A cradle to gate life cycle assessment model has been developed to quantify the greenhouse gas emission and water consumption footprint of a U.S. unconventional shale gas well. Results show that 7.1 kg CO2 are emitted per Mcf of gas produced, equal to an emission rate of 1.48% across the system boundary. Sensitivity analysis shows that for a best-case scenario this rate can be as low as 0.55% of the natural gas produced, whilst the worst-case suggests a CH4 emission rate of 4.3%. The water consumption was found to be 11.2 litres per Mcf of gas production. Economic and policy implications of these results have been assessed to understand opportunities and threats from mitigating these detrimental environmental impacts.
