A Better Way to Estimate Emissions from Oil and Gas Operations

1. A Better Way to Estimate Emissions from Oil and Gas Operations Dr. Susan Stuver Research Scientist 10/10/2013 Energy, Air & Water A Comprehensive Study of the Issues of Today

2. UNIVERSITIES HEALTH SCIENCES AGENCIES Who We Are

3. Research Objectives Problem Statement Solution Policy without Data Conservative data assumptions leads to over estimation– assume 100% engine load and 24/7 operation times Measure Equipment Emissions Engine load data and activity times would make estimates more realistic OUTDATED Calculations Based on Outdated Standards US Regulators use the USEPA AP-42 Standards that assume worst possible emissions Use Engine Emission Factors Use EPA certified tiered engine emission factor data from engine manufacturers

4. Bad Science leads to Bad Policy Max Regional 8-hr Ozone Impact derived from worst case estimates Wind Direction from Eagle Ford into San Antonio Texas

5. How Emission Estimations Are Done -Site Unseen- CALCULATION – the old fashioned way… 2,250 hp Pump truck deck engine and 12 pump trucks engines are used for the hydraulic fracturing process 2,250 hp/pump truck engines x 12 pump truck engines = 27,000 hp ENOx = EF x HP x LF Where, ENOx = NOx Emissions (lb/hr) EFNOx = NOx Emission Factor (lbNOx/hp-hr)-No Emission Controls are assumed HP = Total power output (hp) LF = Load factor-100% assumed So, ENOx= 2.4 x 10-02lbNOx/hp-hr x 27,000 hp x 1 = 648 lbNOx/hr Hey – who messed up the math?

6. New Method Start with Collecting Data

7. New Method Prioritize the Sources EMISSION GROUP RANKING SYSTEM RANK 1 Largest Sources - EX: Pump Trucks (Fracturing/Perfing) RANK 2 Medium Sources - EX: Fracturing Water Pumps RANK 3 Small Sources - EX: Light Carts

8. New Method Find the Correct Emission Factors There are 7 of them - Using worst case can cause huge variation Worst Case

9. New Method Calculating Engine Load GPSA Engineering Data Book (2004)6 and Carl Branan’s Process Engineer’s Pocket Handbook (1984)7 provides the equation BHp = Q x ∆P/1714(e) Where, BHp = Required brake horsepower Q = Fracturing fluid flowrate (gal/min) ∆P = Pump discharge – Pump suction (inlet pressure) (psi) 1714 = Conversion factor (convert to BHp) (e) = Pump efficiency = 90% (see Note) Note 1 – Inlet pressure was not recorded so it is conservatively assumed to be zero (psi) Note 2 - The combination of mechanical and volumetric efficiency is normally 90% or higher for non-compressible fluids (GPSA Engineering Data Book, 2004)8

10. New Method Calculating Engine Load BHp = Q x ∆P/1714(e) BHp= ((65 bbl/min x 42 gal/bbl x (6000 psi – 0 psi))/1714)/(0.90)=10,618 Bhp LF= BHp and divide it by full horsepower. Full horsepower is obtained by the engine HP times the number of engines. LF = 10,618 Bhp/(2250 hp x 12 engines = 27,000 hp) = 39.2% while the engine was under load.

11. New Method Putting it Together 2,250 hp Pump truck deck engine and 12 trucks Epoll = EF x P x N x LFA Where, Epoll = Emissions for pollutant EF= Emission factor in lb/hp-hr P= Brake horsepower in hp N= Number of units LFA = Load factor Average (39% for 7.5hr and 15% for 4.5hr) Nox = 108.5 lbNox/hr AP-42 factors with 100% estimated load = 648 lbNox/hr that’s 539 pounds per hour difference. 539 lb/hr x 12 hour day = 6,468 pounds (3.2 tons) per day for 1 frac job So, ENOx= (1.34 x 10-02lb/hp-hrx 2250hp/eng x 12 eng) x 39% x 7.5 hr/day + 15% x 4.5 hr/day 12 hr/day

12. Results Comparing the 2 Methods • 539 lb/hr • 12 hour day = 6,468 pounds (3.2 tons) per day for 1 frac job • 2000 frac jobs = 6,400 tons of emissions that are not really there. Lets compare the results NoxAP42 100% LF = 648 lb/hr Nox Tier Eng LF Avg = 108.5 lb/hr VOC AP42 100% LF = 19 lb/hr VOC Tier Eng LF Avg = 5.7 lb/hr CO AP42 100% LF = 149 lb/hr CO Tier Eng LF Avg = 20 lb/hr PM/PM10 100% LF = 19 lb/hr PM/PM10 LF Avg = 1.6 lb/hr

13. Results – Graphic Tier IV engines would be much lower Are actually measured in grams (not pounds) per hour

14. No Wonder the Maps Look so Bad 6,400 Tons of Over Estimation

15. Moving on to Rigs ENOx = EF x HP x LF Using engine load is not realistic Too much variance – need an entirely new way to estimate • Conceivable to use • total fuel consumption, • brake specific fuel consumption • diesel density • tier rated emissions • to estimate emissions from a job

16. Example Calculation Assume a drilling operation uses 5,000 gallons of diesel per day for 5 days And Assume we know the BSFC is 0.35 lb/bhp-hr And Assume we know that diesel density is 7 lb/gallon And Assume we know the engines are Tier 1 – 6.9 g/hp-hr for Nox And we want to estimate NOx Emissions Calculating Hp-hr/job = (fuel for job, gallons) X 7 lb/gal = 500,000 Hp-hr/job 0.35 lb/bhp-hr Tons = Hp-hr/job x tier rated emissions g/hp-hr x 1/454 g/lb x 1/2000 lb/ton Nox Tons = 500,000 hp-hr/job x 6.9 g/hp-hr x 1/454 g/lb x 1/2000 lb/ton = 3.8 tons Note: numbers aren't actual This will be compared to the traditional method: ENOx = EF from AP42 x total HP x 100% LF X 100% activity And backed up with measurements to validate

17. NG, Bi-fuel and Dual Fuel No engine certification for emission factors Emission Reduction Potential Not Recognized engines are currently being loaded into the regional air shed model as diesel Measurement of emission reduction is needed. We are securing study sites to quantify the emissions reduced by switching to bi-fuels, dual fuels and /or NG

18. Advances in Measurement Remote Monitoring with Low Cost Sensors

19. Advances in Measurement Wireless Data Networking

20. Advances in Measurement Advanced Analytics for Fugitive Sampling There's no protocol for the use of relatively new technology in oil and gas operations

21. Utilizing the EFD Network Water Screening Kits Fugitive Emissions Produced Water Trmt Soil Impacts Invasive Species Education and Outreach Managing Misinformation Stray Gas Wireless Data Loggers Temporary Roads Adv. Analytics Livestock Impacts

22. Questions? Aggie Pigeon