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Why Vehicle-To-Grid Is So Important for EV Fleet Operators

(Joseph Gottlieb, CTO, Thursday, March 19, 2020)

There are a couple of questions that we often get from potential customers: i) why is vehicle-to-grid (V2G) such an important capability for electric vehicle fleets; and ii) why is it so hard for charger companies to get their chargers certified for V2G operation? My previous blogs have addressed the first question in detail: the quick answer is that V2G allows fleet operators to sell back the unused vehicle power to the grid during peak load times (e.g., when power is expensive), reducing their overall energy costs (see our blog on February 13th for an example of how much can be saved). For organizations such as public school bus operators, using the batteries in the buses during the summer to store energy can be a huge profit source, which is why nearly every school bus electrification project requires V2G as a basic capability.

Answering the second question requires a quick exploration of UL-1741SA and IEEE P1547 (the eventual successor to UL-1741SA).  UL-1741SA was first implemented in California in September 2017 in reaction to the grid stability issues caused when distributed generation (DG) assets such as wind and solar photovoltaic (PV) resources would disconnect from the grid. Essentially, UL-1741SA provides the means to implement a “smart grid”, where the DG assets are actively managed by the grid. There are seven tests required by UL-1741SA/IEEE P1547, including anti-islanding, low/high voltage ride through, low-high frequency ride through, must-trip, ramp rate, specified power factor, and volt/var mode tests. This testing regime is complex and lengthy to pass, especially when other testing requirements such as safety, electromagnetic interference (EMI), and electromagnetic compatibility (EMC) are also thrown in.

As a leader in the development and manufacturing of bi-directional, high-power energy systems for both vehicle charging and photovoltaic solar applications, Rhombus is an expert in the area of V2G charging. Our VectorStat® hardware and software allows customers to gather data from all of their infrastructure  nodes, regardless of connectivity or network issues, to effectively manage their energy resources. VectorStat’s applet-based open architecture also enables the easy integration of new features and functionality, whether to support new hardware or to provide cutting-edge data analytics capabilities. Find out how we can help you by contacting us at

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