Carmel, Ind., is a city of 92,000 that has been committed to environmental sustainability and encourages ecological responsibility throughout its community and across all of its municipal departments.

          In the past few years, Carmel has become the first in the nation to retrofit a vehicle in its fleet with a relatively new Hydrogen-On-Tap — or H.O.T. — technology that can increase a fleet’s gas mileage by 15% while reducing harmful carbon emissions.

          “One thing every city department can do is working to reduce the amount of fossil fuels they burn in their vehicles,” said Carmel Mayor James Brainard. “We’ve decided to work smarter not harder in order to do our part.”

          The initial concept for the H.O.T. technology was developed in 1968 by Jerry Woodall, a distinguished professor of electrical and computer engineering at Purdue University, who is now retired. He eventually filed for a patent, and in 2007, he licensed the process to Kurt Koehler, the president and founder of the Indianapolis-based Aluminum Gallium Co., also known as AlGalCo.

          “Kurt spent several years refining the hydrogen-on-demand process, and in 2013, we began working with him to retrofit some of our pickup trucks,” Brainard said. “Not only does the hydrogen technology allow us to respond to the climate challenge, but it also enabled us to work with a local company that was using a process created by a local institution. It was a win-win-win.”

Add water and stir

          As a clean-burning fuel, hydrogen is an ideal way to eliminate greenhouse gases, but the concept has been a tough sell. Not only do cities lack the infrastructure to transport, store and pump the material into vehicles, few drivers are enthusiastic about the prospect of hauling around a tank full of compressed hydrogen — even if it is less explosive than traditional gasoline.

          Woodall wondered if there was a way to create hydrogen on the spot using an aluminum alloy pod that would release hydrogen when combined with a tank of water, becoming fuel for an engine. Koehler ultimately licensed the technology from Purdue and set up his company in 2007. In 2013, Carmel agreed to partner with AlGalCo to create a prototype using one of the city’s Ford F-250 trucks in order to measure its potential.

          The truck was outfitted with a 45-kilogram metal box that sits in its bed and is comprised of six stainless steel canisters that contain a 113-gram button of aluminum and gallium alloy. When the engine is started, a small amount of water drips onto the buttons, producing the hydrogen that is then fed into the intake manifold. After the hydrogen is released, the remaining material turns into aluminum oxide, which can be recycled to create more pellets. The H.O.T. system prevents the vehicle from using traditional fuels until the hydrogen supply is depleted, and once the truck returns to the garage, the driver can replace the used canisters for new ones for their next trip.

          “Kurt’s technology showed that it not only saves gas mileage, but also cuts emissions by about 20%,” said Terry Killen, operations manager for the city of Carmel. “We don’t have to redesign the motor or store anything, and the units are only about $5,000 a piece. A totally hydrogen-powered vehicle would cost a lot to upgrade and store, but this is a great option, and if the hydrogen runs out, the vehicle can still run on straight gas.”

Ready to roll

          Killen said Carmel’s fleet personnel who have driven the prototype truck say they can’t tell a difference in terms of performance and they are excited to be part of a new and potentially game-changing technology. Once the COVID-19 pandemic restrictions are behind them, the city of Carmel will roll out five more trucks that have been outfitted with H.O.T.

          “The trucks have been ready to go since the summer of 2020, but due to the various restrictions, we have had to limit the number of people who have access to the facility,” Killen said. “Once we get beyond the COVID thing, we’ll be able to get a true picture of what this technology can really save us (in terms of gas mileage and a reduction in carbon emissions).”

          The H.O.T. technology is just one of the many initiatives Carmel has adopted. In addition to making Carmel a walkable community, reducing the number of cars on the road and installing the Carmel Access Bikeways, also called C.A.B., the city has constructed over 135 roundabouts, which help reduce emissions and save on average 24,000 gallons of gas per year, per roundabout.

          Additionally, Brainard has signed executive orders that mandated the use of hybrid or flex-fuel city vehicles whenever possible. He created a “no idling” policy for city employees, replaced failing traffic light bulbs with LEDs and converted over 800 streetlights thanks to an Energy Efficiency and Conservation Block Grant.

          Brainard said testing the new H.O.T. technology fits in perfectly with all of the things his community is doing to make Carmel a green city. He said the feedback the city has received from the community so far has been positive, and he thinks the public is excited for the larger rollout.           “People want to see the government tackling problems and finding solutions, and that’s what we are trying to do with environmental issues,” Brainard said.