Home Solar Power Output - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: August 19, 2016, 10:10:09 am
content: I'm just curious as to the kind of performance forum users are getting out of their PV arrays at home. I just got my power bill for the last quarter (mid-May to mid-August) and I'm generating about 6.23kWh/day on average (for a total of 574 kWh over the past 92 days).I have a ~5KW (probably closer to 4.8KW in real world specs) system on the roof facing North. Because I live in the mountains, I miss out on some sun in the late afternoons due to trees and hills across the road to the west. Keeping in mind it's winter here at the moment. The sun rises at about 0630H and sets at 1730H, so we're getting less than 12 hours of sunlight and of that, only a fraction of it is actually usable on the PV array.(Although I need to stop leaving the ducted AC running all the time and power off some gear when I'm not using it. I burnt through almost 3600kWh in the last quarter! Apparently on average, that's more than a 6 person household. Ouch!)And in case anyone is curious, I'm paying between 21.93 and 24.38 Aussie cents per Kilowatt hour depending on which 'band' the consumption falls into.

author: dannyf
author_rank: Super Contributor
timestamp: August 19, 2016, 02:25:05 pm
content: In the summer, I consume about 3500KwH per month, or 100KwH per day. About 1/3 less in the winter months.Solar will never pay for me.

author: bollio
author_rank: Contributor
timestamp: August 19, 2016, 02:50:36 pm
content: Just for some comparison. I use around 35kWh a day in the summer and rough 10kWh in winter per day. I dont actually know the rating of my system as it was on the house when I bought it, but I generate between 10-12 kWh a day. Winter doesnt really impact my generation out here (Arizona), but I'm usually break even all winter, if not owed a little by the power company. Oh and I'm at 14 cents US, both for use and generation. Fortunately, my system is grandfathered in so I don't get hosed by being paid less than they'd charge!

author: mtdoc
author_rank: Super Contributor
timestamp: August 19, 2016, 03:04:07 pm
content: Rule of thumb: Expect to average about 75-80 % of panel STC (nameplate) rated output during peak sun hours. 5-10 % less if a battery bank is involved (off grid or grid tie with battery back-up). Hotter temps = less, colder = more.Of course the above assumes clear skies.The number of peak sun hours varies greatly depending on location, season, shading, and if a tracker is involved. 4-6 hours is typical.My 4.5 kW of PV in my grid tie with battery back up system puts out 16 -20 kWh on a clear summer day here at 48 degrees north latitude. I also have some late day shading.There are online calculators such asPV Wattsthat will tell you expected average array output based on historical solar insolation data for you location.

author: nowlan
author_rank: Frequent Contributor
timestamp: August 19, 2016, 04:10:41 pm
content: I think pvoutput will let you compare to similar sized systems in your area.

author: Jeroen3
author_rank: Super Contributor
timestamp: August 19, 2016, 08:50:46 pm
content: Quote from: dannyf on August 19, 2016, 02:25:05 pmThat is an avarage year for us.... Do you have electric cooking and climate control?

author: Kilrah
author_rank: Unknown
timestamp: August 19, 2016, 08:56:57 pm
content: 5kW average? Would be more in the order of heating a swimming pool all year long...

author: m98
author_rank: Frequent Contributor
timestamp: August 19, 2016, 10:41:18 pm
content: Quote from: dannyf on August 19, 2016, 02:25:05 pmHow many people do you actually mean with "I"? In Germany, that's round about the average energy consumption per year for a three person household...

author: Zero999
author_rank: Super Contributor
timestamp: August 19, 2016, 11:07:42 pm
content: Quote from: m98 on August 19, 2016, 10:41:18 pmIt's quite likely he could reduce his electricity consumption drastically which would pay, regardless of whether he gets solar panels or not.

author: dannyf
author_rank: Super Contributor
timestamp: August 19, 2016, 11:42:41 pm
content: Quoteeverything electric, other than heating in the winter.

author: Someone
author_rank: Super Contributor
timestamp: August 20, 2016, 12:29:34 am
content: Quote from: Halcyon on August 19, 2016, 10:10:09 amThe data from your bill might only be your export total (the part you got paid for) and not the total generation of the panels. If you're running loads consistently throughout the day and have such high consumption then you're probably close to optimal if that is your export figure. 40kWh/day is wildly excessive unless you're charging electric vehicles, there are some savings to be found around your house before resorting to the poor return on solar power.Its possible to get an accurate estimation of your load factor from the insolation data that BOM provides, calculating for Melbourne in this thread:https://www.eevblog.com/forum/renewable-energy/tilting-(at)-solar-panels/

author: Someone
author_rank: Super Contributor
timestamp: August 20, 2016, 12:48:12 am
content: Quote from: dannyf on August 19, 2016, 11:42:41 pmAnd your other hobby iscoal rolling?

author: dannyf
author_rank: Super Contributor
timestamp: August 20, 2016, 12:57:34 am
content: My latest bill shows about 1400kwh last month: we had a week plus of 100 degree days.

author: hendorog
author_rank: Super Contributor
timestamp: August 20, 2016, 01:14:56 am
content: Quote from: dannyf on August 19, 2016, 02:25:05 pmQuote from: dannyf on August 20, 2016, 12:57:34 amSounds like solar would be perfect for you then. You would consume the power as you generate it, no batteries needed, no feeding power back to the grid at a lower price and buying it back later, and you can get a deal on a large system and _still_ use all the power yourself.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: August 20, 2016, 01:28:08 am
content: Quote from: dannyf on August 19, 2016, 02:25:05 pmI could probably stick my heater in the refrigerator and still have a smaller bill than that.FWIW, family of 4, solar/gas hw, gas cooktop, wood fire. 7kWh per day.

author: bollio
author_rank: Contributor
timestamp: August 20, 2016, 01:41:40 am
content: The killer for me is air conditioning in 120*F summers... I run a net positive despite having 3 computers running, 5 ceiling fans, a TV and most of my house's lights! Even if I've got all my test gear on, as long as the A/C isnt running I'm generating more than I use... I should probably put some shade on my inverter though as currently it's in direct afternoon sun, would that effect longevity and efficiency?

author: Zero999
author_rank: Super Contributor
timestamp: August 20, 2016, 09:09:04 am
content: Quote from: dannyf on August 20, 2016, 12:57:34 amHave you:Replaced all the incandescent lights with CFL/LED?Invested in decent thermal insulation around your home?Shaded the AC condenser and inverter?Installed blinds/window shutters and keep them closed during the day?Planted trees near your house?You could also grow a vine up the walls of the house which get the most sun.

author: dannyf
author_rank: Super Contributor
timestamp: August 20, 2016, 11:51:23 am
content: QuoteYeah. the big breakers on my panels are for ac, water pump, dryer, water heater, ovens and a Jacuzzi. But none of them work as frequently and as long in the summer months, as the ac.i live in a hot and humid environment so no evaporative cooling is possible.

author: Zero999
author_rank: Super Contributor
timestamp: August 20, 2016, 08:22:38 pm
content: The water heater and heat for the jacuzzi can certainly be powered from solar thermal.I don't know whether it's more efficient than photovoltaic and electric air conditioning, but another option is to use a solar furnace to power and absorption cooler for the AC, but it would be a big investment.

author: Jeroen3
author_rank: Super Contributor
timestamp: August 20, 2016, 08:57:52 pm
content: You can get efficient solar water heaters, even in "cold" weahter of ~5c. If the sun hits it, it will heat.New houses have this system installed for heating and hot water. My neighbour has it for his pool. Works great.

author: dannyf
author_rank: Super Contributor
timestamp: August 21, 2016, 11:57:03 am
content: QuoteI have seen them in China. Apparently quite inexpensive as well. Unsightly though.Of all the "solar" stuff I have seen, the most impressive is a "sun wall" that my neighbor got. It is a sun roof with fibre that reflects natural light into a bath room wall, augmented with LEDs.

author: Jeroen3
author_rank: Super Contributor
timestamp: August 21, 2016, 03:42:38 pm
content: They look like photovoltaic panels. Only thicker and slightly more black.I think they are like semi-mandatory on new houses today.

author: dannyf
author_rank: Super Contributor
timestamp: August 21, 2016, 03:44:08 pm
content: the ones I saw had a frame on them and are meant to be placed on flat roofs.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 21, 2016, 07:32:29 pm
content: Quote from: Hero999 on August 20, 2016, 08:22:38 pmI had an idea for a simple DIY solar dehumidifier. A discussion on another forum says that it would probably work quite well, although I haven't actually built one to find out.http://ecorenovator.org/forum/solar-power/2899-diy-solar-dehumidifier.htmlQuote from: dannyf on August 21, 2016, 11:57:03 amStill way better than fossil fuels.