Vehicle-to-Grid (V2G) is a technology that enables electric vehicles (EVs) to not only draw energy from the power grid for charging their batteries but also to send excess energy back to the grid when they are not being used. Essentially, it turns EVs into mobile energy storage units that can both consume and supply electricity to the grid, creating a two-way flow of energy.
Electric vehicles are rapidly gaining popularity in the US after a decade of slow growth, and so does vehicle-to-grid technology. Willet Compton of Delaware University first introduced the concept of vehicle-to-grid technology, intending to provide monetary benefits to EV owners. V2G, abbreviated as Vehicle to Grid, is a technology that enables the flow of power back to the grid from the battery of the vehicle (car) as per the requirement of the electric grid. V2G is similar to regular smart charging. Smart charging enables us to control the charging of EVs such that the power requirement of EVs is satisfied. Vehicle to grid goes one step ahead of smart charging such that power can flow back to the grid from EV to balance the variation in energy production.
What is Vehicle 2 Grid?
Vehicle-to-Grid (V2G) is a technology that enables electric vehicles (EVs) to not only draw energy from the power grid for charging their batteries but also to send excess energy back to the grid when they are not being used. Essentially, it turns EVs into mobile energy storage units that can both consume and supply electricity to the grid, creating a two-way flow of energy.
Need for Vehicle-to-Grid (V2G)
Firstly, today’s world is facing a drastic change in climate, and to mitigate the risks associated with climate change, ways of energy production in power plants are shifting rapidly from conventional to renewable sources. This rapid integration of renewable energy sources makes the electric grid less predictable and increases the complexity of balance in energy demand.
Secondly, the number of automobiles on the planet will increase as long as the world's population continues to climb annually. The issue is that oil and gas won't be able to meet demand, leaving electricity and various forms of electric cars as the sole alternatives. According to estimates, there will be at least 140 million EVs globally by 2030. These batteries can be estimated as having an aggregated capacity of around 7 TWh, and most of the time EVs are standing idle in the parking, connected to chargers.
Further, a pump station is the most common method to store energy nowadays, which is an expensive way as compared to EVs and requires significant investment. So, a common solution is Electricity through renewable energy as Electric vehicles are big batteries on wheels that can be used to store energy when produced in excess and can be discharged to the grid as a variable source during peak hours to tackle uncertainties created by renewable energy sources.
Technological Remedy
During times when parked vehicles are inactive, their batteries can operate as mobile energy storage systems. The amassed electrical power can be transmitted to the grid when there is a shortage of energy. Given that electric vehicles (EVs) are frequently linked to chargers while at a standstill, this configuration empowers them to offer assistance to the grid.
Additionally, employing Vehicle-to-Grid (V2G) technology facilitates increased use of renewable energy during peak hours. Through this approach, utilities can decrease their dependence on costly and less efficient fossil fuel power generation sources when demand is at its zenith.
Architecture: Vehicle-to-Grid (V2G)
In the architecture of vehicle-to-grid technology, there are three major components as Grid Operator, Aggregator, and Driver Interface.
In the V2G ecosystem where tens of thousands of vehicles are connected to the grid performing ancillary services. It is certain that the grid operator will want to have control over the aggregate capacity of electric vehicles rather than dealing with individual vehicles. So, the grid operator will interact with an aggregator to deal with a bulk of electric vehicles. To the grid operator, the aggregator will appear as a large source of rapidly-controllable generation or load – a good source of regulation capacity. The aggregator will have a contract with the grid operator through day-ahead and hour-ahead markets to provide regulation capacity. The grid operator and aggregator would communicate over a secure data link of the same type used to communicate with existing sources of regulation. The aggregator would receive regulation commands from the grid operator and allocates the required regulation to the connected vehicles. Aggregators would keep track of vehicles that are connected and where they were located (with GPS). The aggregator would also serve as the interface for each individual driver. A web server would allow drivers to log in to set up default profiles, check the status of their vehicles, or monitor the value created. Further, location information is needed to determine which zone or control area a vehicle is currently connected to.
Aggregator
In a V2G system, the role of the aggregator is to be the middleman between the grid operator and thousands of vehicles connected to the grid. The aggregator needs to know the default usage profiles of all the vehicles in order to determine a projected aggregate vehicle availability profile. Default usage profiles are entered by each driver into the aggregator’s database through a web interface.
Driver Interface
A vehicle that is a participant in a V2G system would have a web-based home page to allow the vehicle driver to set up various default parameters and track the status of the vehicle.
Applications of V2G
Peak load leveling
The V2G concept allows vehicles to provide power to help in balancing loads by "valley filling"(charging at night when demand is low) and "peak shaving" (sending power back to the grid when demand is high). Peak load leveling can let utilities offer regulation services (keeping voltage and frequency stable) and spinning reserves (meeting sudden demands for power) in novel ways.
Peak power
Typically, power plants that can be turned on for brief periods of time produce peak power. The required period for peaking units can be 3-5 hours per day, and V2G can give peak power, which may be suitable for this purpose. Electric vehicles are able to supply power during peak hours while consuming it during off-peak hours. This reduces the energy demand balance gap in the power networks. Peak shaving has additional benefits, such as lowering transmission congestion, lowering line losses, deferring transmission investments, and lowering the stressed operating of an electrical system.
Spinning Reserves
The term "spinning reserves" refers to the additional generating capacity that, at the grid operator's request, can quickly supply electricity to the operator, often within 10 minutes. The generator gets compensated with additional funds for the energy delivered in case of an event when the spinning reserve is used. So, the use of an EV as a spinning reserve could offer the power system a flexible, controllable generator, which can act on instant request without prior planning.
Frequency Regulation services
Regulation is a real-time control of frequency and is regulated by matching generation to load demand. It must be under direct real-time control of the grid operator, with the generating unit capable of receiving signals from the grid operator’s computer and responding within a minute or less by increasing or decreasing the output of the generator, but this sudden change in the output of generator increases the operating cost of utilities. This additional energy required for frequency matching can be borrowed from EVs since they can power in a short period.
Ancillary Services
Ancillary services support the electricity transfer from the production to the loads with the aim of assuring power system reliability and enhancing power quality. The extended service of demand will raise the yearly load payment, despite the fact that these services can be linked to an improvement in social welfare. EVs can be used to control frequency either as a power source or as a load as EV has the ability to offer auxiliary services that result in a more stable operation of the power system and a decrease in the operation of protection relays.
Benefits of V2G
V2G can help the grid add more clean renewable power and offer new opportunities for EVs to participate in energy-saving strategies.
V2G will create new business models of resiliency, grid stability, assistance in natural disasters, and new economic opportunities.
V2G can save energy costs for all sectors, but especially for individuals and governmental organizations.
V2G can improve the quality of life by generating local jobs.
Challenges to V2G
The adoption of V2G is still in its nascent stages due to various challenges: battery technology, power quality issues, technical limitations, lack of business models, commercial feasibility, and regulatory issues.
Battery technology and the higher initial expenditures incurred compared to ICE vehicles provide the biggest obstacles to a V2G shift.
Although V2G systems have numerous advantages, adding more EVs may affect the dynamics and performance of the power distribution system due to the overloading of transformers, cables, and feeders. As a result, efficiency is decreased, harmonics and voltage deviations are produced, and additional generator starts may be necessary.
Massive adoption of electric vehicles can cut CO2 emissions dramatically. On the other hand, integrating renewable energy sources into the current conventional grid results in significant technical grid limitations, particularly problems with power quality. There is currently no such system in place to integrate EVs into traditional power grids without compromising power quality and simultaneously reducing uncertainty.
Lack of Bi-directional EV charging business models which provide discounts on energy transactions i.e., peak/non-peak charging, and customer loyalty programs.
Patent Filing Trend
Electric car sales reached a record high in 2021, despite supply chain bottlenecks and the ongoing Covid-19 pandemic. Sales increased by almost double to 6.6 million compared to 2020, bringing the overall number of electric vehicles on the road to 16.5 million. In 2021, China sold the most electric vehicles (EVs), with 3.3 million cars, followed by Europe, with 2.3 million, and the United States, with 630,000. The patent data in this article shows information related to Vehicle to Grid, including, the patent filing trend across the globe and the top-rated assignees.
From the number of applications filed each year across the world, it is exciting to know that the patent filing trend jumped in the year 2019-2021. However, in upcoming times, it is expected to grow as research and development in the field are still ongoing. Apart from the top companies, many other companies are also indulged in the research process, and various projects are in the implementation phase including, E-mobility Lab, E-FLEX, Denmark V2G, Bus2Grid, AirQon, etc. Also, between 2015 and 2020, there was an exponential rise in the number of patent applications. However, due to the pandemic, there is a delay in filing and granting patents and a drastic fall in patent applications after 2020. Henceforth, the trend in patent filing is expected to rise to a new level in the upcoming years.
The top assignees to file patents are from China, the US, Korea, and Japan. In terms of investment in infrastructure for EVs, China continues to maintain its lead in the number of publicly available chargers, accounting for about 85% of fast chargers and 55% of slow chargers worldwide. According to the International energy association (IEA), China deployed 680,000 slow chargers in 2021, followed by Europe (over 300,000 installations) and the United States (92,000 installations). Based on the above data on the charging infrastructure of EVs from IEA, China, the European Union, and the United States are key players in the EV market and are heavily investing in building infrastructure for EVs.
Future Scope
One of the few potential flexibility assets, V2G technology, will support grids, assist in reducing the need for peak power plant usage, and at the same time provide financial benefits to EV consumers. V2G extends the promise of electric vehicles, both environmentally and commercially. It makes the environment cleaner and leaves a smaller carbon imprint. The mobility services sector may develop new revenue streams, reduce infrastructure investment, and lower TCO. It’s just a matter of time before V2G becomes a reality.
References
M. El Chehaly, O. Saadeh, C. Martinez and G. Joos, "Advantages and applications of vehicle to grid mode of operation in plug-in hybrid electric vehicles," 2009 IEEE Electrical Power & Energy Conference (EPEC), 2009, pp. 1-6, doi: 10.1109/EPEC.2009.5420958.
S. Iqbal et al., "Aggregated Electric Vehicle-to-Grid for Primary Frequency Control in a Microgrid- A Review," 2018 IEEE 2nd International Electrical and Energy Conference (CIEEC), 2018, pp. 563-568, doi: 10.1109/CIEEC.2018.8745952.
https://blog.forumias.com/v2g-vehicle-to-grid-technology-and-its-future/
