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Waste of Excess Solar Power

07/13/2012 2:38 PM

Most of independant solar installations have battery storage.Batteries have excess capacity ,to take care of cloudy days. Now if we have contnuous sunny days , the batteries do not need the Solar power to the extent Solar panels can generate. Do we have any data/study done on such excess power availability ?

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#1

Re: Waste of Excess Solar Power

07/13/2012 2:53 PM

What do you mean? Excess battery capacity? Excess solar energy?

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Guru

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#2

Re: Waste of Excess Solar Power

07/13/2012 3:04 PM

Um, over here we don't have continuous days, sunny or otherwise. We have days alternating with nights. Most people use electricity at night for artificial light and other things. Did you see this discussion - http://cr4.globalspec.com/thread/79190/24-Hour-Solar-Power ?

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#3

Re: Waste of Excess Solar Power

07/13/2012 3:13 PM

Since solar panels to begin with are not very efficient. Maybe you should be addressing that waste, all that sun not being converted.

Not what some individual(Independent) who has spent hard earned money to become energy self sufficient is wasting.

I would all so question the assumption that most are. A lot are connected to the grid using it as storage.

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#4

Re: Waste of Excess Solar Power

07/13/2012 4:32 PM

To cover all the extreme possibilities and worst case scenarios that can happen on a solar installation, the initial and possibly working costs, would be TOO high to consider investing. S.M.

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#5

Re: Waste of Excess Solar Power

07/14/2012 6:19 AM

Here in the mother country (England) we sell it back to the power grid system, although the weather we've been having lately I don't think much has been sold back.

Bazzer

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#6
In reply to #5

Re: Waste of Excess Solar Power

07/14/2012 9:43 AM

Many isolated installations are done with almost 5 days of storage capacity in batteries,considering cloudy days. But when there are continuous sunny days, the available Solar power is not used up. Has any study been done about this wastage?

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#7
In reply to #6

Re: Waste of Excess Solar Power

07/14/2012 12:30 PM

Why study it? These isolated installations most have no electrical service from utility company to begin with. That why they went solar. The cost to providing the electrical service to them is costly. So much so it wouldn't pay to run it just to utilize this wasted solar power.

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#9
In reply to #7

Re: Waste of Excess Solar Power

07/15/2012 8:39 AM

There is good amount of wastage. How much percentage of power generated is lost is not known. Problem is battery has limited storage capacity. If there is any other means of storage in some form, this energy could have been utilized.

Any such system available and minimum size of such installation?

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#10
In reply to #9

Re: Waste of Excess Solar Power

07/15/2012 3:40 PM

Buy another battery. Buy Two. Get it? For no particular reason, most any word that ends with 'age' is annoying - right up there with 'shall'.

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#13
In reply to #9

Re: Waste of Excess Solar Power

07/16/2012 5:37 AM

I'm getting the impression that you can't use all the power you generate, so get more batteries so you have a good backup, and if I'm reading it right you're not on grid, so neither are your neighbours, so sell them the excess, If they have generators combine the storage you could involve the community that way you would all have backup storage in case of a turbine breakdown.

Bazzer

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#15
In reply to #13

Re: Waste of Excess Solar Power

07/16/2012 11:16 AM

One does not move to some isolated location that has no utility service to have a bunch of neighbor's. If one did have neighbors the distance away would be measured in miles. Who foots the bill for all the wire between them. If it wasn't so costly a utility company would have provided power.

If one would sell excess electricity to ones neighbor's then they no longer are neighbors but are customers. That means a complaint department. Who wants to hear people complain every time there is a mishap with the service. Especially during a time that your most likely working to get power back up for yourself.

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#16
In reply to #15

Re: Waste of Excess Solar Power

07/16/2012 11:49 AM

You're talking India where a distant neighbour is 50 feet away, I know I've watched Big Bang Theory.

Bazzer

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#8

Re: Waste of Excess Solar Power

07/14/2012 11:25 PM

Excess solar power could be exported to the grid or utility or could be used for charging batteries. If Solar panel is made in the shape of a globe, light falling on it from any direction will generate power. If mirrors are arranged around it light will reflect on the mirrors and fall on all sides simultaneously and generate excess power.

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#11

Re: Waste of Excess Solar Power

07/15/2012 8:11 PM

OP appears to be obsessed with utilizing every unit of energy that his solar panel produces. If you feel that there is a point in time where, after a long stretch of continuous cloudless days, the panels are producing more than you are capable of using, then as others have pointed out, simply increase the amount of storage to capture this energy. The problem with this is, as you add storage (whatever form it takes) sooner or later you will reach a point where you are not capturing enough energy to keep your storage fully charged because now your storage is oversized relative to the capability of your solar farm. The complaint will then be that you don't have enough solar capture ability to keep your storage fully charged, then we will be suggesting that you simply add more panels! As you can see this is a chicken and egg problem with no real solution.

The "better" engineering solution is to utilize more of the energy that strikes each square meter of your capture device; i.e., increase its conversion efficiency. One way would be to place a thermal energy collection device sandwiched behind each panel. Simply adding a serpentine coil of water tubes to absorb the heat off the back of the already hot photovoltaic panel will serve two purposes. You will be able to increase the efficiency of the PV cells since it is well known that current cell efficiency is inversely related to its temperature; and two the heat energy captured by the water tubes can be stored and used for domestic hot water purposes. Under this hybrid scenario the conversion efficiency goes from the PV efficiency in the low teens to nearly 75% for exactly the same panel area, a nearly five-fold increase in energy captured. Think of it as a "combined cycle" for solar power. This is the best of both worlds and answers OP's complaint about not capturing all the energy incident on his panels.

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#12

Re: Waste of Excess Solar Power

07/15/2012 8:37 PM

Or here's a(n unoriginal) thought: Build a resevoir at a higher elevation pump water up to it with excess power and use a turbine to generate power on the way back if & when desired.

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#14

Re: Waste of Excess Solar Power

07/16/2012 6:51 AM

Like a lot of 'green energy' I would suggest the amount of power a solar electrical system will make in its life time will not equal the amount of fossil fuel burnt to both manufacture and get the system in place.

In all cases follow the money not the hype. Our solar and wind energy is heavily subsidised in the UK. OK I suppose if you were one of the early guys on board. Long term a real non sense (unless you want to make money from subsidies - again follow the money).

Are you happy selling the rights to your roof cos thats what you do in the UK.

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#17
In reply to #14

Re: Waste of Excess Solar Power

07/16/2012 1:39 PM

It is very much subsidized, but if you look at total benefits , it may not be.eg saving of fossil fuel which will be very expensive some day, saving in Carbon dioxide,devlopement of cheaper and highly efficient Solar panels.

But I feel instead of random use of Solar only, the incentives should target with Solar plus other renewables .Like Wind,Biomass etc. This will reduce battery sizes and expenditure on it also.

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#18
In reply to #17

Re: Waste of Excess Solar Power

07/16/2012 3:26 PM

Not clear on this. Subsidies provide benefits that may not be measureable in engineering units (including $), but they should keep coming so we get more and better unmeasurable benefits?

I'm a huge fan of creative thinking - artificial economies, not so much.

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#19
In reply to #17

Re: Waste of Excess Solar Power

07/18/2012 5:01 AM

You really need to look at the climate. We have had a 14% increase in the amount of installed wind power in the UK. We also have an in crease of 4% in CO2 output.

The solar panels used to generate hot water in countries like Greece I see as being a complete winner. This is real green energy.

Solar for electricity is very inefficient and though it has uses the chemicals and products used are far from friendly.

That said I do believe we need to consider green energy but lets keep it green and clean and keep away from the lies that surround it.

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#20
In reply to #19

Re: Waste of Excess Solar Power

07/20/2012 12:35 PM

The Solar installations in remote areas ,far away from grid are not efficient enough to use up all energy generated by the expensive pabnels.Combination with other sources like wind or biomass or even a pumped up storage can utlize the excess energy. I was looking for other inovative ideas, which are not expensive to use the energy in some form. Say a 20KW only solar unit with 5days of battery capacity can have surplus power of above 30% in a year. But it will not be available at all for a certain periods, when you have monsoons/cloudy days. So the availability of power will be only in certain periods of year. What can be considered to utilize the same ? Even generating hydrogen and store is such an item. But it is expensive. Are their any cheaper option. May be some other chemical storage ?

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#21
In reply to #20

Re: Waste of Excess Solar Power

07/20/2012 2:44 PM

'...some other chemical storage?' Wouldn't that be more batteries? You are trying to get perfect balance between supply and demand with uncontrolled supply and uncontrolled demand. Can't happen. You have 3 options:

1. Control supply - (Shade the cells when power is not needed)

2. Control demand - (Either waste the energy as heat or come up with a controllable optional use. For example, a treadle sewing machine with motor which could be used when excess power is available.)

3. Import or export to balance - (You're just fortunate to have excess. I suppose you could have a portable battery change-out system similar to the propane supply many places have. Then you could exchange charged batteries for discharged ones.)

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#22
In reply to #20

Re: Waste of Excess Solar Power

07/22/2012 1:25 AM

Incorrect, this has nothing to do with efficiency and everything to do with trying to achieve the elusive balance between production, consumption, and storage in real time (something, btw, that utilities achieve in every moment of operation).

In your original post you were concerned that the panels would generate more power than the storage could store, now you are afraid that the load can't consume all the power that is being generated. Clearly you are ignoring all of the sound advice of previous posters, it is now time for you to study it again so that you can gain an understanding of how your circular reasoning is affecting your thought processes and its outcome.

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