Title: Net greenhouse gas emissions savings from natural gas substitutions in vehicles, furnaces, and power plants

Authors: Daniel S. Cohan; Shayak Sengupta

Addresses: Department of Civil and Environmental Engineering, Rice University, 6100 Main Street MS 519, Houston, TX 77005, USA ' Department of Civil and Environmental Engineering, Rice University, 6100 Main Street MS 519, Houston, TX 77005, USA

Abstract: We compare the net greenhouse gas emissions impact of substituting natural gas for other fossil fuels for five purposes: light-duty vehicles, transit buses, residential heating, electricity generation, and export for electricity generation overseas. Emissions are evaluated on a fuel cycle basis, from production and transport of each fuel through end use combustion, based on recent conditions in the USA. To compare across sectors, the emissions difference between natural gas and its alternative is normalised by natural gas consumption to compute the net reduction in CO₂e per MJ of natural gas used. Greatest emission reductions can be achieved by replacing existing coal-fired power plants (78gCO₂-e/MJ natural gas) or fuel oil furnaces (66gCO₂e/MJNG). Compressed natural gas in vehicles yields no significant reductions. Uncertainties arising from upstream emission rates for natural gas and the global warming potential of methane are quantified. The study demonstrates the critical role of deployment choice on the net climate impact of natural gas.

Keywords: fuel cycle analysis; natural gas substitution; greenhouse gases; net GHG emissions; methane; carbon dioxide; CO2; attributional LCA; life cycle analysis; upstream emissions; break-even leak rate; vehicle emissions; fuel oil furnaces; coal-fired power plants; USA; United States; light-duty vehicles; transit buses; residential heating; electricity generation; electricity exports; compressed natural gas; global warming; deployment choice.

DOI: 10.1504/IJGW.2016.074960

International Journal of Global Warming, 2016 Vol.9 No.2, pp.254 - 273

Received: 14 Feb 2015
Accepted: 24 Jul 2015
Published online: 27 Feb 2016 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article