OT: Electric Vehicles--anyone driving them or seriously looked at them?

[Davist]

Originally Posted by tomato coupe

The question still remains; why doesn't a solar setup without battery backup disconnect from the grid and power your house during an outage?

As above, backfeeding the grid is a safety concern.

For the "islanded" operation (ie off grid), the issue comes when you transfer back with frequency needing to be in sync (typically for diesel gensets it's 5 electrical degrees). The reason most inverters are tied to the grid is so that they're in sync and thus don't need to worry about being out of sync, you use the utility as the frequency guide..

Imagine losing power, then when it comes back, the grid can be at a different point in the sine wave than your inverters. If both are at 60Hz, they'll never get in sync and if you connect out of phase, it can be catastrophic, and the grid wins, which means trouble on your end. When you set gensets up, you purposely put them at 61Hz or similar so they'll get in sync passively then transfer back at that time.

With inverters, you'd need to do similar, but at a residential level, most folks wouldn't pay for the controls needed or the upkeep, so you restart every time. Commercial installations call this type of control either parallel with utility (and each utility has different rules on controls) or more lately a microgrid.

[windsurfer]

Originally Posted by dustyrider

I’ll just stick this in here for good measure: Mike Prowse

That would be Will, not Mike.

[AngryScientist]

Any other dinosaurs here ever synced a utility scale generator to the grid manually using a syncroscope? Ahh, that satisfying bang of a breaker closing and a terrifying second to check machine RPMs to make sure you didnt break anything

[dgauthier]

Originally Posted by AngryScientist

Any other dinosaurs here ever synced a utility scale generator to the grid manually using a syncroscope? Ahh, that satisfying bang of a breaker closing and a terrifying second to check machine RPMs to make sure you didnt break anything

"Slow"..."Fast"...I love it. How old is that 'scope in the photo?

[AngryScientist]

Originally Posted by dgauthier

"Slow"..."Fast"...I love it. How old is that 'scope in the photo?

probably 60's vintage, but I guarantee you there are still very large power plants operating today with meters exactly like that to sync generators to the grid.

[NHAero]

Originally Posted by MikeD

I don't know for sure but regulating the power output is probably too hard to do without batteries (think when a cloud shades the panels and the power level drops). Fluctuating input power to devices in the home could be damaging.

This looks promising https://www.solarquotes.com.au/blog/...verter-mb1494/

It's easy to do with some battery capacity. You have a transfer switch just like a generator does.

I'm probably going to add a system to my house that will put a small battery bank and and good sized split phase inverter in place, and a manual transfer switch to keep it simple. And then trickle charge the battery bank (say, 2-4 kWh - a Tesla Powerwall is 13.5 kWh) from the Chevy Bolt EV, whose traction battery is 66 kWh. The trickle charger connects to the 12V battery, and the traction battery keeps it charged via the onboard DC-DC converter.

The car could easily power us for a week or more, as long as we were judicious in what we tried to run. I have circuit datalogging on my panel so I know, for example, that my 15 ft3 chest freezer and my refrigerator both use about 1 kWh/day, the heat pump water heater a bit more, and lights and plug loads are another 1 kWh/day. We wouldn't be powering the range - electric kettle, microwave, and toaster oven would take the cooking duties.

There's a way with more cost and complexity that I could add my 5 kW solar array into the system but I don't see that being necessary - unless we were hammered by a Cat 5 hurricane and power out for months.

[Davist]

Originally Posted by AngryScientist

Any other dinosaurs here ever synced a utility scale generator to the grid manually using a syncroscope? Ahh, that satisfying bang of a breaker closing and a terrifying second to check machine RPMs to make sure you didnt break anything

that's relatively modern, (or I'm relatively jurassic!) we used those "iron vane" synch in the late 80s when I was getting started. Had a big CAT ~2MW V16 close 90* out one time and I was nearby, wow!! never saw anything that big move and jump around

Rumor has it that the real old stuff, was all 25Hz at Niagara Falls (still some 25hz in Buffalo) and that worked by flashing light bulbs.. (hence the 25hz, 60 was too fast to see!)

[windsurfer]

Originally Posted by AngryScientist

Any other dinosaurs here ever synced a utility scale generator to the grid manually using a syncroscope? Ahh, that satisfying bang of a breaker closing and a terrifying second to check machine RPMs to make sure you didnt break anything

Yep. Power electronics as an undergrad a long, long, long time ago.

[Spaghetti Legs]

Originally Posted by AngryScientist

Any other dinosaurs here ever synced a utility scale generator to the grid manually using a syncroscope? Ahh, that satisfying bang of a breaker closing and a terrifying second to check machine RPMs to make sure you didnt break anything

Oh yeah! We had that on my ship, 600 psi steam and used when parallel-ing generators or switching ship to shore power. This was early 90’s but the ship was built in the late 60’s

[oldpotatoe]

Originally Posted by David Kirk

I too wondered about this and my wife had to educate me on this. My wife's work delved deep into this and it turns out that not all crude oil is the same and that it's destined to be turned into different end products. I used thing that "crude oil is crude oil" and that it's all the same and that it can all be turned into gasoline. I was wrong.

Some oil is turned into gas, some into diesel, some into lubricants, some into plastics, some into jet fuel, some into....etc.

The vast majority of oil that the USA exports is not the type of crude that would be turned into gasoline to power cars and it's sold onto the open global market and exported to places that specialize in a given type of production.

dave

I understand than and I was responding to saab2000

I for one would like to try to move past fossil fuels, especially ones imported from places and nations that would love to see us at best fail and at worst would destroy us.

A favorite sound bite is the US being 'energy independent'..and while we export more than we import crude oil is going to be part of the world's economy for a long time.

I applaud you 'doing your part' to reduce CO2..bravo but I'm a 'little' more pessimistic, seeing where 'we' are headed...

[oldpotatoe]

Originally Posted by MikeD

I've got solar power and it makes more power than I use. How come nobody is talking about that? Without that, an EV would make no economic sense, since electricity rates in my area are among the highest in the country.

Well, around here, when certain home builders wanted to include solar on every roof they built, the cry from the local energy company was loud enough that it was nixed. Buy a home and install on your $, fine and dandy but OMG, not on new homes by the builder.

[oldpotatoe]

We export more oil than we import..how does that make any sense?

Originally Posted by MikeD

We don't anymore. That's changed.

We forecast that the United States will continue to import more crude oil than it exports in 2022, reaching an estimated annual average of 3.9 million b/d. However, we expect net imports to fall to 3.4 million b/d in 2023 as domestic crude oil production increases to an all-time high of 12.6 million b/d.

For info

[MikeD]

Originally Posted by Davist

As above, backfeeding the grid is a safety concern.

For the "islanded" operation (ie off grid), the issue comes when you transfer back with frequency needing to be in sync (typically for diesel gensets it's 5 electrical degrees). The reason most inverters are tied to the grid is so that they're in sync and thus don't need to worry about being out of sync, you use the utility as the frequency guide..

Imagine losing power, then when it comes back, the grid can be at a different point in the sine wave than your inverters. If both are at 60Hz, they'll never get in sync and if you connect out of phase, it can be catastrophic, and the grid wins, which means trouble on your end. When you set gensets up, you purposely put them at 61Hz or similar so they'll get in sync passively then transfer back at that time.

With inverters, you'd need to do similar, but at a residential level, most folks wouldn't pay for the controls needed or the upkeep, so you restart every time. Commercial installations call this type of control either parallel with utility (and each utility has different rules on controls) or more lately a microgrid.

I rarely get power failures, so upgrading my solar system to provide emergency power would not be cost effective. However, if I lived in an area that subject to wildfire power shutoffs, I would look into it.

[tomato coupe]

Originally Posted by oldpotatoe

Well, around here, when certain home builders wanted to include solar on every roof they built, the cry from the local energy company was loud enough that it was nixed. Buy a home and install on your $, fine and dandy but OMG, not on new homes by the builder.

Where do you get that from? Many new homes in Boulder have solar panels on day 1. In fact, it's very difficult to get a new home approved without solar panels.

[Davist]

Originally Posted by MikeD

I rarely get power failures, so upgrading my solar system to provide emergency power would not be cost effective. However, if I lived in an area that subject to wildfire power shutoffs, I would look into it.

yes, agreed, it would be worth the additional cost to be able to run "islanded" and have a short "re start" of the system when the utility comes back. I don't think it's feasible to have the no break when coming back to utility power, as the utility doesn't want the parallel time with residential users.