Fugitive Emissions Control Efforts: A Survey of DOE Sites December 2009

Pursuant to Executive Order (E.O.) 13514, Federal Leadership in Environmental, Energy, and Economic Performance, the Department of Energy (DOE) completed an agency-wide inventory of GHG emissions. GHG emissions fall into three categories: Scope 1 includes all direct emissions produced by site activities, including fugitive emissions (direct emissions not resulting from direct combustion); Scope 2 emissions are indirect emissions from purchased electricity; and Scope 3 emissions are indirect emissions produced in support of site activities.

Data for most of DOE's scope 1 and 2 emissions sources were already available through existing energy and fleet reporting processes. However, almost no information was available about fugitive emissions. DOE conducted a data call and interviewed representatives of selected sites regarding fugitive emissions sources and mitigation opportunities. The following sites were selected as they had previously taken measures to account for and/or reduce their emissions of sulfur hexafluoride (SF₆), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs):

• Bonneville Power Administration (BPA)
• Brookhaven National Laboratory
• Hanford Site
• Lawrence Livermore National Laboratory.
• National Renewable Energy Laboratory
• Pacific Northwest National Laboratory
• Sandia National Laboratories - New Mexico
• SLAC National Accelerator Laboratory
• Southwestern Power Administration (SWPA)
• Thomas Jefferson National Accelerator Facility
• Western Area Power Administration (WAPA)

The summarized results of the interviews are below. This information informed Department-wide emissions reduction goals and formed the basis for initial discussions of the Fugitive Emissions Working Group (FEWG).

For more information about these interviews or the FEWG, contact Josh Silverman at josh.silverman@hq.doe.gov or (202) 586-6535.

Executive Summary of Fugitive Emissions Control Efforts

• Keep up with manufactured suggested maintenance
• Incorporate leak rate into equipment performance measures and retirement decisions
  • WAPA estimates replacing two old/leaky circuit breakers on site will save 9757 MTCO₂e/year - cost not given
• Encourage researchers to use lower GWP gasses AND use closed-loop systems
• Regularly check for leaks (leak monitor ~$300)
  • 5% annual leak in a circuit breaker with 200lb SF₆ charge will cost $65.50 (at $753 for 115lbs SF₆ and $0 for carbon) and 108 MTCO₂e per year
  • Most of power agencies' reductions from aggressive leak maintenance
• Various equipment available commercially or designed in-house by Thomas Jefferson to capture gas when evacuating system - available for all sizes of needs - most are more than 99% effective at collecting/reinjecting gas (cost ~$6000 for small unit up to $80,000 for large unit - $80,000 was cost in 80s/90s; other sites purchased for $18,000, designed/built for $35,000-45,000)
  • $35,000-45,000 system is avoiding ~20,000 MTCO₂e/year in current use - designed to be close to 100% effective
  • $6000 system is brand new, not enough time to know how much saved, designed to remove gas from experimental chambers to vacuum
  • ~$80,000 system designed to be close to 100% effective when was new - probably close to needing to be replaced. As used, saves site from venting 4336 MTCO₂e for every maintenance effort
  • $18,000 unit claims to be 99.8% effective
• BPA considering switch to different type of circuit breaker to reduce amount of SF₆ on site (and therefore potentially leaking) - saves about 90-95% of costs of SF₆ (depending on price of carbon)
• It is the opinion of many sites that for large installations, the cost of the gas alone is sufficient to warrant purchasing collection equipment
• For the smaller installations, a price on carbon would probably make collection equipment financially effective

SF₆ at non-Power Agency Sites

• Uses: electrical components (e.g., circuit breakers, electron microscope), static charge chambers for experiments, injector guns, high voltage power supply
• Sources of emissions/leaks: older equipment designed with "acceptable amounts of leakage" at seals, experiments with open-loop design, venting at end of experiment, venting for maintenance
• Calculating emissions: purchase data (assume 100% release, talk with purchaser when amount seems unusual), weigh cylinders (large scales for large installations, small scale (recently ordered) for carrying around to individual labs)
• Capture equipment:
  • Gas recovery systems (hand-cart mounted for small installations, trailer mounted for large installations) - pump out gas, clean it to near virgin quality, reinject in same or different place
    • $6,000 - $80,000 (80,000 was cost probably in 80s-90s)
    • These systems come in a range of sizes, not just the two mentioned here - useful for everybody!
    • System removes gas to vacuum pressure, so only produces small amounts of emissions when decoupling - expensive equipment is available to avoid even these emissions
    • Originally bought trailer system for purely economic reasons (cheaper than SF₆)
    • Labs just grouped funds together to purchase hand-cart system last month (environmental and economic reasons)
  • System to capture and reuse gas during experiment - don't yet know much about this, she is following up
  • Systems designed in house to reduce emissions associated with maintenance of injector high voltage power supply
    • Developed 10 years ago, redesigned 3 years ago
    • Gas is reused in the high voltage power supply line
    • Have captured 2627 MTCO₂e
    • $35,000-$45,000 for equipment and overhead from in-house design process
    • Motivated by savings in $s and time - much faster to reuse warm gas than heat up and inject gas from canisters
    • Definitely could be applicable to other sites with similar equipment (has been recreated in Britain - slightly different design parameters gave less successful results
  • Dilo SF₆ recovery cart D320-R004 (http://www.dilo.com/MINIplus.html)
    • Currently in use by AC shop to evacuate SF₆ from electron microscopes
    • Into service CY2009
    • Storing captured gas in cylinders until full, then picked up by Airgas to manage processing and reselling
    • Cost $18,000
    • Motivated because new transformers use SF₆ and will be cheaper to handle reclamation and reuse on site, but transformers don't need maintenance yet, so AC shop are primary users
    • Cart is small enough to be portable and usable at other similar sites/facilities
  • Pump-out tank to hold emissions during maintenance (returned to same equipment)
• Other management activities:
  • Planning to have circuit breaker manufacturer retrofit/replace leaky-by-design seals with leak-free seals (hopefully will happen in Feb)
  • Work with researchers to design only closed-loop systems
• Known substitutes:
  • Research into suitable substitutes using N₂O, N, and mixtures of N and SF₆ being conducted by International Linear Collider design team, PG&E, DoD
• If not capturing, why not?
  • Not possible to capture tracer gasses, but lower GWP gasses would be relevant
  • Have not thought about it before

SF₆ at Power Agency Sites

• Uses: circuit breakers, small amounts in circuit switches and small transformers
• Sources of emissions/leaks: seal leaks
• Calculating emissions: weigh tanks before and after filings, laser camera; mass balance
  • SWPA expressed opinion that purchase data is inaccurate because gas sometimes has to be added due to temperature-caused volume shrinkage
• Capture equipment:
  • WAPA: Gas cart to capture gas when need to fully evacuate for maintenance
    • Send gas offsite for reclamation
• Other management activities:
  • Fix leaks (WAPA leak rate down to 1.5% from 4-5% 8-9 years ago; BPA to 0.46% from 0.89% in 1999 even though both are increasing capacity)
  • Add SF₆ leaks to performance measures (affect cost of maintenance) and decisions to replace equipment
  • Train maintenance personnel about SF₆ releases - monitor gauges, gas-level alarms
• Known substitutes:
  • None, but EPA is working with the industry to find substitutes
• Equipment upgrades justified on GHG-basis
  • Replacing two leaky circuit breakers at WAPA could save about 900lbs SF₆/year (~9757 MTCO₂e/year)
  • Newer equipment is less leaky as manufacturers have added quality control and now test for leaks
  • BPA did analysis of switching types of circuit breakers to reduce quantity of SF₆ needed on site - purchase costs are about equal, live-tank breakers use ~5% of the SF₆ as a dead-tank breaker, but are not as seismically safe (if price put on carbon, definitely cheaper to switch to live-tank breakers)

HFCs/PFCs

• Uses: chillers, A/C units, experiments
• Sources of emissions/leaks: leaks and maintenance
• Calculating emissions: purchase data (assume 100% release, talk with purchaser when amount seems unusual), starting to weigh cylinders (large scales for large installations, small scale (recently ordered) for carrying around to individual labs), HVAC operators keep track of amounts used to top-off systems
• Capture equipment:
  • Required by 40 CFR 82 Subpart F to capture refrigerant emissions (CFCs, HCFCs, AND HFCs) during maintenance
    • If done correctly, can retain 98% of gas; if lazy and only pump out liquid portion, lose about 20%
    • For most maintenance, gas does not need to be cleaned before reusing
    • As long as ownership of gas does not change, gas can be reused in different equipment at same location without permits (unclear how this applies if collection equipment is owned by contracted maintenance firm)
    • Cost too variable to estimate generically - cost effective at small increases in price of refrigerant/threat of phase-out
• Other management activities:
  • Keep up with manufacturer recommended periodic maintenance and leak checks/repair
  • Encourage researchers to design only closed-loop systems, use different gasses
  • Older equipment will have low-pressure vents w/ high leakage, but most equipment using HFCs (NOT HCFCs) should be new enough to avoid this problem
  • If doing regular maintenance, newer equipment has alarms for low gas pressure o ~$300 to buy really good (find minute leaks) hand-held leak detector - have somebody walk around with this during routine maintenance/rounds
  • EPA rule: sec. 608 (often missed by sites) - within 30 days of finding that a piece of equipment (charge over 50lbs) is leaking more than a certain amount of refrigerant/year, the site must repair the leak, or develop a 1 year plan for retrofit or retirement
• Known substitutes:
  • 75% of refrigerants in use now are HCFCs - often lower GWP than the available HFC substitute
  • Can't always retrofit with a different gas - if change in pressure, lose efficiency