This implies that the level of tax for a litre of diesel should be higher than that for a litre of gasoline, to reflect relative environmental costs. Diesel vehicles also tend to travel further per litre of fuel than gasoline vehicles, as they are often more fuel efficient. This means that social costs such as congestion, noise, accidents and infrastructure wear are also higher on a per litre basis for diesel than gasoline. In the energy sector, the International Energy Agency (IEA) estimates that the sources of around 80% of possible cumulative greenhouse gas (GHG) emissions to 2035 under an energy scenario consistent with international climate goals are already in place or under construction, leaving little room for additional polluting facilities (IEA, 2012).