On Aug 22, 2024, at 2:21 PM, Lawrence Garwin via <lawrencegarwin@...> wrote:

I beg to differ!

Every PV to grid setup (rooftop solar) has a grid following inverter that disconnects from the grid when it is down.

This is a proven and approved technology. ?It is safe for line workers.?

Illustrating this, Ford’s V2G (V2H until utilities allow V2G) inverter is a modified Sunrun rooftop solar inverter. ?(V2HG/H/L = Vehicle to Grid/Home/Load)

DIY folks have used off the shelf grid-tie solar inverters to do V2G, but they are either on at full inverter capacity or off. ?I know of an individual that uses this technique to extract DC current from an unmodified EV via its charge port and puts 5KW onto the grid.?

This by itself IS a fine solution for shedding fossil fuels from the grid. ?Understandably, the utilities would like to have some say as to when these blocks of power are added to the grid, but currently they don’t seem interested in allowing it at all.

Perhaps a Virtual Power Plant could step in to do the inverter coordination and sell the power on the 15 minute spot market, as there are the highest contract prices for electricity.?

Using stock PV inverters doesn’t allow for V2Home or V2Load, but those are unimportant in solving global climate change.?

Please lobby your PUC, utilities, politicians, vehicle and charger manufacturers, and VPPs to add budget electric vehicle based grid storage to our climate recovery portfolio.?

Thanks.?

Lawrence?

On Aug 22, 2024, at 1:48?PM, Arthur Keller <arthur@...> wrote:

?What's delaying
V2G?

Fear of power leaking onto grid when the grid is down. ?In other words, energizing a line when it is down is dangerous to line workers trying to repair the outage.

Best regards,

Arthur

On Aug 22, 2024, at 1:06?PM, Jeff Chan <eaasv@...> wrote:

On Thu, 2024-08-22 at 21:04 +0300, David Herron wrote:

The combination of wind+solar+storage (and maybe hydro) is a
renewable
energy solution.

Apparently, California now has enough grid-scale storage installed
to be
able to time-shift lots of excess solar-power from daytime
production to
evening consumption.? I know of this from Tweets by Prof. Mark
Jacobson
throughout this year.

The issue is what's called "The Duck Curve" which refers to the
shape of
energy production on the grid as more and more solar resources come
online.? When the evening comes, the sun goes down, the winds tend
to die
down, then renewable energy is not available, and the utility
companies
have to quickly ramp up something like natural gas peaker plants.

The purpose of the grid-scale energy storage is to instead soak up
solar
energy during the day, release it during the evening/night, and
avoid using
fossil fuel plants.

"Energy storage" doesn't have to be lithium-ion batteries.? For
example
there is "solar thermal" systems that can heat up something simple
like
rocks, that can later be used to drive a turbine.

Thermal storage is about 60% round trip efficiency. ?Can be higher if
the heat has other uses, like heating.

Battery round trip efficiency is about 80%. ?Pumped hydro and gravity
storage about the same.

One massive storage resource currently being underutlized is Vehicle
to Grid. ?

Perhaps David has good numbers for this, but how much potentially
useful grid storage is there in EV battery packs? ??What's delaying
V2G?

Cheers,

Jeff C.