Big Batteries On Wheels Can Deliver Zero-Emissions Rail While Securing the Grid

Big Batteries On Wheels Can Deliver Zero-Emissions Rail While Securing the Grid

Article lent by Lawrence Berkeley Lab.

The trains have been standing on the sidelines of long-term electrification efforts in the United States because they account for only 2% of transportation emissions, but diesel freight emits 35 million tons of carbon dioxide annually and produces air pollution that leads to $ 6.5 billion in health costs, resulting in an estimated 1,000 premature deaths each year. In addition, these deaths and adverse health effects affect disproportionately disadvantaged and low-income communities, which are more likely to be located near freight stations and railways.

The recent dramatic drop in battery prices has created a new opportunity for electrification of freight trains. Researchers from the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), who are collaborating with researchers from UCLA and UC Berkeley, argue that the United States can retrofit diesel-electric trains with batteries in a way that is cost-competitive compared to diesel. Doing so would avoid these unnecessary deaths and health impacts and save the U.S. freight train sector $ 94 billion over 20 years from reduced air pollution and carbon dioxide emissions. Their study was recently published in the journal Natural energy.

“A rapid transition to the freight rail sector is not only technically feasible and cost-effective, it will bring immediate and lasting health and economic benefits to lower-income communities,” said Natalie Popovich, Berkeley Lab researcher and lead author of the study. “And it would boost our nation’s efforts to stem climate change, especially given that US freight train capacity is expected to double by 2050.”

Trains play a significant role in moving goods throughout the United States, especially heavy goods such as coal, timber, and ore. According to the Federal Railroad Administration, 28% of U.S. goods are moved around the country by rail, and that percentage is expected to grow significantly over the next few decades. At the recent UN climate conference in 2021, the United States joined a dozen other countries in signing new agreements to limit emissions from shipping, and zero-emission solutions for rail freight will be part of that commitment.

Diesel-electric, but not battery-electric

Unlike several other regions of the world, all freight trains in the United States are still diesel-electric, mainly because the typical electrification strategy of building electrified lines over tracks is more difficult to implement in the United States with its long distances. In diesel-electric trains, a diesel engine is connected to a generator, which then supplies electricity to electric motors connected to the locomotive shafts. It is therefore possible to retrofit the trains that need to be powered by batteries, because diesel-electric trains already have an electric motor.

“Dramatic improvements in battery technology, combined with the existing electric driveline in predominantly diesel-electric freight trains in the United States, pave the way for a rapid conversion to battery-electric freight trains and with significant cost savings,” said Berkeley Lab researcher Amol Phadke, co-author of the study. “Also, the weight of batteries is less of a limitation than it would be for electric vehicles or trucks. We can add a car to a freight train built with batteries, and the weight of that battery car is not a problem. by train.”

Diesel-electric trains have been around since the 1920s, and they began to replace steam trains in the 1930s, when they performed better and were less polluting. At the time, it was cheaper to use diesel engines to generate power for the engines on the trains than to try to develop fully electric trains due to high electricity costs. Now, a century later, we are at a point where the price of electricity is competitive with diesel, and the environmental and health costs of remaining dependent on diesel to run freight trains are too devastating to ignore.

“Our analysis shows that a shift to battery-electric freight will reduce the industry’s annual carbon dioxide emissions by more than half and eliminate more than 400 million tons of carbon dioxide in 20 years,” Popovich said.

The study highlights that there are additional avenues for electrifying U.S. freight trains, such as electrifying trains via overhead lines or using hydrogen fuel cells in conjunction with battery-powered trains. But based on the fact that freight trains are already diesel-electric, and given the recent advances in battery technology, researchers show that the battery-electric road offers the most cost-effective, long-term solution with several added benefits.

Their analysis shows that existing battery technology could drive a freight train for 150 miles (the average daily distance traveled). A battery-powered freight train would use half the energy required of a diesel-electric train, and taking into account declining battery prices and environmental costs of diesel, battery-powered trains are on their way to being more cost-competitive than diesel-electric trains. As freight train planning is centralized, the study suggests that railways could achieve high volume use of fast charging infrastructure, which will further reduce costs.

Battery-powered cars are modular and can be deployed in various configurations for locations experiencing power outages, as well as for other sectors, such as ship electrification.

A major advantage of retrofitting existing diesel-electric freight trains with battery-carriages – also known as battery-trailer cars – is that the battery-electric trains can always fall back on the diesel engine as a spare fuel source. This dual-fuel capacity, which allows for either battery or diesel use, is a unique advantage compared to full electrification of the freight train system or use of hydrogen fuel cells.

Modular batteries offer the benefits of resilience

Another great advantage is that battery-electric trains can be used as pure backup power and thus strengthen the resilience of the electricity grid. Historically, diesel-electric trains have been used as power generators in emergencies. In early 1998, a series of ice storms left over one million without power in the northeastern United States and in parts of Canada. In a suburb of Montreal, the mayor moved an all-diesel electric locomotive close to City Hall to provide power for their emergency operations.

With the increase in extreme weather events and power outages, battery-electric trains have the potential to be deployed nationwide to avoid power outages. These modular battery tender cars can be transported to where they are needed and charged in places where electricity prices are low, which provides significant advantages over mains storage. In addition, the battery tenderers could function as modular shipping containers capable of exchanging between freight trains and maritime vessels, with the positive benefits of decarbonising both sectors and extending the range of resilience.

“Converting the U.S. freight train sector to battery electric will generate about 220 gigawatt-hours of mobile storage,” Phadke said. “Furthermore, these battery-powered cars could be deployed during extreme events, such as during the recent catastrophic forest fires in California or the winter storm of 2021 in Texas that left millions without access to electricity. This mobile energy storage capacity would also create a potential new revenue stream for freight train operators.”

From a technical perspective, the researchers demonstrated that there should be no restrictions on moving to fully battery-powered freight trains, but further research and large-scale demonstration projects are needed to optimize the charging infrastructure. “Berkeley Labs systems and market analysis shed light on this overlooked area and showed that we can decarbonize some sectors with existing technology, which will help us achieve our climate goals so much faster, while promoting environmental justice and network resilience. It is a win-win-win, “said Berkeley Lab Energy Storage Center Director Noel Bakhtian.” The techno-economic analysis of battery-powered freight trains shows that we have viable solutions available to enable the transition to a clean, affordable and robust energy future. “

The research was supported by the William and Flora Hewlett Foundation through the Berkeley Lab Foundation.

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