Add a Comment

Comment by Keith Lurie on November 7, 2011 at 17:27

So, instead of getting gas from our own ----, and saving water, they would rather use huge quantities of water to get gas from shale.

Back to solar, as you mentioned, batteries can be charged in a few hours, leaving excess energy to use during the day (free energy). 

There are other ways of 'storing' energy, for example windmill or solar pump water up to a resovior, and allowed to flow down, a small turbine can convert this to electricity.

Probably the easiest system for the user is where excess electricity can be fed into the grid, and use grid power when you aren't generating anything, use grid electricity.

Comment by phillip newmarch on November 7, 2011 at 16:56

Yes, the 'fracking' issue would probably be best covered in another forum. But it may be appropriate to mention it here, as it is sometimes claimed that it is the solution to our energy problems for 'hundreds of years' they say.
But for those who have never heard of it, or don't know what it is about (and that may be many people), 'fracking' refers to a recently developed process for extracting methane from a rather common kind of rock which contains small nodules of gas trapped inside it, which only comes out when the rock is fractured.  By drilling down and then horizontally into the rock, then pumping huge quantities of water and additives in under very high pressure (known as 'hydraulic fracturing'), small cracks are opened up, allowing some of the trapped gas to escape into the well.  The trouble is, to produce any significant amount of gas, it requires astronomical amounts of water, equivalent to reversing the flow of the Orange River, or doubling the rainfall in most of the country.  It is a crazy scheme with a lot of very big money behind it.  

For more see the facebook link NOT SHALE-GAS

Comment by Keith Lurie on November 7, 2011 at 15:28

Phillip, you hit the nail on the head. Probably a discussion for another forum, but I suspect that the shortage of LPG will be used to justify shale gas fracking!!

It's fracking ridiculous- we all are methane gas factories, and yet we see it as a waste product, and use fresh water to get rid of it.  Bio-digesters are the future.

Comment by phillip newmarch on November 7, 2011 at 13:12

You're probably about right, Keith.  If I heard correctly, the Gecko Rock system seems to be 1.6Kw. There seem to be 9 panels, each about 1m2, which be a bit less than 200w per m2, and that sounds about right.   According to a follow-up interview, they are thinking of adding more batteries because the present set charge fully in a few hours.  Karoo sun is powerful stuff!  You can find this on YouTube and the firm involved is http://www.mypowerstation.biz/

We still need more case studies, but I think it is well worth looking at. Start small and add as needed.  Gas is undoubtedly the best for cooking - as long as it is NOT SHALE-GAS (and preferably not any other fossil gas).

On the question of solar-powered cars, on catch is that it would probably need at least 25m2 of panel to properly recharge a small car, and unfortunately that is twice the size of a parking bay. My guess is that interchangeable battery packs would be best - one to drive and one to charge during the day.

Or buy an electric scooter.  This site provides a lot of very handy technical information on the whole subject - worth a visit anyway! 

Comment by Keith Lurie on November 3, 2011 at 18:07

As we move toward more energy efficiency, you will not require as much as 8Kw for a house, 4 should be ample, in fact 1Kw is sufficient for light and a pc or tv, cooking on gas, water and space heating with solar, wash dishes by hand (dont believe the adverts that say a dishwasher uses less water and electricity) A twintub washing machine running during the day when there is ample excess.

The big challenge is to generate enough energy to charge up your electric car with solar power during the day.  It would be ideal if one could drive to work, park in a carport with solar panel roof, that can charge up your car all day. 

Comment by phillip newmarch on November 3, 2011 at 16:59

Keith is right about small users.  This video shows a small domestic PV installation on a farm in the Karoo.  I'm not sure what the cost of this one was, but apparently an 8Kw (about twice the size) runs out at about R200 000 with batteries. That's quite a big chunk, but when you look at how much 20 years eskom power will cost (with increases) it begins to look quite good!

These are silicon panels, I think, which presently seem to be the most 'efficient'.  But at the end of the day, what counts is cost-in-use per watt, and the thin-film PVs could win there even if they are less 'efficient' in terms of watts per m2.

Comment by Gavin Tonks on August 8, 2011 at 14:54

existing coal plants are sold to the Chinese new generation turbines are available at a fraction of the cost

Comment by Keith Lurie on August 8, 2011 at 13:25

The big difference is that solar is available to the small user, we cannot set up our own hydro plant. If escom would just apply the 'refit' system, it would solve some problems

Coal is under a lot of pressure, the carbon issue has even led to a pro nuclear argument, so I think that coal will eventually be phased out.  New generation coal stations are more efficient with less emissions, but still not 'clean'

Comment by Gavin Tonks on August 8, 2011 at 12:48

efficiency at max at the moment is 32% so their is a long way to go. I am not sure why the fixation when hydro power is available 24/ 7 at a fraction of the costs - coal provides major income for people so it is unlikely that there is a great incentive for generating electricity from solar power. the maintenance is also horrendous and their is no proven maintenance costs

Comment by David Clark on August 8, 2011 at 12:34

I have never seen any logic in the argument : "The big disadvantage of electricity generated in the daytime for use at night has been the difficult

• ‹ Previous
• 1
• 2
• Next ›
• Page