Slash Australians’ power bills by beheading a duck at night | RenewEconomy

Slash Australians’ power bills by beheading a duck at night

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Solar has slashed demand for electricity during the day, but left evening peak power demand largely unchanged. That’s why we now need to behead a duck.

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The Conversation

 

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Rooftop solar power has slashed Australians’ demand for electricity during the day, but left evening peak power demand largely unchanged. That’s why, as strange as it may sound, we now need to behead a duck. With a mix of individual household, power company and government action, we could significantly reduce our demand for the most expensive peak-power that requires massive, wasteful infrastructure spending. In doing so, we’d be tackling one of the biggest, most unfair, hidden charges built in Australians’ power bills: we could reduce the A$350 a year that households without air conditioners are being slugged to subsidise the bills of households running air conditioning at peak times. And Australia’s 1 million-plus solar homes can play an important role in reducing that hidden air conditioning subsidy, while also defusing the argument that solar homes aren’t paying their share of electricity costs.

Solar homes powering big changes

The replacement of substantial daytime electricity consumption by PV panels on more than 1.2 million installed solar systems across Australia has visibly changed the way we draw power from the electricity grid. The new-look daily trend in Australians’ power use has been nicknamed “the duck”: the green line on the graph below, from a recent Energy Networks Association publication The Road to Fairer Prices, shows why!

How demand for power over the day has changed dramatically in recent years linked with the rise of solar PV panels. There is now a steep drop in demand during the day but little has changed to the evening peak, sparking this call to “behead the duck”. Energy Networks Association, 2014, CC BY

However, Australia’s power duck is not as benign as Michael Leunig’s well-loved ducks. It drives large amounts of investment in electricity supply infrastructure – and that costs everyone connected up to a power pole more money. So what can we do to avoid wasteful electricity spending to cut down on all our power bills?

Real solar and air conditioning costs

Many now argue that, while solar PV hits daytime electricity sales and revenue, it does little or nothing to reduce this evening peak, as shown in the Energy Networks Association (ENA) graph above. This peak now drives electricity supply infrastructure costs, which comprise around half of our electricity bills. Indeed, the ENA – the national body representing electricity transmission and distribution businesses throughout Australia – has recently suggested that a power consumer without solar PV panels now pays about A$60 a year more to subsidise homes with solar PV panels, due to “under-recovery of network costs” during summer evening peak periods.

The rapid rise of small-scale solar PV installations across Australia. Data from the Clean Energy Regulator, small scale installations summary data , CC BY

The rapid rise of home air conditioners is driving up the cost of power for all Australians. By 2020, experts warn that electricity use for air conditioning looks set to be five times greater than in 1990. Productivity Commission 2013, Electricity Network Regulatory Frameworks, CC BY

Even so, that A$60 a year cost is much smaller than the subsidy to users of air conditioners. The Productivity Commission estimates that the installation of each air conditioner adds A$2500 to the capital cost of powerlines and power stations: costs that all power consumers have to cover. Much of that extra equipment is used for only a few hours each year, mainly on hot summer evenings. However, there are ways we can reduce those big costs by cutting demand in the evening peak.

An expensive night in at home

This graph below, from the Productivity Commission’s 2013 report on electricity networks, shows power use from a sample of 3000 Sydney homes. As you can see, the maximum demand for household power in the evening can be up to 5 kilowatts, or almost double the average demand on evenings for most of the year.

Productivity Commission, Inquiry Report, Volume 2, Electricity Network Regulatory Frameworks, p.348, CC BY

If we look at the difference between the average and peak day, and presume that all of this peak difference is due to air conditioning load, what do we find? It seems peak demand is around 2.4 kilowatts higher between 7pm and 10pm. It would be interesting to audit this sample of homes. Do they have large numbers of halogen lights? How many had several inefficient plasma TVs and multiple desktop computers? How energy efficient are the buildings themselves? And what kinds of air conditioners do they have?

The efficiency of your air conditioner, combined with other factors like the colour of your roof and how draughty the house is, can make a huge difference to your bills. If most of the homes in the Sydney sample shown above have pre-2010 ducted cooling systems with poorly insulated ducts inside black tile roofs, they may be very inefficient: possibly using two to four times as much power as the best technology.

How to keep your cool without air con

One of the most common and costly mistakes people make with their electricity use is to only consider how to keep their home cool – and not to think about why it might be getting so hot in the first place. Key factors to consider:

  • Is heat from the western sun getting into the building in the late afternoon and early evening?

How much are you heating up your home without even realising it? Denis Barbulat/Shutterstock
  • Does your home have shading or heat-rejecting window films, insulation and draught proofing?

Not having those features can allow four times as much heat to enter the house as for a well-designed building – up to 20 kilowatts, equivalent to running 10 plug-in fan heaters on high setting at the hottest time of the day. And every three square metres of extra unshaded window exposed to sun adds the equivalent of another fan heater.

Hot stuff: halogen lamps. Julio Embun/Shutterstock
  • How many appliances and other heat-generating equipment are you using while trying to stay cool?

For example, running 30 halogen lamps can add 1.5 kilowatts of heat, and the radiant heat they give off can make you feel hotter, so that you turn up the air con. Two older plasma TVs can easily add another 600 watts of heat. Cooking can add a couple of kilowatts; even more through wasteful habits such as not putting lids on pots. The range hood fan does remove some cooking heat, but also drags large amounts of hot outdoor air into the house, equivalent to a cooling load of around 2 to 3 kilowatts on a very hot day. And so on.

If we tackled those and other areas of wasteful energy use in inefficient air conditioned Australian homes, I’m confident that we could avoid at least A$250 a year in hidden subsidies for each of those houses. And we could save even more if we targeted high peak-demand homes in areas where network infrastructure is already under pressure.

But what about homeowners with solar panels: how could they help cut down on power bills? We should be encouraging new and existing homes with solar panels to add some battery storage, as well as improving their energy efficiency in some of the ways outlined above. If we did, it would increase the amount of time when solar homes were still using their own power, also helping to cut expensive peak demand. As an example of the potential for change, the graph below presents results from a UK study in which a range of energy efficiency and demand management strategies was used to cut their peak demand times.

Tackling peak evening demand with energy efficiency. The 40 per cent House Project, Heriot Watt University, Edinburgh, 2004, CC BY

The single biggest period of demand for power in the UK happens in the late afternoon and early evening. When the study authors added extra plasma TVs into the mix (scenario 1, the top line), power demand climbed even further. So they showed how it was possible to reduce that demand with a mix of better appliances, LED lighting and low-energy refrigeration (scenario 6, shown with the red line). Combine low-energy appliances with more efficient LCD TVs, rather than plasma TVs, and the demand fell sharply (shown with scenario 8, the bottom line).

Cutting Australians’ cost of living

Energy efficiency is not a topic that grabs many news headlines. Yet report after report shows how under-rated it is as a way to save billions of dollars in Australia and hundreds of billions of dollars globally.

California has kept its electricity consumption relatively flat even as it’s soared across the US. US Energy Information Administration, CC BY

But we need the electricity industry and governments to do more to help individual households, as has happened in places like California. Significantly, if we take the steps I’ve outlined we could cut household power bills far more than by adopting a more simplistic approach of winding back Australia’s Renewable Energy Target, which is currently under review amid speculation of major changes on the way. Instead, we could behead Australia’s most expensive duck – and end up with a tasty meal for all of us. The Conversation

 

 

Source: The Conversation. Reproduced with permission.

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13 Comments
  1. juxx0r 6 years ago

    http://pv-map.apvi.org.au doesn’t seem to agree with the premise of this article. Our peak consumption is in summer during the middle of the day. Therefore solar reduces our apparent demand and reduces the cost and flattens the curve.

    Yes we have a modest duck in winter, but it’s less than summer peaks, so it’s not adding to infrastructure costs. This also means that solar is not adding to winter peaks since they occur after dark and therefore can’t be adding to the costs.

  2. RobS 6 years ago

    I think now is a bad time to encourage homeowners to install battery storage, the reality is the cost us just too high. Let the tech heads, hardcore environmentalists and early adopters for whom cost is not much of an issue install them and do the heavy lifting in terms of encouraging R&D and economies of scale then they will be ready for larger scale adoption in 3-4 years. If we push too hard now and people install them and get burnt on cost the bad press may set back storage adoption a decade or more.

    I absolutely agree on the efficiency though, people look at LEDs on whether the lighting efficiency savings justify them, what they are largely unaware of is that a home full of LEDs on a summer night is like running a 2kw radiator heater whilst trying to air condition the place. You cut 1-2kw of lighting energy use AND 1-2kw of additional cooling power required to fight against a dealing full of little bar heaters. I can’t find a reference now but I read about a Gold Coast resort who swapped out incandescent ceiling ignite throughout their resort for LEDs with supposedly a ~2 year payback and then were astounded when their cooling power upas age dropped by 30-40kw and the resort was more comfortably cool despite the lower cooling energy use, paid for themselves in less than 9 months once that got factored in. Slightly less benefit in cool climates because they do help heat the place, however as radiators at roof level they do it far less efficiently than custom built efficient heaters like heat pumps.

    • Matthew Wright 6 years ago

      RobS,

      You’ve got to be kidding. You don’t know what you’re talking about. A home full of LED downlights producing 2000watts (2kW) would be 286 lights @ 7 Watts each There aren’t too many houses with 286 lights.

      I think you’d find that an LED lit house will use 50-250Watts in an evening. Which is pretty low.

      Time to get some fact checking going – perhaps get some solar quotes while you’re at it.

      • RobS 6 years ago

        I meant a home full of halogen down lights considering I then go on to talk about retrofitting them WITH LEDs, purely a slip of the finger nothing more.
        Considering I have both LED retrofitted down lights and a solar array on my roof the condescending remarks are unnecessary, I never commented on the cost of solar, certainly unjustified to say I should get some quotes as though I was saying it was expensive. I said battery storage was too expensive AT THIS STAGE to justify on cost alone and I absolutely stand by that statement. Basically you’ve massively misunderstood and become fairly condescending over a typo.

      • wideEyedPupil 6 years ago

        Pretty obvious RobS was talking about 1-2kW of halogen given his multiple references to heat generated and retrofitting LEDs as replacements, did you miss out on your boxing session at the gym today, Matthew?

  3. michael 6 years ago

    Demand side management deserves a lot more air time, however it is not as satisfying for the crowd as targetting the big bad fossil fuel companies unfortunately

    • RobS 6 years ago

      Absolutely agree, we’ve certainly seen the benefits personally through low tech demand side management and can see the potential. We recently had our solar FiT dropped substantially, as a result feeding excess power into the grid nets us 8c/Kwh, whereas self consuming that same Kwh renders it worth 28c/Kwh, our retail tariff. Therefore we have simply changed to running our washing machine and dishwashers during the day using their built in timer functions, we run our heating and cooling more aggressively during the day to precool or preheat the house then use the timer thermostat function to wind it back in the late afternoon and my partner who comes home for lunch three days a week does the ironing etc at lunch time rather than in the morning or evening. By doing so our daytime self solar consumption is significantly increased increasing the financial benefit to us.

  4. Chris Fraser 6 years ago

    Although i can’t see gradings on the vertical axis, of Graph 1 (so i don’t know the fraction of energy supplied by solar), i’ve just got to love the green line on ‘the duck’. It looks as though the incipient demand for energy from the Big 3 Retailers gets a bad case of ‘duck’s disease’ around about 12pm !

  5. Simon_Strauss 6 years ago

    One of the simplest ways we could reduce the load would be to extend daylight saving by shifting the clock forwards by two hours from Brisbane down.

    • John Silvester 6 years ago

      A very interesting idea. I wonder if any research has been done on the effect of the current one hour daylight saving on summer peak demand.

  6. Askgerbil Now 6 years ago

    Its not clear from Figure 9.6 why the difference in peak demand for 3,000 homes is so much higher than their average demand. Figure 9.1 on page 336 in the Productivity Commission report confirms what the article suggests: the difference arises because of higher temperatures. Total Queensland demand on Wednesday 29 November 2006 (maximum temperature 36C) and Thursday 30 November 2006 (maximum temperature only 23C) shows virtually identical differences in hourly demand profiles.

    Modifying daylight saving periods won’t help because this is not a seasonal problem. It only occurs on a small number of hot days each year.

    The Productivity Commission report describes the problem at page 337 in volume 2:
    * around 20−30 per cent of the $60 billion of electricity network capacity in the NEM is used for less than 90 hours a year.
    * around 25 per cent of retail electricity bills in New South Wales reflect the cost of system capacity that is used for less than 40 hours a year (or under 1 per cent of time)

  7. Pedro 6 years ago

    Recently I was involved with a solar install using micro inverters. Had 3 panels facing north 12 west and 8 east. Gut feeling is that this is the best way to maximize self consumption, minimize export and teach the ‘duck’ a lesson. In about a years time it will be interesting to see the impact on the bill. However it would be good to have an economic model of this type of install so that we can make a strong case to the end user that facing panels east and west for houses normally empty during the day makes economic sense.

  8. Les Johnston 6 years ago

    Time of use metering has the potential to internalise costs associated with air conditioner use and influence air conditioner use. Although the issue is complex, the public is becoming better informed and more attune to making sound financial decisions. The market mechanism will facilitate this process provided leadership is permitted to change the status quo on energy pricing.

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