Do you really want to go off the grid with your solar power system?

Did you hear about the Queensland proposal a couple of weeks ago that proposed an 8c per kWh GROSS Feed In Tariff? That would mean Queenslanders would have to sell ALL their solar power to the retailers for 8c (yes – ALL of it – even the stuff that they used in their home). And then buy it back for about 30c.

Yup – that would be called institutionalised theft.

Stories like that make most people want to get off the grid altogether.

So I get quite a few quote requests these days for “Off Grid” solar power systems. However most people don’t fully realise what a big and expensive step it is to cut the wires to the grid.

So I made this video to explain what it really means to go off grid in 2012. I hope you enjoy it:

Here’s the transcript:

What is the difference between an On Grid and Off Grid Solar Power System?


Hi, I’m Finn Peacock and today I’m going to answer a question, “what is the difference between an on grid solar power system and an off grid solar power system?”

Well, the obvious answer is one’s connected to the grid, but what does that actually mean practically?

Well, there’s 3 big differences.

Number 1 – it means if the grid goes down and you’ve got a grid connected solar power system, you;re going to lose all your power. An off grid solar power system obviously is not dependent of the grid, so it will keep going no matter what the state of the local grid is (if you’ve even got a local grid!).

Number 2 – An off grid solar power system, let’s use a 5 kilowatt system as an example, will cost you around $30,000 wheras a grid connected solar power system that’s 5 kilowatts will cost you about $8,000. So if you’re thinking about going off grid, it’s gonna cost you a hell a lot of money.

The third difference between on grid and off grid solar is that an off grid solar system will run out of electricity if there is not enough sun. Depending on the size of the battery bank, say you have 2 or 3 really cloudy days with very little sunlight, you will run out of electricity because your batteries can only hold a finite amount of energy. If that happens, then generally you have a diesel generator which you can kick in to generate the electricity in need. And that’s one of the reasons why it’s so expensive because you need these backups, you need batteries, you need all the electronics to control it all that. You need to do a really careful design to make sure that you don’t run out of electricity very often or you don’t use your diesel generator very often because generally that’s very expensive way to generate electricity.

So there’s the main difference between an on grid solar system and an off grid solar system, one, obviously one’s dependent on the grid, one isn’t. Two, the off grid solar systems are still phenomenally expensive, so think long and hard if you haven’t these romantic thoughts about being off the grid, whether you can actually afford to spend $30,000 on a modest sized 5 kilowatt system.

And three, bear in mind the fact that if you have an off grid solar system you will run out of electricity every now and again, and you have to use some kind of dirty back up like diesel to generate that electricity.



About Finn Peacock

I'm a Chartered Electrical Engineer, Solar and Energy Efficiency nut, dad, and founder of My last "real job" was working for the CSIRO in their renewable energy division.


  1. Phil Bramley says:

    When does that convergence of renewable power technology come together – solar, wind, battery – to make it a real alternative to fossil fuel power?

    • 3 weeks ago last Tuesday

    • weterpebb says:

      Probably never. These are all technologies that have been under active development for over 100 years, and still have not come anywhere near being competitive with traditional power sources. They only exist due to massive taxpayer subsidy. Supplementing traditional sources with solar or wind is not cost effective. Configuring these to replace traditional grid power (eg by providing power at night) costs about ten times this again, due to the cost of investing in energy storage devices (such as batteries) which are inherently expensive and inefficient. It is a very long way indeed from being cost effective.

      They are simply dead-end technologies, kept alive for political reasons (through using taxpayer money to buy green votes).

      We have spent the last 30 years hearing about new solar technologies which will make solar power cost effective within the next ten years. But yet they never become so. Older readers may recall how governments spent a fortune subsidising R&D for fusion reactors, which were going to provide cheap clean power real-soon-now. After years of non-delivery, common sense prevailed and the funding was cut. Much the same thing is happening now with solar power; politicians are realising that the claims of solar power lobbyists were massively exaggerated (as were those of fusion proponents), and they are subsidising a dead-end technology. Its just taken far too long for them to face up to the fact they have spent billions of dollars on dead-end technology.

      • Stuart the Cynic says:

        If you’re talking about subsidies, you probably need to mention the ten billion dollars given to fossil-fuel industries each year in Australia.

        Otherwise one might suspect that you work for those industries.

        Terrible cynic aren’t I?

        • weterpebb says:

          Fossil fuels are not subsidised in Australia. Indeed, most fossil fuels are massively taxed; petrol and diesel have taxes equivalent to 39 cents per litre (known as excise tax). LNG is currently taxed at a somewhat lower rate (about 29 c per litre) but this is in the process of being increased to parity with petrol (based on energy content). This direct tax on fossil fuels currently amounts to $14,000,000,000 per annum of revenue for the Federal Government. (Source: )

          So you have it backwards.

          And no, I don’t work in any energy related field, or have any connection to such industries other than as a normal consumer. The only person in this blog with a vested financial interest that I can see is Finn Peacock, who earns money from solar power. So it seems you have this backwards as well.

          • List of Australian fossil fuel subsidies:


            Yes – this quite correctly lists tax rebates as subsidies. If everyone has to pay tax on something but you don’t – you are being subsidised by everyone else.

            On top of those QLD subsidises rural electricity bills (coal and gas fired electricity) by $600m per year. WA has a similar scheme called the regional power subsidy, which subsidises coal and gas powered electricity by about $400m per year.

            Globally, pre-tax fossil fuel subsidies are estimated by those leftwing maniacs at the IEA to be about $400 billion:

            “According to IEA research, 37 governments spent $409bn on artificially lowering the price of fossil fuels in 2010. Critics say the subsidies significantly boost oil and gas consumption and disadvantage renewable energy technologies, which received only $66bn of subsidies in the same year.”

            And those commies at the IMF have released a study that puts post-tax fossil fuel subsidies at 2 trillion. Or 2.5% of GDP.

          • weterpebb says:

            Finn …

            Allow me to quote from this document:

            “The largest subsidy is the Fuel Tax Credits program, which rebates fuel excise tax on diesel fuel
            consumption for many business users.”

            So it rebates the excise fuel tax. “Rebates” means it gives the money back. So these users do not pay a fuel excise tax. They don’t receive money for using fossil fuels. They simply avoid paying (some of) the fossil fuel taxes for which they would otherwise be liable.

            The absence of a tax is not a subsidy.

            And this is the “largest subsidy” according to your document. The other are similar. You can either say that the fossil fuel industry is taxed $14b per annum, or you can say the fossil fuel industry is taxed $20b pa but $6b pa is rebated leaving a net tax of $14b. You certainly can’t say that they receive a $6b subsidy. The nett tax is over $14b pa.

            Indeed the document you referenced has a list of these supposed subsidies on page 2. Not one is a subsidy. Every one is an exception where some category of user doesn’t have to pay some tax associated with fossil fuels.

            Not having to pay some fossil fuel tax is not a “subsidy”. It just means some users pay less tax. Fossil fuel use in this country is massively taxed, $14b pa in fuel excise alone. Yes, if some dispensations were not allowed, the government would receive $20b pa. But this isn’t a net subsidy of $6b pa; it is still a net tax of $14b pa.

            Did you actually read the document to see that there is no subsidy, just a whole series of special fossil fuel taxes for which there are exemptions?

        • Are you able to show how ten billion dollars are given to fossil fuel industries, who receives it, who pays it, how it is paid or are we just expected to believe your off the cuff statement?
          Another cynic.

          • Of course he can’t show that fossil fuel companies receive $10b net in subsidies. Its cloud cuckoo land.

            Fossil fuels are massively taxed in Australia, which the opposite of a subsidy. Excise (tax) on petrol and diesel raises $14b pa net. And that is very much the start.

            Coal miners pay taxes, lots of them. This country makes a fortune from coal. It is our largest export earner. Coal companies pay massive taxes. Much of our economic prosperity derives from being the world’s largest coal exporter.

            The idea that fossil fuel industries are on net subsidised in Australia is ludicrous. In fact the foreign exchange income underwrites our balance of trade, and tax receipts from coal miners largely underwrite our national budget. Australia does not subsidise fossil fuels; cheap fossil fuels subsidise Australia.

      • Chocolate says:


    • Lee Mazengarb says:

      Has always been available. As of at least 5 years ago or more. More actually probably dating back to 30 years ago. Just dont go to a shop to buy it. Build it.

  2. Nathan Jennings says:

    I have an existing on-grid 3kw system installed. I have just ordered a Xantrex 4024 hybrid inverter charger, system control panel and Mppt Controller to upgrade so i have the option to add batteries or a generator during blackouts in the future. What would the estimate cost be for a company to come and upgrade to the xantrex.

  3. Nathan Jennings says:

    I managed to pick up a XW Xantrex 4024 hybrid inverter charger, XW distribution box(dc/ac breaker box),XW MPPT controller, XW conduit box and XW system remote control panel all for less than $2300 online. If you shop around you can get a full off grid set up with 3kw honey trina PV The full Xantrex system (one of the best on the market) and around 24v1800ah battery bank all for less than $9000. The xantrex system in Australia is valued at close to $10,000 (complete rip off energymatters by the way) buying from OS is a much cheaper option.

    • I’m looking to purchase XW Xantrex 4024 hybrid inverter charger online. Price Ranges from $2654 – $4800. I noticed that Nathan Jennings posted on this forum that he bought one for only $2300. Any chance someone could steer me towards a cheaper supplier?

  4. oliver jones says:

    Off grid is of course going to be the best option in the long run, and you can get top quality gear online from america and asia for much much much cheaper than you can in australia. The reason off grid will be best is simple, the energy companies donate a lot of money to both political parties, then when one wins they call in the favor, not capitulating would mean a huge loss of donations which could hobble them next election, and the power companies make it easy on the government by funding fraudulent research and think tank papers to agree with them…
    if you have the space, you dont need the latest and most expensive battery technology, do some research into storage solutions…
    Offgrid might seem “crazy” but these crazy people can see the writing on the wall, as long as the electricity companies are in bed with and protected by the government, off grid is the best long term protection against being financially screwed

    • weterpebb says:

      Perhaps you could tell us how much you paid for your off-grid system, how much battery (or other) backup you have for cloudy days and night time use, and how many kWh of electricity it generated in the last 12 months? These are the basic numbers needed to work out if it is a cost-effective replacement for grid power.

      You do have a fully off-grid system, don’t you? If you do, I would be very interested in knowing how well it works (using the numbers I have asked for above). If you don’t, your passionate defence of off-grid systems would seem somewhat more than slightly hypocritical.

      So what’s the real story? How much did it actually cost in dollars, how much storage do you have for nights and cloudy days in kWhs, and how many kWhs in total did it actually generate last year?

  5. No one has mentioned the alternative Ceramic Fuel cell gas driven system. This is relatively clean and allows generation of double household requirements 24/7 at up to 80% efficiency when waste heat is used for water and area heating (compare that to central power station and extended grid systems). It lends itself to local co-generation completely off grid if designed into housing estates. The problem with any private system solar or otherwise is the increasingly high supply grid up front charges and miserable buy back rates from the Gov’t backed monopolies, any system that relies on centralised energy can be manipulated, including gas. Recent Swiss studies prove that up to 80% of world trade is controlled by interlocked holdings of a very few conglomerates.
    Whilst these people dominate and rake in all kinds of devious ‘rent’ charges don’t expect anything to change. Get out of the system or suffer extortion. Perhaps one day our government will properly represent us. Hmmm!

  6. Lee Mazengarb says:

    Lol, what a joker, totally wrong on his prices. U can go off grid with a complete 5 KW system for around $15,000. It is not expensive. Only these are rorting the government CEC scheme give quotes like this. U pay $1 a watt for solar. U pay $1000- $2000 for invertors to run ur house. The only thing u really need is something for heating and cooking. Which can be either go gas or have your own on again off again generator for excessive loads. Again another $2000 will do it, solar hot water $1500. Battery system will set u back around $2000 to $4000 if u want a lot of batteries which will give u a long time out of the sun power. Again dont use these CEC solar expert companies, they are not in it for the environment but in it to make a lot of cash out of rebate schemes etc on your behalf. So do some research and ignore places like this one.

    • Hi Lee,

      Thanks for the comment. Are you including the cost of a full energy audit, qualified electrician, insurance, warranty support, 25 years of ongoing customer support, staff training, CEC membership (mandatory), GST etc? Or are your prices for DIY with components sourced from eBay?

      Finn (AKA The Joker)

  7. I have been off grid for most of the last 17 years. Three years was a rental situation. For two years I have been grid feeding and earning $2000+ each year. The costs you give are not accurate, in my experience: Five years ago we installed a 4KW panel, 36 KwHr battery system and a 4 kW inverter for $23,000. For two years we never got below 75% battery capacity. Crucial additional information to this argument is REDUCTION OF CONSUMPTION. We have lead an upper middle class lifestyle, and consumed around 5KwHrs a day, including substantial pumping. Secondly, we live in a Mediterranean climate, near Dunsborough, with good solar access. 50kms south, at Margaret River, you would need about 25% more panels – I KW, to deal with SE cloud from off the Bight in winter.

    • Having used nothing but a solar stand alone power system and off grid since installing one in early February, 2003, I would concur with Warwick Rowell. Warwick is totally correct when he suggests that the key is “reduction of consumption”.
      Most people waste about 50% of their electricity purchased through the grid.
      Our solar power system is only 3kW in size and this still provides enough power to charge a 1300 Amp-Hr battery bank: enough power for five days at out current usage without charging from an additional source other than the sun. We use the petrol generator two hours a day, if required, but this might only occur three or four times a year. Petrol costs are around $40 per year at 2013 prices – often less than that.
      Computer, toaster, hairdryer and TV usage is normal. Fridge and separate freezer run 24/7. Heating water in the kettle via electricity is out however – we use gas instead. The total cost of the stand alone system was $37,000 in 2003. Today, the same system installed is well below this cost.
      Coupled with our solar power system, we have solar hot water with gas booster and a gas stove. Heating and cooling inside the house is provided throughout the year via good use of insulation in the ceiling and walls of the dwelling. Ongoing expenses will include deionised water for batteries but little else, Rain water collected properly will suffice for battery fills and this costs nothing but time.
      The big expense eventually will be the replacement of the battery bank. The cost of these is exorbitant and is likely to cost about $23,000 at todays prices – when they require replacing. Looking after the battery bank will prolong battery life considerably and extend the time required before replacement is necessary – which will reduce the annual cost of electricity considerably in the long term.
      Batteries should last at least 12 years and they last a lot longer than this with an adequate maintenance program.
      Overall and at todays prices, off-grid power for us has been extremely comparable to on-grid and with all things being equal – we should be well ahead of anyone purchasing power on -grid.
      An added advantage will be that without blackouts and power surges common to on-grid supplies, household electrical items should last a lot longer before they too, need replacing.

  8. Richard Beadle says:

    You do not need a diesel generator at all. A 5hp motor running a 24v or 12v alternator quickly helps to top up the system quickly and a bit of research into usage habits(i e the size of you fridge when your groceries can remain cold in the shop until you need them and an evaporating system for air conditioning instead of a compressor system)can alter your requirements considerably. It involves a definite lifestyle change. Council approval can also be averted by building your system onto a large trailer. The other myth is that your panels need to be up high. Under the right conditions they can be placed on or near the ground which also facilitates easier maintenance and cleaning.

    • Certainly agree with Richard about the size of the generator required but in particular, the placing of the panels in a position where they can be looked at and maintained easily. Positioning them on the roof of a house is probably the most practicable position for most people, unfortunately however, Solar panels, whilst they are fairly rugged pieces of equipment, can have a tendency to ‘short out’ for various reasons, (lighting strikes – hail damage – creating scorch or burn marks on the panel face, which is not always obvious until one is able to look at them closely) and they do require cleaning on a regular basis (I do mine at least once every six months) to keep them producing power at their maximum efficiency. It doesn’t take long for them to get dirty, particularly in a city location, and this allows lichen to attach itself and grow on the face of the panel in quite large patches.

  9. Jim Fulton says:

    Jim from NSW says:

    My only interest in Solar is to save money.Three years ago I had installed a 3.9 Kw system. Unfortunately, no one told me the basics before I went ahead. At this time I am receiving 60 cents Per Kw that I produce & that should continue for another 5 yrs. unless the rebate is repealed. My 3.9 Kw system, at a cost of $11,000, will soon pay for itself. What it will NEVER pay for is the System Access Charge or the G
    So the Basics are:
    1: If you use an average of 20kWh Per Day over 365 Days, you must have a system that produces at least that much on average.

    2: You have to consider the cost of the System Access Charge & the GST over the life of your system, ( or as long as you’ll live at that address )

    I wish someone had given me that info. before I went ahead!!

    • We have been off grid for 14 years – our first system was an ex telephone exchange inverter and batteries (for free) – new 60 watt panels (8 of with government rebate – from memory around $2000) we are still using the panels – then after 2 years we purchased a selectronic inverter (Australian made) and plasmatronic charge controller (Australian made) for around $3000 – and some second hand BP pv store batteries (free) which lasted 11 years – recently purchased new Exide batteries for $4000 — so our power has cost us $9000 over 14 years – around $650 per year – $12.50 a week – we have gas hot water – cooking and fridge – we start our 3kw generator to wash clothes and vacuum —- REDUCTION OF CONSUMPTION !!!!!

      • Agree –>> “Reduction of consumption” ~ and there are any number of ways of doing that. I use an average of 2.5 kwh per day and don’t go without anything I need. I do live by myself, so there’re no kids/missus to consider; however, since much house consumption is communal (eg fridges) the average consumption would be rather LESS than 2.5 kwh per person.

        And there are other considerations never assessed by ‘commercial-type’ calculations.
        The small generator battery-charger suggestion is one of them; but why not take it further?
        eg Buy a 2kw ‘demand-start’ (or remote-start) petrol generator (under $500 ~ or build one yourself with parts from the wrecker ~ I’m about to convert mine to run o lpg ~ all simple stuff) and use it to run all your short-use power-guzzlers like microwave oven, power tools, washing machine, etc.
        DON’T even consider diesel: overpriced to buy, overpriced to run, and need to run ‘hot’ (stop-start ) use will kill ’em in no time. In practical terms that means you’ll HAVE to consistently run down your battery-banks (which kills them!) and run the diesel generator for ~ at least ~ hours. On the issue of diesel longevity, keep in mind that you can replace your cheap petrol/gas genny about twenty times for the cost of a single diesel one. It’s cheaper to buy the petrol model than to have your diesel even serviced (let alone worked-on) by a specialised mechanic. (assuming you can even find one these days!)
        Y’don’t see draught-horses at the race-track. Never wondered why?

        That way you only need a battery-bank to run a few (low-energy) lights, a (smallish) TV set ~ I have one that runs on 8-10 watts and a 28-inch one that runs on 60 watts. Not only do you spend far less on batteries (which DO have to be replaced, and sooner the more they’re used) but can be topped up more quickly and cheaply. How long can a 100-amphr battery run, say four 10-watt globes and a 60-watt tv? I have a 600amp-hr/24 volt battery-bank (bought only because they were available at a price too good to refuse, and sometimes have to deliberately run the freezer for a few hours just to ‘exercise’ the batteries to prevent them ‘dying’.

        Usually the freezers and fridge run all day from cheap solar-panels and then are switched off when the (solar) output reduces to below what’s needed to keep them going. They stay cold all night and kick in again next day.
        The point being that very little battery-power is needed if you use a few brains:- something the commercial-thinking crowd don’t always do.
        hehehehe. Thought for the day:- ….. If the solar power Industry ever DOES become a major player I can see the day when radical ‘alternative’ thinkers are plotting to overthrow it because of the expense and the dictatorial coercion it enforces…..just as the fossil-fuel Industry did before it!

        To quote Lazarus Long (sort of):- “The more people who say something is so-and-so, the less likely it is to be true.”

  10. I have been on stand-alone solar for 20 years, and still use all the original gear, including the 12 x 2v BP Solar batteries – a record, my solar installer tells me. They’ve never been run flat and do get ‘bubbled’ (by the sun and manual boost) after a run of cloudy days.
    The cost quoted to replace those when they go is about $6000 he says. All imported nowadays.
    I use the backup generator so rarely I would never bother replacing it. I agree the key is careful use of power, thinking about when and what you use, especially when it’s not sunny. I liken it to a cheque account; don’t take much out when you’re not putting much in.
    Who really has to wash, iron or vacuum on cloudy days? (mine are all standard 240v)
    The fridge ( 24v ), lights and my computer are my essentials and I have never been unable to keep using them.

    • $6000 to replace batteries sharyn2013? Hope this is correct because if you are, then you’re on a winner for sure. Of course you don’t say how big your system is so I suppose this could be right! And 20 years for batteries is almost unheard of where I come from so congratulations – it sounds like a well maintained system.

      • Batteries are improving. But they’ll never replace the second-hand ones we used to buy from the SEC depot in Port Melbourne. 2040 amphr/2-volt for either SIX or NINE dollars each. A friend of mine retired a bank of them a coupole of years ago after 28 years of off-grid us.
        Point being that it IS possible to build good batteries. Price is another matter.

  11. i think you need to update some of your information, 50k for modest 5kw system you mentioned , well thats not giving the correct information from several quotes i received.

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