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You're Doing It All Wrong: Solar Panels Should Face West, Not South
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."
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.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The point is, while he may be a special little snowflake, so is everyone else. What TFA really says is "Those who run the electrical grid get the most out of solar panels that are pointed west in California, as this has them pointing directly at the sun during peak electrical grid demand." That's significantly different than "Solar panels should face west."
If you're off-grid, you'll do best with pointing to the optimal location (there are charts available for this -- it's rarely south OR west) and storing the energy harvested for use when you need it. If you're just pumping it into the local grid, optimizing for high demand periods makes more sense (and the charts aren't tuned for that [yet]). However, this assumes that the electrical service you're using allows you to contribute back to the grid, and has a variable pricing scheme. If they don't, what real incentive do you have to optimize your energy collection to when THEY need it most? You'd have more incentive to tune for peak efficiency and sell it back to them when you don't need it -- and then buy back at the same rate when you DO need it.
So this whole thing's kind of a non-issue. Of course, what works best, as long as you're generating a decent amount of electricity, is to just track the sun from sunrise to sunset, assuming you'll offset the costs of the sensors and motors.
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.
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.
I prefer the "u" in honour as it seems to be missing these days.
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.
The optimal position of solar panels depends on several factors:
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.
Just a guess (from an engineer, so it's a sophisticated guess)... Might be $200 per panel because the motor has to be big enough to move the panel in prevailing winds; and, the structure has to be strong enough to keep the panel from being ripped off the roof during a storm. Again, just guessing.
http://www.instructables.com/id/Solar-PV-tracker/
try $130 diy solar tracker... of course it assumes a lot of free parts and the price may be off a bit so budget $200 also since it is green treated lumber that ups the total ecological impact heavily.
https://www.gnu.org/philosophy/free-sw.html
That is not how trackers work. Most trackers simply operate by relative gas expansion. The sun heats one side of the horitontal tube/bag more than the other due to position, and that causes the tracker to push the panel in the right direction. No motor, no eye, almost no moving parts. Not at all over engineered
One of the problems is it has to be rated for high winds; or, you're not going to be able to insure your house if it's mounted on the roof. OK, you might be able to insure it but they might void the coverage if you get wind damage that can be attributed to the panels. Accuracy really only needs to be a +/- a couple of degrees for PV. Hell, most people mount them flat to the roof, which is not pitched anywhere near ideal. some of the larger synchronous motors probably do have enough torque to push over a single panel; and, you can build a cam driven system that tilts the panels in a cyclic fashion. Problem is, if the power ever goes out it's going to be hell to reset all of them. Theoretically, you could use a system that relies on the Sun to heat and expand a liquid, pushing the panels from a "morning" orientation to an "afternoon" orientation. In the end... You're still going to pay more than $200 for a structure with "motor" that's strong enough to do the job and well built enough to survive for 10 years on a rooftop. You could probably make it for a couple hundred dollars; but, you'll never buy it for cost -- you'll end up paying double that (at least) after manufacturer overhead (design and support) is rolled into the cost, and the distributor(s) and installer(s) mark up the price.
Even more important - the panels are more efficient when the sunlight is as direct as possible, when the sun is low they are less efficient.
Also consider that the amount of energy they feed to the grid is energy that don't have to be produced elsewhere at that time and can be used later. It's also possible that if the solar panels pushes down the energy cost during midday then it's possible to reschedule some energy consuming stuff to those hours - like timers on washers and driers.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.