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Consolidated Climate Change/CO2/Global Warming Thread

Discussion in 'Science' started by hlokk, Feb 12, 2007.

  1. antipody

    antipody Member

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  2. RobRoySyd

    RobRoySyd Member

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  3. antipody

    antipody Member

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    True.

    Good on em for setting an ambitious target though.

    The solar farms south of here are going to be pretty impressive. Don't see why we can't just roll out hectares of them and shut down all fossil fuel plants by 2020.

    Electric heating works. So do electric cars.

    It's wouldn't be "renewable", but it would be a much better than the deeply damaging power we generate and indeed encourage use of every day.
     
    Last edited: Jun 3, 2016
  4. Walshy

    Walshy Member

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    Well, there are several reasons.

    1) solar panels don't generate 24/7. While they help considerably with peak cooling load in summer, they're not so helpful in winter, when peak heating load is at night. You also need storage to be able to supply at night or during cloudy periods, and storage, on a GWh scale, is very, very expensive (like, be prepared to triple your current power bill expensive).

    2) Let's crunch some numbers (and please point out if I made any mistakes!).

    • Australia (at least the eastern states connected to the NEM) used 194 Terawatt-hours of electricity in 2014-15. That's 194,000,000,000 kWh.
    • Solar panels in Sydney (not optimum, but perhaps 'average') produce ~1,500 kWh per installed kW of panels, per year.
    • So, at a first approximation, you need 129.3 million kW of installed solar panels. There are currently about 5 million kW of panels installed in Australia, so we need to increase the current installed base by nearly 26 times.
    • For cost, let's use the Royalla solar farm near Canberra. $60million buys you 20,000 kW of panels, so that's $3,000 per kW installed, including land purchase, approvals, site works, supply & install of panels, and connection to the grid.
    • Maths tells us we then need 124.3 million X $3,000 - that's $372 billion - to pay for enough solar PV stations to power the NEM. Assuming average annual demand meets average annual production.
    • But that's not the whole story. You need to have enough panels to cover demand during periods of cloudy weather, so you'll probably need to triple that. Call it a round $trillion.
    • You'll also need storage. A LOT of storage. Say, enough to store half your output, every single day - call it 2kWh per kW of panels. Storage on that scale is not an easy thing to achieve. If we assume the cost is about $800 per kWh, that's another $200 billion in storage costs. And that probably won't be enough - typical designs look at at least three full days of storage, so that'd be $1.2 trillion in storage costs. Assuming you could actually buy enough flow batteries.
    • Even then, you'll need considerable backup generation, because neither demand nor production are neat annual averages.

    Makes the $40 billion NBN look dirt cheap! :p

    And my assumption above of only needing triple capacity to meet demand is probably very generous. Actual values required to meet demand on nearly every day of the year (as seen in some analyses of historical output from non-hydro renewables in Australia) are more like a factor of six to twelve times overbuild. I don't think we can afford to spend $12 trillion on solar panels... :lol:
    (the entire Federal gov't budget is < $0.4 trillion per year, so that's 100% of the Federal budget for 30 years - at which point the solar panels are wearing out and you need to replace them!)
     
  5. antipody

    antipody Member

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    You need to understand that the price of power hides a great deal of reality in terms of costs. It's not in your interests actually to have cheap fossil fuel power.

    It is in your interest to have cheap power and that is acheivable if you don't restrict yourself to thinking in terms of existing state of the national electricity market.

    Maybe it's because we're under such pressure to believe otherwise, but when we use power we manage to forget it's acidifying our air, water and creating a new epoch of climate chaos.

    The cost of simply allowing the mining and burning of fossil fuels (as we once did with slavery) doesn't get factored into your valuation because you're using Australian dollars to represent cost.

    Like all currencies they have a limited life before they become completely worthless and resets, debt forgiveness witness their extinction. But if you want to seriously think about it in those deeply comprimised units, at least acknowledge that deeply disturbing political reality in regards to how cheap burning fossil fuels is today.

    I think you've made a lot of assumptions. Is it rude to call this an economic diatribe with no vision and if anything a hidden agenda?
     
  6. RnR

    RnR Member

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    Walshy - I don't see any need for the tripling of the solar panels. You are already operating under the assumption of an 'average' ie your '~1,500 kWh per installed kW of panels, per year'. To cover the NEM while under cloud needs a small amount of storage, along with standby gas powered generators. I believe scientists are calling for a 90% reduction in our co2 emissions over the long term, not 100% reduction. So the storage costs that you calculated are much too big in my opinion. I am not aware of studies that uses weather data from say 10 years that shows just how much 'reserves' the NEM needs. I do know that the NEM today has 800MW of spare emergency reserves standing by. This is by legislation.

    Finally, using the Sydney insolation value is poor value for money imho. You should be able to get a nice 33% jump in power output by moving these area's of panels inland.
     
  7. Walshy

    Walshy Member

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    Warning: long post ahead! :lol:

    Oh, believe me, I'm well aware of that. I'm a firm believer in adding external costs to the price of fossil fuels, and I think that estimates south of $100 per ton of CO2e are woefully inadequate, given that global warming is an existential threat to human civilisation.

    Why, yes, I have. I thought I made pretty clear what those assumptions were, though. :D

    The biggest one is that I assumed an effort to go 100% solar PV, which was a direct response to the comment I quoted. Nobody would really try that for a whole country (well, nobody sane, anyway! :weirdo: )

    Yes, yes it is. :p I completely understand where you're coming from, though. This was simply an attempt to demonstrate why the simplistic approach of "just shut down the coal plants and build more solar panels" isn't practicable, by giving a ballpark idea of the cost. No more, no less.

    Actually, no, you need more. You need to account for periods of days to weeks where you have heavy cloud cover, and thus reduced output from the panels. If, on average, a kW of solar PV produces 4kWh per day, and demand served by those panels is, on average, 4kWh per day, what are you going to do if you get a week of terribad weather where the panels are only putting out 2kWh per day? Three full days of fully-charged storage would get you through that week. Maybe. ;)

    Smarter people than me have examined this problem. Look at this paper (pdf) by Ben Elliston, Mark Diesendorf, and Iain MacGill of UNSW. I disagree with some parts of their work (in this and other papers), but their basic number crunching appears sound enough.

    Their breakdown, to serve 33.6 GW of peak demand, is as follows:

    • Wind: 23.2 GW
    • Solar PV: 14.6 GW
    • Concentrating Solar Thermal: 15.6 GW
    • Pumped hydro: 2.2 GW
    • Other hydro: 4.9 GW
    • Gas turbines: 24.0 GW
    • Total: 84.5 GW

    So that's nearly a triple-overbuild, in peak capacity. Now, that's for a mix of generation sources that have far more capability to meet daily demand than just Solar PV alone does. I recommend checking out the paper (especially the graphs showing a week or so of generation by source). During winter, those gas turbines run at 100% load all night, every night, and even then, they should have included 25+ GW, because their study falls at least a gigawatt short of being able to meet demand all year round.

    It is, of course, more complicated when you consider 'annual averages', as I did, but I still think a 3x overbuild and three days of storage is being generous to the PV, in order to be able to serve demand during inclement weather in winter.

    The gist, though, is that going 100% Solar PV is a really bad idea, due to the generation characteristics on diurnal and seasonal timescales.

    I think it's at least 90%. The last 10% will be hard, as it's not from burning fuel, but from production of cement & steel, agriculture, land use change, and the like. Those are always going to be hard to fix. Carbon capture & storage (CCS) may prove useful there, if it can be made to work at the right scale. It's pretty damn expensive, though, IIRC.

    That's a non sequitur - it doesn't follow from the previous point at all, as that last 10% of emissions isn't from electricity generation.

    The difference is that the NEM reserves are dispatchable - that is, they can be relied on to provide power any time of the day or night, irrespective of weather. Neither wind nor solar PV can do that, without very large battery banks. Solar thermal may have some capacity to do so, but only if you have signficant excess capacity in the first place, which is hard to come by in winter (the study I linked above suggests CST sized for 24/7 generation in summer wouldn't be able to fill 5 hours of storage during winter, let alone enough to run through a full night after a week of cloudy weather).

    Oh, absolutely, but it was just a thought exercise to demonstrate the impracticality of pursuing 100% solar PV.

    Using a far more practicable mix, such as that in the paper I linked to, would give much better results. For how much money, though?

    Let's look at capital cost numbers from the 2012 Australian Energy Technology Assessment (pdf) It was supposed to be updated in 2014, but for some strange reason, the 2013 update (which didn't provide updated capital costs) is the last one issued :rolleyes:

    • Wind: $2,530/kW x 23.2 GW = $58.7 billion
    • Solar PV: $3,380/kW x 14.6 GW = $49.3 billion
    • Concentrating Solar Thermal: $8,950/kW x 15.6 GW = $139.6 billion
    • Pumped hydro: 2.2 GW (assume already existing)
    • Other hydro: 4.9 GW (assume already existing)
    • Gas turbines: $723/kW * 24.0 GW = $17.3 billion
    • Total: 84.5 GW for $265 billion

    I've assumed that all of the hydro is existing capacity (e.g. Snowy Scheme, Tassie, etc). I haven't taken into account the existing ~2 GW or so of wind, so you could potentially knock $5 billion off the price tag.

    But, of course, you need to add in costs for infrastructure needed (roads, power lines, transformers, etc) to service the new generation facilities. I only have a vague idea how much that would cost, so I'll leave it out, though it could easily double the costs.

    So that's an almost 'ideal' mix of generation technologies, and it costs a quarter of a trillion. If you want to power your gas turbines with non-fossil biofuels to eliminate the last 15% of electricity emissions, you'll need to add the costs for infrastructure to gather the biofuel raw material and process it into fuel suitable for the turbines, which might add several thousand dollars per kW of capacity for the turbines, maybe another $50 billion or more to the total.

    Far, far cheaper than the hypothetical "100% solar PV plus battery storage" that I examined above (which really highlights how impractical that option is). Still rather expensive, but much more affordable (it's 'only' 5 or 6 times the cost of the NBN).

    You could, potentially, fund construction of this (or other zero-emission generation technology) with a carbon tax. That'd be a hard road to walk in this country right now, though, thanks to the destructive efforts of certain right-wing politicians and coal-industry lobbyists.

    Now, on top of all that: what do you do with the ~30% of primary energy use in this country that goes to transportation? Electric cars & trucks are a fantastic idea, whose time has come, IMHO, but they mean demand for electricity is likely to rise by 20-50% over the next few decades, just to charge all those electric vehicles. And many (most?) will be charged at night, when they're parked at home or at the depot.

    In order to make that particular transition, we need a robust electricity supply network that can provide reliable power, and it's going to need to be bigger than what we've currently got. Still plenty of work to be done to figure out how to achieve that.

    Of course, the flat-earthers we currently have in power don't even want to take the first step of really acknowledging we have to get rid of GHG emissions (as opposed to giving it lip service while approving coal mines and gas wells all over the shop), let alone figure out how to actually achieve decarbonisation of both electricity and transport. :mad:
     
  8. Kookooburra

    Kookooburra Member

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  9. adamsleath

    adamsleath Member

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    looks good walshy :thumbup:
    (sorry for the long quote but i was told by a forum moderator to use the quote button :lol:)
    are you suggesting this is a near optimal renewables mix?

    what portion of existing industry would be reliant on fossil fuels??? in terms of total energy use?

    http://www.abc.net.au/news/2015-08-...ia-have-one-of-the-highest-extinction/6691026

    Epstein....the name says it all.
     
    Last edited: Jun 9, 2016
  10. Walshy

    Walshy Member

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    No, the authors of the paper I linked to are putting it forward as a possible generation mix.

    Personally, I think it doesn't cut it, due to over-reliance on biofuel-powered gas turbines.

    Right now, in Australia, the answer is pretty much all of it.

    In addition to electricity use, there's certainly a lot of process heat generated by combustion of fossil fuels (mostly gas, I think). That would need to be added to total electricity demand, if you were trying to go non-fossil. I don't know how much additional demand that would bring, though.

    Why am I not surprised to find out that he cites Ayn Rand as one of his biggest influences?
    I only watched the first minute and a half of that video, and I think I noticed 4 or 5 separate serious logical fallacies in the arguments presented to that point. And that was only the introduction!
    At least he's honest on one point, though - he doesn't even pretend to hide the fact that he's fully funded by the fossil fuel industry.
     
  11. antipody

    antipody Member

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  12. Walshy

    Walshy Member

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    That's some awesome forward thinking by the ACT gov't, well done!

    Thing is, they can only do it because their power is backed up by coal, gas, & hydro. They're not actually running the ACT off 100% renewable power, but are instead paying for renewable power to be generated and dispatched into the market to offset their usage. This works for a relatively small consumer of power, such as the ACT, but will fall down badly if the same thing is tried for the entire market.

    Part of the reason for the ridiculously high wholesale prices recently is lack of renewables generation - as the wind drops off, it has to be backstopped by a dispatchable source, such as hydro, coal, or gas.

    In the case of SA, where prices were particularly high over the past few days, they hit a demand peak of around 2,000 MW just after sunset today, while at the same time wind generation dropped to 30MW or lower (about 2% of the nameplate capacity). They can draw up to 680 MW from Victoria via the Heywood & Murraylink interconnectors, but that still leaves ~1,300 MW of shortfall.

    In SA, this shortfall is picked up by gas (as they recently closed their last coal-fired power station), and there's only so much gas available on the domestic market, so prices skyrocket.

    Contrary to what that article claimed, it's not because the gas is being diverted to the LNG plants, there are guaranteed supply contracts in place for the domestic market for a certain amount of gas - and the LNG plants are running flat chat 24/7 anyway, they don't fluctuate in their gas consumption unless something breaks down, in which case there's excess gas available, not a shortage! If the LNG plants weren't there, there still would have been a gas price spike, because there still would have only been a certain amount of gas being supplied to the domestic market (although there would have been an awful lot less holes drilled in the ground!)

    FYI, wind output is available here: http://energy.anero.id.au/wind-energy (currently running at about 10% of nameplate capacity, though it's been as low as ~5% and as high as ~85% during the last fortnight)
    Price & demand data is available from AEMO, here: http://www.aemo.com.au/Electricity/Data/Price-and-Demand

    Edit: on second thoughts - a similar system of fixed-price contracts could definitely work in the larger market. Guarantee to pay renewable sources a fixed rate per MWh of actual generation, and then the market operator just curtails production as required to match demand. That way, the wind farms / solar farms / hydro dams / whatevers are guaranteed an income according to the actual dispatchable capacity they can provide. I'm not sure exactly how it would interact with the wider market, but perhaps a similar mode of operation, where if the market price goes above the fixed rate, the operator reaps the excess (and presumably puts it in the kitty to pay for generation during times of high wind, when supply far exceeds demand). It could be done, especially if the market operator was a non-profit government organisation, with a mandate to minimise market prices while trying to ensure adequate supply.
    I suspect the overall generation mix wouldn't change all that much, though, until a carbon price was imposed on the coal-fired generators (especially the brown coal generators in the Latrobe Valley, who can supply at ~$50-60 / MWh and still make a profit, as I understand it).
     
    Last edited: Jul 15, 2016
  13. MR CHILLED

    MR CHILLED D'oh!

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    We've just had our hottest June on record.

    We've had a couple of 20C days here in Adelaide during July....just crazy for this time of year :wired:

    "Last month was hottest June on record, scientists say"

    http://www.abc.net.au/news/2016-07-20/hottest-june-in-modern-times-scientists-say/7643240

     
  14. Walshy

    Walshy Member

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    Pretty hot around the rest of the world, too - major heatwave underway in the US, and Kuwait set a new national record yesterday, and a new record for outside of Death Valley, California - 54ºC! :wired: Possibly a tie for the highest temperature reliably recorded anywhere on Earth (outside of an oven, of course! :lol:)
    Details here at Weather Underground.

    The other interesting bit of news I saw today, was about using iron ore as a catalyst to crack methane into hydrogen gas and graphite. While they were talking mostly about using natural gas to produce hydrogen on an industrial scale, I think the potential to use it to geosequester carbon is high - bioreactors full of methanogenic bacteria fed from atmospheric CO2, combined with briquetting & safe disposal of the graphite, and you'd have a hydrogen source that strips carbon out of the atmosphere. Like most of these stories, though, it's purely lab-scale, able to produce a few litres of hydrogen per day at the moment. But yet another possible way to clean up the atmosphere, eventually.
     
  15. RobRoySyd

    RobRoySyd Member

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    Some more far from good news:

    Crisis on high.

    This region is aptly called The Third Pole, it's been largely ignored until recently. I've been close to this region, seen and drank the water that comes from the melting glaciers through ancient underground tunnels . At the moment there's more water than ever but that's not good news.
     
  16. ernie

    ernie Member

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    Methane is the main component of natural gas, which is already the main source of industrial hydrogen. Just more unsustainable fossil fuel use.


    - Ernie.
     
  17. Walshy

    Walshy Member

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    If you read my entire post, you'd see I was mostly talking about using it with biogas of one sort or another, rather than fossil natural gas.

    Only then would it have the chance to be effective from a global warming perspective, otherwise you might as well just run on compressed natural gas, and forget about the difficulties in dealing with hydrogen fuel.
     
  18. adamsleath

    adamsleath Member

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    Interesting article

    -----------------

    Why can't renewable energy be provided at rates competitive to this? Even after factoring in the capital costs of the wind generators / and or PV panels ?
    Surely it is competitive? over a certain time period ?

    https://theconversation.com/south-a...and-batteries-could-fill-the-energy-gap-59164
    ...as you mentioned, this is a good thing...

    and the ACT having renewables contracts seems like great news :)
     
    Last edited: Jul 30, 2016
  19. RobRoySyd

    RobRoySyd Member

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    Not when the cost of storage is factored in. Without storage at times energy has to be bought from thermal power stations and as the penetration of renewables increases there's times when there's no consumers for the energy they're producing.

    Also Solar PV panels and wind turbines don't last for long compared to thermal power stations. There's parts in thermal power stations that do wear but they can be easily replaced at low cost. A thermal power station should be serviceable for at least 60 years.

    It'd be wrong to ignore the advances being made in coal fired power station technology. There are ways to do it better:

    http://cornerstonemag.net/setting-the-benchmark-the-worlds-most-efficient-coal-fired-power-plants/

    Of course even then it's still far from zero CO2, gas fired CCGT also isn't zero CO2. Where the crunch comes is no one is going to invest in better thermal power generation when the demand is for zero CO2 within the payback period of these kinds of power stations. Countries such Japan have because they have to import coal. Here in Au coal is pretty much free. A carbon tax arguably would change that but in a globalized world a carbon tax will only be effective if it's universal.
     
  20. dr_deathy

    dr_deathy Member

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    How long does PV last?

    https://pureenergies.com/us/how-solar-works/how-long-do-solar-panels-last/

    They haven't been around for long enough to find out.

    Also i remember reading a story from japan and a PV recycling center was testing and reinstalling panels and found most worked and above the 80% performance still after 40 odd years.

    So if your only talking 60 years....
     

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