Just getting started on Solar HWS/Power investigations

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Originally Posted by PhilipA

I just looked up the tariffs for green power and it is in NSW an additional 5.995c Kwh for 100% green and a flat $13 per quarter for 10% green.

I wonder how many people would be voluntarily paying an extra 50% at the moment ??? eg approx 6c on 12cents. I would bet that it is < 5% .I would be interested to know numbers but they do not appear readily available on the net.(surprise)

I seem to be the only one willing to research the numbers etc and I cannot be bothered any more.

However I just read some interesting stuff on a number of "green " sites which state that "dispersed" solar power is not the way to go, but Concentrated Solar Power(CSD) is what California is banking on. There is an Australian who has moved to California to implement it.

One site I looked at said the greatest gains in greenhouse will be from energy conservation. I wonder how that gells with the increasing demand in Oz from aircons.LOL
Regard sPhilip A

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Interesting comments, particularly about the aircon, although in at least some cases the increases are at least partly balanced by reduced energy use in winter where reverse cycle systems have replaced resistive heating systems.

From a purely economic point of view, concentrated solar power is more attractive, and is also preferred by power companies and unions. But there are two advantages of the dispersed model. The first of these is that a significant proportion of the cost will be borne by committed conservationists rather than the power company, and the second is that it helps to make the system more robust and fault resistant, as well as deferring the need to improve the distribution network.

I agree that the major gains are to be made from energy conservation - but this is not going to happen unless the cost of power is substantially increased. There is plenty of room for it to happen, but almost everything you do to conserve energy costs money, and most people will not do it unless it saves significant amounts. Like driving - in almost all normal circumstances, the cost of fuel is way down on the list of costs (usually around 25%) for a vehicle, and for there to be an economic reason to conserve fuel, the price has to increase drastically.

John

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Originally Posted by PhilipA

I always seem to be the Cassandra but i was just thinking of theimplications of this subsidy to buy solar for reinjection to the grid in SA detailed by Spudboy.

Some BOE calculations.

Say Normal power costs the distributor 10C per Kwh.( probably very generous)
The subsidy for injecting solar is 44c Kwh. and it appears from the offer that the 1Kw setup is designed only to inject power back into the system. No batteries are mentioned.

If 20% of power were produced by solar, then coal/solar power prices would have to rise by 60% to 16.8c kwh to compensate.

So you buy the 1Kw set up plus solar HWS for $5490

If you can generate 3kwh per day average summer /winter /sunny /dull then you get $9 per week or $450 per year, so you get payback in 7-8 years.
BUT , seeing you are selling it all back into the grid, you still have to use all the energy you are using now.

Now the more people taking up the option the more expensive electricity will come, so that at the end of the day you will pay 60% more for your power!!!

So say you pay $1000 per year now you will pay $1600.

So you gain $450 and lose $600.

BUT you feel really good about yourself for being a committed conservationist and are happy in the knowledge that all those who did not put solar on are paying much more.

Regards Philip A

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It isn't quite as simple as that.

Coal power costs about 4c/kWh to generate, and lets assume maybe 8c for the distributor.

AFAIK, if you install a grid interactive solar system, you don't get to sell ALL the power back to the grid, only your surplus.

However the companies are happy to pay you a premium, because:
(a) they can use/sell the carbon credits from the power you generate
(b) if it means they can delay the construction of new power stations, they are saving money overall.

5.5k!?!?!?!?!?!

Just paint some radiators black and bodge in a bit of piping if its just hot water you want.

some quick points, here in SA there are two companies now paying $0.66 per kwh generated from our solar systems. also as an electrician we generally tell people (though i haven't done the maths lately) that installing a solar hws will cut their power bill by roughly 30% (obviously depends on size of family and length spent in shower etc!). one other point is that depending on who you know, it can save a lot of money if you install the hws yourself and just have a plumber do the connections or check it and sign it off for you (the average installation cost is $700 for solar hws if you just get the company to do it for you). it is a bit of fun getting the tank on the roof though! :)

I think Solar HW makes sense, but like Spudboy our conventional electric HW only uses around $50 a quarter. So, you just can't justify switching for switchings sake. I guess what I'm saying is I will consider it when we're at the point where I think the existing one is going to kark it.

Also, I'm believe that the new heat pump HW systems actually use similar amounts of power to solar by the time you take into account the electric backup and water pumps that some of them need.

Shortly, I'll have a good look into that. It may well be that the two systems use a similar amount of power, but one attracts a government subsidy. :)

ATM my solar gear is all my camping stuff and is 12v /small scale

but it works well enough to run indefindately (well in most of queensland and the summer at albury) out bush without needing to run the vehicle.

It also supplements the house in the event of a power outage.

I'm not keen on doing it for the house ATM no-one sells a to go kit for the handyman (accepting that Id have to hire a sparky to do the final hook up and a plumber to put the water side on) but I am strongly considering it.

i am a plumber and carnt really comment on the heat pump hot water systems as i am yet to instal one but i will be putting one in in the next couple of weeks
but i have done several solar systems and am not really convinsed that there is alot of savings to be had sure you get a rebate but your purchase price is nearly triple of a normal size hot water service and the pannels can break as well and the tank probally wont last any longer than a normal one then you have a pump to circulate water to the pannels let alone the replacment costs of all the different valves that will last about 5 years maybe a bit longer
so whatever makes you feel good is the go
ill update after i have installed the $3000 odd heat pump hws in the near future

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Originally Posted by johnb44

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but i have done several solar systems and am not really convinsed that there is alot of savings to be had sure you get a rebate but your purchase price is nearly triple of a normal size hot water service and the pannels can break as well and the tank probally wont last any longer than a normal one then you have a pump to circulate water to the pannels let alone the replacment costs of all the different valves that will last about 5 years maybe a bit longer
so whatever makes you feel good is the go
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Your figures are interesting - my solar hot water system is fourteen years old and has never needed any parts replaced (possibly helped by the fact that it runs rain water). It uses a gravity feed tank in the roof and a frost valve on the collector for frost protection. There is no pump to circulate the water as the collector is below the panel.

John

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Originally Posted by JDNSW

Your figures are interesting - my solar hot water system is fourteen years old and has never needed any parts replaced (possibly helped by the fact that it runs rain water). It uses a gravity feed tank in the roof and a frost valve on the collector for frost protection. There is no pump to circulate the water as the collector is below the panel.

John

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being a gravity feed tank you should get 30+ years from it :cool: unfortunatly mains pressure ones wont last as long ,there are alot of factors to it to like water quality etc so there is no hard and fast rule to it all but the last post has been my observations from being in the industry for 29 years ;) and there are always the ones that suprise you to :angel:

Sorry if the following is a bit long. Go the last two paragraphs for the 2 second summary.

We installed an Edwards gravity fed solar h/w system as the electric was about to die (confirmed when removed - badly rusted inside). We picked Edwards as had one before and has stainless tank. We were averaging about 5 to 9 kWh per day on the hot water. That is down to zero since August (electric boost not connected yet). The water is very very hot. The Fed Govt contribution was $1000. We paid $2800 after the rebate and RECS.

The Fed Govt contribution to PV panels is $8000 for a 1 kW system that generates 4 to 5 kWh/day, less power than our solar HW saves. IMHO the Govt should increase the incentive to go solar h/w or heat pump. However, the Fed Govt contribution might result in more R & D on PV resulting in tech advances.

We are installing a 2 kW system that should give us 8 to 10 kWh/day. We have a small well ventilated house that uses between 9 to 11 kWh/day. So a 2 kW system should cover all our energy needs. It will cost $14,000 after the Fed Govt rebate (before RECS).

Current retail cost of peak supply electricity in Qld is 14 or 15c / kWh, in Japan is 30c and UK 35c approx using currency conversion. So Qld power is very cheap. Wholesale electicity prices are predicted to double by 2015. The current feed in tarif is 44c /kWh.

I have estimated that a 2 kW system costs about the same over 25 years has buying electicity at current prices. It is a bit cheaper per year than buying Greenpower. The annual cost of PV was estimated by totalling the benefit (electicity savings + income from feedin tarif) minus costs (depeciation and loan repayment at 7%). PV comes out in front if electicity prices reach that of UK, but only by $100 to $200 per year.

Green power is an excellent option for those not wanting to spend a lump sum on a PV system. More demand for Greenpower will mean more Greenpower infrastructure investment. Solar turbine, windpower and geothermal are more economical than PV.