How many of you have solar panels?

[Dream of Freedom]

With the plethora of ecologically minded people here and after reading that solar is becoming competitive with fossil fuels I was wondering how many of you had made the move to solar.

[jacob]

Not here. Economically, it doesn't make sense. Since we're using ~10% of the electricity of the average American household, the payoff time for even a small system is decades. It would make a lot more sense if our consumption was larger.

Add: IL/ComEd does have some kind of system where excess electricity can be sold back for credit. (This was the case last year when I looked into it---It wasn't the case a few years ago when I first looked into it.) Also, there's some kind of trading system in which the state will give you cash for providing green energy. This still seems to be at the stage of "if you're interested in this, please call this advisory number and talk to ...".

That said, a medium sized 2000W panel system is next on my wish list. I don't want to commit to batteries as that does not make sense at all because that's an ongoing expense as they need to be replaced <10 years---it's cheaper just to pay the grid fees and taxes. I consider the 2kW as a backup in case the local powersystem goes down during a 100year heatwave. This would allow us to run a small one-room A/C during daytime. Since we don't have children <5yo or old people >65yo in the house, it would be possible to simply suck it up. Having experienced [how 3+ weeks of constant mild heat exhaustion with no relief feels during] the 2003 European heatwave (that resulted in ~30,000 attributed overdeaths, primarily old people), I'm willing to buy that kind of "hardware insurance".

PS: The nearest house I'm aware of with PV installed is about 2 miles away. Solar is somewhat of a rarity around here.

[prognastat]

None here as there is no requirement here for the power company to buy back energy or even offer to trade energy delivered back to the grid at other times meaning you have to either see a lot of generation go to waste or make up a lot with grid power severely limiting the financial viability. It's still likely to eventually come out cheaper, but not in under 10 years.

[luxagraf]

Lived off 300W of solar with 220ah of batteries in an RV for two years, not sure if that's ecologically minded or not, but it did give me some perspective on solar. Solar is great, if you adjust your lifestyle to the point that you hardly use any energy. In an RV solar still makes sense because there really is no other choice, but after you make that adjustment, as Jacob points out, economically (the upfront investment), it probably won't make sense for most people in stick houses.

If you are looking to go from grid energy to solar without adjusting your lifestyle first. gods help you, you're in for some learning.

[thegreatvoid]

We have a very old photovoltaic system .

[McTrex]

We have a 5400WP installation on our roof, together with a 40 vacuum tube solar collector for hot sanitary water. Around us are quite a few roofs with solar panels, maybe 5-10% of the roofs. In the Netherlands, any solar power you generate is subtracted from your energy use throughout the year, although that’s about to end in 2020.

[Lucky C]

Yes, Rhode Island had excellent solar incentives, so my rate of return is about 12% despite not doing any of the work myself. I have 12 panels installed by RGS Energy (highly recommended especially vs. SolarCity) that are metered separately. So I still get my regular electric bill but it's like I have my own little power plant that makes a profit. I got the 30% federal credit and get paid 38 cents per kWh by National Grid for what I produce, with both these benefits being phased out. About $11k installed after the credit, earning me about $1.4k per year. Although I consume more than I produce, I still get paid more than my electric bill since they pay out so much per kWh. This is a 15 year constant contract (I don't get paid more when electricity costs rise), after which I can just switch to net metering.

[7Wannabe5]

I have a portable 60 watt set that I use when I am off-grid along with a 23000mAh, 100W max battery bank. I think J.M. Greer hit it on the nose when he noted that it is best to reserve electricity for transmission of information. I would suggest that air circulation could be another appropriate use. Very little electricity is needed to just provide enough light and power a phone and/or radio and/or small computer and run a couple small fans.

Of course, there is currently no shortage of fire wood in Northern Michigan, so obvious choice for heating fuel.

[bostonimproper]

Solar is so heavily subsidized in Massachusetts, that if you have a relatively new roof it makes more sense economically to get it and even oversize your array to feed back to the grid (which is what we've done, selling the excess credits to our friends) than to stay on conventional. In addition to the 30% federal subsidy, you get $1000 rebates, net metering, and SREC payments ($285/MWh generated, phased out over 10 years), and heavily subsidized zero-down loans (interest rate offered under our city's program was 1%, looking back I wish we'd used the loan instead of cash).

Our 6.2 kW system was $13k after rebates, expected payback period around 7 years.

[Gilberto de Piento]

I don't have my own panels buy I am paying extra on my bill to use only "sustainable" power sources (supposedly).

If I was living in a house I planned to stay in it would be great to have solar for ffjs reasons but it doesn't make economic sense.

[rube]

A bit if an old thread, but yes we have them on our current house (2100 WP) and I will also get them on our new house, probably around 8500 WP). My preferred target would be to be year round energy neutral or even positive (including heating/cooling).

[steveo73]

I have them. They don't provide all our power but they do kick in a bit.

[fiby41]

Only in my calculator.

[McTrex]

Since my last post on this thread, we added 12 320Wp panels, so we are at 9240Wp now. This was done to offset the charging of our electric car, which we bought around the same time.

So now, when the car is at home during a sunny day, it is charged directly from the solar panels, no grid involved. Feels really good to drive on sunlight

[J_]

I have 2 panels for 6 years now. Next year I will add one more to reach about 750/800 W solar capacity in total. It will be enough for about 3/5 ofour household yearly electricity consumption then. For the missing 2/5 rest I look out for further reducement of our e. consumption.

[mooretrees]

When folks are considering how much of a solar system to build, how do people account for short bursts of high use appliances? For example, we have a very nice professional grinder that works for 30 sec, but it rated at 1000 W. I don't know how to calculate that usage as we're figuring out how much wattage we actually need. We use it maybe once or twice a day.

[jacob]

@mooretrees - The inverter will have a continuous power rating e.g. 1000 Watts and also a surge power rating e.g. 2500 Watts which it can handle for a short time (maybe a few minutes). Your grinder will have similar numbers on the nameplate probably expressed in amps so just multiply by 110V. Specifically it will have a a continuous current rating and starting current (typically 2-3x the cont. rating) that it draws for a short second.

So add up the continuous rating for all the lights and appliances you intend to run simultaneous on top of the grinder. Make the inverter slightly larger than that, like +10-20%. Oversizing reduces efficiency. You don't need to add the surge/starting powers unless you intend to start everything simultaneously. So you're just looking for the maxval for the surge powers which will probably be the grinder. If you want to be nice to the motor (and your electronics), use a pure sine inverter.

The charge controller should be sized to your panels. You can buy both in one package (inverter-charger). In that case, it might be tricky to find the ideal size. The general way of handling this is just to size your entire system according to the average kWh use / average solar input.

[Lucky C]

@mooretrees The vast majority (aka normal people) tie solar to the grid, especially since there is often a significant incentive by the electric company to do so. This means that you are running a small power plant on your roof independent of your incoming power line and energy spikes don't matter. So most people size the system for how much good solar coverage they might get on their roof, or they size it based on their total electrical usage the past year, disregarding how power may vary through the day or year.

For the majority who go off grid, they would be using batteries since it is not realistic to use electricity only when the sun is shining, so you would need to consider what your batteries could supply for continuous and peak power. Off grid is tough unless you live near the equator since you will need a large array to store up power for several cloudy days in a row, and in the winter you get the combo of higher electrical use (ignoring A/C use in summer) with lower solar production. So off-grid seems very wasteful to me due to the larger array and batteries needed. Better in my mind to supply the grid with solar on sunny days and other sources that don't require batteries at night and on cloudy days. But maybe in the future there will be battery and PV improvements such that it will make more sense to go off-grid.

[mooretrees]

@Lucky C, we're planning on trying solar out with our school bus renovation and so will hopefully have very low needs and fewer batteries than a home. I don't think we'll have a fridge and use propane for our cooking heat and wood heat for winter. I wouldn't want to figure out a conventional house for solar as it does seem prohibitively expensive. Our area sun during the winter is fairly low (one chart said around 2.3 hours which seem so so low) so we need to be really smart about usage as we won't be getting much solar in put during the winter.

[Lucky C]

Sounds fun! So you will need to consider battery size to get through times of low sunlight, number of panels to charge the batteries back up in a decent amount of time, and make sure the inverters are a good match for your panels. My solar installer put in panels that could put out a bit more power than the max of the inverters, which I thought might have been a mistake when I found out, but looking at my production data it would only limit the power a small amount for a couple hours on the sunniest days of the year. Probably makes < 1% total difference while being more economical than the heavier duty inverters.

Just as my inverters were not sized for the extreme maximum scenario, you could consider sizing your system and batteries to cover something like 95% of your needs and have an alternative for the worst couple of weeks per year. No need to double your panels and batteries just because it is slightly possible you will have two straight weeks of clouds. You could keep a generator for those times, or if the bus runs use an inverter on it. Or migrate somewhere sunnier / with power for a few weeks each winter!