The role of electric vehicles in a microgrid before V2G

November 6, 2019

If you have read any industry articles or have attended any conferences related to utilities, EVs, or load management in the past few years there are two things that are covered frequently: Microgrids and vehicle-to-grid (V2G). This isn’t surprising as both technologies have the potential to fundamentally alter the electrical utility landscape and they both challenge the way we currently manage electrical load. With the pace of initiatives related to climate change and the decarbonization of the grid gaining momentum these concepts are being researched more heavily. One thing that you may notice is that both topics are often spoken of in conjunction with each other, specifically that EVs will be able to supply energy to the microgrid through V2G. While this could ultimately be true, EVs will play a significant role in a microgrid without V2G and realistically this will occur first.

A microgrid is a local energy grid with control capability, which means it can disconnect from the traditional grid and operate autonomously. One important benefit, which also gives it its name, is that a microgrid can disconnect from the traditional grid, a process called islanding, during an emergency situation. As an example, if there was a severe storm which had damaged some incoming transmission lines a community on a microgrid could still have electricity. Another key benefit with this type of system is that a community could generate its own electricity, typically through renewable energy sources like solar or wind, which can reduce their carbon footprint as well as reduce their electricity bills. Although this might be an ideal situation, these energy sources are not always consistent and the cost of battery storage technology is still high. For this reason there will still be a connection to the existing grid, which will pick up the existing slack when needed. Many see EVs as an essential source of electricity that could be drawn from in these emergency situations or for load balancing, and this would all be enabled through V2G technology.

A realistic outlook for V2G

V2G seems like the golden ticket for utilities as it would provide them access to large flexible loads, however there are a lot of issues that need to be addressed. Some of these issues are familiar to utilities, such as interoperability requirements and evolving standards, but there are also other things they need to consider. The most prevalent one revolves around the impact that this technology will have on EV batteries, which are the most expensive component of the vehicles. Tesla CTO JB Straubel stated in an interview that V2G is, “something that I don’t see being a very economic or viable solution — perhaps ever, but certainly not in the near term.” His skepticism is due to the increased battery degradation caused by the increased amount of charging and discharging. If this technology does in fact lead to reduced battery performance EV owners will be less likely to participate, regardless of any incentives provided by their utility company, as they will not want to risk hurting the most essential component of their vehicle. The actual impact of this technology isn’t certain as there is also a study that proposes that not only does V2G not degrade EV battery life, it might actually extend it. Clearly more research has to be conducted before V2G can be scaled, but this will take time and microgrids, let alone EVs, won’t wait.

The role of EVs on a microgrid before V2G

In a previous FleetCarma article we discussed how utilities could find value in managing EV charging load and all of the topics covered, such as preventing distribution infrastructure degradation or aligning EV load with renewables, apply even more significantly to microgrids. The first thing for utilities to consider is the total amount of power and electricity an EV requires. In a report published by the Smart Electric Power Alliance (SEPA) it was stated that a long-range battery electric vehicle (BEV), with an approximate range of 300 miles, would on average consume 4,350 kWh annually. This type of EV can also draw ~17 kW of power, which is more than triple your average 1.5 ton central air conditioner. Given enough EVs this could account for a significant portion of a microgrid’s generation capabilities, however this concern is secondary to the threat to the distribution infrastructure. In order to avoid dangerous coincident peaks, and to maximize the potential benefits, EV charging load needs to be managed. This can be accomplished using customer controlled programs such as SmartCharge Rewards which incentivizes participants to charge during specific time periods. Eventually charging could be managed using solutions like SmartCharge Manager which enables utilities to curtail EV charging automatically with set energy thresholds or manually curtail the load during a demand response event.

V1G comes before V2G

The EV ecosystem is rapidly evolving and new solutions are being developed regularly. While solutions like V2G might be essential for the future, increased EV adoption is making it critical for utilities to start investing in solutions sooner. There is no defined timeline as to when microgrids or vehicle-to-grid could fully enter the market, so it is important to realize that the two are not dependent on each other. Managed charging can be incorporated into load management solutions today, eventually it can be rolled out to microgrids, and lastly it can be combined with V2G. Managed charging is also referred to as smart charging or V1G, so by definition it should be addressed first.