Transportation Energy Consumption

By Karen Gu

Abstract

Transportation needs consume a significant share of energy use globally. It is therefore crucial for policymakers interested in sustainable development to ensure that the transportation infrastructure develops in a way to maximize efficiency and minimize damage to the environment by using less energy and cleaner energy.

Before determining strategies for addressing energy consumption in transportation, it may be useful to study some trends in transportation use.

1. In the US, highway transportation uses the greatest percentage of energy of all modes of transportation. Of these, light-duty or passenger vehicles use the greatest proportion of energy.¹
2. Car usage is more significantly tied to city form (urban density, location of workplaces, goods, and services) and location than it is to wealth.²
3. Private transport is a significant proportion of daily trips only in the USA, Australia, New Zealand, and Canada.²
4. “Energy consumed per passenger km in public transport in all cities is between one-fifth and one-third that of private transport.”²
5. In the US, where (as mentioned above) private transport is most prevalent, public transportation is relatively inefficient due for two reasons. One, many US cities are ill-designed for public transportation; for example, buses are inefficient forms of public transportation in suburbs where single-family cars are the intended form of transportation. Two, public transport vehicles consume more energy in the US, 26 megajoules per kilometer traveled, “with most other regions under about 16 to 17 MJ/km, down to a low of 10 MJ/km in African cities.”²
6. Currently, only 5% of energy use in transportation is renewable.³

With the above trends in mind, we would like to establish some goals for urban transportation energy usage. They are:

1. to decrease the share of private transport in total city transportation (Trends 1 and 3)
2. to improve energy efficiency of public transport (Trends 4 and 5)
3. to increase the share of renewable energy used in public transport (Trend 6).

These goals are worthwhile to address because they represent a large portion of energy use and a large portion of potential improvements in sustainable transportation, as described by the trends above. These goals will also help achieve the overall energy goal of zero emission public transport by 2050.

Our proposed solutions will fall into two categories, which urban planners and policymakers will need to use in conjunction in order to affect energy use overall. Behavioral solutions are concerned with changing consumption patterns. Technological solutions are concerned with increasing energy efficiency and transitioning into cleaner energy sources by providing the technology necessary to meet current energy demand.

Solutions

Behavioral

Carbon pricing: By placing an explicit, monetary cost on carbon emissions and other externalities associated with energy use, the government can force economic agents to take into account the effects of their business activities. This can begin with eliminating subsidies to fossil fuel consumption, estimated to be $493 billion in 2014 by the IEA.⁴ This method should be used by governments at all levels, from national to municipal, to internalize negative externalities associated with carbon emission for economic actors. However, carbon pricing is generally hard to implement politically and is more effective in wealthy, industrialized nations. This difficulty should be addressed through political pressure from supranational organizations like the UN or from developed nations that provide economic aid to developing countries. This strategy must in addition be combined with appropriate advances in clean energy technology that enable companies to meet carbon reduction goals. The International Monetary Fund (2012) describes these methods: “Encouraging the major emitting developing economies to reduce GHGs could be facilitated by compensation payments. This might take the form of direct side payments (under a tax regime) or generous emissions allocations (under a trading system), though both are challenging to negotiate. In the meantime, the Green Climate Fund (GCF) could catalyze financial flows to developing economies…”⁵

Ridesharing: Participants in carsharing programs such as Zipcar tend to drive fewer miles per year because, while the up-front cost is lower, the per-mile cost is higher.⁶ Ridematching systems such as UberPool and Lyft Line increase efficiency by helping riders coordinate matches that limit the distance traveled.⁶ Although this system has thus far worked best in high-income, developed cities, it can be conceptualized as a flexible transport system (see below) that can be used to meet low or fluctuating demand in low-income or developing cities. Riders are incentivized to use this form of transport by government restrictions such as the ones described below.

Downtown parking restrictions: Downtown parking restrictions limit the amount of parking available in downtown areas, which are more easily accessible by public transport. We recommend this strategy in order to limit the use of private transport and incentivize use of public transport. This has proved effective in Portland, Oregon, where an overall cap of about 50,000 downtown parking spots increased public transit use from ~20-25% to 48% over 20 years.⁷ In addition, parking pricing reduces driving alone and vehicle trips, although this depends on the destination. Comsis Corporation, an information firm working with the US Department of Transportation and the Institute of Transportation Engineers (1993), found that a daily parking fee of $4 reduces vehicle trips to the central business district by 50%.⁸ This fee is likely to mainly affect travelers that can afford private transport vehicles, meaning that lower-income groups that rely on public transit and walking will be only marginally affected. The fee can further be targeted to groups that are most likely to change their commuting behavior by charging parking fees at shopping areas and recreational spots, rather than in residential areas or at workplaces. Such a strategy is best used in cities with strong public transport infrastructure, so rather than reducing overall transport, transport is instead shifted to more efficient and cleaner public transport. Thus, we will next examine technological solutions for improving public transit.

Technological

Increased investment for clean energy research and development

Figure 1. Global new investment in renewable energy by region, 2004-2015, $BN.⁹

China provides an example to emulate with its 13th Five Year Plan, a comprehensive reform plan which includes establishing low-carbon industries, encouraging use of alternative energy vehicles, and creating an online environmental monitoring system.¹⁰ As Figure 1 shows, China’s investment in renewable energy has been growing steadily, in contrast with investment trends in Europe, where investment is declining, and in the United States, where investment fluctuates. “Researchers estimate that China is already exceeding its target of a 40-45% reduction in carbon intensity (greenhouse gases emitted per unit GDP) from 2005 levels by 2020, and the reduction could be as high as 50%.”¹¹ China invested $102.9 billion in renewables in 2015, up 17% from its 2014 total and contributing 36% of the world total investment. This investment resulted in advances such as the world’s first hydrogen-powered tram. Developed by the state-owned China South Rail Corporation, the tram has a 380 person capacity, and its only exhaust is water. The tram was developed in Qingdao, the largest city in the coastal Shandong province of China, where it can be used in urban settings, attaining a top speed of 70 kilometers an hour.¹² The tram can run for 100 kilometers at a time with a refueling period of 3 minutes, making it well-suited for Chinese tramcar lines, whose average length is about 15 kilometers, according to chief engineer Liang Jianying.¹³ In addition, energy savings from the hydrogen fuel technology may help fund more production of these hydrogen trams, allowing Qingdao and other Chinese cities to gradually transition to clean energy public transport. China’s example demonstrates the benefit of building on existing infrastructure; that is, the hydrogen-powered tram replaces less clean trams in the existing public transit system. Policymakers should aim to implement such incremental solutions rather than rehaul an entire system of public transit, especially in more developed cities.

This and other clean energy technologies make it possible to achieve zero-emission public transport by 2050, by incrementally changing current public transport vehicles to those powered by hydrogen, electric, and other clean energy sources. According to the National Renewable Energy Laboratory (2012), 80% of US electricity production can come from renewable sources by 2050.¹⁴ Thus, the first step to achieving zero emission public transport system is electrifying the system in an incremental manner as described above. Although the US is not representative of renewable energy production worldwide, the fact that 80% of US electricity production can be renewable indicates that such a transition in public transport is feasible.

More efficient city structure

Figure 2.¹⁵

Consistent with Trend 2, increased urban density is correlated with lower transport-related energy expenditures (see Figure 2).¹⁵ Public transport is only viable for high-density, centralized urban structures. (See Increasing Density for information on zoning solutions to achieve more efficient city structure.) For low-density cities, in which demand for public transportation is variable and low in certain areas, flexible public transport (FPT) is required.¹⁶ An FPT system requires both physical infrastructure and a sophisticated information system for allocating vehicles and planning routes. Examples of such systems include ridesharing or carsharing systems (Uber, Lyft, Zipcar), as well as extensions of an existing public transport system or destination-oriented transport (for example, transport to a shopping mall). A case study from Campi Bisenzio, a region in the northwest of Florence in Italy, demonstrates the viability of this approach. An on-demand bus service, PersonalBus, was implemented in 1997, serving the entire Campi Bisenzio region (population 36,000). By 2003, the system was serving 117,058 passengers yearly, traveling a total of 321,569 kilometers.¹⁶ Thus, this FPT was able to serve a yearly passenger base of greater than the region’s population size within six years of implementation, demonstrating the effectiveness of the method. Furthermore, this system would be even more efficient applied today, due to better information systems available to plan bus routes today.

Pedways: Pedways are indoor urban walking environments that improve walkability and access to public transport. They are incrementally built as new buildings are constructed, meaning they have a low up-front cost, especially when developed in conjunction with the private sector.¹⁷ Such a pedway system may consist of both underground tunnels and aboveground skyways, which may also connect existing buildings in order to improve pedestrian accessibility. Toronto provides a good example of the pedway strategy. Private business owners connected several store locations beginning in the early 20th century, but by the 1970s the city government of Toronto began to sponsor pedway construction, paying 50% of the gross cost to businesses. This strategy represents a collaboration between the public and private sectors that has resulted in Toronto’s pedway-linked downtown becoming a vibrant neighborhood attractive to both tourists and locals.¹⁸ This solution should be implemented extensively in developing cities, where the pedway system can easily be linked to public transport. However, highly developed cities can still incrementally build a pedway system to better link businesses to public transport, as with Toronto’s example. It is additionally important for planners to carefully consider areas to connect with pedways. Toronto’s pedway system is successful because it linked separate islands of commerce together into a single “urban mall.” For a city to adopt a pedway strategy, the neighborhood in question should contain areas of interest sufficiently clustered together to facilitate walking, and the areas linked should have the same sort of appeal to travelers — shopping destinations or tourist destinations, for example.

Traffic calming: Such a strategy is intended to reduce vehicle speeds and volumes on certain strategic city locations, such as near a shopping district to increase the volume of visitors, or in a residential neighborhood to improve safety and noise level. Used in conjunction with pedways, this strategy of various design techniques can make urban environments more pedestrian friendly, encouraging people to walk or use public transit instead of driving. Traffic calming includes techniques such as rumble strips, roundabouts, speed humps, and other methods to reduce vehicle speed.¹⁹ This technique has applications in many different kinds of cities, providing greater pedestrian traffic in cities with established public transport systems and improving safety in cities such as Delhi with highly mixed transport modes ranging from automobiles to rickshaws.

Conclusion

Improving sustainability in urban energy consumption requires both behavioral changes and technological advances to make cities more pedestrian-friendly and less adapted for private vehicles, to adapt current infrastructure in order to make room for the technological advances of the future, and to develop these technological advances so that clean energy will predominate in our new public transit centered cities.

On the national level governments can consider greater investment for new technologies. On the municipal level urban planners can take into account the physical structure of cities that will facilitate less energy use in transportation. On the individual level people must make an active commitment to use less resources, utilizing programs such as ridesharing to minimize their energy usage. Combined, these efforts will help achieve the listed goals in order to make cities more sustainable and better places to live for future generations.