Vehicle-To-Grid discharge, even at constant power, is detrimental to EV battery performance, study finds

By James Ayre, Clean Technica, May 16th, 2017

There have long been critics of the idea of widespread use of electric vehicle (EV) vehicle-to-grid (V2G) technologies for a variety of reasons, but largely in relation to the potential damage done to EV batteries, and thus reduced battery lifespan.  New research from the Hawaii Natural Energy Institute at the University of Hawaii at Manoa seems to clearly support this assertion — the extra cycling that accompanies use of an EV battery for grid balancing, even when at constant power, reduces EV battery cell performance significantly.

To be more specific, the use of an EV with V2G tech could reduce the working lifespan of an EV battery pack to under 5 years time, according to the new work.

The researchers note, though, that simply delaying the charging of EVs as a means of balancing the grid would have only a “negligible” effect on EV batteries, and could thus represent a better option. However, this could prove to not be the case in environments warmer than “room temperature.”

Green Car Congress provides more: “The Hawaii team performed laboratory testing on commercial Li-ion cells to investigate the impact of bidirectional charging on Panasonic 18650 NCA batteries. The researchers investigated the effects of V2G/G2V combined with different charging schedules (1 or 2 charges a day, immediate or delayed charging) and different charging currents (level 2 or fast charging). Further, the effect of calendar aging at different temperatures was also investigated in a second set of experiments.”

“The team concluded that a V2G step twice a day increased battery capacity loss by 75% and the resistance by 10%. This step once a day accelerated the capacity loss by 33% and the resistance increase by 5%. Forecasts based on the measurement results indicated that that V2G implementation would decrease the lifetime of the battery packs to under 5 years.”

“The team also found that calendar aging influenced the cells little enough that it was beneficial to charge the cells twice a day instead of once. Charging twice per day resulted in 5% less capacity loss and similar resistance increase compared to once per day.”

The new work is detailed in a paper published in the Journal of Power Sources.

By Kyle Field on Clean Technica, May 18th, 2017

Electric Vehicle to Grid (V2G) Pilot In Genoa Aims To Define Operating Standard For V2G In Italy

Vehicle to Grid (V2G) vehicles have arrived in Italy as part of an agreement between Enel Energia, Nissan Italia, and the Italian Institute of Technology. The pilot project will kick off with a set of V2G chargers at the Italian Institute of Technology campus in Genoa, Italy.

The two chargers installed by Enel Energia will initially only provide charging capability for electric vehicles but will be the focus of the V2G pilot after a preliminary regulatory framework has been defined. Nissan has provided two Leaf vehicles for use in the pilot, electric cars that are presumably capable of V2G functionality at some level.

The concept behind V2G is that the grid will have sufficient storage capacity in the event of a high-demand event or reliability incident at a power generating unit, thanks to the bonus storage capacity that comes in the form of a massive, distributed network of electric vehicles, each with its own battery. If capability existed to pool the storage capacity of a network of distributed electric vehicles into what would effectively represent a grid-scale battery installation (or several of them), less storage at the grid level would be needed while still maintaining required grid backup and stability. Drivers would be compensated for the wear and tear on their vehicles’ batteries as a means of sharing the value created by the aggregate solution.

Ernesto Ciorra, Enel’s Head of Innovation and Sustainability, said that “Enel has also signed an agreement with IIT for the development of innovative technologies and solutions in the field of energy efficiency, renewable sources and distributed generation, an important part of the search for new sustainable energy alternatives.”

Enel has also launched a V2G effort in Denmark, which is now considered the first commercial V2G hub in the world. That project was launched in partnership with Nissan and the Danish utility Frederiksberg Forsyning. The Danish installation utilizes 10 V2G chargers and 10 Nissan e-NV200 electric vans. The vans have the capability of feeding power back to the grid for stabilization and grid balancing services for the TSO (Transmission System Operator), for which the owners are compensated.

Nissan is also pursuing V2G projects in the UK, where it has installed 9 V2G chargers at its Nissan Technical Center Europe in Cranfield and another at Newcastle University.

Another version of V2G 16 May 2017 by Steve Hanley

Tesla + Green Mountain Power Offer Tesla Powerwall For $15/Month (Vermont)

Originally published on Gas2.

Tesla has a new idea it calls aggregation and it is the next step in its plan to bring renewable energy to the utility grid. The first phase of that plan is the installation of Tesla Powerpack grid scale storage units at substations throughout the area served by a utility. The second phase is linking thousands of individual Powerwall residential battery systems to provide extra storage capacity.

In partnership with Green Mountain Power, Tesla is now offering GMP customers a Powerwall battery for the bargain price of $15 a month for 10 years, or a one time charge of $1500. The normal price of a the 10 kWh Powerwall with built-in inverter is $5,500, plus installation. Up to 2,000 batteries will be provided and they will be linked together via the internet so the utility company can use some of the power stored in them to balance the utility grid and provide extra power when needed while meeting all the needs of the homeowner.

The plan is similar to what is known as vehicle-to-grid (V2G) systems that allow the batteries in electric cars to feed power back to the grid when they are plugged in but not charging. Electric car batteries can also be used to provide power to the home if wired properly.

Electricity is a curious thing. Despite the fact that it is the energy source of choice for industry, there is not one person alive who can tell you what it is. We can describe what it does, we know how to make it, we can send it long distances, but it remains one of those things, like gravity and light, that defy a complete physical explanation. What we do know is that is ephemeral. Once created, it must be used immediately or it is wasted.

Unless we can find a way to store it, that is. Thanks to its expertise in making batteries for electric cars, Tesla is at the forefront of battery storage systems. It is building the largest and most modern battery cell manufacturing facility in the world just outside of Reno, Nevada. Between the time when the company started building cars and now, it has quietly shifted from being an automaker that also makes batteries to a battery company that also makes cars.

Utility companies operate two kinds of generating plants. One is online constantly and takes care of so-called baseload needs. The other is called a peaker plant, a facility that is brought online when the demand for electricity increases temporarily. Peaker plants are typically used during the hours of 4 pm and 8 pm when demand is highest.

Peaker plants cost money to build. They also cost money to get up and running after they are shut down. In the utility industry, the game is to maximize profits by guessing correctly how much electricity will be needed and when.

Baseload generating plants and peaker plants react slowly to unexpected changes in demand. Batteries can react in milliseconds. That makes them ideal for soaking up some of the excess electricity sloshing around the grid now and feeding it back into the grid later.

While batteries cost more than a new generating plant initially, they save utility companies money over time by keeping peaker plants offline longer — or eliminating the need to build them in the first place. It’s one of those “pay me now or pay me later” kind of things. As battery prices continue to fall, battery storage is beginning to pencil out as the cheapest and most effective solution.

Those 2,000 GMP customers will obviously save a lot of money over the cost of buying a Powerwall separately. Presumably, GMP will also be saving money and is subsidizing the cost of the Powerwall to some extent. It’s a win for Tesla, a win for Green Mountain Power, and a win for customers.

The announcement from Tesla can be unlocked by providing contact information online or you can read it below without sharing your personal information with the company. You’re welcome!

The Next Step in Energy Storage: Aggregation

Today, modern utilities and grid operators are utilizing battery technology like never before. The next step in tapping the potential of energy storage is putting together thousands of batteries to form an energy network that utilities can use to deliver immediate value for the electric system. Tesla can now bundle Powerwall and Powerpack batteries into a single portfolio, also called aggregation, to make the grid cleaner and more efficient. Meanwhile, Powerwall customers who allow Tesla and the utilities to use their battery when energy demand is highest will not only have home backup power, but will also receive compensation for its use on the grid.

To introduce this program, Tesla and Green Mountain Power, a utility in Vermont, are working together to bundle Powerwall and Powerpack batteries into a single resource of shared energy for the first time. Green Mountain Power will install Powerpacks on utility land and deploy up to 2,000 Powerwall batteries to homeowners within the utility’s service territory, which will enable more renewable energy and increase grid efficiency.

For only $15 a month or a $1,500 one-time fee, customers will receive backup power to their home for the next 10 years, eliminating the need for traditional, manually-controlled backup generators that use fossil fuel. At the same time, Tesla and Green Mountain Power will provide a variety of grid services using the network of installed Powerwall batteries, delivering dynamic capacity (energy reserves that can be dispatched when they are needed most) and additional grid stability, while sustainably lowering costs for all utility customers.

Tesla will also work with Green Mountain Power to dispatch the aggregated resource into New England’s wholesale electricity markets, producing additional savings for customers in the region.

The Green Mountain Power program is just the beginning. Tesla is working with energy retailers, grid operators, utilities and aggregators across the globe to unlock the ability for Tesla batteries to deliver grid services while providing reliable power at all times of day. As the deployment of Tesla batteries continues to accelerate, we can scale the adoption of renewable energy, cost-effectively modernize our aging infrastructure, and improve the resilience of our electric grid to benefit everyone.

To find out more about how to aggregate Tesla batteries to strengthen the electric grid and accelerate the transition to sustainable energy, visit