Martin Nicholson’s sober piece prompts a general question about emerging technologies, and energy technologies in particular: Can one rely on a developing technology, like say fuel cells or geothermal energy, eventually becoming commercially successful (and socially useful at the same time) provided that enough time, effort and funding are forthcoming? The answer to this question, implied more often than not, is ‘yes’.

How can this be so? For if it is true of one such technology it must be true of all, and that simply cannot be correct, since some technologies simply must turn out to be superior to others.

So how does one decide, or at least get clues for deciding, which technologies to support with time, effort and funding? Well, precisely as Nicholson does, by reviewing their history. For energy technologies this history is especially rich. Promises, largely unfulfilled, litter the history of energy technology development. And that’s where to look if you want to make the best guesses about the future.

Frankly it does not bother me when speculative investors make decisions based on the promises, or the closest thing to promises that our stock market regulators allow in prospectuses, of new technology businesses. It’s when governments do it that I start to see red. And as Nicholson points out, we now have our very own Treasury, no doubt pandering to the wishes of its masters, punting on future energy scenarios that emulate the decision making processes of the most speculative commercial investor. Trouble is, Treasury can’t lose. Nor can governments that throw money at technologies they desperately hope will be winners. The one factor that brings discipline to investment decisions is absent. They are almost guaranteed to be wrong

The only technology that presently provides any hope of base load supply for peak demand (at 7pm) is the solar hot salt systems, with gas back up, and even this generates power at 4x the cost of nuclear.

Juliar Gillard points to Britain's ambitious emission reduction targets, but conveniently forgets that much of this is achieved by the construction of new reactors.

Never the less, it all falls over because the whole alternative
energy project as visualised is dependant on business as usual.

In a time of zero growth and energy depletion a different priority
needs to be assigned to alternative energy programs.
I do not have the deeper knowledge needed to set the required
priorities but to construct the new systems in a time of zero growth
will be a monumental challenge.
We will not be able to afford to ignore our coal assets is just one
area that will require a major rethink.

How to finance the alternative energy projects in a time of zero
growth will only be possible by either cancelling major existing
projects or suspending urgent projects.
Even some wind projects should be shelved as their return is too poor
to get in the way of more important energy projects.
We may have to suspend the export of coal and natural gas to give us
time to get the permanent projects up and running.

Unless we restructure our alternative energy project away from the
business as usual global warming regime we will fail to have
sufficient energy to run a recognisable economy.
Unfortunately governments are generally terrified of facing the twin
problems of zero growth and energy depletion nothing will happen until
there are mile long queues at service stations.

On the whole I agree with the piece, but I think there's a glaring logical leap the author makes. He says:"If we haven't managed to prove up commercial-scale electricity generation from hot rocks or solar thermal after 40 years, what makes us so confident about CCS?"

Well, for a start, CCS is effectively subsidised by the fact that CO2/CO are waste products. This means they have an inherent cost of disposal, which effectively subsidises their reuse. As the CEO of Monomer, a company spun off from Cornell Uni to commercialise CCS-based polymers, put it: " You couldn't get a better feedstock than CO2. you actually get paid to use it."

On top of that is the fact that CCS technology is already being utilised, both here and overseas. It already HAS some proven tech, although there are lots of blue-sky proposals about as well.

Further, it actually produces something and reduces the need for fossil carbon at the same time. The hotrock tech you mention is just a fairly inefficient form of mining and it too could be improved with better energy density possible using super critical CO2 than using water, as well as no tendency to dissolve minerals into the hot stream.

All this stuff is freely available in the public domain for investigation. I urge the author to do so.

This is an interesting essay. In 1970 I was involved in the Telecom 2000 project, in which the then Telecom tried to guess what society would be like when we were operating on silicon fibre rather than copper wire. I've forgotten a lot of that enjoyable experience, but I do remember our being asked to specify the two technological advances that we thought were possible by 2000 that would have the greatest effect.

My two were a small but very powerful fuel cell, and the cheap desalination of sea water. It is now 41 years since the T 2000 study, and neither of my nominations has quite made it, though considerable advances have been made in both areas.

The reason is alluded to in Tombee's post above. There has to be demand from the market for people to really go down the research/development/commercialisation path in a big way. I was very supportive of solar energy research in the 1980s, and again, considerable advances were achieved in efficiency. But I don't remember much attention to storage at the time, because we were still focussing on moving from black tubes to PV cells, not on what happened when we actually had produced a lot of solar energy and needed to store it for night-time use.

And there still isn't real urgent market demand for solar energy. It only looks like it because governments are picking it as a winner. Same with the fuel cell. Same with CCS. Same with hot rocks. If we didn't have all the fuss about AGW, these developments would be interesting, but not marketable.

In the late 19th century several people in different countries sensed the need for what we call the telephone, as did several other people sensing the need for what we call the motor vehicle. Governments weren't involved at all. And these developments were picked up by the market, and greatly changed the way we live. What we have today is government, pushed by political circumstances, attempting to pick winners. There aren't many successes to point to in this domain!

Antiseptic points to one project, CCS, that can be abandoned without
difficulty once it is realised that global warming is no longer the
major problem facing us.

What world growth exists has been largely obtained by China and India.
The "Western" countries are getting just about zero growth and the
undeveloped countries will get a good dose of contraction.
Surprisingly, our governments seem surprised with the very low growth
that they are getting in our economies.
It just shows how out of touch they are with reality.

I read an article this morning about the financials of the global
solar panel manufacturers. They are selling their panels for
between $1.40 - 1.80 per watt. Yet on a retail level, these
panels cost more like 10$ per watt.

Sounds to me like we need some serious competition there, for
clearly the production cost has little to do with the consumer
cost.

"Commercially competitive power"?

Talk about missing the point;

The appeal of renewable power is that once you buy the generator you pay not a cent more.

The only commercial competition I'm interested in are between manufacturers deflating their prices to chase my dollar.

Otherwise, it's the fact that there is NO commercial gains (read, transactions) in generating free energy that is why it is so good.

King Hazza,

"The appeal of renewable power is that once you buy the generator you pay not a cent more."

You are kidding right. No maintenance, no upgrades, no control? This does not even cover the return on capital that the investors expect. Lots of small generators scattered over the country side cost far more to maintain and control than a few large generators.

90% of the cost of nuclear power is the cost of capital recovery, the cost of the uranium is minuscule, I would guess that the maintenance and running costs of a nuclear power station are much lower than the 1000s of small systems to provide the equivalent power.

renewable energy have been largely unproven, until now there has been no incentive.
Solar sites will be manned by no more than a caretaker. They are very stable and cheap to run.
Without ongoing costs or fuel to produce power, this technology has been in operation for more than 50 years, and ongoing, so no one knows their lifespan.
A power sufficient house would be a good selling point, without doubt.

Not at all Shadow.

As a Solar panel has no moving parts, there is simply nothing TO maintain- and a wind turbine has ONE moving part, making it a much lower maintenance or breakdown probability than generators that require multiple moving parts, high heat, and in many cases, fluid transfer (Nuclear being all three).

The investor (the person who buys an array of either devices for their own use) gets a return after a very short amount of time of not paying the incredibly steep monthly power bills (for my household, easily a few hundred on average). In fact, the devices start to pay for themselves after a year or two. Add to that granted dependence from a power company I would say that is a good deal indeed.

Comparing the un-altered prices of home-installed PV/Wind and (uranium/plutonium) nuclear would not actually place nuclear as a clear lead in any form, as nuclear is fundamentally more expensive.
PV panels are extremely simple devices and easy to manufacture, albeit with photosynthetic material added to the top of the panel. Wind turbines are essentially the exact same turbines present in a nuclear reactor, multiplied by a few hundred times as opposed to a dozen to substantiate the same output.
Outside manufacturing, transport and installation costs (which nuclear is more expensive due to extra measures needed), PV/Wind ceases to cost money or resources, while Nuclear power requires zoning, an outside water supply, a staff, administration costs, logistics for the isotopes going in and out of the reactor, a safe storage for spent rods (with security), higher insulation costs, insurance costs, decommission and decontamination costs, and of course, higher maintenance.
The balance would be if the costs of all these associated with a single reactor outweighed the one-off costs of constructing and installing the amount of panels or turbines to produce the same output.

I do wish people would do some sums before they write such articles. There are plenty of proven technologies and they are economically viable today.

I have in front of me a quotation for the installation of 15 solar panels on my roof. I have had 9 panels for three years and so I know how much power is generated and I know how much power will be generated from the new panels. Most would agree that solar panels on the roof of a domestic house is not the most efficient way of generating power but my 15 panels will pay for themselves within 23 years with a price of 10 cents per kwh. We know that the price per kwh will rise above 10 cents over the next 23 years. We know that the panels will last much longer than 23 years.

All forms of renewable energy are economically viable today if we allow price increases to compensate for the so called opportunity cost implied in discounted cash flow analysis.

Large scale solar systems will pay for themselves within less than 10 years at today's prices. As the price of solar voltaics and solar thermal is dropping by at least 20% per doubling of capacity we know that at today's prices within 5 doubling of capacity the repayment time of renewables will be 5 years or less - a good investment even by the extractive industries standards.

Our society can increase its wealth through the deployment of wide scale renewable energy systems and the sooner we start the better.

Most PV cells have a life expectancy of about 25 years at 80% of peak (new) output. The panels degrade over time from almost the first moment they are exposed to light. After 23 years you'll be at no more than 80-85% of your current output.

I admit renewable energy's costs are not turned into externalities as easily as fossil and nukes. Megatons of heavy metal fly ash doesn't need to be dealt with [coal] and a catastrophic failure rate of 5% doesn't destroy 100s of hectares and lives. [nukes] The one unstated assumption in this article is that fossil fuels will be as available about as long as we'll need to keep nuke wastes out of the biosphere. I believe that assumption is untrue and we really need to focus on providing renewable energy with subsidies as we have fossil and nukes. [Giant navies to keep the oil flowing and nobody in their right mind would invest in nukes without bribes.]

Solar panels allow for the breaking down of some cells over time. That's why when you bye a thousand watts, you actually get one thousand and fifty.
More than 50 yeas ago solar panels were installed on a test site and still operating with Nine hundred and ninety six of the 2 watt cells operating, the original value was one thousand and fifty 2 watt cells.

It's not just the failure of individual cells, but the loss of efficiency. A cell that originally produced 100W will only produce 80 or so at the end of 25 years, excpet in exceptional circumstances. This is because of things like degradation of the glass, degradation of the semi-conductor material itself, degradation of the connections between cells, etc. They'll still be useful, but not quite as useful as they were. A frequent solution is to simply add another module when the power is no longer enough.

Perhaps one of the geniuses on this thread can explain how any of these systems can provide base load.

Given that peak demand is at about 7pm, and is more than double the demand at noon, PV cells are essentially useless and wind cannot be relied upon. Hot rock geothermal is having so many teething problems that it is no longer being considered viable for many decades. Solar thermal (liquid salt) can store heat, but comes in at about 4x the cost of nuclear and about 10x the cost of coal.

Until these issues are resolved, replacing fossil fuels with renewable energy is a fantasy generated by greenies to help them avoid dealing with reality.

PV is a good fit for aircon mostly SM.

Shadow Minister salt heat storage is NOT four times the cost of nuclear and is NOT 10 times the cost of coal. Salt heat storage reduces the cost of generating energy from solar thermal power stations because smaller generators are needed and these generators can run continuously with a constant energy output (base load). Coal run as base load is a very expensive method of matching supply to demand. This is because the plants are best run continuously and for much of the time large amounts of energy are "earthed". The problem is not one of base load but is one of matching demand to supply - in other words it is a battery or storage problem. Why do you think we have off peak low rates of electricity supply?

The most likely future main storage for the system are private vehicle car batteries. Private cars are stationary most of the day but if connected into the grid they become a method of matching supply and demand. A million electric vehicles distributed around the grid solve the battery problem.

Peak power happens at different times of the day at different places. I am on off peak power from 7 pm to 7 am. at 10 cents / kwh.
I think you will see a lot of community power generation rather than every one being on the same supply line. There's no reason the usual power generators are only there for the power hungry users.
If you are using more than 10 kwh / day in a normal house you are wasting power.$2.00 / day. + service fee.60 cents / day.
After 3 years of 1.5 PV I have a credit of near $900. It's a matter of what works for you.

Shadow Minister
Simple answer is solar and wind power obviously does not provide base load.
However, it is a moot point if households consume less electricity than their solar/wind-fed batteries had stored throughout the day (which they do)- you did of course know that these devices come with storage devices, I presume- and not think that consumers actually drew their power from a direct feed from the sun?

Baseload is only important for facilities that must have a constant feed for safety purposes or higher energy consumption- meaning every building that is not a hospital, pumping station, factory or airport (or training facility for the above) would suffer nothing from the absence of a baseload input, so long as their power coverage exceeds their usage.

KH,

My comments were for bulk generation, not house holds.

For domestic load 90% of the cost is in the distribution. Your system with batteries cannot generate power at below 10c /kWhr if the cost of the system is depreciated. Lead acid batteries have a limited life, more so if they are constantly drained.

The only time you are really making a saving would be if you could disconnect from the mains permanently.

Actually, SM, the only way to make a saving is to connect to the grid permanently. That eliminates the need for batteries locally and supplements the load during peak demand for airconditioning.

a597, I have 4 people in my household, which is also my business premises. Average consumption for the home is nearer to 50kWh/day for us, largely because each room is airconditioned and it's nearly impossible to stop their use, human nature being what it is. My business, when it's running well (at the moment it's almost dead) is responsible for another 100 or so kWh/day. While solar may be some part of a solution for some, it's not a panacaea.

What I'd like to see a lot more investigation about is the use of Stirling cycle-based heat pumps. It seems to me that when combined with some other form of power generation these are very efficient at reducing the waste caused by the transfer of low-level heat to the atmosphere.

Yes Shadow- disconnecting from the mains is the whole point people purchase renewable sources- and they very much do generate enough power for my house to live on..

And judging from the lifespan of these products, against the time it takes for the cost of the installed device to pay itself off from saved electricity bills- it is clearly a substantial bargain.

Looks like the fairies have got out of the garden again!

Have any of you people ever lived long term with, & payed the costs of, home generated power systems?

If you'd like some gear to do it, just slip out to the islands, where they have no alternative. You'll find sheds full of almost useless junk, that cost so much time & effort, to keep working, it was more practical to buy diesel, & generators, despite the supply problems with fuel in remote locations.

Most of the owners are embarrassed every time they look at, as it shows what fools they were to fall for the con. Unfortunately they are also too frugal to throw out near new "stuff" even if it is basically useless.

Strange you ask that Hasbeen- I have both Solar energy AND solar hot water built into my house- after only a few months I've made exceptionally great progress on both devices paying themselves off in saved power bill costs (Solar rebates have drastically reduced my power bill (though my output has exceeded my usage had I have used them as a feed-in)- and the solar Hot water system has completely terminated my heating bill entirely- and even improved the performance of my shower).

So you're not using an isolated remote-area power system, but a grid-connected unit.

I hope you have a good quality inverter.

*Solar rebates have drastically reduced my power bill*

Well that is the problem Hazza. You are being subsidised by other
power users. Politics dominates economics here. It started as a
quaint little scheme to encourage people to install PV cells.
Pay them 40 to 60c a unit, they said. The value to the power
company might be 5c, for a big cost of the 20c which they charge
you, is to pay for the poles, wires and maintenance of the line.

Now the scheme has blown out. Its having a significant effect
on the power charges for other users, for somebody has to pay for
the losses. What seemed like a good idea at the time, is proving
unsustainable. So in some States they have closed down any new
entrants, the public are already complaining about rising power
charges and the refund which they pay you, is only making it worse.

Indeed- if the government does end up cutting the rebate and going back on its promise, I will cut myself from the grid and rely on my cells directly.
But as I said- I use much less power than my panels are sending to the company- so it won't be a problem for me at all.

King Hazza said other than these do not need 24/7 power,
meaning every building that is not a hospital, pumping station, factory or airport

How many buildings with lifts do you think there in Australia ?
How do you electrically separate the different types of buildings ?

You either have a constant supply or you evacuate any building over
three floors.

Backup batteries sufficient for every house and other building would
I suspect be impractical from both supply and maintenance availability.
Anything other than batteries would likely have large maintenance
requirements and would be impractical on such a huge scale.

Many schemes are suggested but almost no one even thinks about the
number of technically capable people needed to install and maintain.
Already there seems to be skill deficiencies in the solar panel field.

KH, do you have any storage batteries? Have you priced a bank 48V 1100Ah batteries? Do you know how much work is involved in maintaining a battery bank? Have you priced in a generator and a charger for the times when the sun is covered by clouds for more than a couple of days?

Have you priced in the cost of a new inverter that will set its own output frequency and not rely on the timing signal from the grid?

Grid connect and RAPS are two beasts of entirely different temperaments. GC is convenient for the user, RAPS generaly are not.

Firstly
You differentiate buildings where base-load power is a necessity (hospitals and airports)- and of course by scoping how much power it needs against how much power it can generate on its own of course (factories with electronics and machinery that draw far more electricity than the sum of the PV panels and turbines its property can hold).

Batteries:
Well considering there is absolutely NO 'maintenance' at all I don't see what the problem is. You buy it (they are usually thrown in as an extra with the PV Panels for most Solar deals- had you bothered to ever read one).
And once installed it functions entirely on its own.

So we are in fact talking about a very simple procedure with a one-off payment and a quarter century lifespan of automated functioning to pay itself off (which as far as today's power bills go- a very short amount of time).

KH, I was employed as technical manager at Choice Electric Co., which was the largest distributor for BP solar at the time. I have designed and maintained solar installations in locations from Moreton Island to Barcaldine and specified designs for installations as far afield as coral atols in the Pacific and Aboriginal communities in Central Australia. Believe me when I tell you that you are talking nonsense.

A typical RAPS installation requires all of the things I mentioned and deep-cycle storage batteries are not like car batteries, they require mintenance of the electrolyte and good monitoring of the state of charge. Gel cells can be used for low demnad applications, but they can't be allowed to over discharge or the electrolyte will dry out and slump, exposing the plates.

It's also not cheap.

http://www.solarpoweraustralia.com.au/remote-area-solar-power-for-your-home.html

KIng Hazza tell us;

What type of batteries you have installed and how long ago ?
How many ampere hour rating and voltage ?

You claim zero maintenance. This I find remarkable.
Lithium cells being so expensive for that type of service demand seems
unlikely. They are the closest to zero maintenance because it is a case
of chuck it for dead cells.
If we are to get past just a general waffle lets know about your battery bank.

Antiseptic is absolutely right. I have grid connected solar panels and an uninterruptible power supply consisting of 8 x 375 Ah deep cycle lead acid batteries charged from the panels. You need a changeover switch that detects loss of the grid and switches over to the batteries. You also need a separate inverter to feed the battery power into the house. I live in a rural area where grid power dropouts are much more prevalent than in a city. The switchover is so fast you don’t even know the grid has dropped out.

My batteries hold about 18 kWh so they will last a couple of days with careful usage. But relying on solar panels to charge them means that if the weather is cloudy the batteries will soon run down. If you are not connected to the grid and rely on batteries you will need a petrol or diesel generator to keep the batteries charged. Where I live there are many properties not on the grid but they all need generators to charge their batteries and probably have higher emission intensity electricity than the average city dweller. This is somewhat ironic as they are often Green supporters who want to be disconnected from the grid but are blissfully ignorant about their carbon footprint.

Sorry KH, but the batteries do need constant maintenance by checking the charge levels and acid levels. If you fail to do this it will significantly shorten the battery life which brings me to the cost.

My relatively small storage system (used for emergency only) cost over $8,000 to install two years ago and does not include the cost of a diesel generator. Whereas the cost of panels has fallen in that time, the cost of batteries and inverters hasn’t. So good luck KH with disconnecting from the grid. It is not a cheap option.

My battery bank is non maintenance deep cycle lead acid. The batteries never need topping up. The inverter cuts out at 11.9 volts, so all u use in the batteries is the saturation. The batteries charge to 14 volts. My charger consists of 3 automotive alternators, set up as wind mills. Beside the PV panels. Never run out of power, and plenty to send to the grid.
I think you lot are talking about early set ups; It doesn't take much to charge 12 volt batteries.
It also pays to convert your fridges and freezers to soft start, by adding a capacitor per appliance, the rest is easy.

a597, the electrochemistry hasn't changed much in the last 15 years or so. Your sealed cells will either be gel, or more likely some form of matrix-supported wet cell, which contain a regeneration chamber to capture the hydrogen released at the anode by the discharging process and direct it to the cathode for reuse . This only works if the discharge rate is sufficiently low, so if you run a high load, you'll lose some electrolyte to the atmosphere as the pressure within the enclosure becomes too great and is vented. You'll also lose some if you overcharge. Either way, they're probably NOT true deep cycle cells, even if they're advertised that way. Tha fact that you only discharge to 11.9V means that you're not "deep" cycling your batteries at all, taking them to around 50% of charge. A true deep cycle flooded cell should be able to recover from much deeper discharge than that with no problems, although sealed and gell cells suffer if that happens.

A good set of flooded cells with minimal maintenance (checking electrolyte levels and SG, properly set float and discharge levels, proper control of loads) will last 7-10 years with little loss of performance. For mobile homes it makes sense to use sealed cells because acid is corrosive and it saves hassles on the move. Demands are typically low as well. for fixed installation deep cycle storage or traction batteries are the only solution.

RAPS doesn't cost 4-10 times the cost of GC for no good reason, you know.

There's a good reason for only discharging to 11.9 volts, this is for battery life, a fully charged battery lasts longer. These batteries are deep cycle marine batteries at a fraction of the cost the ones you are talking about, with the same lifespan. The 11.9 discharge rate is controlled by the inverter to protect the battery's from over discharge.
You don,t need a diesel generator to charge 12v batteries.
An excellent system and cost affective.

Whatever works for you, I guess. It's not the sort of thing that would suit most people, however, except when they're on holidays in their caravan perhaps.

Bazz- I don't remember the statistics, though I could dig out my last electricity bill- but on average, with the reabate at 60% I'm now only paying a loss of only 1/3 of my original electricity bill (with the rebate covering the remaining 66%.
Note that I only have a quarter of my roof covered (with another quarter taken up by my Solar Hot Water system- actually making it a third of my available roofing space), and I have a large family with about three computers running for several hours a day with a few others that get some daily usage on top, and like a571, many of my appliances have a terrible power-conservation rating (and I plan to replace them as we have found these to be the main reason our bills are so high). Cutting these (or adding additional panels, or both) would put me into a position of profit, even when the rebate slumps.

Why rebate- my wife talked me into it, if I'm honest- as apparently generating our own power is illegal- but either way we decided the rebate would be a good opportunity to get our money back faster (and it definitely is), before redirecting the power internally (if it is legal of course).

Antisceptic- coming from an engineer who works with PV systems that is definitely good to know. Could you tell me the kind of maintenance procedures that would need to be physically required to keep the storage unit in check?
Cost-wise it is actually not a problem- your figures are similar to what I paid, and it sadly isn't much different to what I would have been paying in power bills over just a few years at the rate they had been going recently (I had been paying a huge increase despite halving my power usage on the first bill I recieved when the prices spiked- which motivated me to quickly transfer as I was being ripped off despite improving my practices- ditto on water).

KH, it's not that hard to maintain your batteries, but it takes a bit of organisation, especially at first, when you're working out how much you use and how much you need to supplement, if any, with some form of generation.

Basically you need to maintain your electrolye levels and concentration within certain bounds. The concentration is measured using a hydrometer to measure Specific Gravity, since sulfuric acid solution is quite a bit denser than water and gets denser with increasing concentration.

http://www.chembuddy.com/?left=CASC&right=density_tables

It might only need to be done once a week once you're properly used to running the sytem, but in the early days you'll have lots of ups and downs in power as you try to balance loads and supplies.

The system that a597 has is very simple, but it won't give you the reliability or the capacity that you seem to want. Have a talk to a good, properly qualified RAPS designer. There's bound to be someone close by. If what you really want is to be self-sufficient, but without the hassle of a generator, you can use a stand-alone system with the grid on the other side of a changeover switch instead of a generator.

There are lots of options, but you do need someone to have a look at your particular needs and design accordingly.

Thankyou antisceptic, that is good to know.

Out of curiosity, if a597's batteries can only safely cover a lower capacity- would it be possible to counter this by purchasing additional batteries and dividing what I generate between them? (not necessarily what I'm planning when cost factors in, but considering all options).

Yes, it would be possible, but they'll still not last as long and they cost a lot more per unit of stored energy.

If you're already on the grid you may be prepared to use a smaller battery bank and use the grid for backup instead of using a generator. Effectively you're making a solar-powered uninterruptible power supply. We installed one of those for a major Brisbane data centre about 12 years ago, but it was actually the batteries that were the most important feature. The solar input was more for show than anything.

You'll need a different inverter to the one you're running now, since the PV won't be feeding the grid, just charging the battery bank. the changeover isolator will kick it out of the circuit.

Alternatively, you could set up the solar to feed into one or the other inverter as desired and take power from the grid to charge your batteries if they run low. Lots of possibilities. As I said, get yourself a knowledgeable local RAPS installer, or talk to one of the distributors.

Leave your solar set up as is, connected to the grid. Treat your battery set up as a completely new set up. Add up all the appliances you have as to their watts needed to run. Very important to fit a run start capacitor to each of your fridges and freezers. This cuts the start wattage to 350 watts without any surge. Individual is trying to flog a battery worth heaps, it is up to you. You can get a 6,000 watt inverter for your battery bank for $ 1,795. A 160 watt solar panel just for battery recharge, plus an alternator set up as a windmill. These chargers are permanently connected, and regulated at 14 volts of charge.
2 fridges and one freezer, TV, lights, kettle, you will need 6 12v deep cycle marine batteries $ 900 . Leave the air con directly connected to the grid or buy more batteries, and add another wind mill alternator.

a597 said;
Very important to fit a run start capacitor to each of your fridges and freezers.
-*-*-*

How would such a capacitor be connected ?
Already being single phase motors they are probably capacitor start anyway.
All refrigeration compressors are capacitor start because you
would not want a centrifugal switch inside the sealed compressor.
Shorted turn start motors would not be used in refrigeration as they
do not produce enough torque to start a compressor and anyway there
is no start winding.

I am curious !

Wrong again. there is a butterfly switch inside the motor and there is a start winding. Capacitors are not added to fridges because it ups the cost, besides that it is all to easy to plug straight into the grid where there is plenty of oomph to start the fridge.
A fridge on start up can pull up to 10 times its running current, that is why we use start run caps;.

What i also should have mentioned is you get a Mashmaster.com switch box
this comes complete with a thermostat and delay start up which u set to 9 minutes delay. U install the thermostat about mid fridge and bypass the original thermostat. You set your off and on temperatures on the mashmaster box. $ 50.00
The capacitors are mounted inside a jiffy box from Jay Carr. for $ 7.00
capacitors are around 14$ and 10 $ from Jay Carr
The jiffy box goes in the existing 240v cord. You cut the cord in half and put a plug on each of the cut ends connect in the jiffy box.
I will find the wiring diagram and let you know.

a597;
Yes I would like to see that circuit.
I presume you bring the start winding out to the capacitor in the box.
If it was a centrifugal switch the start winding would not be brought
out of a sealed unit.
Your description sounded like it was just in series with the mains !
What is the capacitors value ?

Compressors I have worked on all had start capacitors, but then they
were larger than domestic refrigerators.
Come to think of it I do not remember my frig's start capacitor.
However I won't pull it out to look.

I will get the caps value and a resistor is fitted also, which i had to bye a box of ten because it was out of Jay Cars line, that cost me $ 5.oo
I am not home to retrieve the diagram yet, will be home tomorrow about 3pm. The system is magic.
There is one site you can have a look at, this is where you get the thermostat from. mashmaster.com $ 50.00

What a shame that it seems Martin N's main point has been missed.

Given that his general observation seems sound, what explains the persistence of government (and most of its would-be influencors) in the expectation that 'new' technologies will supplant the proven existing ones?

Forrest his general observation is incorrect. Renewable energy does produce commercially competitive power and it does it today - even on my rooftop which gives a 6% annual return without subsidies or tax breaks.

The question to be asked is "We have had commercially competitive renewable energy for 40 years. Why is it that we have not had the investment to make it more widespread?".

The answer is found in the way we calculate the return on long term projects. Almost any project that builds new productive capacity and whose payback is greater than 10 years is unlikely to get funded.