Not dead yet….
Cheap natural gas is not the only headwind for the renewables uber alles perspective/trend. The roadmap to improved efficiency seems clear, and long-lived, both for gasoline and diesel fuels. While automakers only seem (generally) to develop more fuel efficient vehicles under the greatest duress (i.e. mandates), there is plenty of opportunity, and progress. The addition of four, five, six, seven, and eight speed transmissions add, on average 2-3% EACH to mileage. In the limit, variable transmissions add tot this benefit. Variable valve timing has a similar effect. Improved controls and heat transfer in exhaust recycle, air conditioning and heating systems also contributes.
Increased compression can bring up to 30% lower consumption.
The net, based on an MIT study (among others), is that average transport-wide mileage per hydrocarbon gallon could double by 2035. Contributors include better engine/aerodynamics (40% of improvement), hybrid/electric (30%), and materials/lightweighting (12-20%). Significant assumptions include the tradeoff between efficiency and performance, viability of all electric vehicles (MIT is hopeful but skeptical), and continued policy (mandates). Interestingly, the estimated average vehicle price premium is only 10%, with turbo fired gasoline and diesel innovations the cheapest. In general, the greenhouse gas (GHG) improvement is proportional to the reduction in hydrocarbon fuels (assuming reduced share for corn-based and other inefficient ethanol/fuels). As an aside, it is generally the emissions from combustion, not the energy of production, which drives total carbon content – these efficiency opportunities dwarf the source of crude, whether ‘conventional,’ or oil sands.
Contributors to this improvement include precision sensor/controls, ultra-capacitors, cleaner fuels, and advanced materials. The rapid implementation of sensors to monitor and micro-control combustion is having a significant positive effect on conventional ICE.