Solar photovoltaic on the house as an investment

[photoguy]

I'm somewhat interested in solar power as a self-sufficiency and geek topic but there's no way we could ever make it cost effective. Our entire electric bill runs about $30/month (for two adults) and we don't do anything special to keep it down other than turn off the lights.

Are the higher electric bills due to air conditioning (we don't have it)? or heating (we're on natural gas)?

Searching on Google, the average US monthly electric bill is $110. So I guess this counts as a "rebate" for the HCOL in California and other good weather states?

 

[ERD50]

I did a Google search and there were 175 posts on this site containing the word "electric bill", 359 on "solar panels", 127 on "heating bills" and 90 on "LED bulbs" so I think I am not alone in my interest in reducing my energy bills. ...

OK, I'm getting more and more confused. First you say that 'I think cutting expenses like energy bills tends to be underrated topics here', and now you're trying to tell me those post counts show there is a lot of interest in it?

I really don't understand, but this seems to be upsetting you which is not my intention in any way, shape or form, so I will drop out of this conversation. For the record, I think it's great for people to have discussions on this topic.

I felt a comment like " I very much doubt (and I believe I expressed this before) that many of the things you do (thermal cookers, etc), have any significant savings." didn't exactly encourage me or anyone else to post more on the topic.

It's just a simple observation that a slow cooker doesn't use much energy to begin with ( ~ 100 watts for 8 hours is less than 1kw, so < 11 cents max for most people, and the food still needs the initial heating) , there isn't much to save with an insulated pot. I'm not saying there's anything 'wrong' with it, I just like to keep things in perspective.

That's all. Be happy!

-ERD50

 

[daylatedollarshort]

Are the higher electric bills due to air conditioning (we don't have it)? or heating (we're on natural gas)?

Size of house, age (older homes if not upgraded are usually less well insulated), number of people, A/C and heating needs, pool or not, local climate / temps, are people home all day or off at work / school, etc.

Are you in a condo or apartment? At $30 there isn't much to reduce after accounting for keeping a fridge running.

 

[daylatedollarshort]

It's just a simple observation that a slow cooker doesn't use much energy to begin with ( ~ 100 watts for 8 hours is less than 1kw, so < 11 cents max for most people, and the food still needs the initial heating) , there isn't much to save with an insulated pot. I'm not saying there's anything 'wrong' with it, I just like to keep things in perspective.

That's all. Be happy!

-ERD50

Okay, truce, ERD50. I am happy, my thermal pots are happy. Actually my husband tracks our energy usage, we get graphs on it by hour, plus we have a Kill a Watt. It is not the thermal pots alone that make a huge difference - it is finding 100 little things like the thermal pots that all add up X 40 years. Plus the thermal pots are time savers. There are old books online on the convenience of "fireless cooking" -

Fireless Cookers

 

[photoguy]

We were living in 1200 sq. ft. 1930's home in San Jose (2 adults + 1 dog). No A/C, no pool, cooking/heating on natural gas, and we were working most of the time. For cooling we used window fans which was quite effective.

However after firing last year, we've been moving around. Most recently in a small short term apartment in Colorado but our electric bill is also coming to around $30/month.

 

[NW-Bound]

Eh, [-]we[/-] my wife uses a thermal cooker too. It is mainly for the convenience of not having to babysit the pot, as the energy saving is offset by the price of the pot (more than $200 as I recall).

I think the best way to save energy, and water too, is to live in a small house. But, but, but you will need a lot better insulation than what's in my small RV, because if you need to heat or to cool it, man, the poor insulation will gobble up energy like you couldn't believe.

I think a larger home will have a better energy usage, something about higher volume per surface area, the same way hot blooded animals must be of a certain size. But that larger home must be filled up with people; energy consumption should be measured per capita, then a larger home but filled with people will win. We should go back to having 3 generations under one roof.

 

[samclem]

We have an approx 2000 sq ft house built in 1959. I've done some things to save energy (new windows and added attic insulation, plus CFLs, etc), but saving energy is not a hobby of ours--it's 72 degrees all summer (70 at night) and that's where it is staying. I consider our $75-$150 electric bill to be a terrific bargain, I'll cut expenses lots of other places before I try to save two bucks per day by living in an uncomfortably hot house.

 

[samclem]

That would save me $675 per year. 15 years to break even, if I ignore the interest & earnings on the $10K, or if I could get a 0% interest loan.

Assuming no maintenance costs. Assuming nothing like a tree grew up and shaded the panels.
15 years is a long time to wait before seeing any net benefit.

But, you haven't included likely increases in electric rates, so that knocks off a bit. And the savings are tax free, so that would have to be compared to the after-tax interest you'd get on the $10k. And, it seems there's a fair chance they'd last longer than the 25 years (esp if they are modular so one failed panel won't cause much ripple effect).

I'd kinda like to have a few panels--I could mount them on top of a small low-slope metal patio roof and they'd get good exposure and wouldn't be visible from the front of the house. I could fit 4 panels there, so a max output of about 1000 watts and a cost of less than $3K total (incl help with installation, incl fed subsidies). It would only save us about $15 per month in electricity at today's rates, but it would be an interesting hobby. It might even add a bit to the value of the house when it is sold as we get carted off to the nursing home.

 

[NW-Bound]

I am seriously tempted now to get just one panel and one microinverter, spend 1 hour to wire them up then to record the power output to see what kind of output I can get over a day of summer, a month, a year. It's as you say, an interesting hobby. And if it looks promising, I can scale it up.

Here's the cost: 1 250W panel ($275 new, $180 used), 1 microinverter ($155), a 110/220 1kW transformer ($45), hardware ($10). Total: $380-$485.

The transformer is needed because I want to plug this into a normal wall outlet of 110V, while the microinverter works with 220V output. This allows me to use a common Kill-a-Watt to log the power output.

 

[daylatedollarshort]

Eh, [-]we[/-] my wife uses a thermal cooker too. It is mainly for the convenience of not having to babysit the pot, as the energy saving is offset by the price of the pot (more than $200 as I recall).

I bought all of mine used, the last one for $6 at a charity shop. I think the cost savings also depend on how much they are used, how many people in the house are meals being prepared for and the cost of electricity. Our top tier for electricity is 34 cents a kwh, or three times the national average. YMMV.

Plus I want to look like the woman in this ad for a fireless cooker - -

 

[Texas Proud]

I am seriously tempted now to get just one panel and one microinverter, spend 1 hour to wire them up then to record the power output to see what kind of output I can get over a day of summer, a month, a year. It's as you say, an interesting hobby. And if it looks promising, I can scale it up.

Here's the cost: 1 250W panel ($275 new, $180 used), 1 microinverter ($155), a 110/220 1kW transformer ($45), hardware ($10). Total: $380-$485.

The transformer is needed because I want to plug this into a normal wall outlet of 110V, while the microinverter works with 220V output. This allows me to use a common Kill-a-Watt to log the power output.

So, let me see if I am reading this right...

You have to buy all that stuff to get electricity from one panel... and your max production is 250W.... does this mean you can power 250W of lights etc in your house? What is the conversion to KWH?

Also, you say you will plug it into a wall socket? Will this work? Would it not cause some kind of trouble in your house? Would that not only power that one circuit? Or would excess go back to the box and then go to all circuits?

I really do not know enough about electricity to know this...

 

[meierlde]

I am seriously tempted now to get just one panel and one microinverter, spend 1 hour to wire them up then to record the power output to see what kind of output I can get over a day of summer, a month, a year. It's as you say, an interesting hobby. And if it looks promising, I can scale it up.

Here's the cost: 1 250W panel ($275 new, $180 used), 1 microinverter ($155), a 110/220 1kW transformer ($45), hardware ($10). Total: $380-$485.

The transformer is needed because I want to plug this into a normal wall outlet of 110V, while the microinverter works with 220V output. This allows me to use a common Kill-a-Watt to log the power output.

Is the output of the inverter 2 or 3 wires? If 3 then you have 2 110 circuits as well as a 220 circuit. Note that amazon sells a 220 kwh meter for about $110 from EKM

 

[Rick_Head]

Unless you get a massive subsidy, and in Canada you might, it will be silly economically.

 

[NW-Bound]

So, let me see if I am reading this right...

You have to buy all that stuff to get electricity from one panel... and your max production is 250W.... does this mean you can power 250W of lights etc in your house? What is the conversion to KWH?

Also, you say you will plug it into a wall socket? Will this work? Would it not cause some kind of trouble in your house? Would that not only power that one circuit? Or would excess go back to the box and then go to all circuits?

I really do not know enough about electricity to know this...

A panel rated 250W only produces that power in the best of conditions (max insolation of 1kW/m^2), meaning no high cloudiness, fog, or dust, and the sun ray being perpendicular to the panel. As you do not rotate the panel to track the sun, the output will be lower in the morning and the afternoon, and only peaks at midday. Then, you may have about 90% efficiency of getting that to the grid due to losses in the wiring, inverter efficiency, etc...

And then, the midday sun is higher in the summer and at lower elevation in the winter, so unless you adjust the tilt angle with the season, you will not get the best for each season. Do you want to max out the power for winter or summer? An usual compromise is to have the panel tilt angle equal to your latitude, and leave it fixed through the year. In practice, people have their panels facing to whatever their roofs happen to point (and that is usually suboptimal).

Anyway, where I am in the SW where most days are cloudless, a south-facing panel tilted at an angle equal to the latitude (33 deg) will get an equivalent of 6 hours of max sunshine each day, averaged over a year. In June, I would get the equivalent of 7.5 hours of max sunlight (the daylight is longer than 7.5 hours, but the beginning and the end hours are at suboptimal angles for a fixed solar collector). In December, I would get 4.5 equivalent hours.

The above means that in June the 250W panel so oriented should produce 250W x 7.5 hrs/day = 1875 Wh, or 1.88kWh each day. At the peak rate of 22c/kWh, I would get about 41 cents of electricity a day in the summer.

It would be interesting to install just one panel+inverter and to log the data to compare to the above ideal number.

When I plug this into any outlet, the juice will flow over my whole house, and also into the grid. If I have my coffee maker on which draws 1200W, then only 950W is drawn through the meter, and that would be reflected in a lower charge at the end of the month.

Is the output of the inverter 2 or 3 wires? If 3 then you have 2 110 circuits as well as a 220 circuit. Note that amazon sells a 220 kwh meter for about $110 from EKM

I believe the inverter output is 2 wire, because that makes its electronic circuit the simplest. I found a 220V wattmeter for only about $40, but want the 110V output (via the transformer) because I can plug the experiment to the nearest AC outlet, with the panel just laid out on the ground wherever it's convenient. Else, I would need a long 220V cord going all the way back to the power panel at the electric meter.

PS. There are 110V micro inverters which are also cheaper than the popular Enphase models. They are not "name-brand", and I would need to research to see if they are reliable.

 

[davemartin88]

For our system, we use Enphase microinverters and Enphase is the monitoring system. The inverters each report their diagnostic and output information over the power lines through a system called Envoy. You can access the information on a web site. Here's a picture of the output from the system yesterday- shows how much power each of the 32 panels produced.

There are reports and other views but I like to look at this one to make sure all the panels are reasonably consistent.

Information about the systems is also published on a web site at the summary level (if you're okay with it). I think this link will work to get a look. If others are interested in performance and output, you might be able to find a system near where you're located to see how they are doing.

https://enlighten.enphaseenergy.com/pv/systems/335868/legacy/grid/days

 

[NW-Bound]

The 48.7kWh daily production is impressive!

I look at my power consumption, and on the hottest day last year at Jul 24, 2014, with the 24-hr average temperature of 102F, I used 46kWh during peak time (1PM-8PM) at a cost of $10.64 (not including off-peak). Your solar array would supply most of that power requirement.

 

[NW-Bound]

Here's the hourly breakdown of the energy consumption on that fateful hot day.

I can see that even with a large 32-panel array like DaveMartin's, I would still draw net power from the grid. But perhaps I would have surplus on days not so hot.

 

[Mulligan]

I honestly don't know how you got there from what I posted?



I merely tried to explain to you why you don't seem to see such an emphasis on discussions about cutting energy bills. I thought I explained that many/most of us simply don't have a lot of cutting to do there. As I said, your cuts are greater than my entire bill. So that could explain why it does not get as much emphasis as you might expect, right?



I never intended to say in any way that isn't 'okay for you to express an opinion on topics you are interested in and would like to see more of'. I'm interested in these topics as well, I might learn something about cutting my bill a bit.



So please continue to post (as if I can stop anyone!), and I will continue to read for any nuggets I can glean.



I also think the solar panel threads are more about payback, the environment, and general interest in technology. The payback is in the energy bill, but that's just a consequence. Heck, if a solar panel would reduce my food bill, or my property taxes, or my insurance rates and provide a 2 year payback, great - I don't care where the money comes from, ROI is what I'm mainly interested in (plus the other areas).



-ERD50

Same boat here, and reading about them does interest me though. I would estimate my total gas and electric bills (2 separate companies) probably average about $1200 a year...but I suspect over a third of that is in fixed costs just being connected to the grid. Utes have been adding to the fixed monthly connection fees everywhere, so those would still be there despite solar savings.
I wonder if the total projected cost savings from buying these include such things as maintenance and repair.... Moving them if a roof needs to be replaced or repaired...Will insurance cover these types of occurrences?
I see no solar panels in my small town of 10k. But our kilowatt costs are very low here, so either that is the reason or no one is knowledgable about the solar panel expansion.


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[Music Lover]

Same boat here, and reading about them does interest me though. I would estimate my total gas and electric bills (2 separate companies) probably average about $1200 a year...but I suspect over a third of that is in fixed costs just being connected to the grid. Utes have been adding to the fixed monthly connection fees everywhere, so those would still be there despite solar savings.
I wonder if the total projected cost savings from buying these include such things as maintenance and repair.... Moving them if a roof needs to be replaced or repaired...Will insurance cover these types of occurrences?
I see no solar panels in my small town of 10k. But our kilowatt costs are very low here, so either that is the reason or no one is knowledgable about the solar panel expansion.


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Same costs for me...about $1200 a year for heating ($400) and electric ($600), fixed charges included. The only solar panels around here are on government buildings.

 

[Mulligan]

Same costs for me...about $1200 a year for heating ($400) and electric ($600), fixed charges included. The only solar panels around here are on government buildings.

It makes me wonder, and I could be wrong on this so it would be interesting to hear a rebuttal. But I wonder if people have to be aware of "lazy math" going on. As an example... A person who buys a new car instead of fixing the old one because of affordable $400 a month payments, all the while not factoring in sales tax, increased personal property tax, and higher insurance cost. These all being forgotten and just focusing on the car payment.
The fixed monthly connection use cost is still there, plus all of the above scenarios I mentioned could drag down true savings.
Obviously it is becoming more cost effective, but is it truly as inexpensive if the other variables are factored in as a possible net add on cost? Just speculating and like I said I could be wrong.



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[Music Lover]

In addition to those costs, there is also the lost earnings the additional capital cost could have otherwise generated, or the interest that would have saved if had been applied towards the mortgage.

 

[samclem]

Obviously it is becoming more cost effective, but is it truly as inexpensive if the other variables are factored in as a possible net add on cost?

I think the costs are probably fairly foreseeable (except maybe the very long term reliability/performance of the panels). But we probably don't see many of these installations nationwide because, even with the federal subsidies, they just don't make economic sense except in places with high electric rates (for natural or manmade reasons).

More unforeseeable than the costs are the benefits. If electric rates go up a lot in the hinterlands, I'll be sorry I didn't put up panels using the gummint money. OTOH, if rates only go up as fast as inflation, lots of early solar adopters might have been better off investing in something else.

 

[skipro33]

On of the beauties of the public utility is that you don't have to do anything, just pay the bill. No responsibility for any maint., repairs, upgrades, etc. Right? Of course not. Prices are set to recover all overhead costs of running a utility.

So, with a car, it might be argued that the 'hassle' factor of finding a legit auto mechanic, (do you know one?) learning how to do the repairs yourself, recognizing when there's even a problem like bald tires even is outweighed by fixing those costs under one easy monthly payment with a full bumper-to-bumper warranty.

I have a 10 year old truck and a brand new 2015 car for the wife. I love to work on my truck. She couldn't tell a bald tire from a new tire if they were both cleaned and wiped down with shiny stuff. She could easily be sold a left handed smoke shifter to fix a problem with her transmission. So a new car with a full cover warranty is the best option.

She sure can cook though! I can open a can of SPAM. Sometimes without hurting myself....

 

[Mulligan]

I think the costs are probably fairly foreseeable (except maybe the very long term reliability/performance of the panels). But we probably don't see many of these installations nationwide because, even with the federal subsidies, they just don't make economic sense except in places with high electric rates (for natural or manmade reasons).

More unforeseeable than the costs are the benefits. If electric rates go up a lot in the hinterlands, I'll be sorry I didn't put up panels using the gummint money. OTOH, if rates only go up as fast as inflation, lots of early solar adopters might have been better off investing in something else.

The 800 pound gorilla hiding in the closet though appears to be this, and I do not have an answer for mind you. Lets say that a significant number of people "go solar", but still stay connected loosely to the grid. Average daily power consumption need from the Utes goes down significantly. However, PEAK maximum backup power from Utes is still necessary if not mandated. This would cause a tremendous increase in cost per kilowatt as peak backup power is expensive in itself to maintain. If successful meaningful battery backup power is not invented the costs for maintaining the grid will still be fixed and at a higher cost.
I don't think we would immediately see the death spiral of Utility company viability because the grid will still be needed. So I wonder if the costs will just be shifted to higher monthly connectivity fees, thus negating a big savings in going solar?


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[Running_Man]

The 800 pound gorilla hiding in the closet though appears to be this, and I do not have an answer for mind you. Lets say that a significant number of people "go solar", but still stay connected loosely to the grid. Average daily power consumption need from the Utes goes down significantly. However, PEAK maximum backup power from Utes is still necessary if not mandated. This would cause a tremendous increase in cost per kilowatt as peak backup power is expensive in itself to maintain. If successful meaningful battery backup power is not invented the costs for maintaining the grid will still be fixed and at a higher cost.
I don't think we would immediately see the death spiral of Utility company viability because the grid will still be needed. So I wonder if the costs will just be shifted to higher monthly connectivity fees, thus negating a big savings in going solar?


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I think something like this is exactly what you will get similar to state of Washington thinking of implementing a per mile tax to replace gas tax due to so many going hybrid in Washington reducing gas tax revenue.State takes first step toward pay-by-mile road tax | www.kirotv.com But this is probably a decade away at this point in most states.