Engineering vehicle-to-grid connected transportation
How intelligent, bi-directional electric vehicle charging can benefit utilities, cities, and citizens
Battery storage is the rising star of the electric power industry. Countless articles and white papers have proclaimed the great promise of batteries, echoing what McKinsey & Company declared when it called them “the next disruptive technology in the power sector.”
The rationale for so much attention and interest in battery storage is clear. As the price of batteries has plummeted faster than most anyone expected, their role in providing grid stability to smooth the large influx of intermittent renewable generation as well as a ready solution to handle peak load demand has become more and more compelling.
Make no mistake: this represents a profound change for both the power industry and society at large. But in many ways, the use of residential and utility-scale batteries to bolster the grid is just the beginning. If you expand the concept of what is possible with battery storage to include a bi-directional flow of energy to and from electric vehicles and the grid – also known as vehicle-to-grid connected transportation – the implications and potential benefits are even more transformative.
“It’s a win-win-win situation. Cities with electrified bus fleets will get less smog and carbon emissions. Utilities won’t need to add expensive infrastructure to address their peak shaving needs and incorporate more renewables. And citizens win because they have more convenient, efficient, and cleaner modes of transportation,” says Anil Tuladhar, Vice President of Engineering at Rhombus Energy Solutions, a company that designs and builds bi-directional vehicle-to-grid fast chargers.
But achieving those benefits requires far more than lower-cost, high performing batteries. It also necessitates fast, safe, and flexible charging infrastructure that allows municipal fleet managers to operate their vehicles in ways that save money and provide the best possible service to citizens. As aspirational and futuristic as that scenario may sound, the combined hardware and software solutions that enable vehicle-to-grid transportation are already being piloted. “It’s happening right now,” says Oleg Logvinov, the President and CEO of IoTecha, a company that combines its advanced communication capabilities to Rhombus chargers. “Together we are essentially on the leading edge of a tidal wave coming to the market.”
That tidal wave is propelled by a range of technology advancements, including the work companies like Rhombus and IoTecha have done in improving power electronics and communications. “The key infrastructure is coming together with cloud technologies and also power electronics is making a big improvement in the density, flexibility and efficiency of power conversion,” says Kent Harmon, General Manager at Rhombus. “We are focused on higher efficiency switches and new topologies that can reduce the cost and maintain bi-directional requirements and connectivity.”
The promise of bi-directional power flows and greatly improved charging infrastructure are likely to see their first practical use in municipal bus fleets. Why? Cities simply have the most to gain from becoming early adopters of vehicle-to-grid. Logvinov highlights the vast difference between what he terms “dumb” and “intelligent” charging, which is enabled by sophisticated communication features of the type Rhombus and IoTecha have pioneered.
Intelligent charging provides clarity and options to fleet managers. For example, intelligent charging means that an in-depot charging station can automatically determine which vehicles are most in need of a charge, based both on how depleted their batteries are and when they’re scheduled to operate next. “Intelligent charging can assess an entire fleet and prioritize a bus that has 10% of its battery left and is scheduled to leave at 4 a.m. over one that has 60% left and is scheduled to leave at 5 a.m.,” says Logvinov.
The benefits become even greater when bi-directional power flows are involved. For instance, fleet managers can schedule charging either for the times of the day when electricity is cheapest or when renewable energy is most plentiful. They can also reap financial benefits by discharging batteries from idle vehicles when utilities are most in need of peak power or to take advantage of demand response opportunities.
The ability cities and fleet managers have to take advantage of these potential benefits will depend on more than the visibility of information; it will also require a flexible platform to access and utilize the information.
“That flexibility will be increasingly important in the future as bi-directional power flows become more common and as the very concept of municipal bus fleets change from being simply a mode of transport following a set schedule to a more fluid and economically advantageous city service,” says Keith Klarer, Director of Data Architectures at Rhombus.
“We will see that these fleets become dynamic services that can adapt in real time and fleets will become used for a variety of purposes that were not originally anticipated. In many ways, the advanced hardware, software and firmware engineering that is taking place today is creating the foundation needed to deliver the benefits of a smart city and its citizens.”