Last week, Riot spoke to Kisensum co-founder Clay Collier about the future of Vehicle to Grid integration (V2G) and its impact on the IoT. The company drew attention last year with a project at the Los Angeles Air Force Base (LAAFB) that demonstrated the revenue potential of V2G, and we wanted to find out how it worked.
To kicks things off, we asked why the military wanted to be partners in the project, to which Clay noted that the US Military was the largest consumer of energy in the world. “They are currently in the process of trying to significantly reduce their carbon footprint and become a clean energy organization. Hence they were happy to do a project with us.”
The conversation then turned to how charging Electric Vehicles (EVs) could be networked to generate revenue. Clay explained that on all grids, system frequency is a continuously changing variable that is determined and controlled by the balance between system demand and total generation. If demand is greater than generation, the frequency falls while if generation is greater than demand, the frequency rises.
The California Independent Systems Operator (CAISO) has a target grid frequency of 60Hz. It offers contracts to any sites that could respond to a change in frequency, by storing any excess energy on the grid, keeping the frequency close to the target figure. Due to this. frequency response contracts are offered to sites that can respond in under four seconds – which helps to keep the grid stable. Kisensum successfully networked the charging electric vehicle fleet at LAAFB, to bid and access the CAISO frequency response contracts.
To take part in the CAISO four second frequency market, the site at LAAFB must have at least 500kW of reserve capacity. In 2014 LAAFB announced it had procured 42 Nissan Leaf EVs, each vehicle having a 24kWh battery. According to Clay, that put the Air Force well above the requirement.
Clay talked through the various elements that make up the software system and allow the contracts to take place. First comes the fleet management system which involves calculating all the activities of the vehicles that will be charging during trading. Thanks to this, the system knows exactly what state of charge each battery will be in when bidding for contracts. This is achieved via data entry onto the secure server at LAAFB.
Then next stage is charge control, which optimizes the state of charge that the batteries have before the CAISO market begins. Clay says that the system aims to have the batteries at around 50% charge.
When trading on the CAISO begins, the software uses a machine-learning process to understand the rate of flow to and from the grid. This requires fast charge control to optimize all the currents so that they flow at exactly the same rate to meet the requirements of the CAISO market.
Special meter monitoring is also integrated into the software to ensure the contracts are all successfully met. An interface built into the software calculates the bidding options of the network based on the fleet management data and the CAISO market.
Additional hardware was installed to the charging system at the base. A bidirectional inverter made by Eaton was used to access the CAISO 4 second market. Further inverters from Princeton Power Systems and a secure server to access the CAISO were installed at the base.
Clay noted that the LAAFB project provided a software and hardware model that could be applied to other commercial charging station projects in future. The fleet management element of the software could be achieved with access to a vehicle’s GPS, but for security reasons the LAAFB system required the manual entry of data – unsurprising, given that it’s a military project.
There are however several factors currently complicating the adoption of this model as a commercial business position for EV charging station operators. Firstly most charging stations simply do not operate on a scale that would give them enough storage capacity to join the CAISO frequency response market.
There are also significant costs in the purchase of expensive bidirectional metering equipment that would. In addition, the focus of the commercial charging sector is on fast charging and encouraging higher volumes of customers to charge over shorter periods of time. The infrequent and quick charging behaviors from these vehicles are not exactly compatible with a model like the Air Force project.
Electric vehicles connected to a charging station, have the potential to generate revenue, for the owners of the vehicle and the charging network. Through a V2G software system, Kisensum has successfully shown how such a model can work. However, it is some way away from becoming a commercially viable business proposition – although Clay remains confident.