Average Cloudiest Month Map

Steven Lake

I thought you guys would find this interesting.

softdown

That is interesting though I could see potential pitfalls without knowing more about their methodology. I would also bet that conflicting data could easily be found.

We can count on shorter winter days and the angle of the sun to constantly change. Also.....pvwatts.nrel.com clearly shows that solar production has almost everything to do with the length of the day...here in Colorado.

I could see the potential use of this in someplace like Florida that has their rainy season around June. Though pvwatts should recognize that in their charts.

From personal experience....it sure seems like winters are the cloudy season everywhere I have lived.

Photowhit

I would question if this is peoples opinions, it seems odd that there would be pockets of different weather in localized areas, devoid of different terrain. I live in Missouri close to that March bulls eye which appears to be Columbia. I would certainly say our last few years have been worse in November, December than January, February. Though I haven't tried to track it.

Horsefly

I guess I would question what the value of this would be, at least for the people who post here. Knowing what the "cloudiest" month is would be of very little value to anyone trying to be analytical about a design. What if all the other months are cloudless? What if all the other months are almost as cloudy? 

I think the data provide by NREL is much more analytical and useful. I just see no value in this representation.

Steve

mcgivor

True that, map shows Seattle having January, could be any month from November to April there.

softdown

mcgivor said:

True that, map shows Seattle having January, could be any month from November to April there.

Seattle is famous for its fog and cloudiness. I don't see how solar could be highly effective is such an environ.

Dave Angelini

softdown said:

mcgivor said:

True that, map shows Seattle having January, could be any month from November to April there.

Seattle is famous for its fog and cloudiness. I don't see how solar could be highly effective is such an environ.

Well if you had clients or friends there using solar as a power source you would know that they have to compensate with much more solar and a decent generator support plan. It is not a big deal really just a little more thought required.

softdown

Dave Angelini said:

softdown said:

mcgivor said:

True that, map shows Seattle having January, could be any month from November to April there.

Seattle is famous for its fog and cloudiness. I don't see how solar could be highly effective is such an environ.

Well if you had clients or friends there using solar as a power source you would know that they have to compensate with much more solar and a decent generator support plan. It is not a big deal really just a little more thought required.

Clearly...at some point I might be inclined to simply give up on PV solar. I am in solar paradise and still wonder about the merits of going on the grid...there is a line about 3/8ths of a mile away.

Batteries....inverters....charge controllers....constant maintenance. Sometimes it is fun. Except when it isn't. It is alway$ $$$$$$$.

Dave Angelini

I think there is a level at which you have to be able to afford it to do it right. Offgrid requires just about as much knowledge as the person who designs the system! Sitting on the Beach on the Baja is quite a bit easier than Alaska and costs less!
 You must pay for it, or take chances that someone on the internet really understands what you are saying, or has the time to care very much. The last choice is to just have problems all the time and eventually move back to the grid.

Photowhit

softdown said:
Batteries....inverters....charge controllers....constant maintenance. Sometimes it is fun. Except when it isn't. It is alway$ $$$$$$$.

I think there is a time of over scrutinizing/analyzing things. I guess I have been around solar for longer than I'd like to admit. Having a small system on my van wanderings in the late 80's, and on my sailboat and even a total loss system in my 8 month bicycle trip in 1999. All that before I setup my first home system.

I suspect after a while you will become comfortable with things and it will all settle down. I think trying to save money sometimes cost you in 'waning interest'. Working with used fork lift batteries(?) and currently with aged agm batteries might discourage you as you need to put in time and effort to make sure things are working.

I've certainly advocated buying used equipment and rarely have I been burned, but  used panels for a solar store that had been in business for 20 years before I purchased some solar panels from them in 2002 is not a bad risk. I've also bought a Prosine 1800, and a military version of the Prosine 1800 inverter off eBay (which actually has near zero risk as they now, in  general, require ability to returns. Both have been fine. The local 12 volt Prosine 1000 was a bit iffy, but $40 risked and it checked out okay when I got home with a minimal load. I loaned it to someone and it can back dead, said it wouldn't handle a load. May have been a mistake, or my friends might have connected it wrong.

I check the battery bank once a month and I am manually running equalizing. I guess I am always thinking about opportunity to run heavy loads. I currently have an under sized inverter for my system so it's not always simple, I ran my 2 dehydrators off my 'yard work' inverter an 1100 watt Exeltech so I could run my water heater off my home inverter and not worry about when my fridge would kick on and shut down my system. All that is just part of life.

I'm guessing I'll see if I can bet the current energy rates here, which for my local coop would be about 20-25 cents a kwh for a minimal user with their monthly fees up to $33 for the privilege of buying electric from them, and likely to go up... If you use 210kwh a month (7 kwh a day) the cost would be 25 cents a kwh. I suspect I use less than that 9 months out of the year and more during the summer. I once calculated my cost for off grid solar at roughly 26 cents a kwh BEFORE tax credit and with a new inverter which was never purchased.

Long and rambling, I guess I'm tired. I don't really worry too much, I guess I don't think of it as 'fun' but perhaps it would be nice to beat the system and actually be less expensive. but then again the one thing about living on solar, and not wanting to run gas heat. I've got to cut, pile, burn wood... So far so good.

softdown

That used forklift battery may have been my best buy ever. SG in all cells at 1.027.....1650lbs for about $400. The AGMs are looking to be one of my best buys as well.

I am installing more strings and starting to make a *lot* of battery cables. Plus stocking up for cabin solar installations. Solar has plenty of challenges.

Grid electricity is usually cheap by comparison.

If a party grosses 2000/mt and has expenses over 2000/mt....they must buy stuff that can be resold for a profit. Cycle of life.