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Power Technology

You're Doing It All Wrong: Solar Panels Should Face West, Not South 327

Posted by timothy from the electrons-photons-and-all dept.
HughPickens.com writes In the U.S., a new solar project is installed every 3.2 minutes and the number of cumulative installations now stands at more than 500,000. For years, homeowners who bought solar panels were advised to mount them on the roof facing south to capture the most solar energy over the course of the day. Now Matthew L. Wald writes in the NYT that panels should be pointed west so that peak power comes in the afternoon when the electricity is more valuable. In late afternoon, homeowners are more likely to watch TV, turn on the lights or run the dishwasher. Electricity prices are also higher at that period of peak demand. "The predominance of south-facing panels may reflect a severe misalignment in energy supply and demand," say the authors of the study, Barry Fischer and Ben Harack. Pointing panels to the west means that in the hour beginning at 5 p.m., they produce 55 percent of their peak output. But point them to the south to maximize total output, and when the electric grid needs it most, they are producing only 15 percent of peak.
While some solar panel owners are paid time-of-use rates and are compensated by the utility in proportion to prices on the wholesale electric grid, many panel owners cannot take advantage of the higher value of electricity at peak hours because they are paid a flat rate, so the payment system creates an incentive for the homeowner to do the wrong thing. The California Energy Commission recently announced a bonus of up to $500 for new installations that point west. "We are hoping to squeeze more energy out of the afternoon daylight hours when electricity demand is highest," says David Hochschild, lead commissioner for the agency's renewable energy division, which will be administering the program. "By encouraging west-facing solar systems, we can better match our renewable supply with energy demand."
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You're Doing It All Wrong: Solar Panels Should Face West, Not South More

You're Doing It All Wrong: Solar Panels Should Face West, Not South

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  • soo.... (Score:4, Funny)

    by Anonymous Coward on Tuesday December 02, 2014 @08:03PM (#48511267)

    hedge your bets and go 50/50 south and west. Maybe 50% southwest, 25% west, 25% south and setup a water wheel and perhaps an agrarian society.

    • Re:soo.... (Score:5, Funny)

      by lgw ( 121541 ) on Tuesday December 02, 2014 @08:27PM (#48511399) Journal

      hedge your bets and go 50/50 south and west. Maybe 50% southwest, 25% west, 25% south and setup a water wheel and perhaps an agrarian society.

      Lattitude matters too. Where I live, it's dark at 5PM. West-pointing would be a bit silly. Of course, it's a different story in Summer. A home fission plant sounds much more reliable to me! It'll really reduce my lighting costs when I glow in the dark.

    • Re:soo.... (Score:5, Interesting)

      by JMJimmy ( 2036122 ) on Tuesday December 02, 2014 @08:56PM (#48511563)

      hedge your bets and go 50/50 south and west. Maybe 50% southwest, 25% west, 25% south and setup a water wheel and perhaps an agrarian society.

      The direction you point it depends on where in the world you are. Further north you are the more you want it pointed south rather than west. In any case, while the $/watt calculation may be higher for capturing the western sun you'll lose a LOT of watts by pointing west (esp further north).

      What most people don't know about solar panels is that their efficiency goes up the cooler they are. We make more money in winter on our solar projects despite the reduction in hours/intensity of the sun simply because it's usually -10C or lower where we have our installations.

      One option that might be financially viable is to point south but store it in small salt-water geo-sinks to pump into the grid during peak times. Otherwise, I can guarantee that you'll be further ahead pointing south rather than west unless you're in Texas or some other hot/southern climate.

      • Re:soo.... (Score:4, Informative)

        by terminal.dk ( 102718 ) on Wednesday December 03, 2014 @07:06AM (#48513485) Homepage

        I am 56 deg north, here in Denmark.
        I have 50% SW and 50% east, as that is where I had the roof for it.
        Using the EU models for calculating output, the eastern panels should give me just over 80% of full production.
        SW should give me 96% or so og pure sourth, and will produce further into the evening. So it is possible to do adjustments with little loss.

        There are lots of payment models. Here in Denmark, I have a fixed price for the first 10 years. and a slightly lower price 10-20 years, after which it will be market price. ROI is 8 years. But since my electricity usage import/export is summarized per year, I really do not care when I produce.

        The new payment model here looks at import/export every hour for some users, and other users are hit pay selling low buying high for everything the hits the grid, and for them it is advantageous to turn panels further west.

        My production here in the winter is low. My 6kWp installation is expected to make 1.86 kWh/day for december.while in july I made around 48 kWh/day.

        • Re:soo.... (Score:5, Informative)

          by JMJimmy ( 2036122 ) on Wednesday December 03, 2014 @09:22AM (#48513861)

          56 degrees north is another beast entirely. Here's a Sun chart for København, Denmark - http://www.gaisma.com/en/sunpa... [gaisma.com]

          Winter = 8 hours of sunlight
          Summer = 18 hours of sunlight

          Not only is the amount of time the Sun is shining much higher during the summer, the tilt for the panel is only 58 degrees so your average roof angle would do nicely during the summer. In the winter though things change radically, the optimal tilt angle goes down to 10 degrees and the insulating factor goes way up... nearly 14x less light penetrating during December than in July. You would do well to have a 2 part system that you can move around manually - during March to Sept: first part facing WSW and the second part ESE at 34-58 degree tilt. Come September, change the configuration so both parts are facing due south at a 10 degree tilt.

          Where I am (44N) it's 10h/16h, 22-70 degree tilt, and only a 5x insulating factor difference. We just set it around a 40 degree tilt (or less? can't remember exactly) to maximize winter time collection - some is lost in the summer as a result but there are more producing days in winter (due to summer storms) and we found that, since we're in a field, the reflection from the snow would actually increase production. The snow covered field effectively acts like a giant reflector so it generates even on overcast days.

    • It also depends on what you are doing with the power too. If you have a battery to save the energy, are you going to be able to store more with a south facing panel than a west facing one? If you are selling the power back, will you get more money overall (not just from peak times) from a south facing one or a west facing one?

      • Standard batteries for such a use are good for going off the grid but don't make financial sense for what you suggest. One we were investigating was a geo-sink for longer/larger storage but it was borderline due to the drilling costs for the size of our grid. Batteries would have to come down in price by 1/3rd or more for that idea to be viable (or an increase in rates).

      • If your goal is self reliance, your system should be more than capable of storing a days worth of power, which means that conversations about the price of power is irrelevant.

        This guy is thinking of home owners as a resalable resource, and if that's what you want out of your investment, I'm confident his advice will be good for you. I don't think much of it as a goal, personally, but that's just me.

    • Re:soo.... (Score:5, Funny)

      by jandersen ( 462034 ) on Wednesday December 03, 2014 @08:13AM (#48513661)

      hedge your bets and go 50/50 south and west. Maybe 50% southwest, 25% west, 25% south and setup a water wheel and perhaps an agrarian society.

      You're talking nonsense, obviously. Most people watch tv in the night, when the sun is on the other side of the planet, so the panels should actually face down. I would have thought that was obvious.

  • obviously they should track the sun (Score:4, Insightful)

    by CastrTroy ( 595695 ) on Tuesday December 02, 2014 @08:07PM (#48511285)
    Obviously the panels should be motorized so that they are always facing the most optimal direction. A system that moves the panels shouldn't add that much to the cost and will probably pay for itself very quickly with the extra energy collected.

    • Re:obviously they should track the sun (Score:5, Informative)

      by Anonymous Coward on Tuesday December 02, 2014 @08:13PM (#48511321)

      Obviously the panels should be motorized so that they are always facing the most optimal direction. A system that moves the panels shouldn't add that much to the cost and will probably pay for itself very quickly with the extra energy collected.

      Obviously the article covers this...

      Solar panels do not have to be pointed in just one direction; a homeowner can buy a device called a tracker that will pivot them, over the course of the day, like a sunflower, so they always face the sun. A tracker can raise the output of a panel by 45 percent. But adding trackers can cost hundreds or thousands of dollars, and a cheaper way to get the same number of kilowatt-hours may be simply to buy a few extra panels.

      • Re:obviously they should track the sun (Score:5, Funny)

        by Anonymous Coward on Tuesday December 02, 2014 @09:37PM (#48511783)

        Obviously the article covers this...

        What article?

      • What late afternoon sun? (Score:4, Insightful)

        by Roger W Moore ( 538166 ) on Wednesday December 03, 2014 @12:23AM (#48512469) Journal

        a homeowner can buy a device called a tracker that will pivot them

        For those of us up in Canada or Northern Europe you need to mount the pannels on a vehicle which heads a long way south or west trailing a cable if they are going to be pointing at the sun in the late afternoon since the sun sets here around 15:30-16:00 this time of year. Simply pivoting or pointing west is just not going to cut it.

      • Re:obviously they should track the sun (Score:5, Informative)

        by dwywit ( 1109409 ) on Wednesday December 03, 2014 @02:19AM (#48512789)

        My installer recommended against a tracker. He said a tracker system would add roughly the equivalent of an additional 2 panels' output, at a similar cost, and an increase in complexity and maintenance.

    • Unless you are going to rotate the house.

      • Re:But that isn't possible (Score:5, Insightful)

        by Mr D from 63 ( 3395377 ) on Tuesday December 02, 2014 @08:26PM (#48511389)
        An important aspect the author overlooks is that many residential customers prefer aesthetics over optimization, and therefore the panels are often mounted as closely in parallel with the plane of the roof as practical. It is one of the reasons residential based solar, on average, will always trail centrally based, larger scale solar in capacity factor. Centrally based solar installations are optimized for their location. (OTOH, residential power delivery suffers lower transmission/distribution line loss factors than centrally located, but that is a bit off topic)

        The point regarding the incentives simply being for total production & not considering time is true, its one I’ve made here on /. before. Existing incentives drive installations that are optimal from a total MWH generation standpoint over those that lengthen the generation window. These incentives pretty much take tracking mechanisms out of play in favor of adding more panels for the same cost.

        If the goal is clean air generation per $ invested, then generating less just to lengthen the window doesn’t make much sense. It is an energy cost increase on an already costly energy source. This guy is proposing that the government spend even more on incentives for installations that will produce less power overall. Given the existing infrastructure and the fact that other sources will continue to fill in the demand profile when renewables can’t, the proposed changes don’t seem to accomplish much other that increase cost.

    • Re: (Score:3)

      by crow ( 16139 )

      Tracking the sun is out of the question when it comes to rooftop solar on sloped roofs. You're pretty much stuck with having the solar panels match the slope of the roof.

      For ground-based installations or for large flat roofs, you would think it makes sense, but it would seem not, as I see solar farms all over the place (in Massachusetts), and they're all fixed installations. If it made economic sense to track the sun, then I'm sure the large farms would be doing it. Even with the production credits (SREC

      • Re:obviously they should track the sun (Score:5, Interesting)

        by RightwingNutjob ( 1302813 ) on Tuesday December 02, 2014 @08:32PM (#48511431)
        Back in my student days, we had an experiment with a solar panel with a single axis tracker. The panel we got for about $800, the tracker for about 1k, if memory serves. Mind you, this was a single axis tracker with the panel mounted along the direction of the rotation, not offset to the declination of the sun like you'd have with a proper equatorial mount used in astronomy (which you'd still need to adjust every month or so to keep up with the seasons).

        Conclusion: a sort-of OK tracker (that you still need to adjust seasonally) cost more than the panel. And it's moving parts that wear out and need lubrication, and it needs to be accessible for maintenance and adjustment. So about double the cost and not practical for sloped roofs.
      • Typically, large solar farms do tilt slightly to improve effeciency, or have multiple panels arranged so that while one may not be getting good light, others are.

    • Not so obvious. Sun tracking introduces moving parts into a system that would otherwise not have them. It increases both the initial cost and the ongoing maintenance. I'm not sure what the actual numbers are though. It might be hard to find answers since tracking isn't common in small set-ups. It's probably more common in large setups where you've already got staff working on things. There might be economies of scale at work too--tracking with a bunch of large panels in the desert makes sense; but it

    • A system that moves the panels shouldn't add that much to the cost and will probably pay for itself very quickly with the extra energy collected.

      Wishful thinking. It *does* add much to the cost and no it won't pay for itself quickly at all. In case of home installations where the panels are mounted on sloped roofs, it's not even possible in most cases.

      Space-based solar and nuclear are the only things that can completely replace fossil fuels with zero emissions.

    • Re: (Score:2)

      by AK Marc ( 707885 )
      Wouldn't it make more sense to have the panels mounted flat, pointed up, and use mirrors to direct the sun down on them? Fewer (lighter) moving parts) and more flexible than any fixed installation.

      Or should they be at an angle to help keep them clean?

      • If you're using mirrors, why not simply point the panels down?

        Speaking of mirrors, how about covering your root with an optical cable and pointing both ends on a solar panel that sits on the inside somewhere, presumably water-cooled?

    • Re: (Score:2)

      by sribe ( 304414 )

      A system that moves the panels shouldn't add that much to the cost...

      When you just whip something straight out of your ass like that, you risk being very, very wrong ;-)

    • Obviously the panels should be motorized so that they are always facing the most optimal direction. A system that moves the panels shouldn't add that much to the cost and will probably pay for itself very quickly with the extra energy collected.

      The energy benefit for small/mid-scale systems is minimal. Panels are heavy and it takes a lot of energy to rotate them (even slowly). It's also a LOT more maintenance making sure the systems are optimal/aligned accurately. Then there's the computational costs. Finally, the cost for the installation skyrockets with those systems. Passive systems without obstructions on an optimal angle/orientation will be very efficient overall and are very simple in comparison to moving systems and can be installed ea

    • Re:obviously they should track the sun (Score:5, Funny)

      by Kohath ( 38547 ) on Tuesday December 02, 2014 @09:40PM (#48511803)

      They should spin, so the heavier electrons settle around the outside of the disk for easy collection. This would also allow more light to get through in the center of the panel without the electrons casting a shadow.

    • Wind loads
      Self-shadowing
      Increased failure rate

  • At 5PM the sun is down where I live, 4 months out of the year. No, I didn't RTFA, so I assume he has a good rationale for not taking into account seasonal changes.

  • Depends on what your goal is. (Score:5, Insightful)

    by Wycliffe ( 116160 ) on Tuesday December 02, 2014 @08:11PM (#48511309) Homepage

    If you're offgrid and storing excess power in batteries then point in the direction of most efficiency.
    If you're connected to a meter and can run it backwards then point in the direction of most efficiency.
    If you're only producing half your own power and pay a flat rate for electricity then point in the direction of most efficiency.

    There are only a few specific situations where an individual would benefit from aligning solar panels with their usage patterns instead of maximum efficiency.
    My guess is the majority of homeowners don't fall in that category.

    • Exactly. The only situation where the homeowner would want to optimize for the highest use time of day is if the power company was paying them an increased rate for power fed into the grid during that time period. and at that point, it might make more sense for the home owner to store all the power generated in batteries and only send power back to the grid when they are getting the best price.

      Where I live there's a 5 cent difference between the cheapest and most expensive parts of the day. I wonder how

      • I wonder how cheap/efficient batteries would have to get before it would make sense to just charge the batteries at night, and use them during the day

        Typical battery backup systems have a round-trip efficiency (RTE) of about 70%. You can do better with shallow discharge, or exotic batteries, but either of these will increase your capital investment. You can get up to 90% RTE with flywheels, but good quality flywheels are expensive. If you are paying 5 cents base and 10 cents peak, you might make money. If you are paying 15 cents base, and 20 cents peak, then no way will it pay.

      • Re: (Score:2)

        by ptaff ( 165113 )

        it would make sense to just charge the batteries at night

        I'd like to know more about your solar panels that work at night.

        • He's referring to charging them from grid power to avoid paying full price during the daytime. Nowhere in that paragraph does he even mention solar panels.

      • Where I live there's a 5 cent difference between the cheapest and most expensive parts of the day. I wonder how cheap/efficient batteries would have to get before it would make sense to just charge the batteries at night, and use them during the day so I never have to pay the higher rate.

        If this were cost effective then power companies would be doing this. I believe one of the more efficient methods of doing this is
        to pump water back up into a hydroelectric dam but even that's not very efficient. I also believe (again without checking) that
        battery storage for a solar installation pretty much doubles your cost of electricity which is why gridtie is so popular. The only
        reason to have large batteries is for offgrid or emergency use.

    • There are only a few specific situations where an individual would benefit from aligning solar panels with their usage patterns instead of maximum efficiency.

      This is because the economic incentives given to the homeowners are misaligned with the overall needs of the energy market. TFA discusses this. The solution is to have realtime spot pricing, and pay homeowners what their power is actually worth at the time it is fed into the grid. This requires "smart-meters", but those are becoming common anyway.

    • +1 Nailed it.

      Came here to say just that. Where I'm at in CA, PG&E is on net metering for solar, and actually pays you the hourly rate for putting power back on the grid (net metering) which is any time during daylight hours. Better to have your panels pointed to get max total daily output.

    • Except you have hidden in the word "efficiency" the fact that you actually use different metrics for the different problems you pose.

      In the first case you want to maximize kWH.
      In the second case you are trying to maximize the net of the product of the instantaneous power production and the instantaneous price from the utility.
      In the third case you are trying to minimize the net power consumption only during the times where instantaneous power consumption is greater than 0.

      Then there is the question of what

  • When we've all got grid-interactive electric cars, that will be the lowest demand time because everyone will be on the roads trying to get home. Solar tracking is the right way. Fixed position is a financial and maintenance compromise.

  • Until then (Score:5, Interesting)

    by Immerman ( 2627577 ) on Tuesday December 02, 2014 @08:18PM (#48511353)

    Great. So once solar installations start producing more total power than is consumed during peak production hours we should consider intentionally reducing their total output in order to better align production with consumption. Until then total peak solar production is only a fraction of the total energy consumed at the time, so there's nothing to be gained by intentionally sabotaging your total energy production. At least not or the people installing solar panels.

    But sure, if you're more concerned about the power-transmitting capacity of your grid infrastructure than actually producing as much power as possible for a given investment, by all means point your solar panels west. Should be useful for California and, umm, anywhere else is the power companies are allowed to play ridiculous profit-optimizing games at the expense of the citizenry. And you'll be doing your part to please both the solar panel and fossil fuel industries. Good job consumer, the corpoatocracy thanks you.

    • Re: (Score:2)

      by Ichijo ( 607641 )

      On the other hand, allowing the price of something to fluctuate empowers people to save money in a way that doesn't exist with flat rates.

  • ... that are not North-South or East-West aligned?

    Actually this is news from at least one year ago [nationalgeographic.com]
  • The article overstates the difference in angle -- not due west, you mean adjust west of due South. If you are in the northern hemisphere, there is an optimal angle depending on latitude. If you want to shift to later in the day, that is Southwest. If you live in Australia, that would be Northwest.

  • No, they should not. (Score:4, Interesting)

    by WindBourne ( 631190 ) on Tuesday December 02, 2014 @08:35PM (#48511453) Journal
    If you are a home owner, You should have some on both south and west if possible. At my house, we have 43 panels of which 7 are east, 14 are west, and the rest are to the south. As such, we get a lot more electricity when needed, then the average home.

  • My first though without even reading the summary:

    Of course pointing it to the South would "catch" more integrated spectrum, but not all of that can be converted to electricity efficiently (they are more efficient for longer wavelength), so it should not *hurt* much to till them westwards (or eastwards), where/when blue light ("useless for") is filtered by the atmosphere...

    By the way, blue light is still absorbed/heats/damages the cells, but not gets converted to voltage. Or some such... ;-)

    Aligning with pe

  • This article is loaded with suppositions and guesses that don't really nail down any hard believable hypotheses or facts for a reader to take away. There is no takeaway message. I came away from this read having wasted my time. The whole article can be summed into a single line that could maybe be a popular tweet "For some people, maybe, angling solar panels westward might pick up energy when they need it most."

    But the article is clickbait by the whole 'you're doing it all wrong' part that makes potentia

  • Current system assumes only so many users..... (Score:5, Informative)

    by King_TJ ( 85913 ) on Tuesday December 02, 2014 @08:42PM (#48511509) Journal

    I just purchased a solar panel system for our home, and I've been learning a lot about all of this stuff during the process.

    The problem with the author's suggestion is that he's concerned about a problem that, by and large, we haven't quite come to yet. Solar adoption is still such a small percentage of the total number of electric consumers that the "saturation point" hasn't usually been reached yet. The entire "net metering" model for solar isn't really sustainable if you get more than a single digit percentage of homeowners in a given area going solar. I think that will hold true EVEN if you could convince all the new solar installations to use west-facing panels to time shift their power production hours.

    Right now, practically everything about PV solar adoption centers around government regulations creating an "artificial" incentive for it. For example, in my home state of Maryland and a number of others, they have an SREC program in place (solar reclamation credits). How does it work? Basically, they made a rule that the state's utility companies have to obtain a certain percentage of their electricity generation via "Green" sources like wind or solar. If they fail to hit that target, they must purchase these SREC certificates in a sufficient quantity to offset it. (In reality, they're always going to pay for the SRECs rather than adopt more alternative energy generation themselves -- because for them, it's still the more cost-effective and sensible option. They don't want to spend a bunch on new infrastructure and land to place it on, just to meet those percentage targets.) For every megawatt of solar power your home solar panel setup produces, you earn an SREC which you can turn around and resell to the power company (directly, or via one of several auction web sites designed for the purpose). There's even one offering to buy 10 or 20 years' worth of your SRECs in advance, at some discounted price, giving you more "up front" cash to pay off your system's initial installation cost - should you find that the best option.

    Don't forget the Federal tax credit of 30% of whatever you spent to buy the solar panel system, and states like mine who kick in another $1,000 or so. This stuff just doesn't make the same financial sense with all of these constructs removed from the equation.

    The real elephant in the room that everyone's ignoring is the fact that power DISTRIBUTION is the limiting factor for the power companies. As soon as too many people start putting power from solar back onto the grid at one time, in one area? They can't really do anything with it, so it gets wasted. Yet the "net metering" rules require that pay you back for it anyway, at full retail prices. For a SHORT time, you might be able to postpone this by switching more panels to face west instead of south, but soon enough - it will become a problem again.

    Honestly, I predict that what we'll see playing out is government withdrawing all of the tax breaks, followed by the value of your SRECs dropping to very little as they ease up on the requirements the utilities must meet. This will put the brakes on solar adoption, making it one of those things that only paid off for the people who got in on it early - or who have a situation where it STILL pays off (due to especially high power costs). In Hawaii or parts of California, for example, I believe the utilities sometimes bill as high as 90-some cents per kilowatt-hour used. In Maryland, by contrast? I pay closer to 11 cents.

  • Wind (Score:2)

    by OFnow ( 1098151 )
    Mounting sllghtly off the roof, to the roof, gets decent solar generation and shades the roof in high summer and ... minilmizes the danger from high winds. Having panels up in the air on one of those rare 50MPH winds is... scary.
  • Or at least that's what our system does on a nice south facing roof in the UK

  • Effective local energy storage would solve that problem.
    Make the panels as efficient as possible and store the resulting energy. Then use the stored energy at the time of peak need.

    For instance, if it's going to be used for heating or cooling. Just heat or cool an insulated mass inside the house then run the house air through it during peak load times. The cooling process would not be 100% efficient, but it needn't be less efficient that a normal online AC unit.

    The heating process would be 100% efficient, m

    • E.G.. Economy 7 was common in the UK, cheaper electricity at night and people would use storage heaters (radiators with blocks on concrete in them). Heat the blocks up at night. Let the heat out in the day.

  • Electricity prices are also higher at that period of peak demand.

    Only in areas where they have variable pricing. Looking at a map of avg pricing, my state is pretty low anyways and we have fixed pricing whether using it all at 5pm or 7am makes no difference.

    So I wonder if those areas that have variable, are the power companies trying to push demand to other times due to lack of capacity or are they gouging the customer (or both). If either of those are true, that doesn't sound good.

    Course on the flip side, around here you can't sell back to the power company with y

  • You could mount them on a small motor powered by the panel and have the things rotate with the sun. Doesn't seem like it would be all that hard to do. Then you get the better alignment all day long.

    • You must live in a location without wind. A solar panel must be mounted such that it will not blow away in a 100 year wind (if you want it to survive with high probability over the 30 year panel life). This requires a very robust motorized mounting in most places. A very significant expense.

  • optimal solution varies (Score:5, Interesting)

    by hormiga ( 600498 ) on Tuesday December 02, 2014 @09:18PM (#48511653)

    The optimal position of solar panels depends on several factors:

    • Season of year. The sun is lower in the sky during winter, so the slope should be greater. The significance of this factor varies with latitude, as does the slope itself.
    • Value during day. Although demand may be greater at some times rather than others, the payment to you may not be, so what is best for you may not be what is best for the grid.

    Tracking mechanisms work, but they are mechanical and can fail, and they cost money. It may be cheaper to add panels than to add trackers. For seasonal adjustment, some mounting hardware allows relatively easy manual adjustment of the slope.You don't have to change this but a few times a year.

    I have been off the grid at home for ten years, depending mostly on solar but with a little wind. Our panels are pointed in three directions: Southeast to get power in the early morning when the batteries are lowest, south for use during peak sun, and southwest to end the daylight hours with fully charged batteries. We have home-made mounting, and it was cheaper to add a few extra panels than to add tracking hardware.

  • From PG&E's website during summer low demand is 0.143/kWh, high demand 0.336/kWh cents... About 20 cent/kWh differential.

    With EV batteries into the 100 kWh range in our not so distant future and talk of breaking $100/kWh storage barrier market incentives to disruptively break-thru with cost effective buffering seems to be plausible in the short to medium term.

    Solar panels last 20 years...

  • Solar neutrinos (Score:5, Funny)

    by jfdavis668 ( 1414919 ) on Tuesday December 02, 2014 @09:31PM (#48511751)
    I'm installing solar neutrino panels, and facing them down. That way I can get power at night when I really need it.

  • ...somewhat south-west, rather than directly west?

  • It seems to me this is only true when connected to the grid with no storage. If you're running off-grid and storing electricity in batteries to use later, you want to position your panels for maximum output. (This is how mine is configured. Not grid connected, with marine batteries storing power during peak output, and panels facing south.)

    But I would opine that any system, even grid connected, that didn't allow for solar panels to be placed for maximum solar exposure is not designed properly. If this r

  • Posting from upstate New York.

    Homes here are usually oriented east-west with rather steeply pitched roofs and minimum western exposure. What is wanted here most in winter is warmth and light and shelter from gale force winds, rain, sleet, and snow.

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