Electric bike in Shanghai, China
Technical Summary

Electric Bicycles

Project Drawdown defines electric bicycles as: the increased use of electric bicycles for urban travel. This solution replaces the use of mainly 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-bicycles have benefits that conventional bicycles 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-bicycles allows elderly or physically disabled people to make active, low-carbon transportation choices. These benefits, however, are not free. E-bicycles can cost more than ten times as much as traditional bicycles, and their users must be conscious about how they dispose of expired batteries. E-bicycle battery manufacturing and charging also lead to higher carbon dioxide emissions than traditional bicycles.

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

Methodology

Total Addressable Market[1]

The total addressable market considered for electric bicycles 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-bicycles. The vast majority of global adoption has been in China, but Europe is the destination for many of the more high-end bicycles.[2] Total current adoption[3] was estimated to be just under 2 percent of the total market (or over 200 million e-bicycles).

Adoption Scenarios[4]

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

  • Scenario 1: The estimated stock of e-bicycles was calculated using projected annual sales broken out by region. From studies of e-bicycle users, an average annual passenger-kilometers traveled per e-bicycle was applied.[5]
  • Scenario 2: Values from the ITDP/UCD 2015 e-bicycle adoption projections were used. All other variables were maintained as in the Scenario 1.

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-bicycle electricity emissions. The conventional alternative was developed as a combination of modes of transport (that is, car, bus etc.). 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-bicycle and conventional transportation) to compare the two.

Financial Model

Installation costs are taken from a wide range of sources. The e-bicycle data suggests that the battery is the major component of costs, and battery size varies across bicycles. The purchase of e-bicycles was therefore priced based on the battery, measured in Watt-hours of battery capacity. The average of 19 data points was used: US$327,000 per Megawatt-hour of battery capacity.[6] 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 around 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.[7] All variables were weighted by the market share (modeshare) of these alternatives.

Integration[8]

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.[9] Variables shared across this and other solutions had the same inputs.

Results

Given the projections described in the Scenario 1, e-bikes could prevent the release of 1,300 million tons of carbon dioxide-equivalent greenhouse gases and save consumers US$610 billion in lifetime operating costs over 2020-2050.[10] The first costs are also lower by US$380 billion, as e-bikes are cheaper than the conventional alternative (cars) even when battery replacements costs are included. The Scenario 2 avoids 4.1 gigatons of emissions.

Discussion

The ITDP/UCD study found that combined cycling (regular and e-bicycles) could save $24 trillion between 2015 and 2050, and avoid 225 million tons of carbon dioxide-equivalent emissions in 2050. The total bicycle and e-bicycle impact in the Scenario 1 is 172 million tons of emissions reductions in 2050, with total construction savings of $3 trillion from 2020-2050. These results are much more conservative, in part because we do not include car fuel, vehicle purchase and maintenance cost savings, and some other knock-on savings for the bicycle infrastructure solution.[11] Total bicycle and e-bicycle impact in the Scenario 2 is higher, at 493 million tons of emissions reductions in 2050, suggesting that the ITDP/UCD adoption probably lies between our Plausible and Scenario 2s.

As e-bike batteries become less expensive and more energy-dense, the benefits from e-bicycles 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-bicycles 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 2018. This study uses 2014 as the base year.

[4] For more on Project Drawdown’s 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] All monetary values are presented in US2014$.

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

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

[9] The 7 urban Project Drawdown solutions were prioritized by energy and space efficiency, so non-motorized modes like walking and bicycle infrastructure were highest, followed by e-bicycles 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.

[10] The net operating savings for the full lifetime of all units installed during 2020-2050.

[11] We only include costs that would be attributable to municipalities rather than the whole society, such as health costs which are challenging to estimate at the global level.