How much storage is needed in solar and wind powered grid? | RenewEconomy

How much storage is needed in solar and wind powered grid?

How much battery storage is needed for a grid relying on wind and solar for nearly all its electricity needs? Not as much as many think, and a CSIRO study says much of it will be provided by households installing battery storage to help reduce their bills.


The CSIRO and Australia’s electricity network owners this week released a study that showed the best to deliver reliability, bring down costs and lower emissions in Australia was through a national grid powered almost exclusively by wind and solar.

The cost savings over business-as-usual – a grid powered primarily by coal and gas – were significant, with consumer savings of between one-quarter and one-third of their bills.

csriro oz 2050But it does beg a question: If the grid is powered by “variable renewable energy” (or VRE), such as wind and solar (see graph above), what will happen when, as the detractors say, the wind don’t blow and the sun don’t shine? The answer, of course, is storage. But not nearly as much as the cynics suggest. And at not nearly the cost.

Australia will have a number of options for storage: battery storage located “behind the meter” (i.e. in households and businesses), battery storage located at grid level (next to wind and solar farms, and at various points in the network), plus hydro, pumped hydro, molten salt storage with solar towers, and other technologies such as fly-wheels.

Right now, however, it looks like the most prominent will be battery storage, if only because it will be the favoured technology of the anticipated 10 million homes and businesses that will combine rooftop solar and storage to reduce their bills, do their bit for clean energy, and to ensure energy security.

The CSIRO and Energy Networks Australia study was remarkable because it pointed out that – contrary to the political and ideological debate around wind and solar – these technologies can be relied upon to underpin the grid of the future and lower bills.

Over the past decade or two, the estimates for a “suitable amount” of variable renewable energy sources such wind and solar have jumped from as little as 10 per cent to nearly 100 per cent. This is despite the fact that some quarters are now pushing the idea that 30 per cent of total renewables is somehow the logical maximum.

CSIRO Energy chief economist Paul Graham says the 30 per cent estimate is clearly not true because South Australia has boasted more than that for several years. And until this year’s weather and network-related events, this has not been a problem.

“That estimate (of 30 per cent VRE capacity) does not seem to be grounded in reality,” Graham told RenewEconomy.

Graham says that additional storage is not needed for up to 40 to 50 per cent wind and solar penetration. That’s because the grid can rely on existing back-up ( built to meet peaks in demand and for when coal and gas “baseload” generators trip or need to be repaired).

Beyond those levels, storage needs to be part of the equation. But again, not as much as many would think. But as the back-up generators gradually exit the grid, they can be replaced by various storage types, until storage then becomes the principal form of back-up and grid security on the grid.

Graham says that the CSIRO modelling showed that at very high levels of wind and solar, a maximum of half a day’s average demand was needed for storage. In some areas of the grid, only around three hours might be needed.

This is an important point, because some renewable critics say that about a week’s worth of storage is needed, and multiples of wind and solar capacity required for back up. These would be the same people that argue that climate science is a hoax, but it is a view that has more traction than it should.

Graham says the CSIRO modelling indicated that at those very high levels, about 0.8GW of back-up was required for about every GW of wind and solar capacity. This is around the same amount of back up capacity currently needed by centralised power plants to meet peak demand and outages.

The good news in Australia’s renewable energy scenario is that the storage capacity will likely be paid for anyway by households and businesses reducing their dependence on grid load, and reducing their bills.

Screen Shot 2016-12-06 at 7.39.25 AMThe CSIRO and ENA study expects rooftop solar to rise five-fold between now and 2026 to reach 20GW, before nearly quadrupling again to  nearly 80GW by 2050.

Battery storage is forecast to reach 32GWh by 2026, and 87GWh by 2050. Much of this will be “behind the meter” and will need to be harnessed by networks to achieve grid security, meet demand and balance the output of renewables. Such trials are already underway in various states.

Graham says that battery storage costs are falling so quickly that the CSIRO team already had to upgrade its forecasts and bring forward recommended action by five years. While South Australia is already venturing into territory where storage is needed, other states will follow over the next decade and will need to be prepared.

“What you need to be able to do is to meet is average load. You don’t necessary need to size batteries to cover the capacity of everything that is built,” Graham says.

“We will be relying on dispatchable solutions for a while yet, because it is there and it is valuable to use it. As it slowly phases down, then we will replace it with battery storage.”

The CSIRO and the ENA’s report envisages a system where nearly all households stay on the grid, despite their storage capabilities, and are rewarded for helping out the network by providing some of those services – stability and responding to peak demand.

But those forecasts depend on Australia quickly developing a coherent energy policy, and updating its market rules and policies before the battery storage takes off in full flight. On either measure, however, it might be fighting against time.

“We don’t have time to lose another five years,” Graham says. “Otherwise we are going to be locked into a different system.” And that comes from another of the CSIRO scenarios, where policy fails but technology marches on, and millions of consumers respond by quitting the grid.

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  1. howardpatr 4 years ago

    And who knows what will emerge in the battery storage space?

    The RWRNJs who so dominate the LNP seem incapable of seeing past their noses but it might well be that storage technologies will emerge that can supersede home bases batteries and energy will be sold and bought with MW scale distributed storage facilities with block chain technology.

    Such technology would do a lot more to address third world poverty than Mad Monk Abbott’s coal.

    The following is a link to an interesting company working energy storage; like Redflow.

  2. Chris Drongers 4 years ago

    I wonder where the extra roofs are to accommodate 80 GW of ‘rooftop PV’? 80 GW of PV is about 4*10^8 m^2 of panels, or 40,000 ha of blue panels, say double that amount of roof space=8*10^8 m^2 of roof, at 100 m^2 per roof in Australia that is PV on 8 million household roofs, virtually every domestic roof in Australia fully kitted with none of the current 5 kW limit per dwelling. Even the backfeed on the distribution netwrok for that is mind boggling.

    “The CSIRO and ENA study expects rooftop solar to rise five-fold between now and 2026 to reach 20GW, before nearly quadrupling again to nearly 80GW by 2050.”

    Siting that amont of panels on roofs seems unlikely especially in in Qld, SA and WA which are getting close to 25% uptake on residential roofs already.

    • solarguy 4 years ago

      Well Chris, there is still 75% to go isn’t there, sure not all of that will be useable, but there are back yards to utilize.

    • Giles 4 years ago

      Bucketloads of space on commercial rooftops. and a lot of people with existing solar, 1kw to 2kW may want to double their capacity.

    • Mike Shackleton 4 years ago

      New products where the solar PV is either integrated into the roofing product are coming on the market, there are technologies being developed where you spray the solar panels on like a paint, making any surface that catches the sun capable of being a solar panel.

      And as Giles says there are huge commercial rooftop spaces, think of all those massive warehouses/distribution centres in places like Sydney’s West, outer Melbourne etc which are completely unused.

      Solar incentives available to residential properties should be extended to commercial properties. The added bonus is solar produced on a hot sunny day would definitely be used within the building itself as it coincides with peak demand for things like AC.

      • john 4 years ago

        The is in Qld only for large business over 100 mw per year now.

    • Lightfoot 4 years ago

      The existing network operator 5kW limit for single phase residential relates to the inverter, not the solar panels. A 5kW inverter can have up to 6.65kW of PV connected to it, which takes up around 42 m2 of roof space and does fit on the majority of houses.
      I want to know your reasoning for doubling the roof space requirements compared with the 40,000 hectares of PV panels?

      • Chris Drongers 4 years ago

        Doubling roof space requirements is a shorthand way of allowing for unusable roof space (too small for a panel, facing away from the sun, shaded by a gable or close to a rooftop air conditioner or satellite dish, etc)

    • trackdaze 4 years ago

      I flew into sydney the other week and was amazed how many rooftops didnt have solar. Residential and industrial.

  3. solarguy 4 years ago

    Over my 57yrs on this planet, I recall times of prolonged rain depressions over much of the NSW east coast and Victoria. Ring a bell anyone, I also recall at least one of them lasting about 10-14 days with flooding, well you know shit happens, doesn’t it, like PV not producing much and the wind being all but absent in the Hunter Valley, where I live, in that time.

    I would love to see this study, to find out if they have looked at times like this and how they would deal with it. I have a good idea how they could, but I’ll keep my cards close to my chest at this stage.

    • Mike Shackleton 4 years ago

      Head west to Western NSW, Northern Victoria and SA and you have arid areas that receive a lot of sun – so a lot of rain on the coast wouldn’t be an issue as much.

      If all the Snowy, Victorian and Tassie Hydro was converted to pumped storage (where technically feasible) you could run them at full tilt whenever required because you’d be confident you could top the storages up again in times of wind and sun.

      Tasmania hasn’t developed a credible wind power capacity yet and there are areas that catch wind so frequently utilisation/capacity factors would be through the roof.

      We need to take advantage of our geographic spread – our transmission network needs to be federalised and treated like the highways are.

      • Andrew Thaler 4 years ago

        can’t convert many of them to pump-hydro as the reservoirs are not sized for that kind of operation.
        I’m working on a brand-new startup to design and install small pump-hydro systems and get the costs down, and put these out along with my solar farms in suitable areas.

  4. Brian Bartlett 4 years ago

    We have got to start thinking about new ways of doing things instead of basing our calculations on yesterday and today’s criteria. When I was 8 months old we were using wood stoves and kerosene lamps however in 1958 humans were already using solar and battery storage to provide communications.

    Now we have had phenomenal advances in both energy generation and energy efficiency so that, for example, this solar charged laptop uses around 5 Watts to receive and transmit data around the world. A 3.5W LED produces more light than a kero lamp or a 60W incandescent light bulb. My refrigerator uses less than 200Wh per day and my heat pump HWS uses 1.3kWh/day average.

    So with today’s technology solar and wind with battery and thermal storage can easily last many days. EV’s will replace fossil fuel cars, buses and trucks. Sundrops solar farm in Port Augusta can last 11 days without Sun. Tomorrows developments in generation, storage and efficiency will make this a relatively straightforward process.

    • solarguy 4 years ago

      What brand and size is your fridge? Must be bloody small!

      • Brian Bartlett 4 years ago

        Yes it is in the thinking style of ‘Small is Beautiful – EF Schumacher’. The 200Wh/day is the average but in winter it uses around 150Wh and summer as much as 250Wh/day.

        I used a 150l cheap $225 chest freezer off the shelf from a retailer and used an external thermostat $25 off ebay to operate it from 2deg to 6degC as a refrigerator. It runs off an 18yr old Selectronic SA22 inverter which also charges the ebikes and runs a F & P washing machine, 100Wh/load, among things. I also have a 2nd 100l one which I use as a drinks fridge which uses slightly less power.

        I got the idea from here.
        I used low cost products to see if I could get a similar outcome. Not as good but not too bad in our high Qld ambient temps compared to his Vic one.

        I turned it off for 24hrs in 35deg day temps and it held below 10degC without opening it 1 day later so the top opening with freezer insulation system does work even at budget levels. The concept would be ideal to change everyone from the old garage beer fridges typically using 2kWh/day to something using 1/10 of the power. Ditto if we changed everyones HWS to small heatpumps. You could turn off several coal fired power stations quite easily.

        So energy efficiency really can make a big difference just by changing one thing in Aust households. Hence running everything off renewables is easy if we get demand down.

        • solarguy 4 years ago

          Yep Brian, Efficiency is everything and well done with your solution. You maybe interested to know that our Electrolux 520lt fridge/freezer uses about 800w/day. It is of course an upright. Should you like to purchase a bigger fridge you could go for that or look at eutectic fridges even better.

  5. permaculture utopia 4 years ago

    Getting back to reality with the present grid – there are houses that won’t have power restored from a thunderstorm on Tuesday night in my town until 4pm Friday. This is a relatively small amount of properties – 177. There’s lots of storm damage and this area is a poor area of town and probably a low priority. In outages, networks restore the largest areas of people effected first. My point is that grid reliability costs money now and inefficient service models cost money now. The more this problem persists, the more we can all expect grid reliability to take a backwards step before hopefully learning from mistakes and taking two steps forward. Those people living in low priority or fringe of grid service areas, will be weighing up their options as soon as PV/storage reaches near grid parity for their usage pattern and location.

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