TOSCATechnology Opportunities and Strategies for Climate-friendly trAnsport
Technology Opportunities and Strategies for Climate-friendly trAnsport (TOSCA)
Intra-EU-27 transport sector-related lifecycle carbon dioxide (CO2) emissions increased from around 900 million tons in 1990 to nearly 1,200 million tons in 2010, a growth by about 30%. The TOSCA scenarios suggest that these emissions may continue to rise by up to nearly 60% by 2050 in the absence of new policy intervention. If also including half of intercontinental air transportation, the EU-27 transport sector lifecycle CO2 emissions could more than double by 2050.
TOSCA’s techno-economic assessment suggests that energy use per unit passenger-km or ton-km can be reduced by 30-50% for most transport modes using technologies that could become available during the 2020s, compared to the average new technology in place today; natural fleet turnover would then translate these new vehicle-based reductions into the entire fleet by midcentury. For automobiles and narrowbody aircraft, these efficiency gains can be exploited through reduced driving or flight resistances in combination with a radical propulsion system change. For automobiles (and to some extent light-duty trucks), a promising technology trajectory is the stepwise electrification of the vehicle powertrain: from mechanical, to hybrid-electric, plug-in hybrid-electric, to battery-only and hydrogen fuel cell vehicles. For narrowbody aircraft, open rotor engines optimized for a carbon-fiber airframe with unswept wings, operating at slightly reduced cruise speeds promise the largest reduction in fuel burn, unless travel is shifted to advanced turboprop aircraft. For passenger and freight railways, options in addition to lower driving resistance include increased energy recovery at braking, eco-drving, and improved space utilization, along with other measures. The only exception to these opportunities are state-of-the-art medium- and heavy-duty trucks, which are already comparatively close to the technological fuel efficiency limit and thus offer a lower potential for reducing energy use. In addition, intelligent transportation systems (ITS) could reduce energy use by another 5-20%, depending on the transportation mode. And these reductions in CO2 emissions can be further complemented by second generation biofuels and electricity from low carbon sources. A more electricity-based transport system also offers ancillary benefits in terms of reduced energy import dependence.
However, exploiting the potential of these opportunities requires policy intervention. Many of the critical automobile, narrowbody aircraft, and (some) ITS technologies and second generation biofuels rely on substantial (EU-wide) R&D investments in order to be produced at large, commercial scale. In addition, a carbon price of around €150 per ton of CO2 would be required for the proposed narrowbody aircraft technologies to become cost-effective and this price would need to be more than twice for advanced automobile technologies, unless the new technologies are regulated into the market. Moreover, industry would need to be encouraged to make the capital-intensive investments to manufacture these technologies and fuels. Realizing these opportunities thus requires predictable market conditions that need to be ensured by technology and climate policy. Realizing these opportunities also requires society to prioritize climate change mitigation over other needs, as these policy interventions will lead to additional public expenditures (and thus to higher taxes or cuts in other government budgets at times of a public finance crisis) and/or to higher prices and thus decreased mobility.
Importantly, given the continuous growth in transportation demand, even assuming very optimistic adoption levels of promising technologies and fuels, it is unlikely that EC-27 transport sector lifecycle greenhouse gas (GHG) emissions can be reduced to significantly below 2010 levels by 2050, unless affordable and vast amounts of low-carbon biofuels and electricity can be supplied. Hence, it appears that technological measures alone cannot produce large enough reductions in transport GHG emissions to be compatible with EU climate goals, at least by 2050. The question then is better understanding the potential for behavioural measures to mitigate transport sector GHG emissions, which include reducing the need for transport and shifts toward low-emission modes.