Solar and backup options

[bliss]

Well, CA is now a nightmare when it comes to PG&E shutdowns (and for many other reasons).

I'm now re-considering solar with my research revealing that solar panels alone will not solve the PG&E shutdown issue since a working utility electricity connection is needed but not available during a shutdown.

So, a backup is also needed. Two choices - solar batteries or a generator that runs on gas, propane, etc. The top of the heap in the batteries area is Tesla PowerWall, but it turns out that that product - one wall - only lasts a few hours with a cost of around $10,000. Plus the Tesla product is not fully perfected at this time.

Therefore, a generator for backup seems like the only viable solution.

If you have input and/or experience with solar or backup generator issues please chime in. Your input will be appreciated.

[bobcowan]

I'm certainly not an electrical engineer, but here's what I think is correct.

Solar panels are used to recharge batteries. Then you run everything off the batteries. You can also use wind power to charge the batteries.

Using LED bulbs are stuff are pretty helpful here. Big appliances like fridges, washers, dryer, will not run very long on battery power.

You do not need a working utility connection. Hook them up the same way you would a back up generator.

Solar can also be used to heat water. Nobody likes a cold shower.

[twobjshelbys]

For generators you have two choices.

1. Get a gas generator at Home Depot and run extension cords from it to your critical appliances, e.g., refrigerator and well pump, etc.

2. Get a generator that integrates into your electrical panel. Most of these will still not power the entire house, only critical circuits that are moved to the switchover box. In the event of a failure the main is switched to the generator and disconnected from the main. Once main power is restored the generator is disconnected and the main is restored.

The first is cheap, the second not so much. The first doesn't require professional installation. The second does. I've wired many homes but the generator crossover switch is something I'd prefer to leave to a licensed pro.

A google search yielded this:

https://www.instructables.com/id/Eas...-Home-Hook-Up/

claims it's code compliant, and the interlock would prevent feedback when on the main, but I'd want to be absolutely sure that your local codes allow it. Secondly, most portable generators only are good for about 30A, so running a whole house that has a 200A main is unlikely...

[eschaider]

At the turn of the century when ENRON was still around and ripping California off for power along with providing brown outs / black outs, I was building a new home. I didn't want to be held hostage by the power gods in Ca and elsewhere so I looked into a whole house generator rather than just a standby auxiliary unit.

The fuel source I settled in on was natural gas and the power generating capability was somewhere around 50KW and it was powered by a water cooled V8 natural gas engine. The price was not cheap as I recall it was just under $19K. Here is a link to a modern Honeywell equivalent that is about $16K, click here => 48KW Whole House Generator.

These are significant pieces of machinery and will require a robust cement pad and periodic usage and maintenance to keep them ready for an emergency. You will need a 200 amp switch and you should get a switch and generator package that auto starts when the power fails.

This type of setup will power your entire house as if there were no power outage. With the increased dependency we have on cell phones and internet today this sort of failsafe provides both full house power especially important for things like refrigerator and freezer operation, A/C operation, internet access, phone charging and TV operation.

The additional cost above that of a $10K alternative and the continuous whole house power capability makes looking at the little stuff a waste of time.


Ed

[olddog]

I believe diesel operates at the lowest $/Kwh rate. A large fuel tank, not so handy as a Ng line.

Look at the newer better generators that back down to an idle at light loads. I believe these use an AC inverter to continuously give out a 220 volt 60 Hz power regardless the engine speed. I have not dug into the details of how they work, so there are assumptions in what I believe.

The old syle generators require an exact engine rpm to get 60 Hz. Engine RPM affects voltage and the load affects the voltage. At light loads the voltage floats higher. Engine governors are generally a spring pulling against a wind flap or a centrifugal weight system. Therefore they are a proportion only controller, with no integral to trim the rpm to the set point. This mean there is only one load level that the voltage and Hz is dead on the money. So voltage can go high enough to cause plug in surge (voltage spike) protectors to trigger. Since the problem is not a short spike, but a continuous condition, these surge protectors can overheat and catch fire. I have done it. My father has done it. I know dozens more who have had it happen. Stay away from cheap stand alone generators. Trust me on this point.

[eschaider]

You're spot on with your observations olddog. The particular Honeywell unit I had referenced provides the sort of 'special' operational benefits you were speaking to. Because the engine is a 5.4L V8 they can run at a relatively low engine speed which is good for noise abatement but also fuel consumption and engine life.

The particular generator I tagged provides a regulated supply of power similar to the public utilities power grid which is essential for computers, modems, routers etc. Your point about the variability of some standby power generators is particularly important if you are planing to power any electronics. You not only risk unpredictable operation but without something like a standby UPS to filter the power you can fry the electronics if a power spike is sufficiently robust.

Again your observations about diesel being less expensive are spot on. The ability to have a generator that does not require filling a diesel fuel tank along with the always ready and essentially uninterruptible operation was the primary rationale behind my natural gas selection for the fuel.

I suppose there are also some benefits from not having the smell of a diesel and the exhaust soot after operation. The flip side of the coin (with respect to availability) is when the natural gas delivery infrastructure is damaged. So far, in my life, that has only happened once and of course it was in California —fortunately near San Francisco where the underground piping is the oldest and farthest from me.

Lots of considerations if someone decides to pony up for one of these things. The individual person's mix of needs, wants, price sensibility along with frequency and severity of outage will typically drive the potential buyer to a wide variety of choices for their installation.


Ed