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Energy Efficiency Opportunities in EPA's Boiler Rules
On December 20, 2012, the US Environmental Protection Agency (EPA) finalized new regulations to
control emissions of hazardous air pollutants (HAP) from commercial, industrial, and institutional boilers
and process heaters. These new rules, known as the Boiler MACT (major sources) and Boiler Area
Source Rule (smaller sources), will reduce the amount of HAPS such as mercury, heavy metals, and other
toxics that enter the environment. Since emissions from boilers are linked to fuel consumption, energy
efficiency is an important strategy for complying with the new Boiler rules.
Who is affected?
Most existing industrial, commercial and institutional (ICI) boilers will not be affected by the Boiler
MACT. These unaffected boilers are mostly small natural gas-fired boilers. Only about 14% of all existing
ICI boilers will need to comply with the rule. The type of fuel that is burned, boiler size, and the amount
hazardous air pollutants (HAPs) emitted by the facility determine which boilers are affected. For sites
with boilers that burn only natural gas, the rule may not apply or can be met though energy efficiency
practices. Residential boilers and hot water heaters are not covered by the rule.
The rule has different requirements for large facilities, known as Major Sources, and smaller facilities,
called Area Sources. Major Sources are sites that emit (or have the potential to emit) 10 tons per year
of an individual HAP or 25 tons per year of combined HAPs. Area Sources are facilities with emissions
under this threshold that have boilers.
The Right Standards for the Right Boilers
Of 1.5 million boilers in the U.S.,
less than 1% will need to meet numerical emission limits
<1% (about 2,200) would need to meet
numerical emission limits to minimize toxics.
Most of these are larger boilers located at
industrial facilities.
•	Area Source boilers may be found at
industrial plants or commercial and
institutional buildings. Boilers that burn
solid fuels (coal, biomass, etc.), oils, or non-
waste materials will need to comply with
the rule. Area Source boilers that burn
natural gas are not regulated by the rule.
Some seasonal and back-up boilers also
may be exempt.
•	Major Sources are boilers and process
heaters found mainly at big industrial
facilities. EPA estimates there are only
14,000 Major Source boilers and process
heaters out of an estimated 1.5 million boilers in operation in the United States.
197,000
covered
by rules
1.3 million boilers
not covered by rules
13% (about 197,000) would need to follow
work practice standards, such as annual tune
ups, to minimize toxics.
86% are clean and not covered by these rules.
Many of these boilers are at places like hospitals,
schools and churches.
What is required?
For most existing Area Source boilers sized under 10 mmBtu/hour that burn solid fuels (coal or biomass)
or oil; a boiler tune-up is required every other year. For existing Area Source boilers 10 mmBtu/hour or
greater that burn solid fuels (coal or biomass) or oil; a one-time energy assessment is required. For most
existing Area Source boilers 10 mmBtu/hour or greater that burn biomass or oil; a boiler tune-up every

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other year is required. With regard to existing sources, specific emission limits are only required for coal
fired Area Source boilers with a rated heat input capacity of 10 mmBtu/hour or higher. For some
seasonal and limited use Area Source boilers, boiler tune-ups are required less frequently.
For existing Major Source boilers that burn natural gas and other clean fuels, meeting the Boiler MACT
requirements primarily involves conducting an energy assessment and keeping boilers tuned-up and
running efficiently.
Major Source boilers firing solid, fossil, or certain gaseous fuels, must meet specific emission limit
requirements based on the boiler's size, design and fuel in addition to requirements to conduct an
energy assessment and do periodic boiler tune-ups. These boilers have the option to meet alternative
output-based emissions limits, recognizing the emissions benefits of more efficient boilers or combined
heat and power. If applying output-based emissions limits, sources may be able to gain credit for energy
efficiency improvements.
What is a boiler tune-up?
A boiler tune-up is the optimization of the air-fuel mixture for the operating range of the boiler. This
improves boiler efficiency, reduces pollution and is a well known energy management best practice.
More guidance on the boiler tune-ups can be found at:
http://www.epa.gOv/ttn/atw/boiler/boilerpg.html#RULE
What is the focus of the energy assessment?
For sites required to do a one-time energy assessment, the goal is to identify energy savings
opportunities within a boiler and the processes and systems that it supports. Consult the ENERGY STAR
Industrial Energy Guides and Building Upgrade Manual when conducting assessments:
http://www.energystar.gov/energyguides
The assessment also requires an evaluation of site energy management practices. Use the ENERGY
STAR Facility Assessment Matrix to meet this requirement.
www.energystar.gov/ia/business/guidelines/Facility_Energy_Assessment_Matrix.xls
How are efficiency credits for energy efficiency determined?
For major sources that select to comply with the output based emission limits, the rule provides specific
methods for calculating efficiency credits from implementing energy conservation and efficiency
measures related to the boiler system. This guidance can be found at:
http://www.epa.gov/ttn/atw/boiler/20120731doeguidance.pdf
When are the compliance deadlines?
Existing Area Sources - By March 21, 2014
Existing Major Sources - By January 31, 2016 (if needed, facilities may request an additional year to
comply)
For more information:
This handout is intended to provide a brief overview of the rule and how energy efficiency can help with
compliance. For more information and guidance on the Boiler MACT, visit EPA's web site at:
http://www.epa.gov/ttn/atw/boiler/boilerpg.html
http://www.epa.gov/airquality/combustion/actions.html

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