'Tip 1' for Direct Action: Making a million solar roofs matter

This is the first part in a series of 'Tips for Direct Action'.

Note from the author: As we all know the Liberals have been heavy on campaign rhetoric, which is all very well when you are in opposition. But being absent and underweight in deliverable policy doesn't fly when you're in government. When it comes to climate rhetoric Abbott and his protégé Hunt are in their element.  Every time Hunt fronts a camera he is mouthing direct action, but now he has to front the house with a deliverable. I know he is short, so I'm here to help in turning direct action rhetoric into deliverable action. These tips aim to provide meaningful and measurable infrastructure on the ground that will make a difference and beat Labor and the Greens at their own game.

One of Greg Hunt's favourite Direct Action lines is to repeat his party's support for "one million solar roofs". In recent times he has updated his policy to "an additional million solar roofs". This is because the country already has over one million solar households.

If implemented and targeted properly, an additional million solar roofs could be really worthwhile in the transition to a 100 per cent renewables powered zero emissions economy.

With such a good start, how can we make Greg Hunt and Tony Abbott's government support for another million houses count?

Economies of scale: bigger systems

All those households that have solar today benefited from a federal government scheme which artificially capped domestic solar systems at 1.5kW. It costs money to ship equipment to a site and whether you ship lots of equipment or a little equipment it doesn't change the cost much. Same goes for the cost of labour, you've got to get the installers to site, get an inspection and possibly change the meter,. If you install a lot more panels and a bigger inverter the cost goes down per kilowatt of capacity and, consequently, the cost of energy produced is less. Systems that are backed by a government scheme should be a minimum of 5kW unless there is not enough north, east or west-facing roof space to support that size system.


Coupling storage with solar photovoltaic installs has a dramatic effect on reducing grid costs and the cost of provisioning peak power (with wide enough deployment it would eliminate it for good). Commercial storage options already exist with advanced battery management that can shift solar from daytime to nighttime, dramatically improving behind-the-meter economics in a post feed-in tariff world. Storage systems can also help with grid support. 


Systems that are oversized – where the solar array has a greater rating than the rating of the inverter – must be supported. Government support should extend to adding more panels to 5kW systems to enable them to produce a more uniform daily output (less of a bell curve) oversizing can include installations where an array exists facing north and additional arrays face east and west – i.e. at the upper limit of what should be supported, a household may have 10kW facing north, 6kW east and 6kW west all running through a 10kW inverter (with oversizing some production is, of course, lost to clipping – usually on a hot long sunny summer day). 

Where oversizing should be mandated is where the grid operator will not allow an inverter that is at least 5kW to be installed due to the customer being on a rural feeder and not being coupled with a storage system that can isolate production from the grid. In this case a customer may have a 3kW inverter and have 6kW of solar PV installed producing a similar amount of annual electricity as a 5kW system. In addition, under these restricted rural feeder scenarios the customer could be further incentivised to include storage, such systems coupled with active connectivity to smart meters will be programmed with a virtual capacity to not exceed set limits feeding back into the grid – i.e. customer has a 10kW inverter, however the inverter will never inject more than 3kW into the grid beyond the meter by monitoring the smart meter in realtime. This reform would have the additional benefit of allowing remote customers to upgrade their effective supply kW capacity locally without spending tens of thousands, or hundreds of thousands, on getting their poles and wires upgraded.

Upsizing and upgrading existing systems

In co-operation with the states, Greg Hunt should direct the states to agree to a cap on feed-in tariff payouts based on the maximum possible that can be generated under each scheme – i.e. 5kW limit in Victoria, 10kW limit in NSW. Then those households can participate in Direct Action and do their bit to reduce Australia's greenhouse emissions by installing more panels and additional, or bigger, inverter systems preferably coupled with storage systems as well as oversizing.

Grid support reactive power and power conditioning

Grid support in terms of reactive power is now part of the new grid connect standards in Germany. This technology and know-how from Germany can be easily transferred here. Power conditioning (usually coupled with storage systems) will improve the quality of power for rural people, mostly farmers who live at the end of SWER lines and other rural feeders, and would be a great place to support.

Solar appliances decoupled from the grid

The following solar appliance classes should be supported to directly reduce emissions at the source:

– Inverter reverse cycle air-conditioners hybridised with direct coupled photovoltaic

– stand-alone solar photovoltaic solar photovoltaic pool pumping

– Domestic tank water pumping hybridised with solar PV

– stand alone solar photovoltaic stockwatering/irrigation water pumping

– Heat pump hot water systems hybridised with solar PV

All this can be done with a bit of foresight, pushing the envelope to create new and better markets for the technology. If the additional one million house Direct Action policy was achieved targeting the kind of system sizes mentioned above (i.e. an average of 7-10kW per abode) then Australia could have an additional 7-10GW of solar photovoltaic on domestic rooftops producing between 9TW and 13TW of annual electricity (around 10 per cent of the nation's annual electricity). 

Greg Hunt and Tony Abbott, over to you.

Matthew Wright is the executive director of Zero Emissions Australia.

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Rather than solar and wind power to reduce our emissions, we wold be better to put our limited finances into utilizing our abundant natural gas resources to the benefit of Australians. LPG at cost price will reduce our dependence on imported oil, reduce greenhouse gasses and provide inexpensive transport and reduced cost for business. The Browse fields have not been sold yet, we should connect these to the National Gas Grid and reserve the supply for domestic consumption only.
Then we need to invest in developing Thorium power generation for our base load power. We have the largest supply known, we need to start developing a clean, emission free source for our future needs.
The Liberals need to scrap their PPL scheme and put the money into developing schemes that will produce something Australia really needs. There are already enough people on this planet, many of whom are desperate to get here.


Liquid Petroleum Gas is a transport fuel. I think you mean fossil methane gas.

Gas is a poor performing fuel and electricity can do everything gas can do in homes. Heatpump hot water from Australian industrial family Siddons or their competitors Stiebel Eltrom or Sanden each sell units that run on 75% renewable ambient heat, which is solar energy stored in the environment.

Everyone knows about Daikin, Panasonic and Mitsubishi Heavy Industries air conditioners. These units heat for far less cost than gas. and they are commonly 1000% more efficient. (Flue efficiency of gas = 0.8 while Co-efficient of Performance of LG Reverse cycle air conditioner = 5.42. And induction cooktops are cheaper to run and easier to control than gas.

Now that we are linked to international markets gas will cost whatever it costs in those markets. The same goes for petrol and we've all experienced that pain at the bowser. We need to get off these dangerous climate damaging fuels and move to electricity powered more and more from renewables.

Thorium power does not exist as a commercial proposition.


My apologies, should have read LNG, or CNG.
As to thorium, there is plenty of research under way. We should be involved. Everyone wants Australia to go high tech, and reduce fossil fuel use. There are not that many options available. Research is the key.


You're jumping from what we can do now to what we might be able to achieve with a moonshot in 20years time. We've got to stick to the here and now and renewables are here and getting cheaper all the time.

Thorium was something my father (a physicist) was telling me would be the next big thing in power generation when I was 7. That's was a long long time ago. Thorium is like wet wood, it's the nuclear industry's lignite. If you want to daydream about thorium you might as well daydream about battery technologies that offer 4x the density of today's Lithium Ion batteries at half the price and Solar photovoltaic panels that are multi layer and convert 50% of the sun's energy into electricity at half the price per watt of today's panels.


There are many reasons for encouraging realistic house hold solar PV systems. Two that I can think of from the top of my head.
1: If the government was to adopt the German model of feed in tariff's, giving the people true incentives for producing electricity. Making the people power suppliers instead of consumers.
This will quickly with in a few years (not decades) lower demand on out dated single power plants.
In a country with 8 months of the year winter conditions, Germany produced 25% of electricity through solar and wind.
2: energy security, Having many electricity generators if one goes down. It will be easily compensated for through the system. But as it stands today if one CO2 spewing monolithic generator shuts down then there is a massive hole in supply that the grid will need to cover.
.Giving power to the people upsets the powerful. That is the problem in Australia.
On your point about thorium fueled nuclear power. Yes it is the better fuel than uranium the waste is much less dangerous and is actually a more efficient fuel for electricity production.But if Australia adopts nuclear power, it would be a safe bet. That the preferred system will be uranium fueled.
Although Australia has the lions share of the worlds thorium thorium deposits.They have not been developed yet. The infrastructure for uranium mining is already in place.
secondly just like Australia, abandoning the development of Solar PV technology. Alowing other countries to pick it up. The US did the same with Thorium nuclear technology. The US weapons manufacturer that has control on uranium power generation, gave up on thorium apparently it can't be used for weapons grade plutonium.
China is developing commercial size thorium reactors.


LNG is carbon Richard. Don't you get it?


You're forgetting that "Direct Action" is a policy for delaying action. Abbott could take a year to repeal the carbon tax. This gives high income to fund the handouts during the 2013-14 financial year.

Then, I expect we will find that the budget remains in crisis, and that no money is available for Direct (In)Action. The end result, no action against climate change, and happy coal miners. Australia will be laughing stock.


Matthew, leaving aside your patronising introduction, it would be nice to get an estimate of the electricity to be generated from your enhanced proposal re 1 million more solar roofs, the cost per kWh (and how you calculated it), and the likely percentage of power that would be generated.

If you anchored your proposals with actual costs it would be easier to take them seriously (or to reject them if they cost too much for too little benefit - as I suspect). At present, they just seem pie in the sky, and actually totally uncosted.

Another question is whether your elaborate (and expensive) plan has more substance than Greg Hunt's other scheme, soil sequestration. Both are unlikely to be the core element in any solution.

If we want real substantive action on moving to a low-carbon future, wind is the front runner, which we know can be produced for $100 MW, and enhanced geothermal, which could possibly have a similar cost.

Both of these strategies are already supported by the bipartisan 20% RET scheme (whether it is 20% real, or 20% forecast). Getting these in place, after Labor's three year hiatus will be hard enough. Anything further that comes from Direct Action will be a bonus and more than Labor were offering by linking us to the failing EU ETS.

In conclusion perhaps I can offer my own advice to you. Give Greg a chance to do his best, and judge him on his results, and provide us with real costed proposals in the meantime. Perhaps you will win us over to your BZE ideas.


Is it propaganda or just plain ignorance why these conservatives/reactionaries misinterpret the RET as a scheme. The anagram RET stands for Renewable Energy Target. It's the result the goal not the means by which to get that result. In reality it is set very low thanks to bipartisanship.
Secondly Australias price on carbon is not an ETS, In reality pricing carbon through a tax is the better opption, than an ETS, or slap on the wrist punitive measures.
When it comes to Abotward's direct action fines.
A: it will be almost impossible to calculate exactly when the poluter has breached the legislation limit. Then the ey will merely through lawyers at the problem.
If the newly formed $16million department can prove a breach. After blowing its pitiful budget on one case. How high will the fine be? I doubt not very high.
Common sense says that if the find is to low the polluter will just pay it and continue, if it is to high they will throw lawyers at it.
The only reason why wind is slowly at a snails pace becoming the front runner in renewable energy supply. is because. It is the fascist way.


Matthew, mate I know your a much need champion of renewables and that's great to see,but I'm quite perplexed as to why your a champion of heat pumps for hot water. Heat pumps still cost money to run, EVERY DAY, even though the better ones are cheaper to run than an electric storage unit, but only if they can run on off peak 1 or 2. Still better not to uses any electricity 335 days of the year, don't you agree, by way of an Evacuated Tube Solar Hot Water System. That kills the h/pump arguement hands down and nobody has to spend up to $1,300 to replace a failed compressor once every 2- 5 years. In fact most only spend about $30/yr boosting such ET systems! Energy savings over H/Pump speaks for it self there.

On the matter of oversizing PV arrays e.g you stated that a 16kw split array, with 6kw facing East and 6kw facing West and 10kw facing North, using a 10kw Inverter. This would cause the inverter to shut down at times and perhaps cause it to eventually fail because of overlapping bell curves putting to much load on it in certain conditions i.e more than 10kw D.C input.

I know this because I'm a CEC accredited PV power system designer and installer and I also sell Edson Evac Tube SHW systems of which I have a wealth of experience. I know what works and what doesn't. I also sell Heat pumps too, for those who can't utilise solar.

My last point is that if you have an a/c unit, a pool pump or need to pump water from a rain water tank , you don't need seperate PV systems for each, just one roof mounted system that will take care of all household loads including these. More cost effective to boot.

Mainly, with all the rest your fairly correct. But please don't tell the public stuff that isn't true it doesn't help the renewable industry at all. Please seek expert opinion first.



You are a PV system designer and you don't know how an inverter handles excessive input?

So long as the no load voltage of the panel array does not exceed the voltage rating of the inverter's input, then the inverter can always choose to draw less current than is available. All inverters have input tracking to maximise the power deliverable, but this also works as a method of preventing overdelivery.


Thanks Mark, exactly my point. The Clean Energy Council is giving the wrong guidance on the design of Photovoltaic arrays. The system I gave in the example was 22kW on a 10kW inverter. That was really pushing the limits of what is possible with today's off the shelf tech. But I used an upper end example to make people thing about it. I know of SMA 5kW inverters installed in NSW and QLD with 9kW+ of panels on them and they run beautifully producing a lot of electricity at all times of the year. The CEC has an unjustifiable array voltage limit of 600VDC while SMA sells inverters that now do 700VDC. What is there limit 600VDC? No valid reason except that SMA's older models that were around at the time they made up the rule had an upper limit of 600VDC. And there's more silliness They give advice on array oversizing which I think from memory runs at no more than 25%. Why is this? If it is a REC issue why not adjust the REC allocations in these situations.

And finally they haven't gone out to address the issue of the distributors such as Essential in NSW stopping oversizing where they have deemed a limit to the size of an inverter that can be connected. ie they say you can only connect a 3kW inverter and then will reject you if you propose 5kW of panels. Ridiculous.


The coalition will only support the fossil fuel industry because that's where the dirty money landing in their back pockets is coming from. Their policies are always based on pure corruption. When are stupid Aussies going to realise this?


Mark, I know how an inverter handles excessive input and what you have stated is correct up to a point, but and there's always a but. When you put that much load on an inverter the thing will run very hot, this will put a lot of pressure on the electolytic capacitors, espeacially in summer when the sun is almost directly overhead, those E & W 6kw facing arrays will be making plenty of power. So oversizing an array is limited to 25% for good reason. Far better in Matthew's example to use another bigger inverter, say a 17kw, that will cope. I've seen inverters fail within 6months because of massive oversizing and then of course the manufacturer won't warrant the thing. Knowing this, as a designer,I would never install such an over driven system, it's not cost effective and certainly would't make the customer happy when things go wrong.

And Matthew, I noticed you didn't address the issue of Heat Pumps. If anybody who has good solar access and chooses a h/pump over a solar hot water system, has got rocks in their head. H/pumps are far less efficient in winter, so why would you recomend something that would cost the owner up to $50 plus p/quarter to run, when the suns energy is free! My customers are over the moon only having to spend $30 p/annum, with their Evac Tube SHW systems.

If we are going to target zero emissions then a Solar Hot Water system makes a hell of lot of sense in a world of 100% renewable energy. If we can reduce energy use as much as possible, that consequently means less solar thermal, wind and pv power stations and naturally less cost, making 100% renewables more easily acheiveable. And yes I agree it is acheiveable, if we have the will.

Solar Hot Water is the answer not heat pumps. Matthew if you disagree with me I would love to hear why.

Shaun Beck


Shaun, you could offer a 5KW inverter 100 Amps at 500 Vdc and it will still only draw 10 Amps. The inverter is an "active component" capable of adjusting its presented load to suit its own needs, its not a passive fixed load like a light bulb or motor that will draw more current as the voltage rises.

The inverter doesn't have to dump the "wasted" power, because it simply doesn't get generated by the panels. Go look at the voltage current curves on any PV panel spec sheet, at no load (zero current, zero power) the voltage is at its highest, as the voltage drops (under load) it then behaves as a constant current source. A 5KW inverter will be no more stressed when offered 10KW than when offered 5KW because it only takes what it needs. Perhaps you are confusing it with wind generation were any excess power generated must be used or dumped?



Mark, what are your qualifications? I suspect your an arm chair or pub expert. Firstly Mark, were not talking 10kw pv input into a 5kw grid inverter here, bad enough as that is, your stating 100amps at 500v, that's 50kw pv input going into a 5kw inverter. Mate that much power going into a 5kw Inveter would not be tolerated by the capacitors. 10kw into a 5kw Inverter is quite silly and it won't last long. Energy that, can't be used because of design contraints will cause excess heat and bloody lots of it, it will fry the thing in short order. This rubbish of 50kw into a 5kw Inverter is fantasy. An inverter will adjust voltage and current up to it's design limits and it's traker range, go beyond that to much and things get nasty. Mark if you are a sparky who got his install accreditation from a weekend or 2 week course, you need to get a reality check. Bye the way go and ask the tech guys at SMA if they recommend over loading an Inverter past 50% let alone what Wright advocates and also ask if they will warrant it, better still try what you suggested to me yourself. The manufacturer doesn't put limits on Max PV input from an array or the CEC for that matter for no reason. Twits who smoke better stuff than me need to ask why they state MAX INPUT. it's not rocket science Mark, go back to TAFE if you ever were there.


I'm an electronic engineer with over a decade of professional experience. I am telling you there is no design reason why an inverter must draw more current than it needs to. Inverters specify two limits for their inputs, max voltage that occurs at no load, and max current that it will draw up to. Only the max voltage matters regarding part tolerances and warranty.

Shaun, you may be right on all the other stuff you said to Mathew, I don't hold an opinion on it and haven't looked into it, but when I see someone talking shit about something I do know about then I speak up. Speak to SMA technicians yourself and be prepared to learn something new about modern switchmode electronics.


Shaun Beck

Mark,on your wonderful idea to put 50kw into a 5kw inverter. Do you really think I would be embarassed by SMA techies telling me your on the ball. Mate, tell me when you look at the SMA 5000TL specs you will see that the 1st thing it states is MAX DC Input 5,250 watts. NOT TO BE CONFUSED WITH 50,000 watts

2nd point, how many amps does same specs state as max input per tracker, yes that's right it's 15amps isn't it.

As power is amps x volts, oh now you get the picture or do you. Why in the hell Mark do think that they make different sized Inverters,Wait, I know your dying to say I want to kill a 5kw Inverter and you would right accourding to your wisdom, but the answer is Inverters are of different sizes because they don't like to be overloaded, by huge array's saying the least. The Inverter is sized to the Array and visa versa and remember PV modules are current producing devices and capacitors and Mosfets will take so much.

If you want to waste time and money go out and do it, just make sure it's your time and money. and you won't have to bother telling me how it went, because I already know, I'm laughing already.

Please tell me you don't work in the industry, because if you do for god's sake, for everbody's sake change careers and the next time your hear somebody speaking bullshit, quickly get to a mirror and keep on venting your spleen, then when the awful truth dawn's on you, you'll know it's time to see a doctor.

Sorry Mark you needed the reality check. Just repeat 50 into 5 won't go and neither will 22 into 10, repeat.


Shaun, lots of electronic equipment will specify a number for max power input, but you are wrong to think that it is a limitation on the power source you can connect it to, it is only an upper limit on how much the equipment will draw when operating normally.

Did you ever stop to think why your 100W laptop doesn't explode when you plug it into a 240V mains outlet capable of delivering 2400W? Take your laptop overseas and plug it into 120V mains and it will still only draw 100W, but at twice the current to make up for half the voltage. Thats the magic of switchmode electronics.

But here is one last thing for you to ponder Shaun, what happens when you put one of your 200W PV panels in full sun and a 10000 ohm 1W resistor across the terminals? Does it "send" 200W into something that can only handle 1W, or does the resistor only "draw" 5 milliamps at around 50v (ie a quarter of a watt)?

Finally, the reason they sell different size inverters is because it is cheaper to make a lower rated one than a higher rated one. But seeing as you can't grasp basic electrical circuit theory, I'm not holding out hope that you can grasp basic economics either.