A little discouraged

icodebot
icodebot Registered Users Posts: 6
Well I started off excited about the prospects of solar power. I've been doing some reading, and the more I learn about the current state of the technology, and the more math I do, the more discouraged I get.

I'm a computer geek, and this reminds me of the personal computing industry back in the early 80s. Computers then were slow, very expensive, and not all that useful. The only reason to have a computer in your home back then was if you were a computer enthusiast.

I was looking for something interesting and useful to build, and possibly put a dent in my utility bill at the same time. The more I read the more I think I'd just end up putting a dent in my wallet. I'm sure I'd have fun doing so though. :)

I'm in sunny Southern California, on grid, I pay 20 cents per kWatt-hour (including taxes etc), I pay about 150-160 a month for electric, and I want to stay on grid. ( I have gas for heat, water heater, stove, and dryer. )

My goal is (or was) to put together a system that I can grow slowly and gradually, over time. I would do all the work I could myself, and planned to start off by putting together 3 solar panels. I can get the solar cells to make about 3 50-60 watt panels for under 200. (108 3x6 Evergreen solar cells for $165.00, off ebay)

The solar panels are the easy part it seems. The problem I am finding is a good way to bring the generated power in to my house cheaply, and not in an ad-hoc manner.

The only way I see to do this cheaply (and ad-hoc) is to get a cheap inverter running in to a room of my house. This solution doesn't scale though. If I want to get better panels or build additional panels, then how do I extend the system to a second or third room? I just don't see any way to build a scalable system without shelling out a few thousand dollars (or more) for a grid tied inverter.

Then I was thinking well maybe I could just run all my outdoor lights, on solar, and forget about the inside. But then I'm not sure how I would connect flood lights and outside outlets straight to an inverter. I guess I'd have to isolate the outside wiring of my house to a particular breaker, and have that circuit reconnected to an inverter?

Any tips or insights would be appreciated.

Thanks,
Matt

Comments

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: A little discouraged

    First tip.. read all you can,,, starting here and on our host's site.

    Second, learn and do all you can to conserve energy. In ball park terms,, every dollar spent on conservation will save ~$10 in PV costs.

    Third,, PV solar is not an up front money maker,, and in fact is hardly a break even proposition. Depending on your rebates/tax credits etc you can get your installed cost pretty close.

    Fourth, depending on how your utility meters power,, you can use solar to great advantage, even if you net/net consume more power than you produce.

    Fifth, Read steps 1&2 over again.

    Good luck and welcome to the site,

    Tony
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: A little discouraged

    Time for "broken record" post (yet I type it fresh every time ;) ).

    You need to make a decision on why you want solar RE electric power... If it is to (possibly) save money and be the "greenest" you can be--Solar Grid Tied (Utility Interactive) is the only way to go.

    If you need emergency/backup power, then solar off-grid or solar hybrid (combination of Grid Tied + Off Grid) are your options.

    If you want to save money... Conservation, conservation, conservation. And look for possibly a solar thermal system (typically domestic hot water). Solar Hot Water lends itself to do you it yourself (if you like plumbing) more than Grid Tied solar for a first timer.

    Conservation is the best bang for your buck... Lots of insulation, double pane windows, CFL lighting (and/or florescent tube), replace older equipment with energy star appliances, new high SEER A/C, look at your standby loads (older electronic equipment typically) and put on power strip to turn off when unneeded, look at your computer equipment and think about using laptop class product when you can, etc.

    $160 per month / $0.20 per kWhr = 800 kWhrs per month

    800kWhrs per month * 1,000 watts/kWatt * 1/30 days per month * 1/24 hours per day = 1,111 watt load 24 hours per day, 30 days per month.

    So, the first question is why that much power? (not attacking you--that usage is roughly the national average).

    In San Diego, you might not have A/C (did not mention summer/winter bills). A "good fridge" might use 400-800 kWhrs per year or 33-67 kWhrs per month, a freezer would be similar amount. Energy efficient washer/gas dryer use about 0.25 per load each...

    I think you will be surprised where all of that power is going...

    Get a Kill-A-Watt meter (120 VAC 15 amp branch circuit) for $30 or less and start logging your loads. For a whole house meter, either look at the "T.E.D." (the existing "cheap" TED will work on your home as is. The "new TED" will work with Grid Tied Solar--but it is still a ways out).

    Or, find out if your utility is rolling out the "Smart Meters" soon (you will probably have 1 hour energy usage periods that you can read from the Web, or a Watt Meter on the face of the new meter you can walk out and check).

    I would bet, that if you really looked around, you could cut about 1/2 off of your electric bill without altering your lifestyle too much.

    Once you have analyzed your electrical usage--then we can talk better about Solar Power. But--as you have seen, it is not cheap or easy to build a scalable system. For GT solar, you could probably build out in 3 kWatt system increments pretty cost effectively... But if you get your usage down to the 200-300 kWhr per month range, a 3 kWatt system may be all you will need (instead of a 6-10kW system).

    For my own home (2 adults, 2 kids work at home, 20 miles south of San Francisco on the sunny side of the hills, using natural gas for heating, cooking, hot water, etc.), I was aiming for 100 kWhrs per month power usage--as this historically has been about the maximum cost effective system size for an off-grid home (this was years ago when solar was even more expensive). Did I ever hit that number--no... But I did get down to 175 kWhrs per month a couple of times and average around 225 kWhrs per month without being a light switch cop.

    From an "investment" point of view--I think that remodeling for conservation has a better return. You save energy (and save $$$$), get a nicer home (quieter inside with double pane vinyl windows, added wall/ceiling under floor insulation, almost no cold drafts, much more livable in heat waves without A/C because of the insulation and less waste heat being dumped in home from older light fixtures and old fridge/freezer/large-computer), and you would spend much less on whatever solar system you eventually decide on.

    One thing that has become fairly apparent is that adding solar electric to your home does not increase its value in the resale market very much (if at all). Remodeling has a better return.

    Questions, Comments, Flames, etc.?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • TnAndy
    TnAndy Solar Expert Posts: 249 ✭✭
    Re: A little discouraged

    Ditto what BB said...

    Our KwHr use this month was around 700, but I have an old, ineffecient SBS fridge ( 100kwhr/mo right there.....soon to be replaced ) + 3 freezers + we cook and dry clothes with electric. Once we switch to gas and replace some appliances, I expect our use to drop to the 4-500 range.

    I'd be hunting your uses first.


    Then the next thing I'd look at is a panel by panel adding plan using Enphase inverters, which is small ( like 200w ) inverter that goes directly on the back of EACH panel, converting the panel DC to AC right at the panel....those look like the simpliest grid tie method to me....the advantage being you can expand your system by adding one panel/inverter at a time ( assuming you allow for racking/wire runs )
  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    Re: A little discouraged

    Well...I guess I'll have to discourage you a bit more. Sorry, but since no one else has said it yet...I'll do it.


    Home made panels will not be approved by building and safety, and thus you will not get tax credits or rebates and you almost certainly will not get approval for a grid-tie.

    And if you mount them on your house you might invalidate your insurance as well, and you certainly will if they catch fire.

    Home made panels won't last very long (relatively) - so while they might seem cheaper than commercial panels, by the time you figure in the 20-25 year (minimum) life of the commercial panels...commercial will almost certainly end up being cheaper.

    Using home made panels puts you in the "hobbyist" category, which is fine as long as you realize it - the utility company, the dept. of building and safety and your insurance company certainly will.



    I think what you should probably do is check out the solar section of a website of a member of this forum:

    http://2manytoyz.com/

    2manytoyz started out small with a harbor freight rig and has been steadily expanding his system.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: A little discouraged

    And to follow DWH's note about home made panels... Here is an example of "home made style" panels (made from plastic, not UL/NRTL Listed)... Read the whole thread:

    Panel Fire Question

    Building a small panel for fun and education is fine... building a large array of them can be risky.

    What TnAndy says about Enphase--It is probably the best "building block" system architecture out there at this time. However, it will not be cheap.

    For what ever you plan--do a rough costing to see which will work out best for you (remember to include shipping charges, racking, permits, etc.--many times these costs for one or ten panels is about the same--so doing it one at a time may hit you with these relatively large minimum costs).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: A little discouraged

    Well, I'm new here... and unlike everyone else, I am going to encourage you to explore the power of small-scale solar electricity.

    However. I am going to encourage you to use the 12-Volts that the panels are going to put out - and not use an inverter.

    Here's how you can do it. You already know about the 45-watt solar panels. So let's see what you can add to them to get something useful.

    You will need some sort of charge controller. I am using (and highly recommend) a Morningstar SunGuard PWM charge controller. I believe you can get them for about $35 to $45 these days.

    Next, you need a battery of some sort. The Sunguard is meant to charge a SLA (Sealed Lead-Acid) battery. I would recommend one that has about 25-Ah to 40-Ah for this set-up. That means you will be out about $50 to $100 for a battery.

    Next - you need an electrical box to put these bits into. That'll cost you about another $30 to $40.

    ....

    I think I got ahead of myself here. I forgot to tell you what you can do with the 45-watts of solar power that you are going to install.

    You can use it - via the SLA battery - to power LED lighting. 12-Volt track lighting - to be more specific.

    What I have is a self-adhesive MR-16 LED track lighting system that was made by a company that I don't think makes them anymore... Velo(?) or some such. There are other companies that make something similar, though.

    It consists of an 8-foot self-adhesive strip of copper wiring - that three MR-16 sockets clip onto. Then there is another 8-foot low-voltage wire that runs over to the battery box.

    In the day time - the solar panel that I have (21-watts) charges the SLA battery (17-Ah). At night, we use the 12-Volt battery to power three 5-Watt LED lights.

    The amount of light from this is enough to illuminate a room of about 16-feet by 20-feet. Give or take.

    One other thing that is needed - to make sure that you do not destroy the SLA battery - is some sort of LVD (Low-Voltage Disconnect) circuitry. This will disconnect any load (I.E. turn off the lights) when the battery drops to a pre-determined voltage. Mine is set to cut-off at about 11.90 Volts - which is about 90% discharge on a SLA battery.

    Another helpful item is some sort of 'switch' to activate the lights. At 12-Volts - you need to be sure to use one that is rated for not only the voltage - but also the current.

    What I use is part of the LVD circuitry - and uses an IR controller to turn ON/OFF the lights. Pretty slick. I can turn on or off the lights from my easy chair. (This is actually on a Printed Circuit Board that I designed and built.)

    Now. Just how much will this cost? Well, from the above numbers, you can see it is less than a thousand dollars. If you shop around... maybe even less than $500.

    How much will it help you save on your electric bill? It depends. A survey in 2001 puts the percentage of electricity used for lighting at about 10%. I've seen a more recent quote that puts it at close to 20%. If you are spending $150-$160 each month on electricity... that is something like $15-$30 minimum. Per month.

    Another benefit - that many may not think about... is that having a solar lighting system like I have described above - works - when power is lost in the neighborhood. I've personally experienced it twice in the two years that I've had my system installed. One morning - around 5:30am - the entire neighborhood was dark. No lights - as we had a power failure. Except for my home - which was lit up inside - and we were able to continue getting ready for work.

    You mentioned that you also wanted expandability. Well, this sort of system is expandable - if you can run low-voltage wiring to other rooms in the house. Or - perhaps, it is easier to purchase another set of solar panels - and create a duplicate system in another room.

    I have duplicated the system using a smaller solar panel and smaller battery - outside - to power a set of four amber LED lights - for my porch light. It's pretty cool to come home to a dark front porch - and turn on the lights from the car - BEFORE exiting the vehicle. It's great to not have to stumble around in the dark.

    Anyway... I would like to encourage you to explore what you can do with that 45-watts of solar panels that you are thinking about buying.

    If you are content to use it for only lighting - then you may be able to have some fun with a small-scale solar system.

    Regards,

    James Jackson
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: A little discouraged

    JamesJackson makes a great point about, starting small and see what you can (and cannot) do with a small solar PV installation. It is very interesting and informative to play around with a small installation.

    On the other hand,,, a 45 watt PV panel won't put out a lot of useable power net/net over the course of a day. For rough numbers,, I like to take the name plate rating of the Pv array,, divide it by 2 to cover various system loses (wiring losses, charge controller losses, basic battery charging efficiencies, inverter loses etc which can easily add up to 50%) take that number and multiply it by the average number of hours of GOOD sun you can reasonably expect to have. (Seldom more than ~4. Remember, solar panels will put out near ZERO output even when partially shaded,, a shadow from a tree branch or a wire is almost as destructive to output as full cloud cover) People tend to over estimate how much GOOD sun they really get.

    So if you take that 45 /2X4=90 watt hours of usable power/day. (maybe a bit more if you are using it without an inverter and it's losses.) That 90 watt hours is enough to run a 15 watt CFL bulb for ~6 hours.

    As for tying any small PV system into the grid or your house. There are only two safe ways to do it. One is with a Enphase grid tie inverter that converts your Solar to 120 VAC and plugs it into the house. (In effect) This is a UL/Utility accepted product and system to grid tie with a PV array of under ~250 watts.

    The second is to use dedicated circuits in your house that are only powered by your array and it's batteries. ( You will need some battery in this scenario) These circuit(s) need to be completely isolated from your grid circuits via a proper transfer switch so there is no chance of the grid burning up our solar system (sic) or your system inadvertantly energizing the grid.

    The third alternative would be to run "temporary" circuits off of extension cords from your inverter to your loads. Just remember,, going forward that there is enough energy stored in even a small lead/acid battery to cause real damage as a result any improperly fused circuits and loads. While a 45 watt PV probably doesn't have enough power to light a fire,, a 60 ah car battery sure does.

    Also,, 120 vac from an inverter is certainly enough voltage/current potential to kill someone if they were to come in contact with with either a un-grounded energized conductor. Also small inverters that lack a grounded neutral conductor can pose a hazard in a number of ways if they are grounded.

    Bottom line,,, read, learn, play around,, but be safe.

    Ask as many questions as you can,,, and the smart folks here will be happy to try to steer you right.

    Tony
  • System2
    System2 Posts: 6,290 admin
    Re: A little discouraged

    "...solar panels will put out near ZERO output even when partially shaded,..."

    Well... I disagree with this statement. I think that this statement needs to be qualified with 'depending on the type of solar panels you use...'

    I am using Uni-Solar US-21 amorphous solar panels, and even on overcast or cloudy days, my amp meter reads power going into the battery. It may not be a full 1.25 Amps - but it is putting in a trickle-charge... something like 400-ma or so. Of course... if it gets REALLY dark outside - like it does during a thunderstorm, yeah. My solar panel power output goes flat - to zero.

    I've had this system up and running for over two years now, and I am speaking from experience - and am not just 'blowing smoke' like some folks tend to do.

    I will also re-iterate. I am NOT using any inverter. I have run a separate 12-Volt wiring circuit for the LED lighting that I am using. Doing this - makes it possible to power just a lighting system. VERY possible - IF one uses LED lamps - and not those 5mm LED lamps. I'm talking the hi-powered kind - like the 1-watt, 3-watt, 5-watt - etc.

    So - a 45-watt solar panel - IF it is of the amorphous kind - will generate enough solar power - in most daylight conditions - to power a small lighting system.

    Again - from experience - using a 21-Watt solar panel.

    Good Luck - and I hope that you try some small-scale solar power. It's really fun.

    Regards,

    James Jackson
  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    Re: A little discouraged

    I am ashamed that I have had to admit to having used amorphous panels. They are SO much less efficient than polycrystalline. Still, for pico-power apps, they may be suitable.

    Also, I do encourage "playing around." I bought my one Brunton 5W panel a few years ago. It was there on the shelf and relatively inexpensive. Played with it. Didn't do the job. So I bought two 15W panel of the same brand, again off the shelf at a sporting goods store. Minimal improvement toward achieving my solar goals. Hence, my joining this forum.

    Good luck.
  • icodebot
    icodebot Registered Users Posts: 6
    Re: A little discouraged

    Thanks everyone for all your input. The "2manytoyz" site was awesome. I got a lot of useful information from there.

    I'm convinced not to mount home made panels to my house. I read the "fire hazard" thread, and the pictures of the cells looked exactly like the ones I was planning to buy off ebay. Nevertheless, here is an interesting article that got me interested in solar to begin with: http://www.mdpub.com/SolarPanel/index.html It shows the same looking cells that were in one of the panels that survived the fire.

    I'll start small like 2manytoz did, and learn more as I go.

    Thanks again for all the helpful advice!

    Matt
  • lorelec
    lorelec Solar Expert Posts: 200 ✭✭
    Re: A little discouraged

    Regarding the partially shaded / zero output scenario: it's true that a panel or an array that is even minimally shaded will suffer degraded output. Depending on how severe the shading is, you might be lucky to get 10% of what you would have otherwise (unshaded). In really severe situations, it would be the functional equivilant of an open circuit...and in situations like these the bypass diode that is built into many panels will conduct and route power around the shaded module. But for this to work the panel has to be REALLY compromised (down to ~1/2v or less output).

    Cloudiness is usually a different situation, and I wouldn't be surprised if you're getting 400mA from your panel...because it's still receiving diffused light.

    Marc
  • vcallaway
    vcallaway Solar Expert Posts: 157 ✭✭✭✭✭
    Re: A little discouraged

    That 2manytoyz site is pretty good.

    I especially liked the copper bus bar setup. I have three batteries and I really need to have a better setup.

    Here is a pic:

    img_1307.jpg

    I've since added two more batteries and a charge controller. I'm going to add a small inverter like 2manytoyz did for the outside lights. Unfortunately it will be another month before I get my first panel :(

    The silver box is a 3-way automatic transfer switch (grid, inverter, generator).
  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    Re: A little discouraged
    icodebot wrote: »
    here is an interesting article that got me interested in solar to begin with: http://www.mdpub.com/SolarPanel/index.html

    Matt

    Yes, I'm familiar with that site, and there is no doubt that his home made PV panel is pretty cool and works well for his purpose.

    Some things to note though:

    * He's using his home made PV panel while camping and stargazing on his remote piece of land - not on his house.
    * That PV panel is made of plywood, pegboard and plexiglas, and it's not vacuum sealed - it wouldn't last long if it was out in the weather for any length of time.
    * Before he had even tested it, one of the cells failed:

    "Sure enough, a tab popped off one of the cells. Maybe it was due to thermal stresses or shock from handling. Who knows? I opened up the panel and replaced that one cell."


    He also has a decent little home made wind turbine, though it's worth noting that the blades he made came apart in a high wind and he had to do an improvised repair job on them.

    Still, if you ask me, I think his home made wind/sun power setup for camping is pretty sweet.

    There's nothing wrong with being a hobbyist and tinker; I am one myself. But I'm also a journeyman electrician. I might do some things with my camper that I would never do to my house.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: A little discouraged

    As for shading affecting performance,,,,


    Since I started the comment, I appreciate Marc, (lorec) explaining it in better technical terms. My point was (is?) that when you are designing,, and figuring solar out put, you have to have a healthy awareness of of the effects of shading, cloudiness. Cloudiness is rather subjective,,(with out a insolation meter!) and clearly you can get varying output depending on the density of cloud. While it may not be zero,, in the case cited by JamesJackson of ~500ma output,, it is in the real world effectively zero, at least in the ability to do any work. 400 ma might be a "trickle charge" but over an 4 hours is ~20wh (12 volts) after wiring loss, charge controller losses and battery charging losses, might yield ~12 watt hours max. Not a whole lot of useable power.

    Just realize that output is significantly reduced due to shadows,,, and cloud cover,

    Tony
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: A little discouraged

    A link to Icodebot's results after he used a Kill-A-Watt meter to check the loads around his home:

    Kill-a-Watt

    Tie the two threads up with a nice little bow. ;)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset