The Devil's in the Details

The pellet industry is paying close attention to EPA discussions as the New Source Performance Standards rule takes shape.
By Sue Retka Schill | July 16, 2013

The future of the pellet industry will be impacted by the updated New Source Performance Standards being written by the U.S. EPA, as pellet-fueled appliances will be explicitly covered. In the 1988 rule, pellet stoves were not named. Some manufacturers were certified under the standards, while others avoided EPA certification through the fuel-to-air ratio exemption.

The pellet industry has long anticipated the new rule and worked in advance toward getting two key components in place—testing methods and pellet standards. “In the past, pellet stoves have been tested as an adjunct, cobbled-together version of wood stove test methods,” explains John Crouch, director of public affairs for the Pellet Fuels Institute. Several years ago, when the rule updating process first began, appliance manufacturers took the lead in writing a new ASTM test method for pellet room heaters (E1509-12), keeping the EPA in the loop as the method was developed. 

The second component the industry has worked to get in place in advance of the NSPS is an expanded third-party verified pellet standard. “PFI has been anticipating the release of the NSPS for the last couple of years, and early on, we heard from Gil Wood about EPA’s desire to reference our program in the NSPS,” explains Jennifer Hedrick, executive director of the Pellet Fuels Institute. The existing voluntary pellet standards program was modified with EPA input, to fine-tune the grading system and  include third-party verification. One company has enrolled in the program to date, she adds, while others are taking steps to beome enrolled.

That is likely to be at least a year away, if not longer. The development of new environmental standards for home heating appliances has been a lengthy process. The first draft of the NSPS that came out in February 2012 was not well-received, admits Gil Wood, the EPA lead on the program. The following November, a national stakeholder forum was held in Minneapolis to discuss the issues and potential options. Since then, Wood has been making multiple presentations and seeking additional input on the new draft that followed, including a webinar in early May cohosted by Biomass Thermal Energy Council and the Alliance for Green Heat.

The EPA prefers a two-step approach to phasing in the new program, Wood explains, with one level of emissions taking effect immediately and a tighter level five years later. Step 1 reflects levels already achieved by many appliances, while Step 2 strengthens the emission limits to reflect today’s best demonstrated technology. The agency is seeking comment on a second approach that would achieve the same end goals in three steps over eight years.

The first step for room heaters, which includes pellet and wood stoves, would adopt the Washington state noncatalytic emission levels immediately upon promulgation of the rule—a standard that is already met by more than 85 percent of sales of EPA-certified wood stoves, Wood says.  “In general, pellet stoves are a lot cleaner than cordwood stoves, but not all of them,” he adds.

The other category of residential heating devices that use pellets, hydronic heaters (better known as outdoor/indoor wood boilers utilizing water jackets), will start in Step 1 with the emission levels from the EPA’s Partnership Program Phase 2. A total of 36 hydronic heater models from 17 U.S. manufacturers, including nine pellet models, have already qualified at this level in the voluntary program.

The new standards do not affect existing heaters, Wood adds, only new ones manufactured and sold after the new rule takes effect, which is expected sometime in 2014. The agency will allow a market pass-through for some already-manufactured, unsold appliances. The exception will be outdoor wood boilers and certain indoor heaters, where the rules are likely to be effective immediately.  “So many of the units sold in the past 10 years are so dirty, we just can’t allow them to be sold once this rule becomes final,” explains Wood.

The Alliance for Green Heat is one organization that will likely applaud that. The group points out the 1988 regulations only covered wood stoves with a firebox volume of less than 20 cubic feet, an air-to-fuel ratio of less than 35-to-1, a burn rate of less than 5 kilograms per hour and a total weight of less than 800 kilograms. “Thus, whole classes of stoves have cropped up which are specifically designed to avoid EPA regulation through the air-fuel ratio loophole designed for fireplaces,” the alliance says, specifically mentioning outdoor wood boilers, or hydronic heaters. There is also a glut of ultra-cheap wood stoves on the market, according to the alliance.

Tighter Emissions Standards

The new standards will be much tighter than the old, which required residential wood stove particulate emissions be less than 7.5 grams per hour (g/hr) for noncatalytic wood stoves and 4.1 g/hr for catalytic. The new rule tightens the emissions standards to 4.5 g/hr in the first step, and the number “on the table” for the five-year standard, Wood says, is 1.3 g/hr. “We believe that it is a cost-efficient goal.” The rule also eliminates separate emission targets for catalytic and noncatalytic stoves in favor of a single number, Wood adds, due to technology improvements that make separate standards unnecessary.

For hydronic wood boilers, Step 1 is already met by a number of models with emissions of 0.32 pounds of particulate matter per million Btu heat output. The step-two level to be met in five years would cut that in half to 0.15 lb PM/MMBtu. “That’s a number that was discussed by a number of states,” says Wood. “But that number is still on the table.”

The EPA also proposes to change the test methods used to certify appliances, Wood explains. “As the numbers get tighter, we need greater precision.” The testing methods will be targeted for each class of appliance—room heaters, forced-air furnaces, hydronic and masonry heaters—to better test performance experienced in the real-world conditions in which the appliances are used.   

In addition to testing for particulate emissions, the current NSPS draft rules require manufacturers test for carbon monoxide levels and efficiency. Target levels won’t be regulated, Wood adds, but rather the information will be reported to the agency. Manufacturers will also be allowed to publish the appliances’ efficiency ratings. 

Efficiency testing of appliances will be a good thing for the industry, Crouch says. “There won’t be a target, but it will be measured. And it will be on the hang tag for the consumer to see.” Other possible features in discussion for the new rule may be more problematic. There are indications the EPA could include emission caps on different levels of heat output, possibly in four steps from low- to high-heat output, for example. “That could force changes in appliances that might surprise people,” says Crouch.

Manufacturers of pellet boilers are concerned that there may be some features in the NSPS that reflect the European handling of thermal storage, and may be difficult to transfer to the U.S. market. If a pellet boiler, for instance, is certified for emissions using thermal storage and a consumer opts to not buy the separate thermal storage component, the appliance would not be in compliance with EPA rules. The details of how a situation like that may be handled in the rule is the cause of some concern, Crouch explains.

Since many pellet stoves already meet the new emission targets, there is also the possibility the EPA may tighten the standards for pellets. “There’s no reason that we would legally be prohibited from doing it,” says Wood. “But as we look at these units that are competing with each other—wood stoves, pellet stoves—is there a great benefit for squeezing the number tighter, if they’re already doing it?” Issues surrounding the idea have included the potential for backsliding by those now exceeding the standard and the relative cost of the appliances. “We’ve asked for comment on that issue—should we set a tighter limit for pellet stoves?”

Other issues may emerge when the proposed rule is finalized. The Clean Air Act does require that regulations be cost-effective, Wood says. “It looks achievable; it meets the cost-effectiveness test.” At the time of the webinar, during which Wood spoke in early May, the agency was still working on the cost-effectiveness report and Wood couldn’t comment on specific numbers, but he says that the benefits EPA has monetized for this rule are far greater than the cost.

The cost/benefit analysis will be scrutinized by the industry. “We’ll be looking closely at what the cost effectiveness of the various levels will be, and in pellet stoves particularly,” says Crouch. “We are interested in levels that allow appliances to be made that meet consumers’ needs at a price that consumers think is reasonable. That includes not being so carefully tuned that they can only burn perhaps very specific grades of pellets.”

Remaining Steps

The agency expects to get the draft submitted to the Office of Management and Budget this summer, which would lead to getting the proposed rule published in the Federal Register by the end of summer, Wood says. A 90-day comment period will be followed by an agency review. “Typically, it takes a year before the final rule is promulgated,” he says, giving mid-2014 his best estimate for the NSPS to take effect.

Crouch cautions that with the large number of regulations the OMB reviews, the process is likely to take longer. Once the rule is in final form, the industry will be reviewing it closely to see what changes have occurred since Wood began making the rounds to outline the agency’s current thinking and solicit more input. “We think pellets will be well-served by being uniformly certified, depending on what the final regulations look like,” says Crouch. “Until the rule is published in draft form, there’s still speculation on what exactly it says. The devil is always in the details. We want to see the details.”

“We think the first step is going to be pretty good,” Crouch adds. “The Washington state number of 4.5 is certainly doable.” Some manufacturers will need to get appliances certified, of course, he points out. “The details are down the road.”

Author: Susanne Retka Schill
Senior Editor, Pellet Mill Magazine