PFPI-BiomassIsTheNewCoal-April-2-2014

are federally and practically enforceable – even when it is likely that the boiler will have difficultymeeting the 250 ton per year cap, and even though a CEMs on a biomass boiler only measuresemissions from that unit, and not the facility-wide emissions that are supposed to be included underthe cap.The frequent use of the synthetic minor source loophole has important implications for howbiomass power plants operate, and thus for air quality. While the total tons of pollution that aplant emits annually is obviously one index of its impact on air quality, just as important is theshort-term rate at which that pollution is emitted – the actual amount per hour. Permits issuedunder PSD set “short-term” (1 - 3 hrs) and “long-term” emissions limits (often, rolling 30-dayaverages that represent annual emissions). The PSD process also requires modeling before a plant isbuilt to predict whether the plant will cause violations of the short-term and annual NAAQS.Permits that simply cap emissions below 250 tons don’t contain these protective measures.The absence of short-term emission limits insynthetic minor source permits is a threat to airquality. Biomass power plants are notorious forproducing large slugs of air pollution over shortThe absence of short-term emissionsrates in a synthetic minor source permitthreatens air qualityperiods, because the fuels they burn, which include wood, agricultural wastes, and wastes from thepaper-making industry, are inconsistent in composition and moisture content, decreasingcombustion efficiency and increasing emissions. How a plant is operated – at steady state, or in a“cycling” mode, ramping up and down periodically – also affects emissions. Most PSD air permitsand a few state-level permits recognize this, setting different emissions standards for startup andshutdown versus steady-state combustion. For instance, the permit for the proposed 67 MW(gross) Greenville Power plant in Greenville, Texas 35 states that the electrostaticprecipitator for controlling PM, the selective catalytic reduction (SCR) system for controllingNOx, and the catalytic oxidation system for controlling CO and VOCs “may not be fully operational ifthe boiler is operating at less than 75% of base load.” 36 The Greenville permit specifies that emissionrates from the Greenville facility during startup and shutdown 37 (Table 3 ) can exceed those duringnormal operations – for instance, filterable PM emissions increase by more than 700%, comparedto steady-state operation. Startup and shutdown events can take 12 - 24 hours, meaning that thetotal amount of pollution emitted over these periods can be significant.However, synthetic minor permits generally don’t contain limits on startup or shutdown emissionsat all – importantly, the only emissions rate requirement that synthetic minor sources do have tomeet, the New Source Performance Standard for new facilities that sets filterable PM standard at0.03 lb/MMBtu, specifically exempts facilities during startup and shutdown.35Maximum allowable emission rates for Permit Number 9322. Texas Commission on Environmental Quality, December 31,2010.36 Construction permit source analysis and technical review for Greenville Energy, LLC. Texas Commission on EnvironmentalQuality.37Ibid.26