or smog. Smog exacerbates asthma and other lung diseases.

Tests first conducted at the Seneca plant in April detected a surprising result. When the plant operated with the SNCR in place, it cleaned out the nitrogen oxides, but it generated an elevated level of larger-sized particulates, called PM 10. Particulates can be damaging to people’s lungs.

If Seneca ran the plant without the SNCR, the particulate emissions disappeared but the nitrogen oxides increased.

The theory is that in the SNCR, the urea that’s injected into the exhaust to bind with the nitrogen oxides and break them down also was attaching to a minute amount of sulfur in the exhaust to create another gas that potentially forms a tarry particulate after it left the emissions stack, Re said.

But the company doubts that’s happening.

“These are pseudo-particulates or artifacts,” Re said. “They’re not really occurring but in the test method. They’re not occurring when the flow goes out of the stack and into the atmosphere.”

Seneca managers decided that until they have resolved the problem, they will operate without the SNCR because, if they were wrong and excessive particulates were indeed coming out of the stack when the SNCR was running, that would be the bigger risk in the air in Lane County, Re said.

The amount of nitrogen oxides is so small in Lane County air that the air protection agency is not required by the federal government to continuously monitor levels, Hough said. Nitrogen oxides need sunlight to form smog, so it’s less of a problem in the fall and winter, the air agency says.

If Seneca emits significantly higher levels of nitrogen oxides while it operates without the SNCR, it will face additional fines: $3,800 for less than 20 tons above the limit over 12 months; $6,400 if it’s up to 40 tons in the year; and $15,200 if it exceeds 40 tons.

“We’re still committed to meet the standards, but the standards are so exacting it’s going to take longer than we have hoped,” Re said.

BY DIANE DEITZ
From The Register-Guard