Transforming Understanding of Transformers in EV Charging Projects

A non-technical assessment of a very technical topic

I’ve found myself talking about transformers more and more over the last few months. Not the transformers that form the backbone of ChatGPT and other AI language models, but instead the physical transformers critical to the future of our electrification goals. 

Before writing this article I couldn’t tell you what the inside of a transformer looked like or easily explain what was happening at a first principles level. I just knew they were very important, required on every EV charging project, and came with significant lead times and supply chain delays. 

Today I’ll peel back the curtain on transformers, their use in EV charging stations, and why they’re facing such long delays. I’ll caveat this by saying that I’m definitely not an electrical engineer, so I’ll be keeping it high level. You’ll walk away with a better grasp of how these pieces of machinery work and why they’re so critical to our transportation electrification journey 

Basics First - What is a Transformer? 

We will start with a definition from Britannica, stating that a transformer is a: 

device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage. Transformers are employed for widely varying purposes; e.g., to reduce the voltage of conventional power circuits to operate low-voltage devices…and to raise the voltage from electric generators so that electric power can be transmitted over long distances.

Here is a photo of a utility pole-mounted transformer:

Example of a utility pole mounted transformer

Here is another photo of a larger concrete pad mounted transformer: 

Example of a standard pad mounted transformer 

And here is look inside the same pad mounted step-down transformer as above, the type often used in EV charging projects: 

Inside look at a pad mounted transformer

The key part is the low-voltage and high-voltage coils wrapped around a laminated iron core, which enables voltage change through magnetic induction. These are the three things in the center of the transformer in the photo above. In a step-down transformer the high voltage electricity from the grid interconnection causes another current to form in the low voltage coil through something called electromotive force (EMF). 

By controlling the number of times the wires wrap around the laminated core (called turns) we can control the specific change in voltage to exactly match whatever we need on the low-voltage side. This video from The Engineering Mindset on Youtube does a great job of using visuals to explain this in more detail. 

We’ve reached the limit of my ability to effectively convey these concepts. There are a lot more nuances here that people think about when designing and installing transformers, but this should give you enough knowledge to understand what’s happening in the transformer cabinet. 

Why Do Transformers Have Such Long Lead Times? 

With some electrical engineering basics out of the way, let’s dive into the real question, around why it takes so long to source a transformer for a project. 

The first thing to consider is that EV charging is actually not the only or main use case for transformers. Utility scale deployments of solar, wind, and battery storage projects require multiple transformers, both at the point of energy generation and at the point of grid interconnection. These transformers are often physically much larger than those required by EV charging projects, as well as having significantly higher power rating (1-100 MVA for renewable projects vs. 250-800+ kVA for DC fast charging). 

Because of this, transformer manufacturers have focused more of their attention on the larger, more lucrative, and more difficult to produce utility scale transformers. Wood Mackenzie in a recent report highlighted how lead times for these types of transformers have ballooned over the last few years, from ~50 weeks in 2021 to ~120 weeks in 2024. 

Graphic showing the increase in transformer lead time 

Transformer manufacturers are putting time, money and energy into the massive transformers that utility scale companies are willing to pay top dollar for to complete their projects. EV charging projects don’t command the same attention, and so fall lower on the priority list, even though they are often smaller and easier to build. 

Here is a list of some of the largest global transformer manufacturers and their HQ locations: 

• Siemens (Germany) 

• General Electric (USA) 

• ABB Group (Switzerland) 

• Hyundai Heavy Industries (South Korea) 

• TBEA (China) 

• Schneider Electric (France) 

• Mitsubishi Electric (Japan) 

• Eaton (Ireland) 

• Toshiba (Japan) 

• Hitachi (Japan) 

For the whole industry, the COVID pandemic threw a huge wrench into production plans. Manufacturers significantly scaled back production in 2020, anticipating a demand slowdown and not wanting to hold higher inventories. When demand roared back in 2021 and 2022 manufacturers were caught flat footed, scrambling to try to meet the increasing need. 

Additionally, transformer manufacturers are facing multiple other problems that introduce more delays. Things like: 

• General supply chain disruptions (Red Sea, Suez Canal, Panama Canal) 

• Rising raw materials costs and shortages

• Geopolitical tensions, protectionism, and increased tariffs 

Finally, overall grid infrastructure in the US and around the world is aging. Transformers need repair and replacement on a 30-40 year schedule, and many utilities are struggling to perform these upgrades and keep their fleets running smoothly. 

These delays and issues combine into a potent set of challenges for transformer manufacturers and for companies in need of transformers for their energy projects. These also spill over into all parts of the transformer product lines, impacting the full range of transformer sizes. 

What’s Next? 

The rapidly evolving landscape of transformer manufacturing and supply chains will significantly impact the pace of electrification projects, particularly for EV charging infrastructure. As the demand for transformers continues to rise, companies need to think through ways to ensure transformer access to mitigate risks.

Strategic Sourcing and Diversification

To address the prolonged lead times, EV charging project developers can explore strategic sourcing and diversification of suppliers. By engaging with multiple manufacturers across different regions, companies can reduce their reliance on a single source and reduce risks associated with supply chain disruptions. This approach also includes forming partnerships with emerging transformer manufacturers who may have more capacity and flexibility compared to established companies.

Innovation in Transformer Design and EV Charging Project Development

Another critical area for advancement is innovation in transformer design. Researchers and engineers are working on developing more compact, efficient, and cost-effective transformers tailored specifically for EV charging stations. These innovations can lead to shorter production times and lower costs. Additionally, modular transformer designs that can be easily scaled and installed may provide a more adaptable solution to meet varying demands in different locations.

On the EV project side, one of the reasons I chose to join Electric Era is their unique battery backed EV charging station design. Electric Era charging stations come with a 220 kWh battery system in addition to our standard 200 kW or 400kW EV chargers. This battery pack actually allows us to choose a smaller transformer than other industry players for the same project size, improving lead times and reducing project costs. See the graphic below for an example of what this looks like:

Battery backed EV charging station design from Electric Era

Investment in Domestic Manufacturing

Given the geopolitical and logistical challenges affecting international supply chains, there is a growing emphasis on boosting domestic manufacturing capabilities. Governments and private enterprises can invest in local production facilities for transformers, which would not only reduce lead times but also enhance national energy security. Such initiatives may involve public-private partnerships and incentives to encourage manufacturers to expand their operations domestically. The IRA significantly increased domestic investment in clean energy projects, but we need to see a similar increase in manufacturing of the components that go into these efforts.  

Policy and Regulatory Support

Policy and regulatory frameworks can significantly influence the transformer market. Governments can implement policies that prioritize the production and deployment of transformers for EV infrastructure. This may include financial incentives, streamlined permitting processes, and support for research and development in transformer technology. Regulatory bodies can also enforce standards that ensure the efficient use of transformers, reducing waste and improving overall system reliability.

Long-Term Planning and Collaboration

Finally, long-term planning and collaboration across the industry are essential. Stakeholders, including utilities, manufacturers, and EV infrastructure developers must work together to forecast future demand accurately and align their efforts. Collaborative platforms and industry consortiums can facilitate knowledge sharing, joint investments, and coordinated actions to address the challenges in transformer supply and deployment.

By implementing these strategies, the industry can better navigate the current challenges and build a robust foundation for the rapid expansion of EV charging infrastructure. The future of electrification hinges on our ability to innovate, collaborate, and strategically manage the supply of critical components like transformers.

It’s been very interesting to dive into the world of transformers and their crucial impact on EV charging and renewable energy projects. 

I hope you’ve learned something new and can apply this knowledge to your work, and hope you’ve gained a new appreciation for transformers!