Australian bushfires may accelerate push to solar + storage for homes

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The latest bushfire season in Australia has highlighted the risks associated with Australia’s elongated grid: Not only are the wooden poles and wires that connect homes and communities to centralised power stations vulnerable to fire, wind and storms, they are also responsible for causing much of the damage when uninsulated wires are blown over on high risk days and create devastating fires.

The experience in Western Australia and Tasmania in recent weeks has highlighted how vulnerable centralised power systems are to bushfires, although the impacts this year pale into comparison with the devastating impacts of the Black Saturday fires in Victoria in 2009.

power line burnAuthorities are responding with proposals to put some power lines underground, and provide insulation for others. But a new study suggests that they are overlooking a much cheaper option – installing solar and battery storage in at risk areas can virtually eliminate the risk at just one tenth of the price.

As authorities are learning in W.A., Queensland and elsewhere, distributed generation and micro-grids can undercut the costs of an expansive grid and centralised generation by a large margin, and offer both energy and personal security.

The study by Michael Williamson, a master of science student at the University of Loughborough, underlines why the combination of solar and storage should be looked at in terms of value, rather than just cost. Already networks are finding that installing battery storage can cut grid costs by one third – but this study shows how much battery storage and localised generation can save when the grid needs a major upgrade.

The Williamson study looks specifically at the experience of the devastating Black Saturday bushfires in Victoria in 2009, which caused the loss of 173 lives and $5.2 billion in economic damage, and the follow-up recommendations.

Investigations into that fire suggested 92 per cent of the losses were caused by vegetation igniting from uninsulated power lines being blown into trees or on to the ground.

Combined with the Ash Wednesday fires of 1983, Williamson estimates that more than $5.5 billion of damage, and 190 deaths, can be directly blamed on falling power lines in a single generation in a single state.

Williamson has crunched the numbers of the various alternatives considered and put into place by Victorian authorities, including putting lines underground, installing Rapid Earth Fault Current Limiting (REFCL) devices on some lines and Auto Circuit Reclosers (ACRs) on others.

solar storage fire risk

The Victorian authorities also considered putting whole communities off grid, with solar and storage, or of cutting off power on high risk days. But these options were dismissed – because of the estimated cost of going totally off-grid, and because cutting off power because rural homes need power for the internet and other essential services in cases of emergency.

Williamson proposes a compromise solution, by installing enough solar and storage to allow rural homes to be cut off from the grid and have enough power only during days of high bush fire risk and total fire bans – which amounts to as much as 25 days in a year or 4 to 5 days in a row.

This means that homeowners get power, and the grid is not made completely redundant, and there are additional private and public benefits from having more solar and storage on the grid.

And because less solar and less storage is needed than being totally off grid, it is much cheaper – around $23,000 per rural home compared to the $60,000 estimated in 2011.

Based on a comparison with powerline undergrounding, the report concludes that solar PV and storage could achieve the same risk reduction as undergrounding at just 10 per cent of the “net present cost.” And it says this approach is transferable to other fire-prone regions such as New South Wales, South Australia, Western Australia and Southern California.

Not only have solar and storage costs come down a lot, but for Williamson’s solution, they can also be tailored to need.

Rather being designed to operate for 365 days a year, including in winter, these arrays would only need to be sized for the 10-25 days a year considered extreme fire risk – or total fire bans – which usually coincides with hot summer days and good sunshine. In recent years, this has been for up to five consecutive days.

Williamson’s proposal is that on high risk fire days, the power lines are shut off, and the rural homes at the end of the line depend on solar and storage. The proposal takes advantage of good sunshine, the high sunk costs of the grid – which can be used for the remainder of their operating life – and the private and public benefits of having solar and storage on the network.

Williamson’s modeling is based on the needs of a two-person household, which he estimates at 4.6kW of rooftop solar and 14kWh of lithium-ion storage (two 7kWh units).

His calculations do not include the economies and efficiencies that could be gained from carefully managing demand during the period, or the potential for future falls in battery storage costs (which many think will be at least 50 per cent in coming years).

“The ACR offers risk reduction of approximately 50 per cent but the addition of PV and storage reduces this residual risk to practically zero, while offsetting the drawback of time off supply. And it can be done at one tenth of the net present cost of conduction insulation or under grounding,” the report says.

“The analysis demonstrates that the use of solar PV and energy storage is an economically and technically feasible means of preventing power-line initiated bushfires in Victoria.”

Williamson’s findings are significant when considering the scale of the task facing Victoria, and the increased fire risk from climate change in Victoria and many other regions.

The government has so far allocated $A200 million for the powerline replacement fund over 10 years, which will fund the replacement of about 1,000km of single wire earth return (SWER) lines, the ones considered most vulnerable.

But in all, there are a total of 28,000kms of SWER lines in the state, including 12,000km of uninsulated power lines that authorities consider to be “priority targets.” There are a further 50,000 km of multi-wire 22kV lines in rural areas of Victoria, that will need insulation or under grounding to remove risk.

Williamson says this leaves a substantial amount of infrastructure which needs to be made safe, at a cost of many billions of dollars But his approach is transferable to other fire-prone regions such as New South Wales, South Australia and Southern California.

Interestingly, the WA grid operator Western Power is considering the use of solar and storage micro-grids as a cheaper option to repairing and upgrading power lines damaged in the recent fires in the south-west of the state.

And in Tasmania, the vulnerability of the grid to bushfire risk to power lines has been highlighted by instances in that state which have put four hydro-electric plants off line at various times, adding to the problems being created by record-low storage levels caused by the drought, and the so far unexplained loss of the under-sea grid connection to the mainland.

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  • David Osmond

    An awesome idea to consider turbine off power lines and going off-grid only during days of extreme fire danger. Best of both worlds to be mostly self-sufficient, but still have grid back-up for most of the year, particularly during winter.

    Here’s hoping that the authorities and network companies fully consider this great suggestion.

    • john

      The problem is that to rebuild a transmission line is more expensive that putting in RE and backup storage, then use distributed energy.
      The crunch figures are how much does it cost to rebuild against a distributed energy supply and storage.
      I recently; well actually 8 years past; a cost to supply power to a remote installation it would have been over $300k to put in the supply against going off line with PV and battery as well as back up Gen set.
      Needless to say the bloke is very happy with my suggested solution.
      As to how this will play out who knows.
      1 Yes it is very good to have the grid because it is reliable.
      2 If the grid fails not good and your in trouble.
      3 If the cost is more than putting in place distributed energy supply we have a problem.
      I do not think there is a 4.
      Tell me have I missed anything here?

      • hydrophilia

        Yes, if the grid needs to be constructed, going entirely off-grid is often better.

        However, a lot of the grid destruction & associated cost in 2009 was caused by much of the grid being uninsulated and powered and unprotected during the dangerous conditions. If, as the article points out, we can turn the power off in those conditions, the destruction will not occur and the grid can survive (cheaply) to provide important services the other 95% of the time.

        Very nice!

      • Alastair Leith

        it’s not just replacement of burnt lines they are considering, surely? If they are considering cost benefit of insulating or burying lines they’d have to consider any power lines assessed as being at risk in summer on high wind days, not just those where lightning has already struck, so to speak.

        also if PV and storage keeps the network maintenance cost down and the voltage levels more within limits then all the better. I’ve heard reports from PV installers install medium sized systems at dairies of voltage on remote power lines fluctuating way outside the legislated limits when a bunch of dairies on the same line switch their pumps off.

  • stephen

    The $200 million or so in State funding is also matched by some $500 million investments from the network companies. This is ultimately paid for by Victorian power consumers through network tariff increases approved by the regulator.

    This is a great piece of research examining lower cost solutions to reducing the risk of bushfires. Installing distributed generation also creates a lot of co-benefits that people reading this site will be familiar with. The business case for the power line safety program should be revisited to include this approach so that the money can go further in terms of reducing the risks, and so that the investment creates the most additional benefits.

  • humanitarian solar

    Installing solar/wind/inverter/storage in vulnerable properties and communities, is beneficial for all of us by developing much needed pilot studies, and finding the most effective solutions. The process of building and documenting the new paradigm is as important as the installs. Great article in terms of the knowledge being transferable from state to state. Great research.

  • humanitarian solar

    I don’t think people would need 4.6kW of solar and 14kW of storage to get started with a hybrid solar system with grid backup. e.g. If we look at a Peak Sun Hour (PSH) map of Australia, allot of Victoria gets 6.5PSH in summer (when the bush fires happen). PSH is how many hours on average the solar panels are going to produce their rated output. If we work with the figure Williamson suggested of 4.6kW of solar panels, 4.6kW x 6.5PSH = 29.9kWhours of electricity a day those solar panels will produce – without taking into account system loses. That’s allot of electricity. It seems reasonable a rural property would use more electricity than a suburban or metropolitan one with town water. However isn’t the idea this is power for critical system backup, like pumping water, refrigeration and communications. A 29.9kWhour/day electricity bill is a large not so energy efficient house. Therefore, for critical system backup and an energy efficient household, a hybrid solar system could be done for allot less than $23k. I’m getting started with a system a third of that cost, as I’m investing in the properties evolution into renewable energy, and that includes all of us learning how to adapt and integrate the new technology into our lives and the properties infrastructure, like buildings and irrigation. With rural/remote installs, I think there needs to be two smaller inverter/chargers in parallel rather than one big one, or if a big one is used, I think there needs to be some provision of critical system backup with a few DC appliances run directly off the batteries. Even though inverters are allot more reliable than a grid, the last thing people want is a failure during an emergency. This is why I think we need pilot studies of new solar/storage systems and that applied research being available for others. It’s building our momentum as a country.

    • UKGary

      I very much agree – the project should include energy efficiency such as LED lights, and inverter controlled air con units first to reduce the load at each rural home, then the PV and storage can be significantly reduced. (Changing the light bulbs is a minimal cost compared to adding an extra solar panel + an extra kWh of battery.)

      During an emergency, it would be reasonable to limit air conditioning to perhaps one or two rooms at any one time, and perhaps switch it off entirely from bedtime to sunrise. Likewise, laundry can probably be largely deferred until the grid comes back up.

      I would tend to scale back the storage far more than the solar arrays as once you are installing solar anyway, the marginal cost of each extra panel is relatively low. That way, electricity would be quite pleantiful in the daylight hours if a little limited at night, and if any laundry or other discressionary electricity actions needs to be done, the ideal time would be in the afternoon when the battery is full and the sun is still shining.

  • humanitarian solar

    If I were on a remote property, I would want a hybrid inverter/charger with the capability of being able to manage 2x external AC inputs. One input would go to the grid. The other input would go to a generator of some kind.
    When the inverter/charger manages the grid connection, it is going to be programmed to maximise self use of the solar panels first before accessing the grid.
    When the inverter/charger manages the generator, it is going to start the generator at a preset level of battery discharge and when the generator is running, the inverter/charger is often going to supply the load first, then any left over power is going to top up the battery bank. This is far more efficient than running a generator to supply a load directly, as the load may not always be matched to the generators output waisting fuel and being noisy. So to be most efficient, the generator is controlled by the inverter/charger, hence the generator is going to be one producing AC that is going to be wired into the external AC input for the inverter/charger. There are generators that can supply DC and have a few DC outputs on them, though my understanding is these are for city people who are going camping and only supply small amounts of DC. Though this is the field of an electrician I think, especially one working as a solar installer.

  • humanitarian solar

    After a wave of early adopters with grid-connect, we have begun thinking about batteries, as we know their price coming down, is the biggest factor determining the adoption of a distributed paradigm. However thinking of batteries first, before thinking about the inverter/charger, is a fundamentally incorrect way to think about an install. It’s like trying to pull the cart before the horse. The inverter/charger is the brains of the solar system and determines the level of functionality on the property that can be controlled, and therefore, it needs to be planned first. The inverter/charger is a computer, that runs a power control system.

  • humanitarian solar

    Imagine how important the inverter/chargers are for higher level installs, like light houses, hospitals, industry and communities. Due to the level of scale, these inverter/chargers are going to need to control multiple power sources like PV, a wind turbine and a diesel generator. A City Council or a Hospital needs to decide what level of functionality it needs first before planning the batteries. Only after the number of power sources are determined, can the inverter/chargers be determined and then the battery bank can be sized.
    To my understanding, an increased functionality inverter/charger can not simply be easily added later, as the inverter/chargers on the same battery bank need to be the same, either run in parallel to increase the peak output power on small installs, or run three inverter/chargers in a three phase configuration for larger installs. It is the sizing of the inverter/chargers as a complete set, that determines the overall output power of the hospital, factory etc.
    eg. 2x 7.5kW inverter/chargers in series = 15kW and then three sets of these would be needed for three phase power, giving 45kW of output power.

  • adam

    do a trial.

  • humanitarian solar

    EQUIPMENT DIAGRAMS,-back-up-and-island-systems-EN_web.pdf
    Here’s a link to equipment diagrams of a large dairy farm, 2x beach resort apartments and other equipment diagrams of anything needed. The inverter/charger is always central. There’s also a pic of the base camp of mount everest.

  • humanitarian solar

    More EQUIPMENT DIAGRAMS for rural/remote lighthouse, hospital, portable applications, traditional dwelling in sahara,-back-up-and-island-systems_ES.pdf

  • humanitarian solar

    Enphase is releasing their modular, plug and play Lithium battery soon. So it comes in different sizes. I found it on Springers, one of the longest solar installers in Bris who say it has an interface for “All micro inverters and string inverters”

  • MaxG

    So… given the network caused (a lot of) these fires; why are they not paying the damages? Oops… silly me: privatise profits, publicise cost…