Solar EV charging solution to grid constraints

As constrained grids potentially hamper EV charging, renewable off-grid microgrids may present a solution, finds research from IDTechEx.

According to IDTechEx, which provides research on emerging technologies and their markets, although the adoption of EVs across all sectors will contribute to a drastic reduction in tailpipe emissions, for economies where grids are already at capacity, the increased load of an electric transport sector risks blackouts and power supply issues.

This is according to the Cambridge-based company, which predicts over 180 million EVs will be sold annually by 2044, in their report, Off-Grid Charging For Electric Vehicles 2024-2034: Technologies, Benchmarking, Players and Forecasts.

In their report, IDTechEx states that EV fleet operators often must charge at predesignated times to maximise uptime and complete all planned routes.

However, if the grid fails during a charging spot, the entire schedule may be adversely affected by factors beyond an operator’s control.

This is an unusual grid situation; however, it presents a possible worst-case scenario for grid-congested and EV-saturated regions. IDTechEx cites a 2022 heatwave in California, which prompted the state government to ask EV owners not to charge to conserve energy. The growth in EV sales will only make such problems more widespread.

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Microgrids as a potential solution

To demonstrate a potential solution, IDTechEx references the South African utility grid, which is subject to frequent load-shedding, periods when demand exceeds supply and utility operators are forced to impose rolling black or brownouts of up to 50% capacity.

A solution being trailed in South Africa, they state, amongst other places, is harnessing distributed renewable microgrids to form the backbone of charging networks.

Specifically, by integrating a solar farm, large-scale energy storage and high-powered charging outlets, Vredendal-based Zero Carbon Charge plans to build an etruck charging network, decoupling charging from an unreliable grid, avoiding placing excess electrical demand on utilities, avoiding the need for costly grid expansions, and providing free and 100% renewable energy for the trucks to operate on.

In the USA, IDTechEx states there has also been a boom in companies offering grid-free solar-powered charging. Many of these products are smaller scale and transportable, allowing easy setup for EV users who want quick access to EV charging.

Slow charging rates

Although a potential option for e-mobility in a constrained grid setting, IDTechEx adds that the main challenge with distributed solar generation for EV charging is the low power output of photovoltaic panels.

Most produce around 250W per square meter, which is relatively low. To charge at 22kW (generally considered Level 2 fast charging), a solar canopy would need to be at least 10 x 10 meters, a considerable footprint, especially in an urban environment.

The other challenge, they state, is storing energy, as charging will not always be required constantly, so an on-site battery is required to store the generated electricity. Without an integrated on-site battery, charging is impossible when there is no sunlight, necessitating on-site battery storage.

Larger solar farms with integrated energy storage can become islanded microgrids, and with enough on-site storage and photovoltaic production, potential grid-independent fast charging is also possible, states the research. This is the approach proposed for the South African etruck charging network.

They add though that purely solar solutions are likely to be geographically restricted to areas with high photovoltaic potential due to the intermittency challenge.

Despite such challenges, IDTechEx predicts that solar charging systems will make up a sizeable portion of the overall $16 billion off-grid charging infrastructure hardware market by 2034.

According to their research, there are also other technologies likely to be adopted for off-grid EV charging, such as hydrogen fuel cell charging – a solution for use cases requiring much greater power per area, with a particular expected focus on electrified construction sites.

More niche technologies, they add, include AWE (airborne wind energy), which harnesses high-altitude winds for distributed power generation.