Home › Forums › SUSTAINABLE CONSTRUCTION, ENERGY and WATER CONSERVATION › Sustainable Energy & Energy Conservation › Solar peak time use
December 1, 2012 at 6:52 pm #257448
I am getting a 5kWh system installed before the end of the year and I am curious about how to get the best use out of the system. Under non-solar system I try to use dish and clothes washer in off-peak times. Could somebody explain the basic of solar energy to me – is there any advantage in my moving these uses to when the sun is at its peak? ie: Does my solar generation stay the same regardless of when or whether I use any electricity?December 1, 2012 at 7:39 pm #529321
my power is cheaper after 11 to 7 am and weekends
So I try and use washing machines,dishwasher, vacuum cleaners and oven during the off peak times.
Obviously after dark is best as you sell more solar at a higher rate when the sun is shinning so you dont want to cut into that.December 1, 2012 at 9:04 pm #529322
We had a 4+KW (can’t remember exact size) system installed 2 years ago.
Here’s how I manage our electricity use.
My aim is reduce the use of electricity during the hours the system is producing feed in.
Next priority is to use as many appliances in the off peak period when there is no feed in being produced.
Last during peak hours when there is no feed in.
As you can see this maximises the production of feed in at .60 KWH.
This is my understanding of how it works though I often wondered if I’m wrong. I look forward to reading other peoples replies.December 1, 2012 at 9:40 pm #529323
I only have one tariff (we had gas hot water pre solar hot water install), so for me, using electricity as little as possible during the day is the way to go (so agreeing with previous posters) 🙂December 2, 2012 at 2:03 pm #529324
I have 9 panels ,only a small set up.I had intended to install 18
Western power said I couldn’t because the transformer? could not handle more.
I have a solar hot water system.
During the day I use power as little as possible, turn every thing off at the wall ect.
I wash and use other appliances at night.
The result has been that I have all my power paid for and aprox $120 credit each billing session over the summer.
I left some credit in the system just in case for the winter.
So far i have only had a very minimum amount needed to pay around $10 to $15
There is still some credit left and now it is getting warm again I am expecting to produce more power than I use.
You could say I am happy with the way it works BUT I do have to work at it, no turning lights, tele on then leaving them, power switch is your friendDecember 2, 2012 at 3:39 pm #529325
It all depends upon the cost of electricity from the grid (around 20 cents per unit) and how much you get paid for excess you pump back into the system. At the moment without subsidy you should get paid around 8 to 10 cents per unit. In our case we got in early and have a subsidy so we are paid 48 cents per unit.
If you don’t have a subsidy it is much better to move as much electricity consumption to the day during sunlight. Effectively you are paying the 8 to 10 cents per unit (foregone revenue for power used). At night you would be paying 20 cents per unit.
In our case we need to move as much electricity consumption to the night. Electricity then costs 20 cents per unit. If we use it during the day it costs us 48 cents per unit (ie forgone revenue for power used).
In a few years time when the subsidy cuts out we will revert to doing as much during the day as possible.
Currently we have a 3 KW system and are owed around $400 after one year.
AndrewDecember 2, 2012 at 6:03 pm #529326
We are in SA and similarly to Pardalote above we our Feed in Tarrif is less than what we are paying for electricity from the grid, so we try to do our energy hungry things during the day when the sun is shining (using our own generated electricity rather than paying extra pulling it out of the grid).
We get paid about 25c for each kWhr we feed in, but have to pay a minimum of 32c to pull it out (tiered rate, as consumption increases so too does the price, ie first “so many” kWhr/quarter charged at 32c, next “so many” kWhr/quarter charged at 33c, next “so many” kWhr/quarter charged at 38c, next “so many” kWhr/quarter charged at 42c, and so on.
So using our own electricity (ie when the sun is shining and our system is generating, we are using that electricity rather than feeding it into the grid) means that we are effectively using the “cheapest electricity” (sacrificing the 25c “payment”, but meaning that we wont have to pay the more expensive 33c+ price if we did these “jobs” at night)and also it should keep our usage in the lower brackets and hence the cheaper rates (for the grid usage)
I have friends who got in while the “good” Feed in Tarrif of 65c was offered and they do the opposite, feeding as much as possible into the grid being paid at 65c/kWhr then taking it back out at the lower 30(ish) cents/kWhr
Oh and in SA although we have an “Off Peak” tarrif this is a seperate connection so to speak and generally only hotwater systems run on this system – we have three meters in our power box, – Feed In, Peak usage (most of the house) and off Peak (electric Hot water)December 2, 2012 at 6:37 pm #529327
Interesting numbers you have there. I hadn’t realized that costs for electricity and standard feed in tariffs varied so much over Australia.
AndrewDecember 2, 2012 at 10:54 pm #529328
I was discussing this with my hubby the other day. If I use power during the day will I be using my (4.8kW system) own electricity? We got the panels for environmental reasons rather than monetary and I was wondering wouldnt it be better to use the power during the day rather than use the grid power after hours which is most likely coming from a coal fired power station? We were fortunate enough to get our paperwork submitted in time so we get the 44c rebate.December 4, 2012 at 2:44 am #529329
“If I use power during the day will I be using my (4.8kW system) own electricity?”
Yes. However remember that the electricity you don’t use gets fed back into the system and someone else uses it (instead of coal generated power). The effect on coal use is the same; the power produced by your panels cuts down on coal use to the same extent whether you use the power or someone else does.
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