Clean energy: the real brighter future for New Zealand

Over the weekend I launched proposals that will make it easier for families to reap the benefits of solar panels and other small scale renewable distributed generation. At the Sustainable Energy Association of New Zealand conference and expo I talked about the need to establish a fair regime that will help families to reduce the cost of their power bills while receiving a fair price for any surplus energy that they generate.

With the price of solar panels dropping 50% in the last 18 months more and more Kiwis are looking to save money by installing solar PV panels, but they need certainty around what happens to the excess power theygenerate and feed back to the grid.

Gareth solar wideI am proposing a clean energy law that would see an amended objective for the Electricity Authority: “to promote greater use of renewable energy including from distributed generation sources” and a new amended function: “to establish and administer a fair regime for small scale renewable distributed electricity generation power purchase agreements.”

I would also like to see the Electricity Authority to establish and administer a regime to administer small scale renewable distributed generation that would see households or small businesses with surplus solar, wind and biogas electricity fed into the grid receive ten year power purchase agreements and a price paid for their surplus power that is fair and reasonable. You can read more about it here.

There are many benefits to seeing greater small scale distributed generation. Generating power close to where it is being used reduces transmission costs and losses, both at a local and national grid level. Increasing diversity of generation sources makes our grid more resilient. More renewable electricity generation from sources like solar or wind will help New Zealand meet its 90% renewable electricity target by 2025. Being able to see where our power comes from increases awareness of energy efficiency and conservation. Encouraging households to invest and local businesses to install systems will boost regional economic development and create jobs.

Looking to the future, this renewable energy source could play an increasingly important role in meeting electricity demand as the cost of smaller-scale technologies continues to decline and the price of retail electricity continues to rise and rise. Renewables like solar is the brighter future the Government should be looking at.

35 thoughts on “Clean energy: the real brighter future for New Zealand

  1. All the configurations you suggest are possible, however all are what I call “specialist” installations.

    I want Joe Blogs to be able to buy a panel / inverter / mounting frame combo at Mitre10, have a sparky install an inverter-acceptable connector on the wall, and Jo can plug his panel in and begin to save (a little) money. In a couple of months Joe can go and buy another panel / inverter / mounting frame combo, bolt it to the first, plug the new inverter into the daisy chain input of the first inverter, and have doubled his savings.

    This is very different to the scenarios involving $10K or more upfront investment.

    The galling bit is that all this is possible, in complete safety, today, but is regulation-ally not permitted. I agree that the reasons behind the prevention are sound, but the prohibition is so wide so as to prevent decent, safe installations.

  2. “Toyota!”

    I wouldn’t want to put the inverter outside anyway. I’d rather mount it near the switchboard and run a DC feed from the solar panels. The great thing about DC is that you can block the reverse transfer of power with a diode and there are no synchronisation issues. For low power levels, you can use safe voltages – 12 Volts, 24 Volts, etc. For higher power and longer cable runs, the currents at low voltages give prohibitive losses so higher voltages are needed. I could consider a system using DC to DC convertors on the back of each solar array to deliver a common higher voltage DC backbone to a central DC to AC grid-tied inverter. This would allow additional panels to be plugged in up to the full power rating of the inverter – more if not all of the panels face the same way and therefore generate at different times.

    Trevor.

  3. How I wish you were right, Trevor.

    Socket-outlet has a definition in AS/NZS 3000, 1.4.86, stating “A device for fixing or suspension at a point, and having contacts intended for making a detachable connection with the contacts of a plug”.

    The definition of a plug is similarly helpful. And note there is no directional specification. In short, a socket-outlet is something that is fixed in place, and a plug is something on the end of a cable.

    If its any sort of (what I would call a) connector, then it fits the definition of “socket outlet” or “plug”. This is why I’d like the ESR redrafted to be something that actually makes sense.

    As regards your second point, given that any modern inverter (and certainly an inverter compliant with the forthcoming 4777.2) will not invert into no grid, what connector should be on the end? More particularly, what connector (“socket outlet”) should be on the wall it plugs into? Having a male connector with exposed pins on the wall connected to a circuit is totally unacceptable.

    I would say that both connector sexes should be finger touch proof, and none of our current normal connectors meet that requirement. Powercon is an example of a widely used connector which is safe in this respect, but it isn’t available in IP56 or better, which is what you would want for an outdoor connector.

  4. The key words are:
    “…through a socket outlet of that installation”.

    If the connection is not a socket outlet, i.e. cannot be used to provide power, then the prohibition doesn’t apply.

    It is worth remembering that the prohibition is there to prevent excessive fault currents flowing to other devices on the same circuit. Also if a circuit is switched off to allow work to be performed on it, having an inverter liven it up would make that work dangerous. The only way to ensure neither happens is for the inverter to be wired to its own circuit and not merely plugged in. (Fitting an inverter with a 3-pin plug (i.e. a connector with exposed pins) would make that plug dangerous unless you could guarantee that the inverter couldn’t make it live or keep it alive unless there were a connection to the grid.)

    Trevor.

  5. @dbuckley – the way around the Inverter Prohibition is to install a socket for the inverter that is not a power outlet socket, and has a dedicated circuit to the switchboard

    The wording of the ESR is sufficiently wide (I’ve quoted it above – read it yourself) that any type of connector is verboten. Thus inverters must be hardwired. For 20KW arrays that’s a sensible prohibition, but at the sub-2KW level, its excessive.

    Your other points about what inverters need to be able to cope with are all addressed by the relevant standards, AS/NZS 4777 part 2, which I think is in the review stage, so free to download from the Standards NZ site. But what it demands is about the same as regulators worldwide are demanding, so pretty much every inverter on the market should be able to comply.

  6. “So should home generators be paid market rates?”
    Ideally yes, even if the market rate is 0.5 cents per unit. Of course, having some pumped storage so the surplus power can be saved for later would help too.

    Trevor.

  7. Trevor
    There are quite obvious reasons why the power companies don’t want the home generated power and definitely not fixed contracts. They have a bit but that is only window dressing.
    There is a lot of paperwork generated for little value. The power is not dispatchable, and generated when companies don’t want it. The price the home owner expects is too high. Most grid generators are now getting about 6c/unit average and they can generate 24/7. What can the householder offer?
    For example, most of today, the weather has been fine. Since lunchtime, they are giving power away down south. In the north Island is was down to about half a cent a unit until 8pm when it jumped up to 5c. So should home generators be paid market rates?

  8. @dbuckley – the way around the Inverter Prohibition is to install a socket for the inverter that is not a power outlet socket, and has a dedicated circuit to the switchboard – or to wire the inverter directly to the switchboard without going through any plugs and sockets – but this requires a registered electrician. Sensible regulations for the inverters covering operation with a dead grid, frequency overshoots, voltage overshoots and harmonic generation should cover the other issues. However the inverters will cost more if they need to meet these additional requirements because not all of the requirements can be met just by software enhancements.

    Trevor.

  9. ChrisM and photo1nz have both spoken out against the power companies being forced to pay “inflated prices” for the power being fed back into the grid from consumers with distributed generation systems. However Gareth merely asked for price certainty and a fair price, and did not say what a fair price would actually be. Instead he suggested that this should be set by the Electrical Authority – quite a reasonable option in my opinion.

    Trevor.

  10. One form of fast, short term power storage is a bank of capacitors, such as super-caps. These can be used to smooth out short term variations in electricity supply and demand, but have a lower energy density than batteries. Like batteries, these capacitors store DC voltage, so need high power inverters to interface to the grid.

    Solar photovoltaic arrays generate DC power, and thus also need high power inverters to interface to the grid. Other generation with variable-speed generators also have inverters in the form of their variable speed drives.

    One of the issues with many forms of intermittent generation from renewable energy sources is the variation in supply due to clouds, wind variations, variations in waves, etc. This variation requires storage from other parts of the grid or controllable generation or controllable loads so that supply and demand remain balances. An option for providing storage to smooth the variable supply from these renewable resources is to integrate a bank of super-caps into their inverter system, which should work out cheaper than a stand-alone energy storage system. Similarly if longer term storage is needed and some form of battery system is chosen, there are opportunities to integrate the battery system (which is also a DC storage system) and a generation system based on renewable resources such as solar PV.

    Whether such solutions would be cost-effective for small systems is another question.

    Trevor.

  11. @NathanS – useful link, but I don’t see anything that backs up your claim that large scale infrastructure will be unaffordable. We need more renewable generation, and that means putting the generation where the renewable resources are, whether that is wind, solar, tidal, wave, hydro or geothermal. Of these, only solar is really suited to distributed generation, and that doesn’t help us during long cloudy winter spells. To ensure that we can power our homes during spells of unfavourable weather, we need hydro and geothermal power – the intermittents can contribute by allowing us to save the hydro power for these spells.

    One renewable resource which will be impacted by transport fuel costs is biomass, but my own opinion is that biomass is not suitable for year-round generation, and we are better off using it as the raw material for transport fuels. There may be a case for running biomass powered generation – preferably CHP – during winter high demand periods.

    Trevor.

  12. As a matter of principle, this proposal is exactly what this country needs.

    Yes there are some connection and control issues, but they are very solvable. All that is needed is the will to solve them. This government, with its focus on big business and economies of scale show no willingness to solve the issues of distributed generation.

    The days of retailers spinning a home gen meter backwards are nearly done – it is simply not economically sustainable for them. And technological innovations and experience with distributed generation are solving the connection issues.

    Last year I scoped a small scale wind generation project. Small scale being 20Kw. A sell price for surplus generation of 12c/Kwh gave a capital pay back period from three year and 13%+ IRR. Since then, retail electricity prices have increased making home gen even more appealing as an investment. And that is what it would have to be – an investment – so the greed and envy arguments above are a nonsense.

    It is clear to me that small scale distributed wind generation can now be justified on economic value alone. Solar PV, despite significant cost reductions of the past two years, is still not giving those returns and will not until new technologies improve solar efficiencies – probably within 2-3 years.

    My point is that, despite the real issues, right now is the time to develop policies and a national culture of small scale energy generation and all the things that go with it. I applaud the intent of this policy.

  13. If the system doesn’t have battery storage, and the residential meter is the reversing type, there would be grid contribution during the day and grid download at night and dark periods. In New Zealand the chance of a 5 KW system making a net contribution to the grid is almost nil, so as long as the consumer doesn’t ask for payment if there is a net contribution the system would still benefit the consumer and the nation.

  14. @ChrisM
    You miss the point I’m afraid. Take a look at the facts r.e. future energy supply. Shortages in liquid fuel for transport will mean that large scale infrastructure, particularly in low population density areas, will be simple unaffordable. Local power generation is the only viable future, and the sooner we get started on it the better for those that get it…
    http://transitionnetwork.org/blogs/rob-hopkins/2013-09/interview-nafeez-ahmed-unprecedented-opportunity

  15. Personally I don’t see this type of system being cost-effective.

    Depends how you define “cost effective”. There are clearly economic advantages in the large scale generation of electricity, so if you compare the investment of a 300MW plant against a rooftop solar, the price per KWh generated will be massively in favour of the big plant.

    But customers buy electricity at retail, and after the cost chain has done its thing, the difference is significantly reduced.

    I’ve already illustrated a system that has a payback period of under a dozen years, and then will deliver essentially “free” electricity for nearly as long again thereafter, with the calculations assuming that retail power prices remain constant. The key to having “free” electricity is to ensure that one’s consumption fits in the envelope of power produced by the system, on a month by month KWh basis.

    I’d say that is pretty cost effective.

    The system I have illustrated requires only a minor rewording of a regulation and an acceptance by retails to support “in and out” metering, which their billing software probably already does.

    And next year, the price of PV will have reduced still further, and I bet utility electricity prices don’t.

  16. I suppose what I am concerned about is the repeat of the private school conundrum with power.

    When those with money can opt out of the communal system, the problem is that they are no longer concerned about the quality or effectiveness of the communal system. The result is they not only want to stop contributing to it, but they are happy also to run down and degrade the communal system so their contributions can be less.
    Unfortunately this comes at a cost to the rest of us, as foreign exchange is used to build less efficient household scale systems.

    Don’t get me wrong, I am all for distributed generation, such as run of the river projects, but they are most efficient at larger scales than single households.

  17. They also need two meters (inwards and outwards).

    Welcome to 1970 :)

    Modern electricity meters are a marvel of microprocessor technology, having more computing power than landed man on the moon. They can easily distinguish direction of power flow, and thus account for both directions seperately. And even report it over the airwaves back to base.

    Utility takes power consumed, subtracts power contributed, and bills customer for difference. (but – in my world – customer never gets paid for excess, this isn’t about making money, its about reducing peoples bills)

    There would need to be good protection system for the outgoing power so it couldn’t back-liven the lines. This would bump up the price of your system significantly.

    and

    If you get people generating at home, the voltages could go up to 260-270V on a bright sunny weekday.

    All these issues have been adderssed in regulation for some years, and AS/NZS 4777 has all this stuff covered. An inverter to 4777.2 will not screw up local voltages, and will not backfeed a dead grid. The safety and operational issues are all solved issues, and again, the wonder of digital electronics makes this stuff not cost any extra than an inverter with none of these protections, as it is all software, and software is free. (more accurately – it has a NRE cost, but not a per item shipped cost nor an inventory cost)

    We really are in a different world than we were just a decade of two back, and what we all knew then is now simply past tense.

  18. dbuckley – I am not sure that you have interpreted the inverter ban quite rightly, or if you have, why you consider it to be an issue. The ban affects inverters that have a lead and plug, allowing them to be plugged into a power outlet socket.

    It is an issue because it bans the very sort of inverter I’m saying are the right answer!

    The intent of the regulation is to ban “guerilla” inverters that plug into a standard 10A outlet, but the reg isn’t that specific, it states it bans inverters with “lead and plug to allow electricity to be supplied into an electrical installation through a socket outlet of that installation.” it doesnt specifically state a 10A GPO socket, it says “a” socket, meaning “any” socket, actually meaning every possible conceivable socket, and irrespective of the wiring connecting that socket.

    I am calling for a variation of guerilla solar to be made legal and even common, so the ban is a problem in that respect, and thus (in my opinion!) needs redrafting, or at least clarifying.

  19. What is a fair price for electricity companies to pay to take excess generation?

    If their pricing systems charged more at peak times and less at off peak (and even lower at night rate), then there would be less of an issue with the electricity companies having to pay the same rate that they charged. This would also encourage all consumers to reduce their peak demands and even out the load peaks.

    The bulk rates that the companies pay is less than the power that they take back is worth to them because of local line losses. However the retail price is too high, as there are costs involved in administering any purchasing of the surplus power. A fair price is somewhere between the bulk rate and the retail price.

    Personally I don’t see this type of system being cost-effective. Where I do see a niche for solar power is for sites that already have battery backup and a relatively constant load – telephone exchanges, cell phone sites, data processing systems with their UPSs (Uninterruptable Power Supplies), and radio transmitter repeater sites. (Hospitals?) These niche applications don’t have the large variations in their own loads that lead to periods of excess generation, and also don’t need to convert and synchronise the DC power generated by the solar panels into AC power for the grid, as they are already set up to use DC power. (With more battery storage, they could also reduce their grid power usage at peak demand times, but that is another story.)

    Trevor.

  20. Trevor

    The problem is a lot of invertors converting DC back to AC don’t generate anything like a sinewave but a series of chopped up square vwaveforms. These normally need capacitance or a transformer to smooth them out. Good inverters are expensive. If the householder feeds back a noisy signal, it can affect all the households nearby. There is generally no problem if only one or two people do it. The big issue is if everyone wants it. The most common failure seen nowadays in industrial plant is bearings in motors prematurely failing from arc pitting caused by the chopped signals fronm VSDs which are only back to back inverters. I believe it also can stuff up electronics and microprocessors, but that is getting way outside my knowledge.

    Your are right on SLER acronym – called SW(ire)ER in places like Australia. It is still very common in rural NZ. Just looking while driving around, I would say there is still thousands of kilometres of lines, but I don’t think it would be a very high % of domestic / agricultural load. It is still common in 10 acre block territory. That is often where people see the potential to install wind turbines or solar generators because they don’t have near neighbours who would object. And they have to pay a lot more for their power.
    They allow it in Australia under strict rules.
    http://www.ergon.com.au/contractors,-suppliers–and–developers/electrical-contractors/solar-pv-system-connections/connection-essentials?SQ_DESIGN_NAME=print

  21. ChrisM – why would there be harmonic issues if consumers fed power back into the distribution system?

    And I am guessing that SLER stands for Single Line Earth Return, but not working for a lines company, I don’t know. Why would that cause any issues, and how widespread is SLER anyway?

    Trevor.

  22. dbuckley – I am not sure that you have interpreted the inverter ban quite rightly, or if you have, why you consider it to be an issue. The ban affects inverters that have a lead and plug, allowing them to be plugged into a power outlet socket. It does not apply to traditional inverters which are used to supply power to equipment that is not connected to the grid, such as an inverter with an output socket.

    Or you could just choose appliances that will run off low voltage DC. 12 Volt LED lighting anyone?

    Trevor.

  23. DB
    It isn’t only frequency control that is needed.
    Most distribution transformers are designed to take power from the grid to the consumer with no voltage control. That means the voltage out of them depends on load and distance. It can go from 230 to 250V, though in some areas it is a lot worse. If you get people generating at home, the voltages could go up to 260-270V on a bright sunny weekday. Then appliances won’t last long.
    They also need two meters (inwards and outwards). There would need to be good protection system for the outgoing power so it couldn’t back-liven the lines. This would bump up the price of your system significantly.

  24. ChrisM raises some excellent points wrt infrastructure changes required to support surplus power redistribution.

    I’m not sure that forcing powercos to buy back surplus is sensible; after all, we dont compel wholesale consumption from distributed suppliers in any other industry at a set price.

    Better to treat PV and other local energy sources as an option for personal resilience – bearing in mind the capacitance / storage / peak load constriants – than present it as a false solution for network resilience.

  25. Rooftop solar would be uneconomic for most households if we were not being grossly overcharged for grid power.

    Yes, but the overcharging is not going to change, is it. Even if the Labour / Greens thing comes to fruition, we’ll still pay a huge proportion of our hopusehold incomes on electricity.

    What micro solar can give you is less electricity consumed from the grid, so less of that overpriced juice to pay for.

    Plus: it feels good to say “my house runs on sunlight – see”

  26. Better to concentrate on energy savings such as solar direct water heating…

    Those days are on the cusp of being behind us.

    Time was when direct hot water heating was a very sensible thing to do, but the costs of direct hot water heating have remained constant, whereas PV prices continue to fall, so the sums are now you’ll get better value connecting PVs to the hot water heating element. And thats before you factor in the costs of a new tank which is a very sensible thing to do for direct heat.

    PV for hot water doesn’t need inverters either, just connect panels to element. Obviously, there is a match to be made in terms of numbers of panels and how to connect the panels together, but the economics of it mean that this will very soon start to be a common installation.

    The wriggles aren’t completely out of it yet, but now would be a bad time to buy solar hot water without considerable thought.

  27. Feeding the grid with household generation is an issue that needs to be addressed so good to see Gareth dong it.

    As for think big projects, many are hugely environmentally destructive. There is so much potantial for small scale power generation, such as Gareth is promoting; catching on can’t come soon enough.

  28. Rooftop solar would be uneconomic for most households if we were not being grossly overcharged for grid power.
    Overcharging both as stealth taxation and to make the privatised power companies look more efficient than they are.

  29. Small, household scale, distributed generation is inherently less sustainable and resource efficient than larger scale power generation, even allowing for reticulation losses.

    Simple engineering sums about scale effects would show you that.

    For example, everything from a dam to a windmill gets more efficient with larger size.

    Better to concentrate on energy savings such as solar direct water heating, home insulation and energy efficient buildings, along with building efficient sustainable generation such as wind, tide, geothermal, solar and hydro, on the national grid.

  30. This bill fails in many ways, in particular, ideologically, and technically, and its also a fair few years out of date.

    It is true, the price of PV is coming down significantly, and continuing to come down, and it is true that Kiwis should be able to benefit from PV to reduce their electricity costs.

    The first part of Gareth’s goal is laudable:

    I talked about the need to establish a fair regime that will help families to reduce the cost of their power bills

    But his bill isn’t about that; its about enabling people with significant spare capital to generate an income stream from distributed generation. This isn’t democratising power, or reducing power bills for us all; this is enabling a sector of society to profit from “small scale” generation, which simple economics tells us can only occur as a cost to the rest of us.

    If Gareth really wants to reduce people’s power bills, heres what needs to be done.

    Firstly, there is no payback for surplus energy generated. You can use your own PV system to reduce your electricity bill, but you are not being paid to be a generator and exporter. If you want to be a power provider, then you can do that today. No normal person’s house needs a 10KW array. And if PV costs fell to the point where everyone could afford a 10KW PV system, under current arrangements (ugh! pun!) the grid would be wrecked through instability.

    So, having taken the profit element out of it, now we can concentrate on technology.

    So secondly, limit the output of a domestic small scale system to 2KW. That is a reasonable size for a household system, and that limit has advantages that will become clear as we proceed. It also means that if there was wide scale deplyment, the impact on the grid would be reduced. People with a lot of money can still build a big system and export (at some price) if they wish, but that isn’t most of us.

    Although panels are coming down in price, a “full” PV system is still a significant investment. I want a familiy to be able to get into solar (legally!) for $1,000. The technology to do this exists, but it is currently banned in New Zealand.

    Thirdly, mandate changes to AS/NZS 4777.2 to require that intertied inverters between 52Hz and 53Hz (or perhaps 51Hz and 52Hz?) linearly reduce their output to zero. This will limit the instability contribution from solar systems.

    The technology I would promote is that of “micro” solar generation, perhaps better known as “guerilla solar”, but guerilla done right. Essentially, each panel has its own tiny inverter on the back.

    “Traditional” guerilla solar is banned in New Zealand by the Inverters prohibition – 12 January 2012. This is a badly crafted regulation, banning an entire category of device because of an edge condition in large installations.

    It should be redrafted to specifically allow a micro solar installation up to 2KW to be connected by means of a dedicated connector, RCD/MCB and wiring. This connector would have to be provided by a person competent to do such things, as this is Prescribed Electrical Work.

    Furthermore, the allowed systems should be those that require no wiring involving tools like wire cutters and screwdrivers and terminations, the systems should just clip together using connectors. It has to be safe for Jo Householder with no electrical experience beyond plugging in his telly to assemble.

    This isn’t a dream, all the technology exists today and is commercially available, at the prices I suggest. An example of a suitable micro inverter is the Micro RePlus from ReneSola, which is available in New Zealand, and today complies with all the required standards, and so should be able to be made to comply with 4777.2 when it comes into force.

    So, $500 (generous) for an electrician to install a connection point, and $500 for your first panel and inverter, and you’re reducing your electricity bills by 250W in full sunlight. Add additional panels and inverter at $500 a pop.

    Assuming just 3 hours of full output a day, payback for a system of three panels ($2,000 install) is a dozen years, on a system that should run for 20 plus years, assuming power prices remain static, which they wont. And this system can be started for as little as $1,000.

    Now that is democratising power for the people.

  31. Trevor
    Only some truth? What have I said that was wrong? The problems with large scale solar can be simplified to three issues: technical, social cost, safety.
    The distribution system is designed for power to go from the grid out to the consumers. Reverse that and there are harmonic & voltage control issues. Needs expensive transformers and control systems to correct. Then there is all the SLER which is still very common in rural areas.
    The overseas experience is that wealthy people put in the alternative generation, attracted by the generous subsidies (the distributer having to buy power at the same price as they sell it is a major cost) This is paid for by the poorer consumer and is a major cause of the energy poverty afflicting Europe.
    Backlivening of the distribution network kills quite a few linesmen each year in Oz and US. More distributed generation will increase that deathrate.

  32. There needs to be big, high inertia generators on the grid with specialised transformers and heavy duty transmission lines just to copy with the normal variations in supply and demand, or means to synthesise system inertia. Essentially the requirement is for short and medium term energy reserves or storage, and system control. Intermittent renewables adds to these requirements but they have always been there.

    Rather than trying to absorb generation spikes from sudden wind gusts etc using inertia, an alternative is to have controllable load that can be switched in and out as required to maintain the correct system frequency. Storage systems can also be used, but they tend to be pretty expensive for their power or energy ratings. New Zealand is lucky in that we already have a lot of hydro generation which is a form of storage, although most of it is concentrated away from the highest demand centers.

    The challenge ahead is to find new cost-effective ways of allowing a diverse range of new renewable generation technologies to contribute to our electricity system without causing system instability or increased risk of system failures.

    Trevor.

  33. Forcing power companies to buy power at prices HIGHER than what they pay for wind power, hydro, and geothermal, will do what to power prices?

  34. There is some truth in ChrisM’s comments.

    During most of our peak demand periods (cold winter days and mornings and evenings), the output of solar systems is low to zero, so solar systems contribute nothing to resilience then. However solar power could help meet sunny summer afternoon peaks.

    Given the large swings in both demand and the supply from wind farms, the swings in supply from solar power are negligible at the scales currently foreseen. Having diversity in the generation mix is desirable, so the renewable energy generators are not all ramping up and down together. Solar power can help, particularly if it is distributed over a wide range rather than concentrated in a few small areas.

    Gareth has pointed out that the costs of the solar panels have fallen, but this means that the other costs involved in installing a solar power system become more significant, including consent costs, frames to mount the panels on and the control systems. In the land of the long white cloud, I doubt that solar power generation can be justified except in a few niche cases.

    Trevor.

  35. This has got to be one of the silliest schemes that you have promoted yet, which is a major achievement in itself.
    Generators get paid about 7c a unit for generating reliable power that has to meet strict quality requirements. They also get penalised if they don’t comply. Wind gets subsidised by not having to make many of the specifications.
    Why would power companies want to buy anyone’s surpluses at inflated prices, especially when it is unreliable and most of the time in offpeak hours? The people with solar need the grid to supply them with frequency and voltage stability. That costs money, especially if there is a lot of solar generation. All these small schemes don’t make the grid more resilient, it actually makes it more unstable. There needs to be big, high inertia generators on the grid with specialised transformers and heavy duty transmission lines just to copy with the spikes that solar or wind cause.
    If households are totally offgrid, there needs to be very expensive storage and control systems, even for very limited capability. Just by being on the grid, they have other consumers subsidising them.
    If you don’t understand all that, you shouldn’t be the energy spokesman.

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