A question about rooftop solar

For the experts on site, how did NSW reach almost a GW of solar PV today when it was overcast all day in Sydney?

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45 Responses to A question about rooftop solar

  1. pbw

    Another question for the well-informed. I have assumed that the subsidies for renewables are not reflected in the retail price, but in the various taxes that everyone pays. Am I correct in this? If so, can the total average cost of electricity, including taxes, be calculated?

  2. MatrixTransform

    Ive seen solar push about 25% on a cloudy day.
    Surprising really.

  3. Confused Old Misfit

    It only reached that level for a few minutes around noon.
    Declined rapidly after that.

  4. Anthony

    Was it just Rooftop? Possibly, it was grid scale farms in less overcast regional NSW.

  5. Geriatric Mayfly

    Homogenised electrickery.

  6. Tel

    Swings and roundabouts, it was overcast but also pleasantly cool and rained hard last night so the cells were clean and running maximum efficiency.

    Full hot sun gives you more input energy but less efficiency … as RobK has pointed out, some cells are badly installed and cannot ventilate so those become stupidly inefficient on hot days.

  7. 2dogs

    The Solar PV figure is net of what the houses use – what goes onto the grid.

    While the overcast day did mean a decrease in Solar PV produced, it also meant home owners turned off their air conditioners.

  8. Probably using the same methodology as does the BOM in calculating the hottest day ‘evah!’.

  9. 2dogs

    Actually, looking at that graph again, I suspect I may be wrong about that. The figure may, instead, actually be gross.

    But they don’t how much the Solar PV households actually use themselves of what they produce, so they estimate the daily production, and just plug that figure in each and every day.

  10. Mark M

    Jan 2018, Forster: “The biggest uncertainty in our climate models has been their inability to simulate clouds correctly. They do a really bad job and they have done ever since they first began.”

    https://www.carbonbrief.org/in-depth-scientists-discuss-how-to-improve-climate-models

    April 2002: “Clouds remain one of the largest uncertainties in the climate system’s response to temperature changes,” laments Bruce Wielicki, a scientist at NASA’s Langley Research Center.
    “We need more data to understand how real clouds behave.”

    https://science.nasa.gov/science-news/science-at-nasa/2002/22apr_ceres

  11. BoyfromTottenham

    Can someone tell me whether these days rooftop solar PV installations actually provide power to the home, or just back to the grid, for which they get a rebate (and feel good while they do it)? And is it true that if the grid fails, houses with solar PV cannot access their solar power?
    PS There power is off here in SEQld at the moment due to a storm blowing a tree across local power lines. My suburb is blacked out till about 10 pm tonight. I am enjoying a taste of the future – three candles and a torch for lighting, no power, no TV, no regular Internet. fortunately I have gas hot water and cooking, a fully charged phone and iPad, some nice music recorded on the iPad, and a bottle of nice Shiraz.
    I had eggs on fried bread with baked beans for dinner, followed by runny ice cream topped with port. I have had worse meals, but this was not up to my usual standard. If the power doesn’t come on by 10 pm I will be throwing out a pile of frozen food tomorrow, and probably eating breakfast on my way to work (but in another suburb of course). Is this Really what the ALP and Greens want as the future for Australians? This federal election could be interesting.

  12. Richard Bender

    Must remember to close link tag…

  13. Leo G

    Miraculous rooftop PV performance. Not just overcast over Sydney, cloud covered the eastern third of the state throughout the day.
    Australian Government Bureau of Meteorology Bureau National Operations Centre Satellite Notes for the 0600 UTC Chart Issued at 5:37 pm EDT Monday on 18 March 2019:

    A large area of cloud is associated with an upper disturbance over NSW and
    Queensland, and a surface low pressure system off the southeast coast of New
    South Wales. Thunderstorm activity associated with these systems lies offhsore
    of the NSW coast, southern Queensland and parts of inland NSW.

  14. duncanm

    Richard Bender
    #2963031, posted on March 18, 2019 at 8:32 pm

    The actual generation according to the AEMO data peaked at about 700 MW. According to , installed capacity in NSW is around 1,500 MW. Depending on the extent and thickness of the cloud cover, and noting that NSW is not just Sydney, 700 MW is not implausible.

    Of course, that 700 MW absolutely pales in comparison to the amount generated by black coal, so when anyone tells you how easy it is to switch to 100 per cent renewables, tell them to fuck off.

    That link gives the game away.

    $3B spent on 1500MW of rooftop solar – lucky to push out 500MW.

    Cost of a single coal fired station – $3B, but it’d push out 3000MW day and night.

  15. duncanm

    I think you’re reading it wrong, but the numbers still don’t really add up.

    Reduce the graph to only ‘rooftop solar’ and (non rooftop) ‘solar’.

    There are two numbers for each colour.. but the second is accumulation of all sources viewed. Use the left-hand numbers.

    Around midday – it peaked at 0.8GW of rooftop, and 0.5GW of non rooftop.

    Rooftop is believable, depending on what they mean by ‘1.5GW of installed capacity’, since it was a cool day (panels more efficient), and not that overcast in much of the state, even Sydney only had patchy rain and light cloud.

    But how can we get 0.5GW of power out of 0.36GW installed capacity for non-rooftop?

    The answer is that department of planning installed capacity link is out of date compared to the map – it doesn’t have Manildra (50MW) and Coleambally (180MW).. so installed capacity is something more like 630MW.

    0.4GW lasted about 6 hours out of 24.

    Capacity factor 0.4/0.63 * 6/24 = 16% . ie: Shite.

  16. Chris M

    The ‘small / rooftop solar output’ is a guesstimate based on assumed total consumption – they simply don’t have this data.

    Can someone tell me whether these days rooftop solar PV installations actually provide power to the home, or just back to the grid, for which they get a rebate (and feel good while they do it)? And is it true that if the grid fails, houses with solar PV cannot access their solar power?

    Yes they provide power to the home, any excess will feed to the grid. yes if the grid fails the PV system will disconnect also so you are no better off at that point. Unless you have a battery system configured to take over (most aren’t). In a blackout some solar inverters can be fired up by feeding them an A/C signal such as with a small genset provided you are isolated from the grid of course (mains off & isolated). In which case you can have a good deal of available power while there is sunlight.

  17. yarpos

    A very Sydney centric question. Big place NSW, despite what the media says there is life beyond Sydney Metro.

    The gloom was mostly coastal

  18. Lilliana

    Subsidies for renewables are factored into your retail electricity prices and are around 6-10% of your bill.

    The 0.8 GW rooftop is the amount fed into the grid after all requirements of the household are met. Not bad but the problem is it’s at the wrong time. We need electricity for the morning and evening peak hours hence the push for batteries.

    A new coal fired generator will probably cost around $3B for 600MW installed capacity and then fuel costs on top of that – not cheap.

    Like it or not solar is here to stay.

  19. Ben

    The figure appears to include solar farms and rooftop PV.

    http://www.opennem.org.au

  20. struth

    Subsidies for renewables are factored into your retail electricity prices and are around 6-10% of your bill.

    Rubbish.
    How naïve to expect that is all you are paying for renewables.
    Couldn’t be bothered with you, but others here will make you wish you’d never said that.
    If they don’t, then I’ll come back.

  21. max

    Vaclav Smil :
    Today, coal, oil, and natural gas still supply 90% of the world’s primary energy. Since 2000, “we have been increasing our global dependence on fossil fuels. Not decreasing,”

  22. max

    Vaclav Smil :
    the cost of electricity generated by residential solar systems in the United States has not changed dramatically since 2000. At that time the national mean was close to 40 U.S. cents per kilowatt­-hour, while the latest Solarbuzz data for 2012 show 28.91 cents per kilowatt-hour in sunny climates and 63.60 cents per kilowatt-­hour in cloudy ones. That’s still far more expensive than using fossil fuels, which in the United States cost between 11 and 12 cents per kilowatt-hour in 2011. The age of mass-scale, decentralized photovoltaic generation is not here yet.

  23. Fat Tony

    Lilliana
    #2963163, posted on March 18, 2019 at 9:59 pm
    A new coal fired generator will probably cost around $3B for 600MW installed capacity and then fuel costs on top of that – not cheap.
    Like it or not solar is here to stay.

    duncanm
    #2963086, posted on March 18, 2019 at 9:08 pm
    Cost of a single coal fired station – $3B, but it’d push out 3000MW day and night.

    A helpful hint – don’t come here and spruik bullshit, bimbo.
    And I wouldn’t be too sure that “solar is here to stay”. There will be a reckoning for those who have foisted all this renewable shit on us.

  24. Gbees

    You can get low light panels which even produce some energy in moonlight, but it’s tiny. On cloudy days depending on cloud coverage, generation may get to 15% of panel capacity.

  25. Miraculous rooftop PV performance.

    My assumption is that some bastard is lying through their arse.
    99% chance of being right.

  26. Lilliana

    Not spruiking bullshit or anything else and haven’t been called a bimbo in years! I just happen to work in the electricity industry.

    A 600MW generator, if running at full capacity, will generate 14 400 MWh in 24 hours.

    Renewables are partly funded by electricity retailers and other large electricity consumers having to buy small and large “certificates” from renewable energy providers. The price of the certificates fluctuate but the cost estimate is correct. It’s not a secret and is generally be on your electricity bill. You can google it if that makes you feel better. The small certificates cover the rebate paid to small PV system owners.

    Stating that solar is here to stay is just a fact of life not an endorsement.

  27. Nob

    max
    #2963268, posted on March 18, 2019 at 11:28 pm
    Vaclav Smil

    His books Energy, https://www.amazon.co.uk/Energy-Vaclav-Smil/dp/1851684522 and Oil https://www.amazon.co.uk/Oil-Beginners-Guide-Guides/dp/1786072866/ref=pd_lpo_sbs_14_t_1?_encoding=UTF8&psc=1&refRID=B3ZBY293X12X8MAG1ME7 are essential primers for anyone interested in how the world works physically.

  28. RobK

    http://www.wattclarity.com.au/articles/2016/06/the-opacity-of-distributed-small-scale-solar-pv-output/
    Sampler:

    Today I’m posting some comments on the invisibility opacity of distributed solar PV.

    1)  Comparing different estimation methods

    We should start by noting that no-one actually KNOWS, in aggregate, how much small-scale solar PV systems are injecting into the NEM (or indeed in any grid).

    Aggregating data in real time (or even delayed) to provide clarity about injections seems like the type of internet-of-things + Big Data problem that would have technology companies clamouring over themselves to attack.  However, what business problem would they actually be solving?

    Today in the NEM there are at least two different methods in use to ESTIMATEaggregate output from the growing number of small-scale PV systems across the NEM:………

    As mentioned above; its a guesstimate. More detail in the article.

  29. duncanm

    Lilliana
    #2963409, posted on March 19, 2019 at 7:31 am
    Not spruiking bullshit or anything else and haven’t been called a bimbo in years! I just happen to work in the electricity industry.

    A 600MW generator, if running at full capacity, will generate 14 400 MWh in 24 hours.

    Lilliana, your bullshit is the $3B for a 600MW coal fired power station.

    My numbers were also wrong ($3B for 3000MW)

    From the Australian Power Generation Technology Report, pp120, the capital cost of a Black Coal super critical plant, without CCS, is $3000/kW.

    $3B buys you a 1000MW station. that’ll run at 60-70% capacity, versus 500MW of rooftop solar running at 15%

  30. Cynic of Ayr

    Lilliana

    A new coal fired generator will probably cost around $3B for 600MW installed capacity and then fuel costs on top of that – not cheap.
    It is cheap, and it’s self funding, if left to compete fairly. Jesus Christ, that has been proven for years and years! Modern Coal Stations are even cheaper and a darn sight better as well!
    Renewables are partly funded by electricity retailers and other large electricity consumers having to buy small and large “certificates” from renewable energy providers.
    Guess where all this money comes from? The freaking Tooth Fairy? Get real!
    You lost this argument a couple of times here. If you work in the Power Industry, you really need to read other material, not out and out lying propaganda. A cheap place to start is Jo Nova’s site. Or, work on the German figures.

  31. Stan

    Probably because a bunch of subsidy farmers were running generators to light spotlights on their solar panels. Like they used to do in Spain.

  32. Rafe Champion

    Lilliana can you find some spreadsheets for the cost of wind and solar that include the subsidies and the cost of new grid required to reach country sites and existing grid upgrades to handle fluctuating loads?

  33. Lilliana

    https://www.aemo.com.au/-/media/Files/Electricity/NEM/Planning_and_Forecasting/Inputs-Assumptions-Methodologies/2019/9110715-REP-A-Cost-and-Technical-Parameter-Review—Rev-4-Final.pdf

    Sorry – can’t work out how to add a link.

    duncanm – I got my numbers from the above AEMO paper. It should be a 750 MW not a 600 MW plant but actual output is a lot less.

    Cynic of Ayr
    Agree that subsidies distort prices. I’m not sure what your point is regarding certificates? We are looking at wind farm at the moment. It will be funded by the Chinese and its revenue stream is sales of large scale renewable certificates and flogging electricity into the NEM (backed by financial contracts with retailers or even other generators).
    So I’m not sure what argument I supposedly lost as I didn’t realise I was having one. Someone asked a question and I provided an answer.

  34. Lilliana

    Rafe

    Can’t promise but AEMO have costs for wind and large scale solar. I can have a look but transmission and distribution is costed separately. I know there is definitely an issue with generation in remote locations. I think AEMO may have even released an issue on the subject. There is a reason why power stations are close to loads (areas of demand).

  35. John A

    Mark M #2962962, posted on March 18, 2019 at 7:46 pm

    Jan 2018, Forster:

    “The biggest uncertainty in our climate models has been their inability to simulate clouds correctly. They do a really bad job and they have done ever since they first began.”

    https://www.carbonbrief.org/in-depth-scientists-discuss-how-to-improve-climate-models

    April 2002:

    “Clouds remain one of the largest uncertainties in the climate system’s response to temperature changes,” laments Bruce Wielicki, a scientist at NASA’s Langley Research Center.
    “We need more data to understand how real clouds behave.”

    https://science.nasa.gov/science-news/science-at-nasa/2002/22apr_ceres

    “I’ve looked at clouds from both sides now
    From up and down, and still somehow
    It’s cloud illusions I recall
    I really don’t know clouds, at all.”

  36. Tim Neilson

    I just happen to work in the electricity industry.

    Do you mean the real electricity industry – i.e. the one that generates and transmits electricity – or the fake one i.e. the one that hoovers taxpayer subsidies and kills avian life while generating next to nothing?

  37. duncanm

    Lilliana
    #2963815, posted on March 19, 2019 at 3:34 pm
    https://www.aemo.com.au/-/media/Files/Electricity/NEM/Planning_and_Forecasting/Inputs-Assumptions-Methodologies/2019/9110715-REP-A-Cost-and-Technical-Parameter-Review—Rev-4-Final.pdf

    Sorry – can’t work out how to add a link.

    duncanm – I got my numbers from the above AEMO paper. It should be a 750 MW not a 600 MW plant ..

    pp49 – $1.8B for a 750MW supercritical black coal without CCS. Surprise, that’s actually $2400/kW. Not your number of $3B/600MW ~ $5000/kw.

    .. but actual output is a lot less.

    I hope you don’t mind me saying – durrrggh. That is called capacity factor. That paper you linked had an output of ~630MW for a 750MW plant. ie: 84%

    Solar capacity factor is more like 10-25%.

  38. Genghis

    No RAF you are wrong if you go to https://anero.id/energy/ and shut off all other power sources then shut off each state apart from NSW that solar worked at about 0.5 or less GW’s BUT that includes power from far western NSW solar forms.

  39. Lilliana

    Tim – both “real electricity industry” and bird killer one.

    duncanm – thanks for the the explanation but I do know what a capacity factor is – perhaps others do not. Also I was using the generator capital costs on pp 46.

    Given that solar only works from around 10am to 4pm (depending on latitude and time of year) the relatively low capacity factor is understandable unlike a coal generator that can operate almost continually.

    Rafe – don’t have the info. regarding transmission and distribution costs . It’s not as easy to find as generation costs.

  40. duncanm

    Lilliana
    #2964175, posted on March 19, 2019 at 8:34 pm

    Tim – both “real electricity industry” and bird killer one.

    duncanm – thanks for the the explanation but I do know what a capacity factor is – perhaps others do not. Also I was using the generator capital costs on pp 46.

    Why would you use the Carbon Capture and Storage numbers? Of course they’re going to inflate capital (and running) costs

  41. Lilliana

    duncanm – I’m not using the ccs numbers I’m using the general costs in Table 25 – the ccs are an additional $1.3b or so on top of the generator costs.

  42. Lilliana

    duncamn – I used the generation only costs in Table 25. The CCS capital costs are an additional $1.3B or so.

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