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 allow elderly or physically disabled people to make active, low-carbon transportation choices. These benefits, however, are not free. E-bicycles can cost more than 10 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 to 2050. E-bicycles are compared with other mobility options because 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 such as scooters.

Methodology

Total Addressable Market

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.[1] Total current adoption[2] was estimated to be just under 2 percent of the total market (or over 200 million e-bicycles).

Adoption Scenarios

Impacts of increased adoption of electric bicycles from 2020 to 2050 were generated based on two growth scenarios. These were assessed in comparison to a Reference Scenario in which 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.[3]
• 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 (e.g., car, bus). 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 suggest 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.[4] A learning rate of 6 percent was applied, based on estimates ranging from 6 to 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 two to six years, depending on type. Our calculations indicate that lead-acid batteries may last around two years, whereas lithium-ion batteries have a life span of around six 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.[5] All variables were weighted by the market share (modeshare) of these alternatives.

Integration

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

Results

Given the projections described in 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.[7] The first costs are also lower by US$304 billion because e-bikes are cheaper than the conventional alternative (cars), even when battery replacements costs are included. Scenario 2 avoids 4.1 gigatons of emissions.

Discussion

The ITDP/UCD study found that combined cycling (regular and e-bicycles) could save US$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 Scenario 1 is 172 million tons of emissions reductions in 2050, with total construction savings of US$3 trillion from 2020 to 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.[8] Total bicycle and e-bicycle impact in 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.

Note: August 2021 corrections appear in boldface.