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Nigel Clark, Energy Consultant to Transport Energy Strategies

Nigel Clark holds a B.Sc. in Chemical Engineering and a Ph.D. in Engineering from the University of Natal in South Africa. His broad expertise is in energy systems research and development, with emphasis on engines, fuels, emissions, and transportation. Dr. Clark consults in the areas of fuels, engines and emissions, providing analysis, modeling, review, seminars, expert opinion and business evaluations. His most recent contributions have been in ethanol emissions, marine liquefied natural gas (LNG) use, emissions inventory, and engine controls. He served on the faculty of West Virginia University (WVU) for 34 years, is now the George Berry Chair Emeritus in the WVU Statler College of Engineering and Mineral Resources. Early in his academic career, Professor Clark was honored as a National Science Foundation Presidential Young Investigator by George H.W. Bush.

As a research leader, he has conducted programs for the Departments of Energy, Defense and Transportation, the EPA, NASA, CARB, numerous state governments, federal government laboratories, the Environmental Defense Fund, the World Bank, the International Council on Clean Transportation, the Coordinating Research Council, and major energy corporations and engine manufacturers. These programs have addressed conventional and alternative fuels for light-duty vehicles, trucks, buses and locomotives, as well as stationary and marine engines. Nigel’s research included the measurement, quantification and estimation of emissions, with emphasis on real-world impacts, and he has developed test procedures and schedules that are employed widely today. He has extensive experience in the deployment of natural gas and renewable fuels for transportation and has played a major role in advancing free piston engine design for electric generation. He holds patents in engine design and emissions control.

Dr. Clark has served on National Academies committees addressing vehicle fuel efficiency, is a Fellow of the Society of Automotive Engineers, and has authored or co-authored over 500 papers and technical presentations.

Selected Publications & Studies:

  • DELGADO, O., THOMPSON, G., and CLARK, N.N., “Modeling Transit Bus Fuel Consumption Based on Cycle Properties,” Journal of the Air and Waste Management Association, Vol. 61, April 2011, pp. 443-452.CLARK, N.N., McKAIN, D.L., KLEIN, T., and HIGGINS, T., “Quantification of Gasoline-Ethanol Blend Emissions Effects,” Journal of the Air & Waste Management Association,
  • NUSZKOWSKI, J., THOMPSON, G.J., TINCHER, R., and CLARK, N.N., “Heat Release and Emission Characteristics of B20 Biodiesel Fuels During Steady State and Transient Operation,” Society of Automotive Engineers Paper 2008-01-1377, SAE International Congress and Exposition, Detroit, MI, April 2008
  • CLARK, N.N., ATKINSON, C.M., THOMPSON, G.J., and NINE, R.D., “Transient Emissions Comparisons of Alternative Compression Ignition Fuels,” 1999 SAE Transactions, Journal of Fuels and Lubricants, Vol. 108, pp. 468-482
  • DURBIN, T., JIANG, Y., YANG, J., TAN, Y., YOON, S., CHANG, H., COLLINS, J., MALDONADO, H., CARLOCK, M., CLARK, N.N., McKAIN, D.L., COCKER III, D., KARAVALAKIS, G., and JOHNSON, K. “Evaluation of Emissions Benefits of OBD-based Repairs for Potential Application in a Heavy-duty Vehicle Inspection and Maintenance Program” Atmospheric Environment, Volume 247, 15 February 2021, 118186,
  • CLARK, N.N., HIGGINS, T., KLEIN, T., McKAIN, D.L., “Emissions from Low- and Mid-level Blends of Anhydrous Ethanol in Gasoline,” SAE World Congress, SAE Paper 2019-01-0997
  • JOHNSON, D.R., HELTZEL, R., NIX, A.C., CLARK, N.N. and DARZI, M., “Greenhouse Gas Emissions and Fuel Efficiency of In-Use High Horsepower Diesel, Dual Fuel, and Natural Gas Engines for Unconventional Well Development.” Applied Energy, Vol. 206, pp. 739-750, 2017, H., LIU, S., LIEW, C., GATTS, T., WAYNE, W.S., CLARK, N.N., and NUSZKOWSKI, J., “An Investigation of the Combustion Process of a Heavy-Duty Dual Fuel Engine supplemented with Natural Gas or Hydrogen.” International Journal of Hydrogen Energy, Vol. 42, pp.3352-3362, 2017.
  • PAVLENKO, N., COMER, B., ZHOU, Y., CLARK, N., and RUTHERFORD, D., “The Climate Implications of using LNG as a Marine Fuel,” International Council on Clean Transportation Working Paper 2020-02, January 2020.

Terrence S Higgins, President, THiggins Energy Consulting

Terrence Higgins is president of THiggins Energy Consulting, providing energy consulting services to the petroleum, biofuel and related industries. His primary area of focus is crude, refined product and biofuel supply/demand and the impact of fuel quality trends on refining and application of new refining technology. With over 50 years of experience in various capacities associated with the petroleum industry, he is a recognized expert in crude/refined product markets, fuel quality and impact of quality requirements on refining, product markets and emissions. Mr.  Higgins retired from Hart Energy where he founded Hart’s World Refining & Fuels Service. Mr. Higgins’ experience also includes 14 years as the Technical Director for the National Petrochemical and Refiners Association (NPRA) (now the American Fuel & Petrochemical Manufacturers) and assignments with an energy and environmental consulting firm, the U.S. Department of Energy and international petroleum refining companies. He has managed several projects for foreign countries related to development and implementation of fuel/air quality strategies and biofuel programs.

Selected Publications & Studies:

  • Development of Global Biomass Diesel Supply and Demand and Analysis of the Impacts of Tariffs Imposed on Argentina and Indonesia, 2018 (project leader and author for global supply and demand, co-author for economic and tariff analysis) (prepared for proprietary client)
  • Development of detailed refining and refined product balances for the U.S. PADD 1 market over the next 10 years
  • Development of Detailed Petroleum Supply and Demand Balances and Forecasts (at pipeline terminal level), 2018 (co-author) (prepared for U.S. refined products pipeline company)
  • Evaluation of the Technical Aspects and Project Economics for Proposed Merchant Octane Production Project, May 2017 (author) (prepared for proprietary mid-stream oil company)
  • Evaluation of Technical Feasibility, Market Opportunity and Economics for a New Technology Application for Petrochemical and Refinery Octane Component Production. (author) (prepared for proprietary commercial client).
  • The New Economics of Octane, 2017 (co-author) (prepared as subscription product in conjunction with OPIS)
  • Economics of GTL Diesel Component Blending and Development of Marketing Strategy for Maximum Revenue, 2014, (co-author) (prepared for GTL operating company)
  • Evaluation of MTBE to Isooctane Conversion Project, (conducted twice 2007 and 2012) (author) (prepared for SABIC)
  • Technical and Policy Assistance for Biofuel Market Development in El Salvador, June 2009 (co-author)
  • Global Diesel and Heavy Fuel Outlook, 2012 (co-author) (prepared as multiclient subscription report

David McKain, Consultant to Transport Energy Strategies

David McKain holds an M.S. in Mechanical Engineering from West Virginia University. He currently directs and executes EPA certification testing of locomotives for Norfolk Southern and the American Association of Railroads. His professional responsibilities include assuring that data collection equipment, test conditions and procedures, data post-processing and reporting comply with EPA test regulations. He has extensive experience interpreting, handling, manipulating and analyzing large datasets and extracting information from publicly available datasets and reports. During his twenty five year professional career he has directed and/or participated in numerous projects related to emissions and performance heavy-duty engines, vehicles, fuels and aftertreatment systems and has authored or co-authored numerous research articles. He has broad experience with fuel chemistry having conducted engine emissions and performance testing with both liquid and gaseous fuels including novel work with fuel blending and engine knock as well as comparative testing for federal and state regulatory certification. Mr. McKain currently works with the West Virginia University Research Corporation as a supervisory engineer.

Selected Publications & Studies:

  • Clark, N.N., McKain, D.L., Klein, T., and Higgins, T., “Quantification of Gasoline-Ethanol Blend Emissions Effects,” J Air Waste Manag Assoc. 2020.
  • Clark, N., Klein, T., Higgins, T., and McKain, D., “Emissions from Low- and Mid-Level Blends of Anhydrous Ethanol in Gasoline,” SAE Technical Paper 2019-01-0997, 2019.
  • Clark, N.N., McKain, D.L., Johnson, D.R., Wayne, W.S., Li, H., Akkerman, V, Sandoval, C., Covington, A.N., Mongold, R.A., Hailer, J.T., and Ugarte, O.J., “Pump-to-Wheels Methane Emissions from the Heavy-Duty Transportation Sector,” Environmental Science & Technology 2017 51 (2), 968-976.
  • Clark, N.N., McKain, D.L., Johnson, D.R., Wayne, W.S., Rudek, J., Mongold, R.A., Sandoval, C., Covington, A.N., and Hailer, J.T., “Future methane emissions from the heavy-duty natural gas transportation sector for stasis, high, medium, and low scenarios in 2035,” Journal of the Air & Waste Management Association, 67:12, 1328-1341, 2017.
  • Durbin, T.D., Johnson, K.C., Karavalakis, G, Miller, J.W., Jiang, Y., Carlock, M., Ventura, L.M.B., Clark, N.N., and McKain, D., California Air Resources Board: Final Report – Heavy-duty On-Road Vehicle Inspection and Maintenance Program, Contract No. 15RD022, January 2019.
  • Johnson, D.R., Bedick, C.R., Clark, N.N., and McKain, D.L., “Design and Testing of an Independently Controlled Urea SCR Retrofit System for the Reduction of NOx Emissions from Marine Diesels,” Environmental Science & Technology 2009 43 (10), 3959-3963.
  • Clark, N., Khan, A., Wayne, W., Gautam, M. et al., “Weight Effect on Emissions and Fuel Consumption from Diesel and Lean-Burn Natural Gas Transit Buses,” SAE Technical Paper 2007-01-3626, 2007.
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