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Transport

Electric Bikes

A German bicycle mechanic trying out the latest electric bike from his shop in Berlin.

Electric bikes are the most environmentally sound means of motorized transport in the world today. They come in many shapes and forms and are accompanied by a small battery-powered motor that can make hills manageable, journeys swifter, and longer trips more viable. As they grow more effective and affordable, e-bikes are increasingly drawing people out of more polluting modes of transportation, such as driving solo.

E-bikes are all the rage in China, where millions of people use them to commute and e-bike owners outnumber car owners by a factor of two. The trend dates to the mid-1990s, when China’s booming cities put strict antipollution rules in place. These pedal-motor hybrids are on the rise in many parts of the world, as urban dwellers seek convenient, healthy, and affordable ways to move around congested cities.

An e-bike’s battery gets its charge from the nearest outlet, tapping into whatever electricity is on hand—from coal-based to solar-powered. E-bikes have higher emissions than a regular bicycle or simply walking, but they still outperform cars, including electric ones.

References

Chinese e-bike owners: Ji, S., et al. “Electric Vehicles in China: Emissions and Health Impacts.” Environmental Science & Technology, 46, no. 4 (2012): 2018–2024.

“largest adoption of alternative fuel vehicles”: Cherry, Christopher. Quoted in Daniel Cusick “Can E-Bikes Displace Cars?” Scientific American. February 22, 2012.

China…e-bike sales: Mason, Jacob, Lew Fulton, and Zane McDonald. A Global High Shift Cycling Scenario. New York and Davis, CA: Institute for Transportation & Development Policy and the University of California–Davis, 2015.

urban trips…easy distance: Mason et al, Scenario.

more effective and affordable…[more] people: Fishman, Elliot, and Christopher Cherry. “E-bikes in the Mainstream: Reviewing a Decade of Research.” Transport Reviews, 36, no. 1 (2016): 72-91.

e-bikes sold in 2012: MacArthur, J., J. Dill, and M. Person. “Electric Bikes in North America: Results from an Online Survey.” Transportation Research Record: Journal of the Transportation Research Board, 2468 (2014): 123–130.

e-bikes…outperform cars…[most] mass transit: Cherry, C. R., J. X. Weinert, and Y. Xinmiao. “Comparative Environmental Impacts of Electric Bikes in China.” Transportation Research Part D: Transport and Environment, 14, no. 5 (2009): 281–290; Fishman and Cherry, “Mainstream.”

[cost vs.] a classic bike: Gunther, Marc. “Will Electric Bicycles Get Americans to Start Pedaling?” Yale Environment 360. April 22, 2013.

lead acid batteries: Fishman and Cherry, “Mainstream.”

first…patent for an electric bicycle: Bolton, Ogden. U.S. Patent No. 552,271. Washington, D.C.: U.S. Patent and Trademark Office, 1895.

Others…working to motorize [bicycles]: Roberts, Ronald. “Electric Bike History, Patents from the 1800’s.” ElectricBike.com. November 9, 2013.

fastest-selling alternative-fuel vehicles: Navigant. Electric Bicycles. Boulder, CO: Navigant Research, 2016.

view all book references

Technical Summary

Electric Bikes

Project Drawdown defines electric bikes as: the increased use of electric bikes for urban travel. This solution replaces the use of internal combustion engine (ICE) cars.

Electric bicycles (e-bikes) offer many of the same benefits as traditional bicycles, especially ease and versatility of mobility for urban commuters, but e-bikes have benefits that conventional bikes do not. By using an attached motor and battery to make it possible to traverse steep hills or cover long distances with little effort, e-bikes allows elderly or physically disabled people to make active, low-carbon transportation choices. These benefits, however, are not free. E-bikes can cost ten times as much as traditional bikes or more, and their users must be conscious about how they dispose of expired batteries. E-bike battery manufacturing and charging also lead to higher carbon dioxide emissions than traditional bikes.

This report examines the net environmental and financial impacts of increased e-bike usage around the world from 2020-2050. E-bikes are compared to other mobility options, as research has indicated that many e-bike users would have used a wide range of other modes available for their mobility, including light duty vehicles, mass transit, regular bikes, and motorized two-wheeled vehicles like scooters.

Methodology

Total Addressable Market [1]

The total addressable market considered for electric bikes is the total urban transport demand projected to 2050, measured in passenger-kilometers. These values were collected from the baseline projections of the International Energy Agency (IEA) and the International Council on Clean Transportation (ICCT). The Institute for Transportation and Development Policy, alongside the University of California-Davis (ITDP/UCD) provided data on adoption estimates for e-bikes. The vast majority of global adoption has been in China, but Europe is the destination for many of the more high-end bikes. [2] Total current adoption [3] was estimated to be just under 2 percent of the total market (or over 200 million e-bikes).

Adoption Scenarios [4]

Impacts of increased adoption of electric bikes from 2020-2050 were generated based on three growth scenarios, which were assessed in comparison to a Reference Scenario where the solution’s market share was fixed at the current levels.

  • Plausible Scenario: The estimated stock of e-bikes was calculated using projected annual sales broken out by region. From studies of e-bike users, an average annual passenger-kilometers traveled per e-bike was applied. [5]
  • Drawdown Scenario: Values from the ITDP/UCD 2015 e-bike adoption projections were used. All other variables were maintained as in the Plausible Scenario.
  • Optimum Scenario: A linear growth in e-bike passenger-kilometers was applied to 6.5 percent in 2050. This is approximately the current e-bike usage in China and bicycle usage in India according to ITDP/UCD, and would indicate a global level similar to these countries. It is also assumed that only ICE car users switch to e-bikes, rather than people from other complementary modes of transport (mass transit, bicycling, walking). [6]

Emissions Model

Emissions were estimated based on grid and fuel energy usage for both alternatives, as well as indirect emissions from production. Global grid emissions factors are applied for e-bike electricity emissions. The conventional alternative was developed as a combination of modes of transport (that is, car, bus etc.), except in the Optimum Scenario. Some of these modes use electricity, while most use fuel. After weighting the energy usage, grid and fuel emissions were calculated per billion passenger-kilometers of travel for each alternative (e-bike and conventional transportation) to compare the two.

Financial Model

Installation costs are taken from a wide range of sources. The e-bike data suggests that the battery is the major component of costs, and battery size varies across bikes. The purchase of e-bikes was therefore priced based on the battery, measured in Watt-hours of battery capacity. The average of 7 data points was used: US$391,000 per Megawatt-hour of battery capacity. [7] A learning rate of 6 percent was applied, based on estimates ranging from 6-9 percent for battery cost reduction due to rapid research in battery technology (applicable to cars, mobile phones, and other mobile devices). The lifetime of batteries was estimated to be between 2-6 years, depending on type. Our calculations indicate that lead-acid batteries may last just 2 years, whereas lithium-ion batteries have a life span of around 6 years. Battery replacement, therefore, is included in these first costs.

Operating costs were taken as the cost of grid electricity, assuming that e-bike users use on average 12 Watt-hours per kilometer of travel. [8] All variables were weighted by the market share (modeshare) of these alternatives.

Integration [9]

Since e-bikes are considered a high priority in the set of urban transport solutions, integration effects were not of major concern. Thus, the full projected adoption for each e-bike scenario was applied. [10] Variables shared across this and other solutions had the same inputs.

Results

Given the projections described in the Plausible Scenario, e-bikes could prevent the release of 960 million tons of carbon dioxide-equivalent greenhouse gases and save consumers US$226 billion in net operating costs over 2020-2050. The first costs increase by US$107 billion, as the frequency of battery replacement is higher for e-bikes than for the conventional alternative. The Drawdown Scenario avoids 3.5 gigatons of emissions, and the Optimum Scenario reduces emissions by 7 gigatons from 2020-2050.

Discussion

The ITDP/UCD study found that combined cycling (regular and e-bikes) could save $24 trillion between 2015 and 2050, and 225 million tons of greenhouse gas emissions in 2050. The combined Plausible Scenario figures—150 million tons of emissions reduction in 2050 and total savings of $2.8 trillion from 2020-2050—are much more conservative than theirs, although we do not include some other knock-on savings. [11]

As e-bike batteries become less expensive and more energy-dense, the benefits from e-bikes will grow. However, a large increase in the use of lithium-ion batteries will necessitate large-scale production and battery recycling methods that are not yet commercially or practically viable. Nevertheless, there is great opportunity in the use of e-bikes to get urban travelers out of their cars and avoid billions of tons of carbon dioxide emissions.


[1] For more on the Total Addressable Market for the Transport Sector, click the Sector Summary: Transport link below.

[2] Most e-bikes in China have lead-acid batteries, whereas the higher-end batteries are lithium-ion.

[3] Current adoption is defined as the amount of functional demand supplied by the solution in the base year of study. This study uses 2014 as the base year due to the availability of global adoption data for all Project Drawdown solutions evaluated.

[4] For more on Project Drawdown’s three growth scenarios, click the Scenarios link below. For information on Transport Sector-specific scenarios, click the Sector Summary: Transport link.

[5] Based on workday ridership of 10 kilometers and weekend ridership of 5 kilometers.

[6] As cars are more polluting than the combination of all the modes together, this change increases the impact of e-bikes.

[7] All monetary values are presented in US2014$.

[8] Equivalent to 20 Watt-hours per mile.                                                                                     

[9] For more on Project Drawdown’s Transport Sector integration model, click the Sector Summary: Transport link below.

[10] The 7 urban Project Drawdown solutions were prioritized by energy and space efficiency, so non-motorized modes like walking and bike infrastructure were highest, followed by e-bikes and other partially motorized solutions. Some solutions of lower priority had adoptions reduced to ensure that total passenger-kilometers did not exceed the total predicted by sources like the IEA and ICCT.

[11] Only direct vehicle costs that would be attributable to vehicle owners were included, rather than the whole society; costs which are challenging to estimate at the global level, such as health costs, were excluded.

Full models and technical reports coming in late 2017.

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