Since there are no currently active contests, we have switched Climate CoLab to read-only mode.
Learn more at
Skip navigation
Share via:


Battery electric drive retrofit protocol for small commercial vehicles. Used cars, vans, delivery trucks--carbon emission free.



The Proposal

Write the protocol, a builder’s manual, for installing battery-electric drivetrains in older commercial vehicles. Share the manual under Creative Commons license with auto maintenance shops and other interested parties. Free pre-packaged engineering will help make the EV conversion economically attractive.

The Problem

"Clunkers" are dirty. Aging road vehicles emit more pollution per mile, including CO2 emissions. Compounding this reality, for many operators, aging vehicles provide lower cost utility. There is no penalty for climate impact. For the individual, it is a rational choice to “drive the thing until the wheels fall off.”

The other reality (as opposed to some future “ideal” reality) is that massive transportation infrastructure is in place to accommodate the types of vehicles we’ve depended on for the last hundred years or so. That capital investment will not be abandoned. Streets, roads, and highways will continue to be primary for most short and medium distance travel. We will continue to use cars, trucks, and buses on those roads.

Greenhouse gas emission targets cannot be met if CO2 producing combustion engines remain in service.

The Economics

Conversion to an electric powertrain is expensive only if the capital investment is compared with the optimistic “do nothing” alternative—keep driving, hope the tired old engine and transmission hold together and pretend there’s no payment at the pump.

Real world experience:

  • Trolley in Savannah
    • $12,000—14,000 miles @3.5 mpg @$3/gal
  • CAT (Clemson Area Transit) Proterra battery electric buses
    • $1.00/mile maintenance savings compared to diesel

Projected BEV trolley cash flow (yearly):

  • -$2,000—electricity (10,000 kWh @ $.20/kWh)
  • +$12,000—no gasoline
  • +$14,000—lower maintenance ($1/mi, 14,000 mi)
  • +$24,000—net

Conversion cost:

50 kWh battery at $200/kWh, $10,000. Traction motors, two required at around $5,000 each. If the balance of system cost is a like amount, $40,000 total.

Payback: 20 months

Is this proposal for a practice or a project?


What actions do you propose?

The project is a series of steps, data gathering, data analysis, choosing a test bed vehicle based on the analysis, drafting the installation and operator’s manual, and documenting the actual physical vehicle drivetrain transplant.

Data Gathering

Compile an inventory of commercial vehicle types.

  •     Load carrying capacity
  •     Interior cargo space
  •     Ground clearance
  •     Engine power rating
  •     Performance data (acceleration and top speed)


Compile an inventory of commercial vehicle missions.

  •     Daily range requirement
  •     Type of cargo
  •     Time of day operation


Compile an inventory of commercial vehicle operating environments.

  •     Need for heating or cooling of cargo space
  •     Commercial value of being a good neighbor 


Compile an inventory of BEV models currently on the market.

  •     Battery capacity
  •     Motor rated power


Compile an inventory of battery manufacturers.

Compile an inventory of battery form factors.

Compile an inventory of available drive motors.

Compile an inventory of government incentives and tax treatments that may influence capital equipment decisions.

Inspect vehicles of types identified in inventory.

  •     Confirm actual condition of potential battery mounting locations.
  •     Measure voids that might be suitable for battery installation.

Interview current operators.

  •     Confirm actual usage patterns.
  •     Confirm planned life (usage) expectancy of the vehicle.
  •     Confirm actual fuel and maintenance expense in use.


Interview individuals who have been involved in previous battery conversion projects, including hobbyists.

Review trade publications and press releases from battery manufacturers to discover trends in price and design.

Data Analysis

Identify vehicles with the greatest opportunity for cost savings based on usage patterns.

Identify vehicles with the easiest conversion, including consideration of removal of the existing combustion engine and hardware, battery mounting locations and ability to connect to existing drive wheels.

Identify vehicles with greatest carbon footprint opportunity based on the number of vehicles that can be converted.

Identify vehicles which are well suited for their mission and which people do tend to “drive until the wheels fall off.”

Choose a Mule

Sort all gathered data and choose a test-bed vehicle for the prototype battery electric conversion.


  • Familiar brand vehicle; auto, truck, bus mechanics know Fords.
  • Sufficient under floor space to attach the battery pack.
  • Modest range requirements mean modest battery pack size.
  • Modest speed requirement; energy used goes up as the square of speed.
  • If it is a moderate external operating environment for the mission; no weather extremes.
  • No unusual or special equipment to be accommodated for the mission.
  • Use of a donated vehicle should be considered.


Write Installation and Operator’s Manuals

Specify battery, battery charger controller, drive motor, any speed reduction gearing required.

Produce shop drawings for any parts that must be fabricated—mounting shelves, attachment brackets, enclosures, etc.

Specify necessary wiring and wire routing.

Produce shop drawings for guidance in locating specific components.

Write safety precautions for dealing with system high voltages.



A university, in a state that is supportive of the rapid transition away from fossil fuel, agrees to be the lead co-sponsor of the project to develop the EV conversion protocol. An engineering department, Electrical Engineering or Mechanical Engineering, would recognize and accept the project for Masters level research and degree award at completion.

A technical college with a program that trains auto mechanics would be a co-sponsor, with a faculty member serving as de facto shop foreman during the physical conversion. 

A private sector company, like Historic Tours of America which operates a large fleet of tourist trolleys in seven U.S. cities, would be a co-sponsor and contribute a vehicle to serve as the test bed.

        About a metric ton CO2 every ten days.

A city or other governmental jurisdiction which wishes to accelerate the reduction of CO2 emitted from within its borders would be the fourth co-sponsor. Its contribution would be advocacy for, and assistance in acquiring quickly, any approvals needed from any state or federal agency for licensing and insurance prior to operation on public roads. A university town, or a city like Savannah with a very active tourism industry, would be a plausible candidate.


Performance requirements for 40 passenger tourist trolley:

  • 40 miles travel during a typical day. 
  • Top speed 60 mph.
  • Ability to climb steepest street ramp with a full passenger count, starting from a dead stop.
  • Ability to charge overnight using 240V Level II grid connected charging stations.


Hardware needed to meet the above requirements:

  • 60 kWh battery capacity (one Chevrolet Bolt battery or two Nissan Leaf batteries) At the low speed of trolley operation, one and a half miles per kWh is a plausible average power consumption rate. 60 kWh would provide an ultimate range, between charges, of double the expected need.

 15 kWh drawn to scale.  Ten modules will provide about half the daily energy required. 4 battery banks like this is sufficient for approximately 100 % reserve.


     24V 70 Ah    1.5 kWh     28 kg

  • One Tesla S electric motor (the smallest offered--382 hp) or two Nissan Leaf motors operating in tandem or parallel will be adequate. It can likely be electric motor direct drive with no transmission required.
  • Other assorted hardware, including on board charger and motor controller.


Converted vehicle characteristics:

  • The electric drive system will be silent.
  • Passenger compartment temperatures will be somewhat lower because there would no longer be an engine and exhaust system heat cloud enveloping the vehicle. For the ICE (internal combustion engine) drive trolley likely 90% of the fuel energy goes off as waste heat. For the electric drive, it will be in the range of 10%.
  • Vehicle acceleration and top speed capability should be little changed.
  • Energy cost will be approximately $3/day, compared with $30-35 for propane or gasoline.
  • Routine maintenance expense for the drivetrain will be minimal.


Conversion Cost:

  • A retail market for the purchase of the major components is virtually non-existent at this date. Cost can be inferred. The drivetrain of a new vehicle might represent more than half, but less than two-thirds of the total vehicle cost. A $30,000 Nissan Leaf might cost $25,000 to produce and $15,000 of that could be for the electric drive system.
  • Battery prices have fallen drastically during the past five years. As the Leaf was being developed, $1,000/kWh was the general consensus on the cost of Lithium Ion battery capacity. Today, Tesla Motors is claiming cost is $125/kWh, with the expectation that it will be below $100/kWh in the near future.
  • The cost of the motor-battery package will soon be in the range of $10,000. If an equal number is assumed for the balance of system components and the installer is granted a 25% markup, installed package price comes to $25,000. 
  • For this scenario, $10,000 annual savings in fuel expense is probable. From conversations with transit system operators already operating battery electric buses, considerable savings in maintenance expense should also be expected. If there is a very modest $2,500 reduction of that expense, the total two-year operating expense savings is equal to the total conversion cost. It’s a two-year payback on equipment investment. The motor-battery pack should function well for ten years or longer.



Maintain a running builder’s log. This log should include a video recording of all major steps, starting with the removal of old drivetrain components. It should include any unexpected difficulties or surprises, for example, severe corrosion where none was expected.

The video record could be created through a collaboration with the university’s film or communications academic program. The video should be captured keeping in mind an end goal of publishing a series of instructional segments that would be valuable to any person or company preparing to do a battery electric conversion.   

Who will take these actions?

The key person for this project would logically be a graduate student seeking a Masters degree in Electrical Engineering or Mechanical Engineering. Facility with design software and understanding of electricity fundamentals will be valuable.
Another approach could be to consider it more of a business management exercise. An MBA student with some engineering background could develop this as a case study in how to take a relatively straightforward technology application problem from concept to prototype.
In the development phase, faculty advisers would be an integral part of a team managed by the student. If treated as an engineering project, assistance from business/finance faculty resources would be valuable. If it’s a business management project, university engineering school assistance could be requested.
During prototype construction, assistance from a technical school that offers a program in auto mechanics would be valuable. Alternatively, an established auto repair company interested in entering the battery-electric conversion business might be willing to participate without monetary compensation.
A particular community, a city or town, might partner in the project if it saw an opportunity to further its environmental responsibility goals. For example, the City of Boston or City of Savannah could legitimately take credit for reducing greenhouse gas emissions if trolley fleets transitioned more quickly away from combustion engine drive systems.
Other partners might include battery manufacturers. The potential market opportunity is very large if one assumes it might be necessary to convert every vehicle during the next twenty years.
Two other potential corporate partners merit mention. Proterra, a pioneer in battery electric bus development announced recently, delivery of its 100th vehicle for transit service. Proterra buses serve the university town of Clemson, South Carolina. Another company has expressed interest in the concept and might be the source of a test bed vehicle. Historic Tours of America of Key West, Florida takes seriously environmental stewardship responsibility. HTA’s Old Town Trolley fleet is being upgraded from diesel to propane partly because of its superior environmental footprint. The company would welcome the opportunity to continue footprint improvement if the economics are sound.  

Where will these actions be taken?

The immediate action, creating the protocol, could be done anywhere. A university campus where the project would be part of a graduate degree program would be a natural setting but certainly not the only one.
This author imagines the protocol as a property of the commons. An alternative is to develop it as intellectual property that could be licensed. This work could be funded privately, and then plans and manuals sold for profit. 
Once the protocol/design is written, it could be used anywhere in the world where there are internal combustion engine vehicles.

Another possible track should be investigated based on climate impact over the next twenty to thirty years. There is opportunity because of growing vehicle use in developing countries.

Mid-life used vehicles are being shipped from the United States to lesser developed countries. In these places, the demand for mobility will likely continue to grow. Likely too, is that older vehicles will remain in service there for many years.

A problem generated by the drive to modernization and improved living standards is that the benefit from modern mobility technology is perceived to be much more valuable and a more urgent unmet need than the longer term damage that will accrue from fossil fuel usage.

Particularly for countries which do not have fuel reserves and well-developed energy distribution infrastructure in place, the combination of solar or wind-generated electricity and battery electric vehicles for mobility offers promise. Total life cycle cost of this option compares favorably to use of fossil fuel and the building of 20th-century centralized power infrastructure.

One way to reduce the up-front cost of getting the rolling stock into place is to convert mid-life conventionally powered cars and trucks to battery drive. The five-year vehicle can easily have another twenty years of life in it and be available used for one-third of a brand new one with similar capabilities. Even after the battery electric conversion, total cost to a purchaser in a developing country could be less than the gasoline or diesel new vehicle alternative or a new electric vehicle. If charged with low-cost solar energy, for example, operating cost can be a fraction of what it would be for a conventional vehicle.

In countries like Senegal or Mozambique or Cameroon, for example where energy consumption per capita is very low, perhaps one-twentieth that of the United States, at least in part because it is expensive, the solar/wind and battery electric drive makes economic sense. It may be that in places like this await the discovery of the really low hanging fruit for dealing with the GHG climate change crisis.


In addition, specify the country or countries where these actions will be taken.

United States

Country 2


Country 3


Country 4


Country 5

No country selected


What impact will these actions have on greenhouse gas emissions and/or adapting to climate change?

Impact on greenhouse gas emissions must be measured against some standard. Twenty pounds of CO2 or five gigatons has no meaning unless in context. One generally accepted reference point is 2 degrees Celsius and the 80% reduction in GHG emissions by 2050 that will be required to meet that target maximum rise in the earth’s temperature.

In the U.S. over half of emissions come from electricity generation and transportation. The rapid decline in the cost of electricity from wind and solar, makes reducing the contribution from power generation to near zero feasible. The 27% of the total now originating in the transportation sector can be mostly eliminated too. However, roughly one tenth of transportation emissions are from air travel. At present no technology is obvious to eliminate fossil fuel combustion for air travel.

If it is assumed that every sector must reduce its share of emissions by 80%, and the portion generated by air travel is off the table, remaining elements (travel modes) must carry a larger burden. Ground transportation may have to reduce by more than 80%.

As a first approximation, that means removing 80% of combustion engines. Of the 13 million commercial vehicles in service in the U.S., more than ten million need to come off the road or have their drivetrains replaced.

Incremental electricity demand increases caused by switching to battery electric drive will not divert the pollution to another point of emission. Electricity as fuel will be clean because renewables are the low-cost source for additional generating capacity. 

About half the 13 million commercial vehicles on the road operate in small fleets. A large portion is engaged in short distance missions, less than a hundred miles a day. These vehicles could function with a once a day battery charge to provide the needed energy.

To keep the math simple, consider this example: A mid-sized delivery truck, like a UPS van, travels 50 miles at 10 miles per gallon. 5 gallons of fuel is used each day and 20 pounds of CO2 emitted for each gallon of fuel used. Roughly 15 tons of CO2 sent into the atmosphere each year.

Ground transportation will transition to electric drive. The economics will soon be very favorable for new electric vehicles. To meet goals and address the underlying problem, too much CO2 in the atmosphere, almost all vehicles must be electric powered. 

This project will make the economics of conversion better for the vehicle owner. If by the year 2025, two million commercial vehicles have been converted, this project might claim half of them, one million at 15 tons per year. The project will result in commercial fleet CO2 pollution being reduced by 15 million tons annually and continuing to decline.

What are other key benefits?

Electric vehicles are quiet. Combustion engine vehicles are noisy, particularly so for the many trucks that share the soundscape with pedestrians. The city is a more stressful and less pleasant place because of the noise generated by people rushing about in cars and trucks. Much of that noise will be eliminated once those vehicles are battery driven.

Combustion engines emit pollutants in addition to CO2. Mandated emissions equipment and better fuel formulations have reduced these poisons drastically over the past 50 years, but some still escape. Diesels especially, emit particulates which are implicated in respiratory diseases. With electric drive, these undesirable side effects of mobility go away.

In addition to economic benefits that will accrue to individual vehicle owners, there are macro benefits as well. This is particularly so for communities that don’t receive revenue from the sale of fossil fuel. States that don’t extract the stuff export massive amounts of money to purchase it. In the case of Florida, it’s on the order of $50 million a day (in 2015, over $100 million/day), for Massachusetts, a slightly less painful number, $15-20 million (in 2015, over $40 million/day). For an energy/transportation economy based on renewables and electric drive, much of that money stays home.

For specific applications, there may be other hard to quantify benefits. The tour trolley provides an example. On the 90 minute, nine and a half mile drive through Savannah, three gallons of gasoline or an equivalent amount of propane or diesel fuel is turned into motion and waste heat. It’s mostly waste heat, likely 90% of it, and all that heat follows along in a cloud engulfing the riders. They get cooked. A bit over-the-top graphic, perhaps, but that waste heat, 90% of the 360,000 BTUs released from the fuel, could theoretically raise the body temperature of the 30 riders to 150 degrees, beef medium well. 


What are the proposal’s projected costs?

The project initially is the creation of a document, a builder’s manual for replacing the combustion engine of a work vehicle with an electric drive motor and batteries as the onboard energy supply. This initial phase will require minimal resources in terms of material, facilities, and purchased professional services.

If a graduate student acts as project manager and this effort is accepted as part of a degree program, and if potentially interested parties agreed to contribute, prototype development expense might involve primarily the purchase of drive motor-controller and batteries. There is no obvious reason why the prototype vehicle, once built couldn’t be sold and the net cost reduced to near zero.

Following completion of the manual, the protocol, the small shop or garage that would use it might be able to offer a complete conversion for a vehicle like a tour trolley for perhaps $25-35,000. The owner would then have a vehicle with a functional life expectancy of ten years and much lower operating costs. Plausibly, the owner would have committed $50,000 (conversion plus used vehicle) for ten years as an alternative to $150-200,000 for a twenty-year new vehicle. (emphasis intended) That new more expensive to buy vehicle will also cost much more to operate!

Challenges include inertia, people’s tendency to just keep doing what they already know. Most people haven’t driven an electric car. They pass up even the advantages of a hybrid car like the Prius because it’s not like what they’ve always had before. That inertia is visible in people’s tendency to think that some things, and some expenses, are a given. It’s a given you have to buy groceries, pay your taxes, and go to the gas station to buy gasoline.

Another challenge is the reality of engineering risk. The modern gasoline engine is an extraordinarily developed machine, nearly bullet-proof. Good as Elon Musk’s Tesla S is, it doesn’t have the benefit of 100 years of materials refinements and improvement in design. As simple as a battery and electric motor are, there are still mistakes to be made in the electric drive application.

A really big picture challenge is a paradox. The newest, cleanest, combustion engine vehicles coming off the assembly line now have the worst projected total negative environmental impact. That’s because they will pollute for the next twenty years unless modified. They will contribute the most CO2 to the atmosphere. 


This is a do now project. CO2 emissions reduction is an urgent task. Any low hanging fruit in that regard should be picked now. Future battery chemistries are promising, so the transition away from fossil fuel consumption will likely accelerate, but reductions now should not be passed up. The cost of PV solar is still on a downward trajectory. It will drag down the cost of electricity for electric vehicles, making the payoff for substituting that power source even more attractive over time compared to buying gasoline and paying for maintenance.

If writing the protocol is done as a graduate school project a one to two-year time line seems reasonable for that phase. Someone willing to take it on as a business investment with the expectation of selling licenses or doing actual conversions could likely have a fully functional prototype in a matter of months.

Once the builder’s manual is published the logical next step is to market it. It will have no value if not delivered into the hands of workshops that will do the actual conversions. Marketing will likely be an ongoing process for the next few years. 

About the author(s)

Bill Ferree has been a student of the climate-energy-politics nexus for the past several years. During this period the urgency of the task of reducing greenhouse gas emissions has become more and more obvious. The actual track of climate change is closer to the “worst case” side of the range of earlier forecasts.

Bill lived in Florida for two decades and held elected office there. He sat on a regional transportation planning board. He witnessed close-up some of the recent political foolishness regarding the issue of global warming, the outright denial of the state’s certain vulnerability to rising, warming waters.

This proposal is a logical continuation of earlier efforts, which included co-founding a small company that installed electric car charging stations, writing a book that advocates for a faster transition away from fossil fuels based on the economic benefit, and a run for higher office that among other things tried to draw attention to the climate problem.

Other recent experience that Bill believes will serve this project includes the completion, after many years of work, of an owner built aircraft. (First flight was in September 2017. Successful, but with an unexpected ending--story for another day) 

For the past year and a half, Bill has been a historic tours trolley conductor in Savannah, Georgia.

Related Proposals


commercial vehicles in service

CO2 produced per gallon of fuel

GHG sources