The definition of what constitutes a smart city can be as disparate as the many urban centers around the globe striving to achieve that designation. For some, it’s all about harnessing the power of sensors and other technologies in order to use resources more wisely. For others, it’s about achieving more connected neighborhoods or improved public safety.
Though a strict definition may be elusive, one goal shared by smart cities across the globe is a dramatic improvement in air quality and a reduction in greenhouse gas emissions. Simply put, a cleaner and more sustainable city is smart. And one common strategy many cities have identified as essential to achieving their sustainability goals involves electrifying their medium- and heavy-duty vehicle fleets, including buses.
For example, late last year, the city of Los Angeles took a major step toward reaching its goal of having an all-electric bus fleet by 2030. They ordered their first 25 electric buses manufactured by Proterra, an LA based company, which will be delivered in 2019. The decision by Los Angeles and other cities to transition aggressively toward electric bus fleets will not only have a big impact on air quality and greenhouse gas emissions, but also on economics and health. While the upfront cost of diesel buses is lower than their electric counterparts, a 2016 study by Columbia University found that electric buses save about $39,000 per year in fuel and maintenance costs and an additional $150,000 per bus from a reduction in respiratory and other related illnesses.
Achieving these important goals, however, will require more than buying a fleet of clean, electric buses. Cities also need to have the charging infrastructure in place to keep electric buses (e-buses) efficiently running. Actually selecting and implementing the charging solutions that allow buses to refuel quickly is a critical matter – one that requires a combination of experience and expertise. “A lot of work needs to be done upfront,” said Mark Joseph, Global Chief Development Officer of the Transdev Group, one of the world’s leading operators of zero emission vehicles, including for municipal fleets. “Fleet managers need to balance and optimize based on the range of their vehicles, the terrain they’re running over, the time of year, and other factors. Once you understand all of that, then you start to think about charging solutions to optimize the operation.”
The acceptance of electric passenger vehicles in the transportation market has been the driver of innovation in the battery technology field as well as in charging technologies. More efficient batteries, longer life, and higher capacity require better and faster charging technology. Today, passenger cars are the main driver in these technologies. And companies shipping chargers for the passenger vehicle market have transitioned to selling their chargers into the bus market.
Unfortunately, a passenger car charger isn’t equivalent to an electric bus charger. E-buses have larger batteries, operate at higher voltages, and they reside in a different ecosystem. Essentially, buses are people transportation energy tankers. They move people throughout the day while carrying lots of energy in their batteries. When the batteries go empty, the chargers fill these batteries quickly. However, when the buses are not in use, they potentially can deliver emergency backup power, on-demand, back to the grid. This can be done through the charger. Throughout the day, buses move from bus depot to bus-stops and back to the bus depot where hundreds of buses are being charged for the next day. These industrial chargers are heavily utilized, delivering up to megawatts of energy to each bus.
Given these circumstances, bus chargers need to be more robust, have a higher charging capacity, may be required to deliver energy back to the grid, and must be able to adopt to different charging platforms. Rhombus Energy Solutions, Inc. is a San Diego-based supplier of charging infrastructure and other power conversion and management solutions. Rhombus is a major player in the engineering and manufacturing of high power, fast-charging technologies and works in concert with companies such as Proterra to build charging stations to the specifications and exact needs of their clientss
Another development that has made high power fast charging viable today is improved economics. “Just like battery costs are going down, infrastructure costs are going down and faster charging is more of an option,” said Ben Prochazka, vice president of the Electrification Coalition, an advocacy group working to speed the adoption of electric vehicles as a way to reduce America’s reliance on foreign oil and bolster national security. “Companies like Rhombus are supplying vehicle to grid options in their chargers, allowing cities to be smarter with their electrical demands and better overall economics.”
As important as the economics are, the practical reality that charging technology can now be deployed to meet the real world needs of municipal fleet managers is very exciting. Rhombus Energy Solutions focuses on the importance of safe, low maintenance, multi-purpose and efficient units that provide for today’s needs without neglecting tomorrow. The right solution depends on the particular demands of the fleet. “For example, school buses that are only used twice during the day, and not during peak summer periods, are a great application for vehicle to grid,” said Joseph Gottlieb, chief technology officer of Rhombus Energy Solutions. “Others require on-demand charging so they can rapidly charge as they progress along their routes during the day, which requires units that are safe for the chosen locations.” Gottlieb defines high power as anything above 50 kilowatts and fast charging as a recharge time of less than 30 minutes for a passenger vehicle and rapid charging less than three hours for a heavy duty vehicle like an e-bus.
The technology solutions to match the varying needs of different municipal fleets already exist and are rapidly improving. But there is a need for increased awareness of what is possible and of the importance of working collaboratively with utilities to build the right charging infrastructure. “A lot of decision-makers look at electric trains and trolleys and don’t understand the amount of technology behind them,” said Gottlieb. “Each bus has to be recharged and cities are relying on the utility to prepare for rapid charging of buses while the utilities are relying on the charger manufacturers for chargers that are smart enough not to upset the grid.” Electricity is everywhere, but quality products that intelligently interface to today’s grid without interference are required.
The mindset is beginning to change – out of necessity. “We see cities across the U.S. with mandates to have full EV or zero emission vehicles by 2025 and we are starting to see some big numbers this year and next year,” said Transdev’s Joseph. “We are talking about ambitious replacement schedules for these vehicles and that is going to drive charging solutions for this very important industry.” Companies like Rhombus Energy Solutions will play a key role in making this happen.
