Open Letter to Policymakers: Transition to Non-Combustive Powertrains

This post is Part 2 of a two-part blog series of student and attendee reactions and takeaways from the March 2021 Tufts Energy Conference.

By Max Melnick

Operating on the type of favoritism that contributed to today’s rapid obligation to transition away from fossil fuels has the potential to lead to uncomfortable externalities. Legislators should therefore be technologically agnostic when considering the best avenues for heavy-duty transportation decarbonization.

Governments across the globe have identified a need to reduce our dependence on fossil fuels and increase the integration of renewable and efficient energy. Here in the US, there are a lot of fundamental shifts occurring in the electric grid as a result of clean energy’s proliferation and improved economics. And just like there are multiple technologies aimed at decarbonizing the grid, the transportation sector has multiple paths to impact reduction.

Legislators will likely need to create policy environments that allow for multiple technologies to dominate transportation. Unlike the common practice of the fossil fuel era, technology agnosticism will foster the most rapid return on investment as well as the greatest emission and carbon reduction impact.

Two energy experts spoke on March 11th at the 2021 Tufts University Energy Conference: Cassandra Vickers, a Senior Clean Transportation Product Developer at the National Grid (a utility) and, Abas Goodarzi, President and CEO of US Hybrid (a private company). National Grid has approximately 20 million customers under its service, and as those customers start using products such as electric vehicles and energy-efficient “smart” appliances, the utility will play an increasingly more important role in managing all of these changes and shifts in demand. US Hybrid is one of the many transportation companies taking advantage of the engineering opportunities in the transition to decarbonized alternatives.

The guiding principles for both the public utility and the private company are to provide clean air to local communities— particularly those most vulnerable to negative environmental impacts— and to reduce the degree to which humans influence the climate. National Grid spoke with expertise in fleet electrification, and US Hybrid spoke with knowledge on heavy-duty vehicle electrification as well as hydrogen fuel cell vehicles. The panelists explored the conditions that favored one technology over the other, and it was recognized that there is a deep synergy between the two engine approaches.

Both speakers clarified that residential transportation was not the easiest, most lucrative, or most aggressive manner of facilitating the transition to non-combustive powertrains such as fuel cells or batteries. A powertrain is a group of components by which power is transmitted from an engine to an axle that moves the vehicle forward. Modern powertrains are using far fewer moving parts than their legacy contemporaries, but most importantly the modern powertrains such as battery electric and fuel cells both result in low-emission power generation. Decarbonizing the transportation sector would have a monumental impact on the nation's emission rate— nearly 30% of US greenhouse gases come from the sector— but the fraction of that 30% that is disproportionately detrimental to human health are the emissions that are frequently associated with fleets that burn diesel fuel. As a result, multiple studies have indicated that fleet decarbonization is a more compelling case for developers, investors, system upgraders, and the local community.

Example of a battery-operated electric vehicle. Source: EVreporter.

Example of a battery-operated electric vehicle. Source: EVreporter.

Fleet operators are more intelligent end-users than residential customers, and they intimately understand the operational demands of their vehicles, thereby allowing them to expedite the development and implementation of new technologies that improve their bottom line. The overall return on investment— which should not only capture the fiscal but also societal and environmental parameters— is therefore significantly easier to calculate with fleet operators. Both electric and fuel-cell systems can support cleaner air for the communities in which they operate and travel, so the principled goal is indeed being met by either technology.

But battery-electric powertrains cannot meet the demands of all fleets given the battery’s physical limitations.

Batteries do not have the energy density that gasoline, diesel, or the hydrogen gas used in fuel-cells vehicles have.  Materials in the battery have an inherent amount of power that they can store, and while clever chemical and material manufacturing techniques can be implemented to get the greatest electrical potential possible out of these materials, there are physical characteristics that are unlikely to be surmounted. As a result, gasoline, diesel, or hydrogen carry out most of the heavy duty work.

It appears as though only a paradigm-shifting breakthrough in battery science would change this dynamic. Fuel-cell vehicles run on hydrogen, the most abundant element in the universe, which means that humans are unlikely to fully exhaust the resource. Hydrogen is a gas on earth’s surface, which presents different parameters than the liquid fuels that we are used to using. As a result of hydrogen’s gaseous nature, fuel-cells are able to provide an increased range without impacting the weight of the vehicle as dramatically as batteries do.

Example of a hydrogen fuel-cell operated vehicle. Source: Alternative Fuels Data Center.

Example of a hydrogen fuel-cell operated vehicle. Source: Alternative Fuels Data Center.

Therefore, there are situations in which battery-electric may outperform fuel-cell vehicles and vice versa. The determination of which approach will be best for the fleet operator will come down to the state of the grid in a specific geographic region, the operational demands of the end-user, and the inherent strengths of each technology.

Demand expectations for fleets are more consistent than residential vehicles. Standard routes, short distances, and a “home” that is responsible for reliably charging the vehicle are ideal for battery-electric fleets. Anything that requires long distances, quick refueling times, or heavy payloads may be better suited for hydrogen systems. Given the current state of battery chemistry, extremely long distances and the management of massive payloads are physically inaccessible by battery-electric vehicles. The opposite is true for hydrogen systems, they could in principle take over the demands of electric powertrains, but the system economics are not strong enough to support that transition. If subsidies were provided to either technology to the extent that they are provided to fossil fuels, then the above challenges may change dramatically.

The two panelists, therefore, recognized that there seemed to be space for both technologies given their respective economics and inherent strengths. Vehicles intended for tugging, lifting, and moving heavy objects generally do not make sense for batteries; and there are vehicles (such as amazon delivery vehicles, refuse vehicles, etc.) that cannot integrate hydrogen affordably given the current economics of hydrogen systems. 

Fossil fuels have maintained a hold on the energy economy for decades. Investment, infrastructure, and supply chain inertia supported its ubiquitous integration even when alternatives may have been more compelling. This should be avoided during the transition to the new energy economy. Lobbying for one technology over the other may cause disruptions that have yet to be understood. The two experts agreed that case-by-case techno-economic analyses provide the most robust and long-lasting impacts. There is no clear one size fits all approach to facilitating the transportation transition. A policy environment should reflect this gradient accordingly and allow the data to determine where investments should be made.

Max Melnick is a young professional in the renewable energy space with an interest in becoming an interdisciplinary cleantech expert. He is interested in integrating the necessary technology and policy to influence the likelihood of operating on 50% renewables by 2030.