Increase in Electric Powered Vehicles, How Will The Grid Respond?
Electric Vehicle (EV) technology has improved considerably over the past few years. Electric powered vehicles in the US have grown at a 32% compound annual growth rate over the past four years and “as of February 2017, more than 580,000 EVs have been sold in the US, representing approximately one terawatt-hour (TWh) of annual electricity consumption. According to Bloomberg New Energy Finance, EV power consumption is projected to increase to approximately 33 TWh annually by 2025, and 551 TWh by 2040” (Pyper). This will only be beneficial towards reducing CO2 emissions if the electricity used to charge the vehicles is generated from a sustainable source and utilities can determine a way to manage unusual spikes in demand. As conventional power plants are retired (and no new ones are being built), how will the power grid handle spikes in usage due to EVs becoming mainstream?
At the Statoil 2017 Energy Perspectives conference in NYC, Eirik Waerness, Senior Vice President and Chief Economist at Statoil, discussed three separate cases for the future of energy, none of which are business as usual; renewal, reform, and rivalry. Achieving the goals set by the renewal case is the only way to decrease emissions enough to reach the 2 degree Celsius target set forth by the Paris Agreement. In order to reach this goal, we’ll need rapid electrification of all vehicles weighing below 3.5 tons. 50% of global car sales will need to be electric by 2030 and 90% by 2050, with the current EV battery on the market holding around 34 miles per 100 kWh.
We’re already on our way there, with some progressive states pushing the agenda. The zero emission vehicle mandate in California requires that a certain percentage of auto companies’ sales be electric cars and trucks. California’s goal is to put 1.5 million EVs on the road by 2025. This mandate has spread to nine other states including New York, New Jersey, Connecticut, Vermont, etc. (Union of Concerned Scientists).
EVs are not dispersed evenly across all territories, as there has already been real-world evidence that they are clustered in particular areas, such as California. As a result, transmission costs will likely increase due to increased congestion. As the number of electric vehicles on the road increases, utilities will need to upgrade existing infrastructure or build new capacity to handle growth in electricity demand. “Electric vehicles can create risks for utilities, such as peak load increases, transformer and substation impacts, or the new phenomenon of “timer peaks,” an inadvertent result of time-of-use rates. The problem here is that even though time-of-use rates have helped shift charging hours to preferred times of the day – late evening and early morning hours – customers often schedule their vehicles to begin charging at the moment off-peak rates begin resulting in sharp load ramps.” What can utilities do to alleviate poor peak load management (i.e. spikes in demand and blackouts)?
Managed charging allows utilities to remotely control when vehicles charge their batteries by turning it on, off, up or down to better meet grid supply. This is very similar to demand response and requires a smart grid for execution. Utilities will be able to distribute the charging hours across all off-peak hours and/or periods of high renewable energy production – mid-day when the sun is shining and at night when the wind is blowing. “Managed charging is essentially a combination of infrastructure and communication signals sent directly to a vehicle to control a charging event. Indirect efforts to manage charging patterns rely on customer response behavior. For example, EV time-of-use rates provide predetermined price signals to influence when a customer charges a vehicle.”
Benefits of Managed Charging: (SEPA, p.10)
Reduces emissions by using surplus renewable generation during times of high charging demand
Reduces grid stress and maintains grid stability by minimizing charging ramp rates and reducing the strain on distribution transformers
Reduce the need for new peak generation and distribution capacity resulting from EVs charging during peak hours, particularly as more drivers choose EVs in the coming years
Managed charging is currently the primary solution for handling the strains that EVs put forth on the grid through increases in electricity consumption. However, there are different ways to implement managed charging which are still working out the most efficient way to manage the oncoming changes in fundamental ways the public uses energy. “The growth of the managed charging industry depends heavily on the actual value of the grid services that EVs can provide.” The Chevrolet Volt, an electric vehicle, can mitigate a timer peak through a delayed charging mode. You can program the exact time you wish to depart and this program randomizes when your car begins to charge in order to avoid sharp spikes in demand. If many users adopt this technology, then all the charging start times will be random and consequently smooth out unintentional time of use peaks.
Utilities may have the opportunity to receive additional revenue from an increase in load but the more important value of electric vehicles comes from avoiding any costly grid updates. “Clustering” is when there are multiple EVs connected to one distribution transformer at a certain time, which causes strain on the equipment. Sacramento Municipal Utility District (SMUD) ran a study that determined about 17% of its transformers may need to be replaced (~$7,400 each) due to the increase in demand from electric vehicles.
Another issue that PEPCO noticed through its pilot program were the inconsistencies in the communication system from the EVs themselves to the utility. “One of the main issues to date is deciding on a uniform messaging protocol amongst a large field of open and proprietary protocols deployed by different vehicle and charging equipment manufacturers. The development and use of the appropriate and uniform communication standards is the most effective way to move the needle on managed charging” (SEPA, p.6). PEPCO found that the communication equipment was too inconsistent to be economical. The Electric Power Research Institute is currently working on an Open Vehicle-Grid Integration Platform (OVGIP), which connects EVSE and EVs to various nodes through a software application that would assist utilities in managing charging. “The platform will ultimately allow utilities to provide TOU pricing, peak load reduction, load balancing for intermittent solar and wind production, demand-charge mitigation and other grid service to EVs” (Pyper).
EV sales are expected to increase as prices decrease. Larger companies like Tesla, Chevy, and Nissan will be selling cars for approximately $30,000 in the next few years and by 2020 some of the newer models will be less expensive and technologically superior to gasoline fired cars. Global EV sales grew by 60% in 2015, which is compelling because that is Tesla’s annual growth rate prediction through 2020, and was the same growth rate that propelled the Ford Model T past the horse and buggy in the very early 20th century. The most important fundamental task to overcome is the high cost of batteries.
By 2040, demand will increase 1,900 terawatt-hours of electricity due to electric vehicles. “Since 2013, the world has been adding more electricity- generating capacity from wind and solar than from coal, natural gas, and oil combined. Electric cars will reduce the cost of battery storage and help store intermittent sun and wind power. In the move toward a cleaner grid, electric vehicles and renewable power create a mutually beneficial circle of demand” (Randall). This is a perfect combination for states like California that are well supplied with solar energy.
Union of Concerned Scientists- Science for a healthy planet and safer world. (2016, October 31). What is ZEV? Retrieved 2017, July 20,
U.S. Department of Energy- Electricity Delivery & Energy Reliability. American Recovery and Reinvestment Act of 2009. (2014, December). Evaluating Electric Vehicle Charging Impacts and Customer Charging Behaviors- Experiences from Six Smart Grid Investment Grant Projects. Retrieved 2017, June 26.
August 1, 2017
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