GHG BACT Analysis Deanna L. Duram, P.E., C.M. August 4, 2011 Air & Waste Management Association Southern Section Meeting trinityconsultants.com.

GHG BACT Analysis

Deanna L. Duram, P.E., C.M.August 4, 2011

Air & Waste Management AssociationSouthern Section Meeting

trinityconsultants.com

Outline

EPA Guidance and 5-Step Process Differences from traditional BACT

approach Highlight a biomass case study

throughout

EPA BACT Guidance Case-by-case determination Performed by applicant; approved by agency EPA recommends 5-Step top-down BACT evaluation

process Emission limits achievable considering…

Economic impacts Environmental and energy impacts

EPA guidance materials PSD and Title V Permitting Guidance for GHGs White Papers on GHG Control Measures On-Demand Video Training Materials, including sample

BACT assessments Enhanced RBLC

5-Step Top-Down BACT Process

Step 0 – Define the Source Step 1 – Identify available control options Step 2 – Eliminate technically infeasible options Step 3 – Rank options by control effectiveness Step 4 – Evaluate most effective controls and

emission limits achievable Step 5 – Select BACT

Step 0 – Define the Source

Applicant defines goals, objectives, purpose, and basic design

Source definition generally provides key design elements that are not under consideration through the BACT process

Define in permit application Permit issuer must discern which

design elements are inherent to that purpose and objectives and which may be changed for pollutant reductions

Step 0 Case StudyNew Combined Heat and Power System at

existing pulp and paper mill 620 MMBtu/hr bubbling fluidized bed boiler 40 MW Steam turbine generator Biomass combustion (bark, mill residuals) Natural gas for startup burners and some load

burning, < 250 MMBtu/hr Installation allows for shutdown of 1 coal/oil/gas

power boiler; removal of coal/oil from a second power boiler, retaining only gas combustion

Objective is to generate renewable energy to replace fossil fuel energy on site and for potential sale to the utility grid

Identify all control technologies available to the source, including: Inherently lower-emitting processes

and designs Add-on technologies Control methods applied at similar

emissions sources Feasible combinations of these

technologies Considers facility-level impacts

No off-site impacts considered, technology must represent emissions reduction at facility

Step 1: Identify

Available Control Options

(1/2)

Not required to include options that “fundamentally redefine the nature of the source”

No clear guidance re: which technologies redefine nature of source

Fuel type as BACT? EPA guidance considers: Cleaner versions of primary fuel Increased usage of secondary fuel Alternative fuel for which source is not

already configured EPA guidance leaves door open for

stricter interpretations by permitting authority

Use relevant white papers as starting point

Step 1: Identify

Available Control Options

(2/2)

EPA Guidance Potential carbon neutrality (based on life-cycle of biofuel)

not considered At facility-level, CO2 emissions from biofuels similar to

fossil fuels Biofuels must represent emissions reduction at facility

level to be considered viable GHG BACT option Biogenic carbon deferral

3/21/2011: EPA proposes deferral of GHG permitting requirements for CO2 emissions from biogenic sources

EPA issued guidance for determining BACT for bioenergy production

Promulgated 7/20/2011 Effective immediately for delegated states SIP approved states may incorporate into rules

Step 1 Biofuel Considerations

Step 1 Energy Efficiency Considerations (1/2)

EPA BACT guidance stresses importance of energy efficiency Primary Step 1 option(s) for combustion sources

Construction of new facilities GHG BACT evaluated on facility-wide basis, including

energy efficiency Evaluate emissions from non-emitting, energy

consuming equipment Modification to existing facilities

BACT applies to new or modified emission unit, not necessarily to energy consuming equipment

EPA guidance still encourages permitting agencies to consider energy efficiency

EPA guidance recommends benchmarking evaluation Collectively assess small energy saving

measures by benchmarking efficiency of new unit of similar design

EPA resources to support benchmarking analyses ENERGY STAR program Sector-specific tools, Energy Performance

Indicators (EPIs), etc.

Step 1 Energy Efficiency Considerations (2/2)

Step 1 CCS Considerations Carbon Capture and Storage (CCS) One of primary distinctions between traditional BACT

and GHG BACT Per EPA, consider CCS in Step 1 for large CO2

emitters, sources emitting high-purity CO2 streams Hydrogen production Ammonia production Natural gas processing Ethanol production Ethylene oxide production Cement production Iron and steel manufacturing

Even if non high-purity CO2 stream, may need to include as a “possible” control option

Step 1 Case Study CCS

High-purity stream? Not on EPA list Limited industrial applications

Efficient Boiler Design Technology selection of BFB boiler over other designs Redefining source?

Lowest Carbon Fuel Consideration of back-up fuels as primary (natural

gas) Source redefining concerns – not evaluating any other

fuel possibilities Energy Efficiency Options

Number of options in EPA guidance documents New boiler – state of the art

Step 2: Eliminate

Technically Infeasible

Options

Is technology available? Reached licensing and

commercial development stage Compliance with BACT limit

demonstrated at similar facility Is technology applicable based

on physical, chemical, and engineering principles?

Per EPA, absence of a commercial guarantee for GHG emissions not sufficient to eliminate option from consideration

Step 2 CCS Considerations

Must consider technical feasibility of each step Capture, transport and storage

If any step infeasible, CCS considered technically infeasible Low-purity stream? Space Right-of-ways Access to storage reservoir

May suffice to demonstrate difference between CCS considerations at applicant’s facility and demonstrated CCS

Many state agencies prefer to monetize everything (eliminate from Step 4 instead)

Step 2 Case Study CCS

Low-purity stream? No available storage/pipeline

Boiler design Addressed supercritical steam design (greater than

3,200 psig operating pressure) as infeasible for this boiler size

Fluidized bed, suspension, stoker, and pile combustion feasible options

Lowest carbon fuel Use of natural gas feasible

Efficiency options Feasible

Step 3: Rank

Remaining Control Options

Ranked by effectiveness of control Traditionally presented as:

Percent pollutant removal Controlled emission rate Reduction in emissions over time

For GHG, EPA advocating efficiency-based control effectiveness Consider thermal efficiency by using

emissions per unit of output (rather than per unit of fuel input)

Must rank logical combinations of the technologies

Can be challenging given variety of iterations on energy efficiencies

Step 3 Case Study Compared boiler efficiencies

In this case, ranked based on energy efficiency – fluidized bed is the clear choice

What if proposing to install a new stoker boiler with a lower energy efficiency?

Is this an area an agency can look at – redefining the source?

Did not do a straight comparison between remaining options

Proceeded to Step 4 with a BFB boiler, and lowest carbon fuel and energy efficiency options to be reviewed

Step 4: Evaluate

Most Effective Controls

(1/3)

Ranked by effectiveness of control Traditionally presented as:

Percent pollutant removal Controlled emission rate Reduction in emissions over time

Top-down – Start with most effective control option

Consider economic, environmental, and energy-related impacts BACT typically focuses on economic

considerations But EPA guidance suggests other

collateral impacts increasingly important for GHG BACT

Step 4: Evaluate

Most Effective Controls

(2/3)

Economic considerations Evaluated on a per ton CO2 equivalent

basis instead of per ton individual GHG EPA guidance considers average cost

effectiveness and incremental cost of adding compatible control technology

No cost effectiveness threshold ($/ton CO2e) in EPA guidance Work Group’s Interim Phase I Report

identifies cost effectiveness range from $3-$150/ton CO2e

Additional local economic factors (new for GHGs) High control cost relative to project cost Potential movement to overseas

production Local job losses

Step 4: Evaluate

Most Effective Controls

(3/3)

Additional considerations Direct energy costs (e.g.

combustion sources) Indirect energy usage (e.g.

purchased electricity) For CCS, consider parasitic load On-site and off-site environmental

implications (e.g., life cycle of biofuels)

Step 4 Case Study Environmental benefits of project

Combustion of plant residuals - Identified by EPA as a CH4 control measure for on-site landfills, so used that logic as a benefit for the project

Significant reduction in coal generated power on-site Reduction in wastewater through scrubber removal Off-site benefit – generation of renewable energy, sale of

renewable energy to grid, likely displacing fossil-fuel generated electricity

Natural gas is a non-renewable fuel Higher costs than biomass Biomass carbon-neutrality? Recent EPA guidance –

biomass combustion is BACT State of the art energy efficiency options for new

unit

Step 5: Select BACT

(1/2)

Select BACT based on most efficient control option or combination of options not eliminated by Step 4

Permitted BACT standards vary Emission limits (output basis,

accounting for energy efficiency) Averaging time periods Equipment specifications Work practices Associated monitoring, recordkeeping,

and reporting EPA advocates BACT limits with

longer averaging periods to address GHG emissions and load variations inherent in combustion equipment

Step 5: Select BACT

(2/2)

May include work practices such as an Environmental Management System (EMS) focused on energy efficiency ENERGY STAR provides guidance BACT limit may include implementation

of energy saving measures identified by EMS

EPA’s Sample GHG BACT assessments Municipal solid waste landfill Natural gas-fired boiler Hydrogen plant at petroleum refinery Coal-fired electricity generating facility Kiln at a cement plant Natural gas compressor station Gas-fired combined cycle power plant

Step 5 Case Study Proposed BACT limit based on vendor provided data 0.45 lb CO2e per lb steam on a 12-month rolling

average basis Anticipated CEM for monitoring for CO2, and

subsequent calculations for CH4 and N2O Since application submittal, EPA released biomass

deferral proposal and bioenergy GHG BACT guidance

State agency was considering a range of options, even having mentioned the possibility of “good combustion practices” as BACT

Stay tuned...

Questions

Deanna L. Duram, P.E., C.M.Trinity Consultants

(678) [email protected]