There’s a growing consensus in the climate change community that the key to transitioning the US economy from fossil fuels is to electrify everything — shift the electricity grid over to carbon-free power and shift other big polluting sectors like transportation and heating over to electricity.

When it comes to transportation, electrification is going to be tricky. Not long ago, the consensus was that the cost and power limitations of batteries would make it difficult to fully electrify anything larger than passenger vehicles.

But batteries have been progressing in leaps and bounds. Full electrification is still beyond the reach of huge vehicles, the long-distance airliners and container ships, but recently it has become a possibility for a large and significant category of vehicles in the middle: medium- and heavy-duty trucks and buses.

According to the Environmental Protection Agency, just 6 percent of the registered vehicles on US roads in 2018 were medium- and heavy-duty, but they were responsible for 23 percent of transportation-sector greenhouse gas emissions (about 7 percent of total US emissions).

Since they mostly run on diesel engines, they also produce enormous amounts of air and noise pollution, which fall disproportionately on low-income and communities of color that may live closer to highways and are more likely to use buses. Long-haul trucks alone, while responsible for less than 6 percent of vehicle miles traveled on US highways, produce about 40 percent of its particulate pollution and 55 percent of its nitrogen oxides.

The global toll is immense: 180,000 deaths a year from diesel pollution.

That’s where medium- and heavy-duty electric trucks (MHDETs) come in. They are quiet, emit zero tailpipe pollution, and draw power from an increasingly clean electricity grid. An impossible dream a decade ago, they are now the subject of fierce competition from big automakers like Daimler, Volvo, VW, and Tesla, with multiple models slated to hit the road in coming years.

As countries across the world start cracking down on carbon emissions — and cities ramp up their fight against diesel pollution — there’s going to be an enormous market for clean alternatives. According to the Department of Transportation, there are over 14 million large trucks and buses on US roads. Wood Mackenzie expects the number of electric trucks on US roads to rise from 2,000 in 2019 to more than 54,000 by 2025, around 27 times growth. The research firm IDTechEx expects the MHDET market to reach $47 billion by 2030.

Demand is partly being driven by big fleet owners like Amazon, Walmart, Ikea, Anheuser-Busch, and Pepsi, which are transitioning to MHDETs. (Amazon recently ordered 100,000 electric delivery vans.)

Policymakers are helping, too. In July, governors of 15 states signed a memorandum agreeing to set up a MHDET task force, develop an action plan, and jointly “strive to make sales of all new medium- and heavy-duty vehicles in our jurisdictions zero emission vehicles by no later than 2050,” and in the interim, “strive to make at least 30 percent of all new medium- and heavy-duty vehicle sales in our jurisdictions zero emission vehicles by no later than 2030.” New York City, Los Angeles, Houston, and other cities are already exploring electric buses.

And don’t forget Jeff Bezos. One of his big climate gifts was $100 million over five years to the World Resources Institute, which will use it in part on a program to electrify school buses. Before him was the Hewlett Foundation’s 2020 Zero Emission Road Freight Strategy 2020-2025.

MHDETs are gaining momentum and there is every reason to believe that they will come to dominate the market. But societies do not have to simply sit back, watch markets, cross their fingers, and hope for the best. They can accelerate the spread of MHDETs — and their associated health and climate benefits — by targeting the many barriers that remain in a smart, proactive way.

To get a better sense of those barriers and opportunities, let’s look at two reports that were recently released on the subject, one from the Electrification Coalition (a collection of businesses and nonprofits) and one from the Environmental Defense Fund (EDF). Both focus on the challenges of electrifying MHDETs and how to overcome them.

The total cost of fleet electrification remains high

The purchasers of big buses and trucks are not typically buying single vehicles. They are almost all managers of fleets of vehicles. So the question of whether to electrify goes beyond whether the next truck might be cheaper electric. Electrifying a fleet is a big, complicated process that involves buying and installing new charging infrastructure and changing operational procedures, in the face of considerable uncertainty and risk.

EDF offers a framework that tries to pull all these costs and risks together into a single metric: the total cost of electrification (TCE). TCE goes beyond the conventional metric of total cost of ownership (TCO), meant to be inclusive of capital, operations, and infrastructure costs, to include less quantifiable social, operational, and even psychological costs.

So what are these barriers to MHDETs? The Electrification Coalition identifies nine:

1. Higher upfront vehicle costs and associated tariffs

Several surveys have found that the higher upfront costs associated with fleet electrification — not only the vehicles but the associated infrastructure — are the primary deterrent for fleet managers. And upfront costs are higher today, though that is changing. Bloomberg New Energy Finance expects medium-duty EVs to reach cost parity by 2025 and heavy-duty EVs by 2030.

Here’s a graph from the Hewlett Foundation showing when TCO parity will be reached by various kinds of electric trucks. Note that all classes of EV trucks will be cheaper on a TCO basis by 2030:

In addition, new heavy-duty trucks face a steep (12 percent) federal excise tax, which is even more on the higher-price EVs.

“The near-term higher upfront costs associated with MHDETs are likely to remain a substantial barrier to fleets for the next five to 10 years,” the Coalition writes.

2. Costly and complex charging infrastructure processes

Fleet managers are daunted by the complicated considerations involved in determining how much charging infrastructure is needed to support a fleet of MHDETs, finding a way to pay for it, and then fighting through the siting, permitting, and interconnecting hassles.

3. Early market and limited model availability versus limited fleet demand

Because there hasn’t been much regulatory pressure and MHDETs are relatively new and untested, fleet managers have been wary and demand has been low; because demand has been low, there are limited models and options available. (This should change soon as models roll out in coming years.)

4. Entrenched market advantages of diesel trucks

Diesel has been playing a big role in commercial transportation for a century; consequently, the vehicles, supply chains, and service networks are well-developed. MHDETs are newer and still trying to work all that stuff out.

5. Commercial and industrial electricity rate structures not aligned to charging needs

On average, electricity is a cheaper fuel than gas or diesel, but that cost advantage can be eroded or erased by bad rate design, with fixed rates or high peak charges.

6. Lack of verified data on total cost of ownership and performance specifications

Because there aren’t that many MHDETs on the road, and pre-production models don’t release their specs, it can be difficult for fleet managers to verify whether particular MHDETs can meet their fleet’s operational needs.

7. Limited availability of certified service centers and technicians

Again, because this is nascent technology, there aren’t many support services and trained technicians — that’s a major problem when it comes to these big vehicles because they tend to be used intensely and require continual support.

8. Concerns with grid resiliency

As more fleets electrify, there are greater concerns about the pressure put on electrical infrastructure that is in some cases already under stress, especially in congested areas. “Without proactive evaluation and investment to support these potential grid and generation upgrades,” the Coalition writes, “the transition to electrified freight could see significant delays and infrastructure impediments.”

9. Antiquated vehicle and facility ownership structures

Many fleet operators use leased facilities that may not have the infrastructure to handle electrification, and even if they can persuade the owners to allow upgrades, they have little incentive to take on all the costs for a property they don’t own. The cost of facility upgrades needs to be shared, perhaps with utilities as well.