Mobility is a key factor for economic growth and improving living standards. On current trends, passenger travel and freight transport will continue to grow, as they are essential to creating an affluent society by the free movement of goods and services, as well as access to work, education and leisure. Growth in OECD countries will be moderate, as vehicle ownership is reaching a saturation of the mature population. Population aging may even cause a serious “mobility divide” in a couple of decades. Public transportation and city policies reduce traffic and congestion. On the other hand, growth will continue in India, China, and other high growth economies, particularly as local production is expected to turn out affordable vehicles. By 2050, the total stock of light duty passenger vehicles could triple, and reach 2.2 to 2.7 billion.
Thus, the International Energy Agency projects more than a doubling of the baseline energy requirement for the mix of all transport modes. It estimates that it would be difficult to supply the volume of liquid fuels required by this forecast. It also warn about the danger for the climate stability to allow the corresponding CO2 emissions: on a “well to wheel” basis, the total fleet of transport mode would cause between 16 and 18 Gtons of CO2 emissions, against a total 2050 Blue Map safe mitigation target of 14 Gtons for all energy related emissions.
Pushing our transportation modes below the desired maximum CO2 allowance of 5 Gtons, a 70% reduction from the business-as-usual trend, will be difficult. Electrified rail can feed its energy, on the go, from a remote source that can evolve to zero or low carbon electricity. All other modes need to embark a stock of energy sufficient to cover the range between reloading points. In this critical aspect, nothing beats diesel, gasoline and kerosene for energy density per volume. They are also easy to distribute, meter and store on board. Those simple advantages have prevailed, even though they need complex mechanical engines to convert them into CO2, waste heat, and, in the end, only about 25% is available for motion power.
Fuel efficiency has already gone a long way. There will still be progress in tires, body light-weighting and streamlining, and power train efficiency that should amount to a combined 25% lower energy needs from the baseline. Higher CO2 efficiency power trains can come with technologies such as hybrid or pure biofuels and compressed bio-synthetic gas, as long as they can prove a low net carbon balance, a sustainable life-cycle impact, and be farmed in ways that conserve soil fertility and preserve food security.
2011-2012 is the stage of renaissance of the rechargeable battery-electric motor power train for medium range light weight vehicles and longer range plug-in hybrids. The mechanical simplicity and conversion efficiency of the electric power train is still held back by the very low energy density of its storage (100 + times lower than diesel). But it fully benefits from the evolving carbon footprint of the grid or even, as already proposed by some vendors, from a rooftop photovoltaic or wind generator. At the beginning of the learning and production curve, acquisition costs will be significantly higher, and the lower mileage and maintenance costs will not be sufficient to attract a large market, without additional cash or fiscal incentives. Electricity produced by on- board hydrogen fuel cells are another development route for zero CO2 vehicles that are likely to be more adapted for large commercial vehicles.
While there is creative competition of low carbon mobility solutions, the IEA scenario also counts on an important switch from individual mobility to public transportation, car sharing and rail, from business air travel to videoconferencing, and from road freight to rail. In addition, mobility management that fosters collaboration between transit operators with user- friendly services and ticketing-travel cards enable commuters to make better mobility choices. For instance Japan has successfully managed to maintain CO2 emissions below their 2002 level. On the strength of this experience the Japanese Automobile Manufacturers’ Association estimates that such measures could ensure that CO2 emissions peak in 2025 and decrease thereafter. Still, the IEA scenario expects the 2050 vehicle stock to stabilize around 1.8 billion. This avoids 2 Gtons of CO2 from the baseline, another 5 Gtons reduction comes from vehicle efficiency improvements and electric vehicles, and 4 Gtons from alternative fuels. But it remains 2 Gtons short of the most desirable goal.
Business as usual would soon run into fuel supply bottlenecks, and exacerbate prices. Transport cannot continue to claim 40% of oil resources. The low carbon scenario imposes a 10% investment cost on the fleet improvement, but saves significantly on fuels. Therefore, by 2050 there is no net cost, and the improved vehicle stock keeps saving fuels and avoiding carbon. There are also collateral benefits in lower road pollution that affects health and ecosystems sensitive to particles, NOx and SOx.
Road safety cannot be overlooked. Nearly 1.3 million people die each year and another 20 to 50 million are injured as a result of a road traffic collision. 90% of road accidents occur in low to middle-income countries. The UN launched 2011-2020 as the Decade of Action on Road Safety. It calls in particular for speed calming measure, enforcement of personal and vehicle safety features, education on safe driving, better road design and availability of affordable public transportation. Road safety requires a comprehensive three-pronged approach to drivers’ behaviors, enhanced vehicle safety designs and maintenance of the traffic environment.
Sustainable mobility is also about a modal mix with enhanced benefits of comfort, swift access and movement. In this mix public transport becomes more important but it must be convenient, clean, reliable and affordable. Otherwise empty trains, trams and buses end up with higher CO2 emissions per passenger-km and unrecovered infrastructure and operating costs.
A 2050 world will clearly have more cars and intercity traffic. But it may also have a quieter, safer, more efficient city mobility system that leaves space for nature and culture where people live and work.