Anybody here using solar power?

[Sooner or later]

I do have NG for water heater and emergency heat. I have been spending about $800 a year on electricity and $600 a year on NG. 2600 SF home.

[red-beard]

Originally Posted by jyl

As mentioned the NREL site says I can generate $481 of electricity annually with rooftop PV.

I found another site, which exposes the details a little more. Below is a screenshot of the result I got. This is with manually specifying as many panels as will physically fit on the roof. The site's default output had fewer panels.



Does this mean that I simply can't use solar to generate all my home electricity, unless I can cut consumption by 50%? It looks like my house simply doesn't have the right roof area to interior volume ratio, plus I live in the rainy side of Oregon.

You can always put in ground mounts, if you have the space.

[red-beard]

Originally Posted by jyl

As mentioned the NREL site says I can generate $481 of electricity annually with rooftop PV.

I found another site, which exposes the details a little more. Below is a screenshot of the result I got. This is with manually specifying as many panels as will physically fit on the roof. The site's default output had fewer panels.



Does this mean that I simply can't use solar to generate all my home electricity, unless I can cut consumption by 50%? It looks like my house simply doesn't have the right roof area to interior volume ratio, plus I live in the rainy side of Oregon.

The issue is "insolation" aka incoming solar radiation. If you have cloud cover most of the year or are at a high latitude or both, you will not generate a lot of solar electricity.

I usually run the calculations FIRST with a 1kW system to see the average kWh/kW installed. Then I size the system to offset the electric usage.

This is really far more compicated when you consider if you have net-metering, or not, and if the net-metering is full retail or partial re-payment.

MY electric provider will pay me exactly ZERO for electricity sent to the grid. Nada y Nunca! For me to take a 50% run, I have to switch to a $0.10/kWh plan. For full freight, I'd need a $0.15/kWh plan.

[RWebb]

Originally Posted by red-beard

You can always put in ground mounts, if you have the space.

and they can be elevated on posts to form a shed, just the right ht. to park a car under...

[dan79brooklyn]

We had solar 40 solar panels put on our roof this year. They’ve been generating approximately $200 of electricity per month. We paid zero for the install, we’re essentially letting the company that installed the system have all of the money for eight years and then they give us the system for free.
Hopefully by then we can get an electric car and use the car’s battery to power the house at night.

[jyl]

Originally Posted by red-beard

You can always put in ground mounts, if you have the space.

No space. Tiny lot.

My buddy a few blocks away gets enough electricity from roof panels to have zero net electricity bill over a full year. But he has a single story house with much larger roof to volume ratio. He has an EV, and some sort of electricity plan with time of use pricing, he charges the EV at night and generates electricity in the day.

[red-beard]

The larger panels are 1mx2m. Some of those can produce 450 Watts.

To me, if we can get to 50%, that will be the game changer. Even small buildings will benefit from solar.

The problem with Portland, so many cloudy days. The good news, with diffuse light you can mount the panels anywhere. Angles and direction pretty much do not matter.

[RWebb]

How long are you willing to wait?

they are doing R (& some D) into various ways to make PV panels more efficient esp. at lower light levels - you might have to wait many years tho... also, the convertors and structure for PV panels now may work fine for nex gen panels

[red-beard]

What I see is wavelength "tuning" with multiple layers. I bet less than 10 years to 50%. Cost will not be an issue.

On cost, the PV Panels are the cheapest part of the system. The Racking, inverters, protective breakers/fuses, cables and labor are far more. For most of use, it makes sense to just add a few more panels than to do tracking.

[RWebb]

yes, that is one direction

also a lot of news about perovskites

How long you stay in the house is an issue too

[red-beard]

The perovskites are the ones that are cheap and easy to tune. They have degradation issues that need to be solved.

[RWebb]

yes - last I checked they were trying to filter thru the numerous possible paths for degradation to see which ones should be addressed first

[jyl]

I will need a new roof in a couple years, and that is motivating me to look seriously at this now.

I will also need a new panel as mine is at the end of its breaker capacity. I've had to install two subpanels. The old panel is right next to the laundry sink which is no longer legal (surprised it ever was). I think it'll be easier to move the sink than relocate the panel.

If I do this, I'll want a charging station for an EV in the driveway.

[biosurfer1]

Originally Posted by jyl

If I do this, I'll want a charging station for an EV in the driveway.

Anything more than a 240V charger is Overkill and when (not if) residential demand charges come, anything more will be an expensive paper weight.

Hell, with some of the highest efficiency HVAC units out there, even the 240V quick chargers could be setting your demand charges right now.

[tdw28210]

Have 10.4 KW an array on the roof. Pro tip; if you live in area with squirrels, get the base of the panels blocked off by screens - aka Critter Guards. It seems squirrels like the cozy quarters of the panels near the roof. And then sometimes gnaw on the wiring to pass the time.

[red-beard]

Originally Posted by biosurfer1

Anything more than a 240V charger is Overkill and when (not if) residential demand charges come, anything more will be an expensive paper weight.

Hell, with some of the highest efficiency HVAC units out there, even the 240V quick chargers could be setting your demand charges right now.

Most of the level 2 chargers are 16 or 32 Amp. Some are 40 and 50 Amp, which assumes the car can accept that.

16A = 3.8kW
32A = 7.6kW
40A = 9.6kW
50A = 12kW

Any 14 Seer Air Conditioner under 4 Tons will be under 3.8kW

[gregpark]

Pulled the trigger and signed a contract yesterday. 10.4 KW in panels, new main breaker box swap out included for 27K.
Should pay for itself in 5 years, I have plenty of sun. The rebates are going away and I figure now is the time. Panels are better and cheaper too. Nicer looking blacked out panels and I don't have to lift a finger. Seems like a no brainer, time will tell I guess but everyone I've talked to says they wished they had done it years ago

[red-beard]

At the price of electricity in California, it makes sense to put in solar

[Evans, Marv]

Originally Posted by gregpark

Pulled the trigger and signed a contract yesterday. 10.4 KW in panels, new main breaker box swap out included for 27K.
Should pay for itself in 5 years, I have plenty of sun. The rebates are going away and I figure now is the time. Panels are better and cheaper too. Nicer looking blacked out panels and I don't have to lift a finger. Seems like a no brainer, time will tell I guess but everyone I've talked to says they wished they had done it years ago

I think you got a decent deal. My 7.75kW system cost $27K (before rebates, etc.) four & a half years ago. I think your 5 year payback time is a little optimistic. I roughly estimated my payback at six years, so I have about a year & a half to go.

[gregpark]

Probably right. I did quick math in my head on the 5 year recovery. However, we have been running the AC many more days these last 2 summers and PG&E does continue to raise its prices every year (nowhere else to go but solar). It appears that the decision will pan out no matter. Also, regardless of the money saved in the long run, I'll be enjoying the satisfaction of cheating PG&E out of some of their blood money. That alone is worth something to me.