16 ms·

The top comment from u/theysayso on the same Reddit thread seems to put things in a good perspective: Other posters have already noted that you can still have

by bsirkia 13y ago

The top comment from u/theysayso on the same Reddit thread seems to put things in a good perspective: Other posters have already noted that you can still have the solar panels, you're just not going to get paid for net metering. What people typically want is the best of both worlds, to charge onto the grid when the produce more than they use (and get paid for it) and have the grid available to supply power when they generate less than they use. But maintaining the grid also costs money. If all your ratepayers split, it makes it more expensive for those "left behind". Who gets left behind? Typically people with less money, that can't afford the systems in the first place, apartment dwellers, etc. The other noted challenge are battery systems. You can go completely off the grid but installing the batteries is WAY more expensive, takes and takes up a lot of space. The technology is disruptive, which the article really didn't go in to. For PV to push electrons onto the grid it needs to be at a greater potential. So if your local grid is 120v the PV needs to adjust to 120.1v. Then your neighbor installs one, and this her/his neighbor. If you're on a long radial line the voltage at the head end might be 126 just to get it to be 118 at the tail end. Normally a utility will install capacitor banks to adjust the voltage. Now you have PV going in everywhere totally screwing with the voltage so it becomes a bit of a grid management challenge. You need to know where all that is going in, what its rate of power is at any given moment (clouds/rains suddenly everything changes and the utility has to compensate). So yeah, a sticky problem that could get out of hand pretty quickly. http://www.reddit.com/r/technology/comments/1tey5l/a_solar_boom_in_hawaii_proved_so_successful_that/ http://www.reddit.com/r/technology/comments/1tey5l/a_solar_b... credit: http://www.reddit.com/user/theysayso http://www.reddit.com/user/theysayso

bavcyc 13y ago
Capacitors are typically used for power factor and voltage correction. A minor correction on what theysayso wrote. If the line is long enough, voltage regulators are used to increase the voltage at a certain point. Phasing for lines is checked by a rotation meter, it is either A-B-C or A-C-B. Get it wrong and your motors spin backwards.
ams6110 13y ago
Sounds like a fairly typical "reality slap-in-the-face" as almost always happens when new technology is introduced into established infrastructure.
scotty79 13y ago
You could power just AC from solar. Or everything, through sort of dual input UPS.
- deleted 13y ago
  [deleted]
- spiritplumber 13y ago
  Here's a redneck way to build something like that: 1) Get a beefy inverter and a beefy battery - the inverter should be rated at 150% of your load, and the battery should be whatever car battery happens to be on sale. 2) Get a beefy car battery charger. It has to be able to handle 150% of your load as well. 3) You now have a UPS that doesn't discriminate where its power comes from. 4) Get some beefy diodes, as beefy as possible. You'll need quite a few, so buy a 25-pack on digikey. 5) Hook up your solar panels so that they give you 12 volts nominal. Then, use 21 of the diodes to create a shunt that triggers at 14.7 volts (just connect them in series). That is your overcharge protection. 6) Use four more of the diodes to connect the battery charger and solar panel to the battery, in such a way that each power source does not "see" the other (common ground, two diodes in parallel from panel+ to battery+, two diodes in parallel from charger+ to battery+) 7) For the love of God, ground this thing (battery-, charger- and panels- to a metal pipe or a ground connector in a socket). You now have a complete, if small, setup for only calling upon the power grid when your solar panels aren't cutting it. This system can be dismantled into its components quickly, which is nice if you need to charge a battery or need an inverter.
twelvechairs 13y ago
Unless subsidised its a long way before home PV makes sense. if I notice PV at the larger or more convenient locations for it in my area (the pool, the storage warehouse, the substation, apartment blocks) I might start to consider whether viable as a cost effective single-house solution.
- bsirkia 13y ago
  I know that in New England, where I'm from, it's only major state govt subsidies that make home PV economically viable. Even then, it takes 15-20 years to break even.
  - icefox 13y ago
    As someone that lives in Mass (which is in New England) and purchased them in 2011 See http://benjamin-meyer-home.blogspot.com/2011/08/solar-panel-installation.html http://benjamin-meyer-home.blogspot.com/2011/08/solar-panel-... looking at my data i'll be breaking even in about 3 more years (about what I planned which was 4-5 years). And this takes into account the fact that SRECs are worth a bunch less than when I started.
- matthewbadeau 13y ago
  In Hawaii, PV was subsidized for a long time. Unfortunately they've cut those back earlier this year. (Around January 2013) Since electricity is so expensive[1] here many people could reclaim their investments in as little as 5 years. With the subsidies reduced, it may be 7 years. That's incredibly short if you compared Hawaii to the mainland. [1]http://www.heco.com/heco/Residential/Electric-Rates/Average-Electricity-Prices-for-Hawaiian-Electric,-Maui-Electric,-and-Hawaii-Electric-Light-Company http://www.heco.com/heco/Residential/Electric-Rates/Average-...
  - blazespin 13y ago
    You recoup your investment immediately when you sell, frequently with a healthy multiplier.
- 13y ago
crdoconnor 13y ago
>Other posters have already noted that you can still have the solar panels, you're just not going to get paid for net metering. What people typically want is the best of both worlds, to charge onto the grid when the produce more than they use (and get paid for it) and have the grid available to supply power when they generate less than they use. This ought to be the best of both worlds for the electric grid, too, since solar generates electricity when load is at its highest. However, the grid is not concerned with running efficiently, or with minimizing environmental damage. They're concerned about their net profit. Profits on day-generated electricity are much higher than profits on night generated.
- grandinj 13y ago
  >This ought to be the best of both worlds for the electric grid, too, since solar generates electricity when load is at its highest. Unfortunately, not. Demand peaks early morning and early evening, when solar is near its minimum. And in winter, solar is near zero at those times. So solar net metering has always been a bad deal for the utilities when you take into consideration the fixed costs they have for maintaining the necessary reserve to cover peak usage.
  - pcl 13y ago
    And in winter, solar is near zero at those times. Note that Hawaii is (mostly) below the Tropic of Cancer, so gets quite a lot of solar radiation even in the winter, and the length of a day only varies by a couple hours throughout the year ([1], [2]). I don't know the math offhand, but even without adjusting the panels, I'd expect that the winter output is probably pretty significant. [1] http://www.timeanddate.com/worldclock/astronomy.html?n=103&month=12&year=2013&obj=sun&afl=-11&day=1 http://www.timeanddate.com/worldclock/astronomy.html?n=103&m... [2] http://www.timeanddate.com/worldclock/astronomy.html?n=103&month=6&year=2013&obj=sun&afl=-11&day=1 http://www.timeanddate.com/worldclock/astronomy.html?n=103&m...
    - ignostic 13y ago
      We tend to think of Hawaii as sunny and warm all the time, but it's actually just an "above average" place for solar generation. Honolulu gets about 90 sunny days and 181 partially-cloudy days.[1] Phoenix on the other hand gets 211 sunny days and 85 partially-sunny days.[2] It's not just about sunrise and sunset, but UV index and cloud cover. Here's some actual data on actual solar generation: http://www.nrel.gov/gis/solar.html http://www.nrel.gov/gis/solar.html This shows that even on the sunnier Oahu and Maui, solar generation is more like Nebraska than California. The fact is that sunny days drop about 30% in the winter and UV index is down.[3] I wasn't able to find real-world MWH in Hawaii per month, but I'm guessing it's about a 50% drop overall with some days actually at ~0. Certainly not 0 for the month, but the fact remains that you need backup power for low-solar periods with more capacity if you want to leverage excess power in high-solar periods. 1 http://www.currentresults.com/Weather/Hawaii/annual-days-of-sunshine.php http://www.currentresults.com/Weather/Hawaii/annual-days-of-... 2 http://www.currentresults.com/Weather/Arizona/annual-days-of-sunshine.php http://www.currentresults.com/Weather/Arizona/annual-days-of... 3 http://www.weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,Honolulu,Hawaii http://www.weather-and-climate.com/average-monthly-Rainfall-...
brownbat 13y ago
That's not really an accurate picture of net metering. The terms of almost every net metering plan are in the power company's favor, even if the net meterers somehow never bought power. Net metering, as currently implemented, only allows you to earn credits on your bill up to the point where your maintenance fee kicks in. You're earning credits by producing power for the company during the day, when power is expensive. You're burning those credits to keep the lights on at night, when the company's cost of power is nonexistent. No one is paying net meterers market rate for time of day, so the power companies are coming out way ahead on cost of power. Even if that weren't the case, they still baseline your bill to a maintenance fee.[1] Moreover, Hawaii has never had any clue how to balance a grid, so if HECO is now blaming customers for problems with the terrible system they built, my default position is skepticism. [1] HECO's net metering bill guide, including the minimum monthly fee even for no power use: http://www.heco.com/vcmcontent/EnergyServices/NetEnergyMetering/Understanding_Your_NEM_Bill_Summary_Brochure_FC.pdf http://www.heco.com/vcmcontent/EnergyServices/NetEnergyMeter...
- brownbat 13y ago
  I'm really pulling for a neighborhood microgrid movement in areas with abundant solar, terrible power monopolies, where a bank of vanadium batteries is overkill for one house. Don't get me wrong. Only some power companies are awful monopolies that barely do their job, most work fine. Still, those awful monopolies should face some threat of revolt.
  - masklinn 13y ago
    > I'm really pulling for a neighborhood microgrid movement in areas with abundant solar This is a nice scheme around and between the tropics, and just about nowhere else. Because you need not just abundant sun, but abundant sun year round.
    - brownbat 13y ago
      Germany's already getting a lot out of the source with terrible insolation. Temperate areas would need to lean on storage more. As generation efficiency increases, storage losses matter less. As storage technologies improve, poor insolation matters less. But sure, someone invents a nice kitchen-sized baseline reactor that anyone can run, then this microgrid movement really takes off. Probably not in the next couple weeks. ;)

by bsirkia 13y ago

bavcyc 13y ago

Capacitors are typically used for power factor and voltage correction. A minor correction on what theysayso wrote. If the line is long enough, voltage regulators are used to increase the voltage at a certain point. Phasing for lines is checked by a rotation meter, it is either A-B-C or A-C-B. Get it wrong and your motors spin backwards.

ams6110 13y ago

Sounds like a fairly typical "reality slap-in-the-face" as almost always happens when new technology is introduced into established infrastructure.

scotty79 13y ago

You could power just AC from solar. Or everything, through sort of dual input UPS.

deleted 13y ago
[deleted]
spiritplumber 13y ago
Here's a redneck way to build something like that: 1) Get a beefy inverter and a beefy battery - the inverter should be rated at 150% of your load, and the battery should be whatever car battery happens to be on sale. 2) Get a beefy car battery charger. It has to be able to handle 150% of your load as well. 3) You now have a UPS that doesn't discriminate where its power comes from. 4) Get some beefy diodes, as beefy as possible. You'll need quite a few, so buy a 25-pack on digikey. 5) Hook up your solar panels so that they give you 12 volts nominal. Then, use 21 of the diodes to create a shunt that triggers at 14.7 volts (just connect them in series). That is your overcharge protection. 6) Use four more of the diodes to connect the battery charger and solar panel to the battery, in such a way that each power source does not "see" the other (common ground, two diodes in parallel from panel+ to battery+, two diodes in parallel from charger+ to battery+) 7) For the love of God, ground this thing (battery-, charger- and panels- to a metal pipe or a ground connector in a socket). You now have a complete, if small, setup for only calling upon the power grid when your solar panels aren't cutting it. This system can be dismantled into its components quickly, which is nice if you need to charge a battery or need an inverter.

twelvechairs 13y ago

Unless subsidised its a long way before home PV makes sense. if I notice PV at the larger or more convenient locations for it in my area (the pool, the storage warehouse, the substation, apartment blocks) I might start to consider whether viable as a cost effective single-house solution.

bsirkia 13y ago
I know that in New England, where I'm from, it's only major state govt subsidies that make home PV economically viable. Even then, it takes 15-20 years to break even.
- icefox 13y ago
  As someone that lives in Mass (which is in New England) and purchased them in 2011 See http://benjamin-meyer-home.blogspot.com/2011/08/solar-panel-installation.html http://benjamin-meyer-home.blogspot.com/2011/08/solar-panel-... looking at my data i'll be breaking even in about 3 more years (about what I planned which was 4-5 years). And this takes into account the fact that SRECs are worth a bunch less than when I started.
matthewbadeau 13y ago
In Hawaii, PV was subsidized for a long time. Unfortunately they've cut those back earlier this year. (Around January 2013) Since electricity is so expensive[1] here many people could reclaim their investments in as little as 5 years. With the subsidies reduced, it may be 7 years. That's incredibly short if you compared Hawaii to the mainland. [1]http://www.heco.com/heco/Residential/Electric-Rates/Average-Electricity-Prices-for-Hawaiian-Electric,-Maui-Electric,-and-Hawaii-Electric-Light-Company http://www.heco.com/heco/Residential/Electric-Rates/Average-...
- blazespin 13y ago
  You recoup your investment immediately when you sell, frequently with a healthy multiplier.
13y ago

crdoconnor 13y ago

>Other posters have already noted that you can still have the solar panels, you're just not going to get paid for net metering. What people typically want is the best of both worlds, to charge onto the grid when the produce more than they use (and get paid for it) and have the grid available to supply power when they generate less than they use. This ought to be the best of both worlds for the electric grid, too, since solar generates electricity when load is at its highest. However, the grid is not concerned with running efficiently, or with minimizing environmental damage. They're concerned about their net profit. Profits on day-generated electricity are much higher than profits on night generated.

grandinj 13y ago
>This ought to be the best of both worlds for the electric grid, too, since solar generates electricity when load is at its highest. Unfortunately, not. Demand peaks early morning and early evening, when solar is near its minimum. And in winter, solar is near zero at those times. So solar net metering has always been a bad deal for the utilities when you take into consideration the fixed costs they have for maintaining the necessary reserve to cover peak usage.
- pcl 13y ago
  And in winter, solar is near zero at those times. Note that Hawaii is (mostly) below the Tropic of Cancer, so gets quite a lot of solar radiation even in the winter, and the length of a day only varies by a couple hours throughout the year ([1], [2]). I don't know the math offhand, but even without adjusting the panels, I'd expect that the winter output is probably pretty significant. [1] http://www.timeanddate.com/worldclock/astronomy.html?n=103&month=12&year=2013&obj=sun&afl=-11&day=1 http://www.timeanddate.com/worldclock/astronomy.html?n=103&m... [2] http://www.timeanddate.com/worldclock/astronomy.html?n=103&month=6&year=2013&obj=sun&afl=-11&day=1 http://www.timeanddate.com/worldclock/astronomy.html?n=103&m...
  - ignostic 13y ago
    We tend to think of Hawaii as sunny and warm all the time, but it's actually just an "above average" place for solar generation. Honolulu gets about 90 sunny days and 181 partially-cloudy days.[1] Phoenix on the other hand gets 211 sunny days and 85 partially-sunny days.[2] It's not just about sunrise and sunset, but UV index and cloud cover. Here's some actual data on actual solar generation: http://www.nrel.gov/gis/solar.html http://www.nrel.gov/gis/solar.html This shows that even on the sunnier Oahu and Maui, solar generation is more like Nebraska than California. The fact is that sunny days drop about 30% in the winter and UV index is down.[3] I wasn't able to find real-world MWH in Hawaii per month, but I'm guessing it's about a 50% drop overall with some days actually at ~0. Certainly not 0 for the month, but the fact remains that you need backup power for low-solar periods with more capacity if you want to leverage excess power in high-solar periods. 1 http://www.currentresults.com/Weather/Hawaii/annual-days-of-sunshine.php http://www.currentresults.com/Weather/Hawaii/annual-days-of-... 2 http://www.currentresults.com/Weather/Arizona/annual-days-of-sunshine.php http://www.currentresults.com/Weather/Arizona/annual-days-of... 3 http://www.weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,Honolulu,Hawaii http://www.weather-and-climate.com/average-monthly-Rainfall-...

brownbat 13y ago

That's not really an accurate picture of net metering. The terms of almost every net metering plan are in the power company's favor, even if the net meterers somehow never bought power. Net metering, as currently implemented, only allows you to earn credits on your bill up to the point where your maintenance fee kicks in. You're earning credits by producing power for the company during the day, when power is expensive. You're burning those credits to keep the lights on at night, when the company's cost of power is nonexistent. No one is paying net meterers market rate for time of day, so the power companies are coming out way ahead on cost of power. Even if that weren't the case, they still baseline your bill to a maintenance fee.[1] Moreover, Hawaii has never had any clue how to balance a grid, so if HECO is now blaming customers for problems with the terrible system they built, my default position is skepticism. [1] HECO's net metering bill guide, including the minimum monthly fee even for no power use: http://www.heco.com/vcmcontent/EnergyServices/NetEnergyMetering/Understanding_Your_NEM_Bill_Summary_Brochure_FC.pdf http://www.heco.com/vcmcontent/EnergyServices/NetEnergyMeter...

brownbat 13y ago
I'm really pulling for a neighborhood microgrid movement in areas with abundant solar, terrible power monopolies, where a bank of vanadium batteries is overkill for one house. Don't get me wrong. Only some power companies are awful monopolies that barely do their job, most work fine. Still, those awful monopolies should face some threat of revolt.
- masklinn 13y ago
  > I'm really pulling for a neighborhood microgrid movement in areas with abundant solar This is a nice scheme around and between the tropics, and just about nowhere else. Because you need not just abundant sun, but abundant sun year round.
  - brownbat 13y ago
    Germany's already getting a lot out of the source with terrible insolation. Temperate areas would need to lean on storage more. As generation efficiency increases, storage losses matter less. As storage technologies improve, poor insolation matters less. But sure, someone invents a nice kitchen-sized baseline reactor that anyone can run, then this microgrid movement really takes off. Probably not in the next couple weeks. ;)