Using Tesla car as free storage for renewables — feature suggestion

[Robert.Boston]

And in case anyone thinks that there isn't a problem...

PG&E (the SF utility) is in the middle of its RFO process to acquire 1,500 GWh of renewable power starting 2020. In that RFO, and emphasized on the bidders' web-conference, PG&E highly values the ability to curtail a resource to avoid periods when taking the power would cause system issues. The California energy markets (like most modern market designs) can put a negative price on power, i.e. you have to pay to inject power. Likewise, you get paid to use power. This is not just some far-out unlikely scenario, but something that PG&E thinks serious enough to include (and emphasize) in its bid process. If you were in a position to draw power out of the grid during these periods (or even in periods when the price was very low), you could see a real financial up-side.

 

[stopcrazypp]

Whole bunch of different things bring discussed.
V2G is a set of technologies that allow the grid to control EV charging. It does not necessarily mean electricity delivered to the grid; it can also mean charge throttling.
Couple of distinct ideas discussed already:
1) electricity from EV to grid
2) charge rate throttling (during user initiated charging session)
3) power company initiated charging session (to avoid renewable source throttling)

2&3 seem to be no-brainers (doesn't really cost EV owner anything).

1 does not make much sense for low cycle life battery cells like what Tesla uses, but might make sense for high cycle life cells like a123 or SCiB. As for the upside for the power company vs a stationary installation, they only have to pay the marginal cost of using the battery cycle, plus they don't have to finance a large sum of money nor are they at risk of under-utilization. That's why bi-directional power is not a dead end idea.

 

[callmesam]

Can Tesla do it better than Nissan?

http://green.autoblog.com/2013/12/10/six-nissan-leaf-evs-power-an-office-in-japan/

Tesla batteries should have a lifespan of 2-3K full cycles. Why not use a bit of that in grid buffer at work or home?

 

[Robert.Boston]

Can Tesla do it better than Nissan?

http://green.autoblog.com/2013/12/10/six-nissan-leaf-evs-power-an-office-in-japan/

Tesla batteries should have a lifespan of 2-3K full cycles. Why not use a bit of that in grid buffer at work or home?

Because it's a very high-cost buffer. If LiOn batteries have about 1,000 full cycles before the degradation makes them unuseful in a car, that means you have about 85,000kWh to amortize the replacement cost of the battery. Assuming 7% annual reduction in cell unit-costs, but no reduction in other component costs, the replacement cost will be about $30,000. That puts the unit cost at about $0.35/kWh (about $0.12/mile), or $350/MWh. That figure is far above the cost of using grid services nearly always nearly everywhere.

I can only see sufficient value as an emergency power source during an outage.

 

[callmesam]

Because it's a very high-cost buffer. If LiOn batteries have about 1,000 full cycles before the degradation makes them unuseful in a car, that means you have about 85,000kWh to amortize the replacement cost of the battery. Assuming 7% annual reduction in cell unit-costs, but no reduction in other component costs, the replacement cost will be about $30,000. That puts the unit cost at about $0.35/kWh (about $0.12/mile), or $350/MWh. That figure is far above the cost of using grid services nearly always nearly everywhere.

I can only see sufficient value as an emergency power source during an outage.

1. 1000 full cycles before degradation?

2. Unuseful in a car? Please define as status of charge.

3. Can't I run the nuts off the pack and hook the pack up to the grid at my house?

4. If I get a new battery from Tesla for the car, then I can be a mini electric company. I buy power when it's cheap and sell when it is expensive. Use what I need. Pay (or get paid!) the difference. Add generation (solar, wind, water) as needed. AND solves the problem of intermittency.

I would sign up for this if Tesla Motors would jump in.

 

[Tharo]

I've always thought that electric cars are the perfect complement to renewable energy, but not controlling Tesla recharging, the electric companies that should put charging points in workplaces where cars spend 8 or 9 hours every day standing , where recharge would be triggered only if there is excess electricity into the grid at the time, and you always need to provide an incentive to users to make them , they could offer as cheap as they get their electricity at night . And always serious network recharge the car, never backwards to avoid damaging the batteries.
Taking advantage of the Tesla batteries are high capacity and with future developments of batteries only have to recharge every few days , you could refresh only when there is excess electricity.
I am from Spain , and as the first country you mentioned , I am happy to say that right at this moment is covering half of the energy demand with wind energy. Although not all of this December has been so, in Spain a few days ago has been a great controversy because the price of electricity in the last quarterly auction has soared by 11% on a price that was already very expensive, and electric have blamed this December had very little wind blowing over the previous year, but just a few days after there has been a storm of wind and electricity prices in the wholesale market has gone from 71.64 € MW/h on Sunday to 5.42 € MW/h yesterday .

In this chart you can see in green the amount of wind energy produced now and in yellow the total energy demand .

Here you can see the mix of production now in Spain.

 

[PV1]

What it sounds like the OP is proposing to me is that real-time grid energy generation and usage is monitored, and when there is a considerable amount of excess power, trigger cars in the affected area to soak up this excess. The cars do not feed power back to the grid when demand is tight, it is only one way.

What could easily be done on the car side is have Tesla add parameters to allow the owners to define how many miles or what SoC they want the car to charge to. Say an owner drives 75 miles a day quite regularly. They could set the car to charge to a certain SoC or to 100 miles, for example. This way, the owner ensures they have enough charge, but the car still has enough spare capacity to soak up quite a few kWh's. There could also be an on-screen button to bypass the limit for the current charge cycle to allow a full charge in preparation for a trip.

On the grid side, communication equipment of some type (OVMS or Tesla API?) could interface with the car to trigger charging to absorb excess. This would allow the cars to charge above their defined stop points until the surplus ends, at which point the cars stop charging. The cars would use this surplus power to drive, and won't start charging until SoC falls below the threshold, or overrided by user preference.

In day to day use, the car routinely charges to 100 miles, then stops. One day with excess power available while the cars are charging, the owners come out and find their cars with maybe 250 miles of charge. They can use the excess charge, and their car, even if plugged in, won't charge until there is less than 100 miles on the charge, it gets temporarily overrided by the owner to prepare for a trip, or if they change their threshold. Also, battery life is extended by keeping the battery in a central SoC and by not increasing cycle count.

 

[Evpro2]

Does the MS have a 120VAC outlet for camping and home emergencies, and if not, why not?

 

[spleen]

Does the MS have a 120VAC outlet for camping and home emergencies, and if not, why not?

1) it does not and 2) you'd have to ask Tesla

 

[ndavis6]

This scheme is very similar to the one my company, WattTime, is implementing. We are developing a tool to shift charging times from dirty (high carbon production) to clean (low carbon production) times. We are curently developing a Tesla application which would automatically select the best time for charging while ensuring the car is fully charged in the morning. If anyone is interested in being part of our Beta testing team, please PM me.
Nate Davis | watttime.org

 

[TheTalkingMule]

1) it does not and 2) you'd have to ask Tesla

Aloha! When I first say this concept I immediately thought of Hawaii. As you know they have tons of solar, so much solar that they have to throttle installs to save the grid. What if the state of Hawaii pushed the entire rental car operation on Oahu to grid-tied pure EVs and placed dedicated parking spots all over the island as part of a solar dump initiative?

All rental companies would be required to be tied into the Hawaiian Electric smart grid/smart charging system. In and around the major tourist areas and airport there are smart charging spots for these vehicles. Users will be incentivized to keep their car plugged in by only being charged for "unplugged" rental time. You get in(theoretically any vehicle) and use your smart key to operate the rental. Smart charging could keep these things at around 50% charged until 11am then start ramping them up to 90% as the solar capacity begins to outshine demand.

Seems to me the OPs idea really only makes sense if you have control of the entire system and there is clear incentive to keep vehicles "online".