Interesting side problem on solar photovoltaic power systems in Hawaii.

[MechAg94]

Why not just require all the solar systems installed have a battery back system in place to handle short term issues like clouds?

[AZRedhawk44]

The reason "solar sucks" is because everyone is doing it wrong.

They're doing it wrong, because the "experts" tell them the best way to do it, is to slave your residential solar system into the grid.

That's a great big bucket o' stupid, right there.

The right way to do solar, is to have a PV-solar array in your home pumping into a battery bank and charge controller, with an AC inverter pushing dedicated off-grid circuits.  No messy grid integration.  No worries about your AC being in-phase with the grid.  No worries about power distribution or demand problems.

Put the high amperage intermittent use devices onto the grid, and your low amperage long term use devices onto your solar circuits.

If you really want to get fancy, have an electrician tie a make/break knife switch into your home mains that switches the home grid from city power to solar power if you routinely experience grid failure and want to distribute your solar power across your grid-dedicated home circuits.

Screw grid integration.  It's stupid.  They pay you a fraction of the value of the power.  Independence is far more valuable.

[Fitz]

Yeah, that is what every one things until Democrats tell them they are rich and will be taxed.

I think you missed my sarcasm

[GigaBuist]

The right way to do solar, is to have a PV-solar array in your home pumping into a battery bank and charge controller, with an AC inverter pushing dedicated off-grid circuits.  No messy grid integration.  No worries about your AC being in-phase with the grid.  No worries about power distribution or demand problems.

Put the high amperage intermittent use devices onto the grid, and your low amperage long term use devices onto your solar circuits.

Something I ponder every now and again is if you were running solar and wind at home, powering a battery bank, is how much gain would you get if you were to wire up the house to run off DC power?  That way you're not inverting it back to AC and switching it back for DC usage.  If we could start standardizing everything to run off, oh, 24V, wouldn't that get us some efficiency gains?

Google does something like this in their data center shipping containers.  The computers are all designed to run off 12V DC, no 5V/12V mix like you see on most computers.  Every computer has it's own UPS that supplies 12V DC, no inversion needed.  Instead of having a PSU on every machine stepping it down they just do it once for the data center and pipe that feed into the computers.

Another idea I had, when my wife was telling me about some island in the Florida Keys where grid power isn't available, they all do solar, but they have problems where you flip the microwave on and you get a house-wide brownout, is making intelligent devices that can be programmed with a priority.  Your central power supply can blit out some kind of current performance level and if you flip on a microwave when there's not enough power half the lights shut off, or all go off, or just down to "emergency" levels until the high draw device is done.  The fridge and freezer could be smart enough to hold off from kicking on until power was available, unless it was absolutely required, but an event like that could force all of the stupid stuff like TVs to shut off.

Unfortunately neither idea is easy achievable unless there's a major revamping of our entire appliance and lighting industry, or the person implementing it has the skills to rip out the PSU of every device they own and replace it with a custom job.  So, a bit of a pipe dream.

[AZRedhawk44]

Something I ponder every now and again is if you were running solar and wind at home, powering a battery bank, is how much gain would you get if you were to wire up the house to run off DC power?  That way you're not inverting it back to AC and switching it back for DC usage.  If we could start standardizing everything to run off, oh, 24V, wouldn't that get us some efficiency gains?

Use RV lighting equipment and you can go DC for your household illumination, at least.

Switch the stove to natgas.

Never heard of a DC microwave.  Probably could be done, but they don't even do it in RV's.  They do make DC fridges, but they are twice as expensive as conventional ones.  When your juice is free off the solar array, it don't much matter how much electricity loss you have from inversion.

The good thing, is:

You can rig your household direct-DC illumination off one or two new circuits very easily, through the attic and ceilings.  You don't have to rip out all of the existing circuits en mass and replace them under the same wiring plan.

[geofan]

This problem is not a problem at all with renewable , taxes . but instead a problem of storage ie batteries/ the best when considering degeneration, line loss , inverter loss ect is hydrogen . fuel cell power plants are an up and coming phonomonome and home systems are well outside the current ROI projections with exception to very large industrial apps. So really the only problem is not one of tech , not one of knowlege , but instead one of money . My question is why is it ok for our gov. to allow GE to pay next to no taxes , oil companys to see a net gain for the privlage the gov gives them to rip us off , but the second someone wants to fund something that actually works and makes sence . every cry baby rich boy wets his pants

things that make me say hmmmmm   

[GigaBuist]

When your juice is free off the solar array, it don't much matter how much electricity loss you have from inversion.

Ah, but it does matter when the sun isn't out and you're running off your bank of batteries.  That's why Google does everything on 12V DC. 

Granted, for home applications with a variety of stuff running off that battery bank it's simply cheaper to pile on more batteries.  But if we had the gumption/resources to rework everything like Google did, well, I wonder what could happen.

As I understand it, and I'm not an EE nor do I know much about electricity, every transformer plugged in has a "phantom" draw and basically everything does an AC -> DC transformation in a PSU of some kind. Consequently even appliances that are off have some kind of draw.  One well made transformer in the house stepping things down to 12V or 24V DC could net us some efficiency gains and make for an easy transition over to battery banks too. 

I believe it would also make capturing the waste heat easier. If I reach over and grab the power brick supplying this laptop it is warm to the touch.  It's only job is to transform AC to DC.  If I just had one big transformer in the house doing that for every appliance I could capture the heat off it and use that for the water heater or furnace.

I don't expect that any of these ideas I'm tossing out are cost effective.  They're just pie-in-the-sky thoughts and general ramblings.  I'm not trying to be argumentative or proving a point, just thinking out loud.

[Jim147]

They got rid of PCBs. Good luck on finding a large enough well made transformer.

If you can find a used RV ammonia fridge, it will work off 120, 12 Volt or propane. It's just not a good choice for cooling or freezing large amounts of food at once.

Some of the newer 120 volt fridges use less then 2 amps to start. It's the defrost heater hitting 400 watts that suck down the power about three times a day.

Maybe building an inverter all refrigerator with an off cycle defrost (non heated) would be a good option for the home owner off the grid.

I'll have to think about that one. I think they are going transformer to inverter but I'll have to reread a book.

jim