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>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. Deman

>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-...
  - D9u 13y ago
    The newer PV panels will produce on even the cloudy days, and I know this is fact because I've been using solar for over 15 years now. Your guesses are way off.
Ma8ee 13y ago
What you say is probably true in Michigan, but not so much in Hawaii. For big parts of the US, AC stands for most of the consumption, and you do have the highest power demand when the sun is strongest.
- jsmcgd 13y ago
  Just to muddy the waters further, most people are at work when the sun is strongest leading some to recommend that home PV arrays should be orientated towards the evening sun. Of course if your home and work electricity grid is connected then this could be mitigated.
  - stcredzero 13y ago
    In the current architecture, electricity can't be shared out of your own neighborhood, so this wouldn't be the case for bedroom communities.
bandushrew 13y ago
That is actually incorrect for the majority of places. Industrial and business related consumption tends to dwarf home owner consumption, and is usually at its peak during the day.
ac29 13y ago
>Demand peaks early morning and early evening, when solar is near its minimum. And in winter, solar is near zero at those times. That might be true in some places, but neither point is true in Hawaii. Insolation is nearly the same all year, and grid loads peak midday with insolation (think AC): http://www.heco.com/vcmcontent/StaticFiles/Images/Articles/typical_load_profile.gif http://www.heco.com/vcmcontent/StaticFiles/Images/Articles/t...

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-...
- D9u 13y ago
  The newer PV panels will produce on even the cloudy days, and I know this is fact because I've been using solar for over 15 years now. Your guesses are way off.

Ma8ee 13y ago

What you say is probably true in Michigan, but not so much in Hawaii. For big parts of the US, AC stands for most of the consumption, and you do have the highest power demand when the sun is strongest.

jsmcgd 13y ago
Just to muddy the waters further, most people are at work when the sun is strongest leading some to recommend that home PV arrays should be orientated towards the evening sun. Of course if your home and work electricity grid is connected then this could be mitigated.
- stcredzero 13y ago
  In the current architecture, electricity can't be shared out of your own neighborhood, so this wouldn't be the case for bedroom communities.

bandushrew 13y ago

That is actually incorrect for the majority of places. Industrial and business related consumption tends to dwarf home owner consumption, and is usually at its peak during the day.

ac29 13y ago

>Demand peaks early morning and early evening, when solar is near its minimum. And in winter, solar is near zero at those times. That might be true in some places, but neither point is true in Hawaii. Insolation is nearly the same all year, and grid loads peak midday with insolation (think AC): http://www.heco.com/vcmcontent/StaticFiles/Images/Articles/typical_load_profile.gif http://www.heco.com/vcmcontent/StaticFiles/Images/Articles/t...