Thoughts on this idea to reduce power bill?

J

Jladan

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Hi all,

SO obviously doing a full on power solution is pretty damn expensive. So I'm thinking about approaching this as follows:

Step 1: Install Solar panels and inverter and link to DB board, have enough capacity for the house to run off mainly off solar during the day. The logic being base house load which is around 1kw to be taken up by solar, spikes above will still be carried by eskom. In theory this should then lower my electricy bill and pay off panels and inverter.

Step 2: As money is saved expand panels and inverter (Not sure if I can just but one good inverter once off) until I have enough to carry full house load. From power monitoring I seem to do around 35 - 45 Kwh per day.

Step 3: Once enough panels and inverter capacity is in I should then not be paying for power at all during daylight hours. These saving will be used to pay for panels etc, then once that is done start saving towards bats that will eventually store exccess power for over night.

Some questions I have:

1. Ball Park what would the above phases cost? What sort of initial array and inverter would be able to accommodate a 1 KW base load then be easily expandable to around 4 - 6?
2. Is there special insurance you need to take out for Solar panels? I would imagine a good hailstorm could wreak havok?
3. How do you solar guys deal with large spikes? I've noticed that at times the hours does pull 6-8 KW, I tihnk this is the very rare occasion where EVERYTHING is used at once.
 
First things first, have you done everything you can do be as lean as possible first.
IE low energy everything.
 
If you're doing a hybrid setup (grid + battery), you need to be aware that feeding back to the grid is illegal in many locations (but not all).
In some locations - eg Cape Town, it doesn't make sense to grid tie, as they add daily fee's which make it financial suicide to implement.
Lastly, you can't feedback if you have a pre-paid meter, as it will either shut off, or *charge* you extra (depending on unit and configuration).

If you can ensure that usage is *always* less than generation (eg with a smart inverter), then you can try a small system out, even with all the above limitations, although to be legal, you need to use units that are NRS.97 approved, and have an engineer sign off on your system, together with an solar signoff.

Essentially the rules in .za are quite biased against people installing solar, although many people just ignore that.

Solar wise - panels are the cheapest part of the system. I always suggest get more panels than you need, as its a no-brainer.
Before looking at any of that though,your daily usage sounds high. I'd suggest reduce that first before even thinking about solar.

First steps are to reduce the major users of power.
Likely culprits are: heating - i.e hot water, cooking..

Change your electric cooker to a gas one.
Change your geyser to a solar one. (I recommend you size about 100L per PERSON in the house).

Once you've done that, then look at the other energy hogs in the home - Halogens, and other high powered lighting should all be replaced.
Do NOT buy CCFL's, they're horrific for the environment and should be banned outright. 4th gen COB LED are really efficient (the ones that look like normal bulbs, and don't get hot).

If you still using heating in the house in winter, I highly recommend installing proper insulation in the roof, it makes a world of difference.
I wrote up some details on that here - http://goingsolar.co.za/2016/01/08/...ion-keep-it-cool-in-summer-and-hot-in-winter/


First be efficient, then look at solar.
 
@isheed_cn: If daily fees are too high and no real benefit in pushing power back in this use case wouldnt more sense to just have a prepaid main connection for any times where solar isnt enough, and then solar is too much dump that power into water heating.

Sorry for always hijacking threads, but just rather interested in the field.
 
Jladan said:
Step 2: As money is saved expand panels and inverter (Not sure if I can just but one good inverter once off) until I have enough to carry full house load. From power monitoring I seem to do around 35 - 45 Kwh per day.
Click to expand...

damn

you go through alot of KwH a day :wtf:
 
Yeah I do go through a lot a day, we have LED everything , solar geysers, however they do pull 2kw from 2-4 am for morning showers. The biggest culprit is we have multiple fridges and a fairly over the top it setup. End result is when we aren't doing anything in the house we pull 900w as a baseline. I am considering as part of the project putting certain plug circuits on timers to properly turn certain not being used areas off when not at home
 
I'm also not necc looking to feedback to the grid but rather just initially reduce the amount coming from Eskom. I.e. reduce my "base" load to 0 the pay for power usage above 1kw. If I can reduce my paid consumption by 12 kWh per day it would be a good start
 
Jladan said:
Yeah I do go through a lot a day, we have LED everything , solar geysers, however they do pull 2kw from 2-4 am for morning showers. The biggest culprit is we have multiple fridges and a fairly over the top it setup. End result is when we aren't doing anything in the house we pull 900w as a baseline. I am considering as part of the project putting certain plug circuits on timers to properly turn certain not being used areas off when not at home
Click to expand...
Sort that out first. There is no need to have such an excessive base load. I do about 1/10th of that.
 
Jladan said:
I'm also not necc looking to feedback to the grid but rather just initially reduce the amount coming from Eskom. I.e. reduce my "base" load to 0 the pay for power usage above 1kw. If I can reduce my paid consumption by 12 kWh per day it would be a good start
Click to expand...
I am going to read between your posts and assume you think that 1KWp worth of panels would provide 12kWh per day? If you het half of that, you would be doing well. Have you looked into what your usage spread looks like? Ie on average how much energy are you using at what time of the day. It is usually biased a lot more to the dark hours than people think.
 
Thanks for the feedback guys, will look more into seeing how to reduce base load, it is a tad ridiculous, and no I didnt think 1kw of panels would give me 12 kwh of power per day. I was thinking something along the lines of 10x 300w panels might give me enough to cover base the base 1 kw
 
Do you have an it business from home?

Average of 40kwh a day is A LOT.

And you have a solar geyser,so something is leeching big time.

There has to be some way to easily cut it down to 25 a day,and by the looks of it,someone is home all day or as you mentioned your it setup,hence me asking do you have a small home business/employees there.

I know of a family of 7 who uses 3 freezers and they do about 25kwh,and use a normal geyser.
But they are at work/school and have a lot of electronics running at night time.
 
Got alot to do with the size of the house + all the gadgets and automation. There households out there burning up nearly 200kwh day.
 
Any grid tied system (even if it's not feeding in) needs to comply with municipal regulations - check those first. What you want to do is illegal in a huge part of the country.

That's all I can contribute to your question, but I do want to remind people why these laws are in place. It's not because we're backwards or greedy or stupid - they're there to protect the grid, the people working on the grid, and the grid's pricing mechanisms.

As a society, we want you on the grid or off it. In between is deleterious to everyone.
 
I did a bit of an experiment last night and got my "base" load down to 600w while we slept. After adding up the various bit and pieces I get to 600w calculated easily.

How one earth do some of you get your base load down so low? My biggest issue is short of turning off fridges / IT stuff and or security we aren't going to be able to lower this base load much.
 
Fridges/freezers are killers. Dont have more than one, and don't try to put timers ob them, that is a bad idea. Rather raise the temperature setting. And check for vampire devices. One of my lcd tv uses 15w in standby. Some old devices can use a lot. Track these down and replace or unplug them.
 
Agree turn of one freezer at least. Turn of pc's you are not using,if you want to go solar,you have to first become lean as mentioned. People don't seem to understand that point so much.
 
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