Upstream greenhouse gas emissions generated during fuel extraction, feedstock cultivation, refining, and distribution.
Well-to-Tank (WTT) encompasses all upstream greenhouse gas emissions from the extraction of crude oil, gas, or biomass, through industrial processing, electricity generation, transport, and delivery to the vehicle's fuel tank or charging connector.
Essential for accurately evaluating alternative fuel carriers (HVO100, bio-methane, hydrogen, and electric fleets) where upstream production accounts for the primary climate delta.
WTT = Fuel_Delivered * Upstream_Factor. For fossil diesel: ~0.60 kg CO2e/L. For HVO from waste oil: WTT includes collection and hydro-treatment footprints.
Upstream WTT factors must be sourced from authoritative databases (GLEC default dataset or verified supplier certificates) and cannot be arbitrarily set to zero.