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How to replace Liddell with a dispatchable renewable energy plant

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Hey ho, Hey ho, its off to work we go,

we shall not take our bag and stick,

hey ho, hey ho, hey ho”

Snow White and the seven dwarfs

Renewables for energy, gas for firming

In this note, a follow on from yesterday’s analysis of the costs of keeping Liddell coal fired power station open we sketch out a “transitional” renewables plant that will have an average output of 1.1GW, a minimum output of 650MW and is largely renewables based.

It’s only transitional because we use carbon emitting, expensive gas combined cycle plant to firm up the output. Even so, on our estimates the carbon intensity of the entire system is just .11 tCO2/MWh – a big improvement on Liddell (nearly 1.0tCO2/MWh – and probably at lower cost.

We very, very roughly estimate this system with 1GW dispatchable ouput and 1.1GW average output would need a price in the order of $90/MWh.

We think recent reductions in renewables costs, the increases in the price of gas and coal make this an entirely economically realistic proposition. The news service Coalwire today carries news that the world’s 4th largest reinsurer will basically no longer offer reinsurance for new coal or lignite plants.

NSW, a net electricity importer, a state where residential and community opposition to new gas and coal fields is very obvious, as are legal restrictions, nevertheless has a clapped-out fleet of coal generators and is badly in need of new power.

The answers are right in front of us and we just need politicians to get out of the way and get on the bus. Time is money and time is short, let’s get on with it.

NEM Review is the only tool, Windlab provides the inspiration

Without NEM Review’s data and database tools  this work would not be possible for a tiny operation like ITK. Thanks guys. Windlab’s Kennedy Energy Park proposal provided the inspiration.

The numbers and the model presented below are at best a “sketch” and not a plan.

No account is made of bidding strategies and in fact a fixed real price is assumed. We do think the results provide some useful insights into how NSW might go about replacing Liddell and one way to think about the Generator Reliability Obligation.

Methodology, wind, pv, gas and battery

Over the past 12 months there has basically been 554MW of wind capacity operating in NSW. This has increased very recently due to the startup of White Rock wind farm but we have adjusted for that.

Thanks to NEM Review we can use the half hourly output from NSW wind over the past 12 months and scale it up (by a factor of 3) to move from 554MW to 1.6GW.

At this point we note that the last 12 months has been a relatively low wind output year, but we expect new build to have slightly higher capacity factors. So this gives us the half hourly output for a 1.6GW windfarm.

Similarly we can use half hourly output from the Moree single axis tracking plant 56 MW/AC and scale that up by a factor of 8 to give 448 MW of PV.

We didn’t put much time into the ratio of wind to PV. We used Kennedy as a guide but observed that the correlation between the wind and PV output fell a little bit as the ratio of PV to wind increased.

Then we  assume we have a 650 MW combined cycle generator that can start up instantly. In reality it takes 1 hour to get to full output, but we assume the battery with its 100 millisecond response time takes care of that, and also provides frequency control.

We believe other sources of dispatchability could be as or more economic than gas, but we know gas will work, and the overall plant CO2 output is low. Using an alternative to gas, then becomes more about economics than CO2 emissions.

We also added in a 300MW/1 hour battery at a cost of $300 million. The battery increases the 1000 MW dispatchability target from 71% of all half hours to  87%, but it adds relatively little to the cost. We think we could increase the battery size to 300 MW/ 2 hours for only a small increase in cost but did not explore this case.

Dispatch algorithm 

We then set a target level of dispatchable output. We chose 1GW being broadly equivalent to Liddell’s average output. For each half hour we add the wind and the PV output together. If the total is less than 1000 MW we then use the gas generator up to its limit of 650 MW to make up the difference.

Still not enough, then the battery can run for an hour if it’s not empty.  The battery can’t run if it’s empty but we assume it can be fully recharged in half an hour.

We don’t allow for power to recharge the battery or round trip losses. The intuition is that in this system those missing items won’t change the results much.

Results

A summary of the system is:

Figure 1 Summary stats for 1100 MW dispatchable system. Source: ITKe

Figure 1 Summary stats for 1100 MW dispatchable system. Source: ITKe

The table shows that the minimum output of the system is 650 MW and we are pretty sure we could get that to 900 MW using a bigger battery for not much difference in overall cost.

The key line in the table is the average ouput. Average output is 1.15 GW and gas average output is .33 GW, so the renewable share is about 70%.

The gas plant runs at about 50% capacity utilisation which is roughly the right level for combined cycle gas. We don’t model how many starts. We think only a modern purpose-built gas generator designed for frequent fast starts is suitable for this task.

Plants such as Pelican Point would likely not be particularly efficient.

However, your author is a financial analyst not a power engineer and I could easily be missing the point on the technical capabilities or otherwise of the gas plant.

Based on 0.4 t CO2/MWh for the gas plant the emissions intensity of the entire generator is about .11 t CO2/MWh (gas share of output 30% * carbon intensity 0.4).

Dispatchability measure

A better picture, although you need to look at it properly, of the dispatchability of the system is showing the following figure.

This is based on Windlab’s presention of the Kennedy wind-solar park project in north Queensland, except that we are using half hourly data rather than daily. The figure shows the percentage of time each component, and the total system, has an output less than X where X is the vertical scale.

So for instance, 13% of the time the total generator output is less than 1 GW. However the lowest level of output is 650 MW (when the wind and pv aren’t operating and the battery is empty). About 15% of the time the output is over 1.5 GW. We don’t show the battery for simplicity.

The generator achieves its dispatchable target of 1 GW 87% of the half hours. Demand management or a larger battery could easily take care of the missing half hours to get 100% reliability. Still, even the best coal plants have the odd forced outage. On average we expect wind utilization to improve.

Figure 2 Dispatchability indicator. Source: ITK

Figure 2 Dispatchability indicator. Source: ITK

An example of the generation is shown below – “Series 2” is the PV, and the time period is 6500 half hours in 2017. My copy of Excel complained and became confused when asked to do its job on this chart. Apologies.

Figure 3 Sample output from the dispatchible generator. Source: NEM Review ITK

Figure 3 Sample output from the dispatchible generator. Source: NEM Review ITK

The average output by fuel over the course of an average day is shown below. The figure shows the PV reducing the gas usage on average in the middle of the day.

In practice gas is only being used if output is less than 1 GW so the averages reflect a combination of situations when wind & PV exceed the 1 GW target and when they don’t. On average the battery is used more at night.

Figure 4 Average output by hour of day. Source: ITK, NEM Review

Figure 4 Average output by hour of day. Source: ITK, NEM Review

Economics: Needs about $90/MWh. Giddy up

We estimate the system needs around $85-$95/MWh based on a gas cost of $9/GJ and after allowing for various fixed costs.

Gas consumption should be about 20 PJ per year so the fuel cost is sub $200 m ignoring transmission. In general we have ignored transmission but this is a big system.

For the sake of simplicity, and speed, we have assumed around $20/MWh of operating cost for the wind and $15/KW for PV and added in $40 million of fixed costs for good luck.

Although not cheap, if done via a Govt PPA a lower price might be possible as risk is reduced. Really, if the gas is contracted, then the only real risk is the building the gas plant, and its NSW not Victoria so even that is manageable.

The highly simplistic NPV model follows:

Figure 5 dispatchable renewables about $90 MWh. Source: ITK

Figure 5 dispatchable renewables about $90 MWh. Source: ITK

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  • Chris Drongers

    Surely Malcolm knows that Liddell is a clunker that is going to cost more than alternatives and that big coal-fired generators don’t address the problem of how to cover big generation units going off-line on hot days, when a boiler pipe bursts, when wind and solar are under-bidding them on the NEM?

    No, Malcolm has to have coal to prevent the RWNJ on his back bench revolting and taking his job. At best, no coal in the plan would see the RWNJ withdraw support bringing on an election that the LNP would lose.

    So no matter what Malcolm knows will work, he has to have coal in any plan. Or his government will destroy itself.

    I would love Malcolm to use his last days as PM pushing advocacy of renewable power and restoring discussion of climate change and its implications to the public realm. The uproar from the RWNJ would only shorten the term of this government by a few weeks.

    • Mike Shackleton

      MT has clearly stated he will resign from Parliament when he is no longer PM. Would the coalition want to risk a by-election in Wentworth? Especially if the SSM survey comes back a resounding yes, and they fail to legislate according to the result. 80% of Wentworth support SSM.

      He also has the party over a barrel with respect to his “loan” last year for the election. The Liberal Party is not in a great position financially.

      He is playing to his back bench but knows the reality. Renewables will win out on cost. LIddell cannot be saved. A direct coal fired replacement will take years to construct and won’t be in operation by the time Liddell closes. AGL aren’t interested in selling Liddell because they want the area to become a hub for Renewables – they will need the existing interconnect to do that.

      The issue is the voting public has heard all his talk on renewables and sees that he has done a massive back flip. The swinging voters know the reality.

      • Brian Tehan

        I agree 100%. It’s hard to see where Turnbull is going with this. They’ve managed to muddy the waters in implying that Liddell is just about to shut down, not in 5 years. The fact that AGL have a comprehensive plan to use the site for renewable generation has barely been mentioned – most people wouldn’t realise – except in Newcastle where it’s been in the Newcastle Herald and on ABC Newcastle – where it’s been covered much more objectively.

        • The Awul Truth

          interesting got a link? not much wind around there would figure the gas could be put there but not much else.

        • Joe

          Labor’s Joel Fitzgibbon, the Federal MP for The Hunter, knows about AGL’s plans. Apart from his recent interview on ABC’s Lateline program he scarcely gets any coverage of what AGL has planned. That is apart from the shirt fronting by Joshie F. in the corridors of Parliament House that managed to get onto our TV’s the other night showing us all what a…’Strong Leader’…Joshie F. is

        • Jon

          Who says AGL have a comprehensive plan to use the Liddell site for renewable generation…..surely only someone working for AGL would know that?

      • Peter Campbell

        I think you are right re MT pandering to the RWNJs. The thing that disappoints and puzzles me is that he doesn’t read them the riot act and point out they will lose the next election if they don’t embrace the future. As much as they think they have MT over a barrel, surely he has them over a barrel? As you point out he could threaten to go out in a blaze of glory if they don’t agree to be led by the leader. However, I think he has left it too late. When he was new and high in the polls was his moment to turn around an renege on whatever he promised to get the job. The RWNJs would have called foul and blustered but what could they do?

  • RobertO

    And with Solar there is also the hidden solar installations as well (places like Boggabilla with its 4.7 MW and King School in Sydney (200 KW?) and even my local school which is planning on solar on just 2 building at 180 KW. Bio gas may also play its small part. The current trouble is that this has become poticial hot potato rather than enginnering / economical issue, hopefully when Malcome get the AGL price he drops the Liddell plan.

  • trackdaze

    Lets be clear the governments goal in dragging the expensive unreliable liddell coal plant down the road is just as much to do with scaring off investment decisions for competing renewable plants in the interim.

    That and maybe a donor or two stand to gain from extended coal supply contracts.

    • Mike Westerman

      Then let’s all stand and laugh when NSW blacks out this summer when a large thermal unit falls over. Sorry poor New South Welshmen, but if that’s not your choice of scenario for Christmas Day, get out and make a difference.

      • Joe

        We / NSW went close to blackout in February this year. This summer anytime the weatherman forecasts a 40 degree plus day it will be panic stations. But Big Mal will be our ‘Strong Leader’ and assure us all is well…Liddell is going gangbusters!

  • Steve159

    We know Malcolm is not stupid. So his insistence on keeping Liddell open or selling it, despite him knowing it’s a clunker, must be due to a deeper agenda, beyond simply keeping the LNP donors happy.

    Watching Joyce on tv, seeing how he talks down to the electorate (insofar as he pushes a clearly non-optimal energy solution) got me thinking, it must be something in their DNA. In my opinion it’s their “command and control” of the electorate.

    The late British MP Tony Benn explained how they do that:

    “See, I think there are two ways in which people are controlled.
    First of all, frighten people, and secondly, demoralize them. An educated, healthy and confident nation is harder to govern.

    And I think there’s an element in the thinking of some people: “We don’t want people to be educated, healthy and confident, because they would get out of control.”

    The top 1 % of the world’s population own 80% of the world’s wealth. It’s incredible that people put up with it, but they’re poor, they’re demoralized, they’re frightened. And therefore, they think perhaps the safest thing to do is to take orders and hope for the best.”

    So Bananabe and his LNP crew work at keeping the electorate both demoralised and frightened. Hence why they didn’t knock negative gearing and capital gains tax on the head — keeping people scrambling for a place to live, and having them running around trying to pay for it all, is exactly what you do to demoralise. Then hold press interviews with a few flags, replete with dudes in gas masks, and you’ve put the frighteners on a fair whack of the electorate (so they don’t jump ship).

    • Steve159

      Oh, nearly forgot, having a gazillion micro power-stations (solar on rooftops, with batteries), is really hard to command and control. You’d have to invite them to export to the grid, rather than milking them through centralised power providers.

      When the Liddell nonsense is all-too-soon forgotten, because cheaper, cleaner alternatives are installed, watch how the next big push from the LNP will be to control the individual householders as to how, when or if they can export power to the grid. They’ll yell, kick and scream how micro-grids, a no-brainer, will destroy “reliable, base-load” power or some such. So predictable.

  • bedlambay

    Will be interesting when AGL again wrong foots Turnbull in 90 days time. When they offer cheaper and more reliable alternatives to Liddell how will Turnbull respond. Very similar political chicanery as SSM plebescite which is insisted on by the same toxic ratbags, Abbott, Craig Kelly, Andrews, Bernardi, Christensen et al.

    • Rod

      AGL should hold a press conference and release a statement minutes before the meeting.

  • David Mitchell

    This is a great analysis and really shows up the “extend Liddell” proposal for what it is, a knee jerk thought bubble.

    However, I cannot understand the fascination with CCGT. This is exactly the wrong technology to match wind and solar. They don’t start fast (assumptions notwithstanding) and the maintenance costs scale poorly with frequent start/stop operation. When they are operating at low capacity they use nearly as much gas as at high capacity.

    Far better would be a power station composed of large reciprocating gas engines, say 15-20MW each. These are then bought on line in modular fashion as demand rises and falls. They can synchronize to the grid in less than 10 minutes from a warm start. They operate at peak efficiency and have built in redundancy. They are also more efficient than turbines, so less gas. There is absolutely no maintenance penalty for stop/start operation, merely a function of run hours.

    • Malcolm M

      The NSW market already has fast-ramping hydro generators in the Snowy, and its coal generators vary their output in line with demand more than those in other States. There are also open cycle gas generators such as Uranquinty. So a combined cycle gas unit would complement the existing mix.

      • David leitch

        I am going to do some more work on this. Because the gas is expensive, and because we need a big plant and because there are these fast start plants in the USA and because we can use the battery in some situations I tend to think that the CCS plant may be beat the reciprocating engines.

        In the 12 months studied the gas plant would have run for an hour or less 58 times and 88 times for 2 hours or less, 104 times for 3 hours or less. its average running hours was 41 and median 15. Longest run was 310 hours.

        If I changed the algorithm around to dispatch the battery before the gas gen and bumped up the battery storage to say 2 hours you could maybe lower startup costs on gas significantly.

        • Mike Westerman

          David why wouldn’t you include PHES? A 6GWh storage cycled for 300h of generation pa (1,800GWh/a), with capex of $2B amortised over 25y at 7.5% has a levelised cost of less than the cost of gas for a CCGT – combined with solar that would result in an average price much lower than $90.

          • David leitch

            There are a couple of reasons. 1 Is that i’m not yet convinced about the cost of pumped hydro. 2 It would have made the “modelling” i.e. spreadsheet more complicated, I would have to allow for refilling and 3. Which is a bit cultural is that I want this idea of “largely renewable dispatch able to have a broad audience and so by including some gas it can identify me as “not in the loony 100% renewables club”. The carbon output is low with the gas. It might be cheaper with pumped hydro, but its a harder sell. Hard enough already.

          • Mike Westerman

            Hopefully you will be pleasantly surprised by the SA Bulk Energy Storage funding round! Certainly by the end of the year you will have benchmark prices on several PHES.

            I’m indifferent to gas – it has to compete without government subsidy given exploration costs are so heavily subsidised already, tho’ I know it can’t. I don’t see why gas is less “looney” than the largest form of energy storage in the world by a huge factor, using a technology that predates gas power by half a century!

          • RobertO

            Hi David. NZ had some very bright pollies. They decided that Meri Meri (MM) Coal power in the late 80’s was too expensive so they order production to be shut down and be on 8 Hr standby. Waikato River has lots of Francis Trubine on it that are pumped hydro stations that used excess MM to send H2O back up system at night. Enter the drought and about 6-12 months later power shortages as lake flows reduced. Pollies ordered MM back up to full production but it took about 6 months for rain fall to recover and power shortages to stop. About 2 years later the system was where it should have been fully recharged plus on standby MM used about 80% coal hence savings were negligible. I think 6 are pump hydro stations and have been used for many years.

            https://waikatoriver.org.nz/wp-content/uploads/2014/09/23-Hydrodams.pdf

            Our biggest problem is no plan. If coal feeding does become more expensive that building new wind or solar then what to stop the coal just pulling the plug and closing up shop. Finkel said 3 years notification which need to be done now and include records to prove intention to keep running. Failures are accepted as normal mechanical issue but you can accelerate issues easily to distroy the system. Paying for coal just to be in the system is not good either. The other change that may impact is EV and we still do not have stardard efficency rules for ICE for transport. I worry that the change will happen without any plan and faster that our pollies realise despite all they are doing to stop the change. Will we get to 100% RE perhaps in 100 years or so, but 50-70% yes in maybe 10 to 20 years. Liquid FF or Gas FF possibly last to leave (and may never leave system required as backup but never used unless Bio/H2 stroage improves).

          • RobertO

            Hi David Long term we are going RE in some volumn. We need storage both short (batteries) and long term (Pump Hydro or PH) and there may be others of both types. Batteries in Australia may turn into a recycling nightmare if not handled correctly. Where I work we get Paper for less than 1 cent per Kilo and people still put paper in our general waste at 15 cents per Kilo or even on our tipper truck at 19 cents per Kilo. The common attuide is “that only one sheet of paper” when the reality is that they will toss wads of paper (it not uncommon to find 30 to 50 mm wads of A4 sheets). Another example is Aluminium Cans, SA is about 97% where as NSW is about 27% (even at work I think it is only about 50% and the state gov has delayed the cash for cans a couple of times already). We run a full recycling program of bins, red for waste, yellow for plastics and metals and blue for paper and cardboards. I estimate about 1/3 of the waste is recycleable
            PH has a big advantage in that area. The enviromental damage is a lot less overall (less or two evils) and the life cycle a lot longer in dams.

            http://www.snowyhydro.com.au/our-scheme/snowy20/snowy-2-0-faqs/

  • howardpatr

    As Chris Drongers said, “Surely Malcolm knows that Liddell is a clunker that is going to cost more than alternatives” – he almost certainly does but it seems he must placate a blithering fool of a so- called Deputy Prime Minister and fellow RWRNJs, like Mad Monk Abbott.

    David Lietch’s article just serves to demonstrate what rabble the Coalition really is and what a dismal failure Turnbull has turned out to be.

    Turnbull – the man who said in 2009:- “I WILL NOT LEAD A PARTY THAT IS NOT AS COMMITTED TO EFFECTIVE ACTION ON CLIMATE CHANGE AS I AM”.

    As each day goes by Turnbull demonstrates that despite being well positioned to take on the dinosaurs in the Coalition he will act in his own interests before those of the nation and the planet.

    • Peter Campbell

      Since neither Turnbull nor his party seem to be committed to effective action, the statement seems to be true.

  • Radbug

    I cannot understand why, given that all these generators, fossil & renewable, are out in the middle of nowhere, while our local shopping centre roof & carpark remains without PV coverage.

    • trackdaze

      They are on 3-5yr contracts costing 8-12c per kilowatt. As these mature and costs go up solar will make sense.

      Some roofs aren’t capable of carrying the loads or retain wind ratings.

  • Nick Thiwerspoon

    Most interesting analysis.

    The implication is even more interesting: if your model–wind, solar PV, gas & batteries– can produce target output 87% of the time, then the same should be true for the NEM as a whole, only more cheaply, because of the greater geographical spread of wind and solar farms. Liddell today; the NEM tomorrow. I wonder if Trumbles and Bananaboy realise how subversive an AGL proposal like this in effect be.

  • Colin Edwards

    When Josh Frydenberg was interviewed by Rafael Epstein on Liddell and alternative energy sources, he misleadingly (deliberately?)
    conflated “dispatchable” with “baseload”, as if the two are the same! Somebody sort him out please?

    • Joe

      Premier Jay is ready for another shoulder to shoulder… ‘discusssion’.

  • solarguy

    Not that impressed with this article sorry. Better to think it through and get some expert engineering opinions before producing this sort of thing.

    • David leitch

      It makes me laugh solar guy. Just shows how my perception differs from others. You are more than welcome to your opinion and you may be right, but I personally think it’s the best and most original piece I’ve written this year.

      Cheers

      • solarguy

        Sorry if I hit a nerve David, it’s just that you do such good work normally and I thought it was a wee bit premature. And yes I know it’s a hypothetical splurge, with a bit to much supposition in it. BTW you may not of thought of Tomago smelter re: “storage” as it uses ridicules amounts of energy 24/7 so PHS would have to be built to take care of that at night and shitty days. Perhaps later you could include that in your modelling.

        I’m all for using Biogas as a peaker and back up, though this an under utilized currently, but it’s a huge resource that really must be used going forward. ………………….your thoughts?

        • David leitch

          No nerve hit. I’m often surprised at the difference as to how I perceive things compared to others. I think about Tomago a lot, its kind of why I wrote this note. The generator modelled here could run Tomago with plenty left over. However Tomago wouldn’t be economic paying that electricity price.

          • RobertO

            Hi Remember that the mix may not be local and it may also use power from other states when we have poor production in NSW. Even demand management may save more that what we lose in 2022 when Liddell closes. There are lots of little things that can be done that do not cost the earth (some are already underway in the background, commerical lighting is one) Trangrid has a few plans but need to do the RIT-T paper work first. Some Wind farm that have DA’s but not started may be completed before 2022, some have started but target is next year. The article works for me. I have been planning a CH4 project for 6 years.
            I was talking to an 84 sparky today. 40 years ago every new building had own Diesel Gen set in the building. Today most new building do not have any back power except Hospitals and Banks (often UPS Diesel systems) or critical buildings.

          • Ian

            David, glad you think about Tomago. Why is this industry mollycoddled with cheap 24/7 electricity like it’s the Queen of England? There is technology available to make aluminium smelting more demand responsive. It’s time this industry pulls its weight in creating flexibility in the grid.

            The chemical engineering and process engineering of aluminiumsmelting is complicated and difficult but this seems an interesting area for modernising and redevelopment.

          • David leitch

            Data centers will soon consume as much electricity as aluminum. The world needs and can have large quantities of power with low or zero carbon. EVs will consume power, electrification of industrial processes likewise.

            I’ll check out that virtual battery.

          • solarguy

            So what’s the answer for Tomago if it’s too expensive. Do you have any suggestions on how it could be made economic to power the smelter at night?

        • RobertO

          Bio gas 2M3 =1Kwh, sewage on it own about 80 Kwh per 1 ton solids, add 1 ton pizza boxes to the mix about 560 Kwh. Any natural biodegradeable product has it own production rate. I tried to get Sydney Water (SW) in 1984 to plan a 100 year program to pump all sewage over the Blue Mountains (start small and build in more each year). They were just pumping out to sea with no treatment. LA in the United States using primary treatment only had 24 * 1500 Hp electric generators running at one plant. The engineer said State Government would not let them do it. 2011 I discovered they were using 5 Bio plants but primary treatment only. 2017 SW supplying humus to a farm. Secondary treatment at long last but they still waste most of the H2O
          Israeli was doing this in early 1950’s. CH4 for cooking, Humas for fertiliser and water for the crops. Read one of my dad’s mag about study of food chain in Israeli about 1964, 200 000 people showed about 0.0003% increase in infections but one MD stated that he/she thought that this increase was due to 20 000 new people in the study group, not being use to the local bacteria. Bio gas is storable but not a huge resourse. Long term wind, solar, Hydro (all types) CST, Natural Gas (added H2 from wind/solar overproduction after charging all batteries systems up to 10% by vol) then Bio gas. Heavy transport will possibly use H2 fuel cells, with batteries
          Sydney Water
          http://www.sydneywater.com.au/SW/water-the-environment/what-we-re-doing/energy-management/index.htm
          Transport
          https://nikolamotor.com/
          Food to electricity
          https://earthpower.com.au/

          Hope this help

          • solarguy

            Not sure if you figures are correct or not from memory, but I remember this, 1 tonne of human waste = 1 cubic meter of bio gas and that is the energy equivalent of 2lt of petrol. The treatment plant near my place receives 1.5million litres of sewage a day. Now a litre of water weighs 1kg, but being mixed with solids would weigh more, so 1,000kg = a tonne and I’m sure you can do the math from here. That is a shit load of energy (pardon the pun) going to waste and polluting the atmosphere with methane.

            If we used this huge resource as well as green and animal waste, I believe were on a winner, kill two birds with one stone. If we build plenty of plants like this as well as PV, wind and CST with storage, I’m thinking problem solved for the most part at least.

            CSIRO research has confirmed if we react CH4 with water at high temps by way of CST the H2 gain produces a fuel with 25% higher calorific value.

          • RobertO

            hi, 1 person deposits about 80-120 grams and uses 150 litres H2O per day. It’s a very weak mixture. I may be wrong with 1 ton solids (sewage) but Pizza Boxes 1 ton (dry weight) is about 960 metre cubed gas hence 480 Kwh is the best producer of gas. Add green grasses and the numbers are from 120 to 340 (dry weight) CH4 production. All the materials combine to produce what ever comes out of the plant.
            Pump it all out to sea = no CH4 production and all the H2O wasted (in 1984 it was 250 liters per person but water saving devices are having an effect) Sewage plants use about 1 Kwh per person for pumping and Bio Digester Sewage plants reduce that to 0.3 to 0.6 Kwh, but add additional materials the system becomes positive producer of Kwh and if the H2O can be reused (increase food production in Murray Darling basin).
            The system losses to pump it up the top of BM were Pump Hydro losses plus a bit more loss, but the food production made it a very cheap loss. Murray Darling was in drought that year and people are still complaining about water use in the basin. H2O put into three or more river system at the top Bogan Macquarie and Lachlan or other.

          • solarguy

            Perhaps PV can reduce this pumping loss, maybe even eliminate it.

          • RobertO

            It would never get past the pollies. Any idea no matter how good it is, if the pollie can get a benfit out of it for the next election then it got no hope. I was told that in 1984 and it still valid today. Look at how long it took the engineer to get primary treatment started in SW. I gave him the print out from the LA system about the 24 generators they had. If Turnbull hates the AGL ideas then even if he public accepts them he will still blame RE for any Blackout until he gone for parliment. AGL are being made a scapegoat by the Fed Gov.

  • Malcolm M

    Surprised there has been nothing about new high voltage transmission as a solution. For example, on the hot day in February 2017 when Tumut 3 was producing 1700 MW, imports from Victoria were limited to ~400 MW because of transmission limitations between Tumut 3 and the 500 kV network at Bannaby. The current NSW high voltage transmission plan includes a proposal to extend the 500 kV network as far as Tumut 3. This would increase the import capacity from Victoria by at least 2100 MW. (Most of this power would probably come from the Murray station, which while physically in NSW is within the Vic market, rather than stations in Victoria itself.) This transmission investment would be needed anyway for Tumut 3, and for more solar in the Riverina. While the Vic network also has its own pressures, heatwaves in Sydney are typically a day later than heatwaves in Melbourne, so it is extremely rare for both the Vic and NSW markets to be under pressure at the same time.

    There is also the possibility of additional transmission capacity from Queensland. For example a transmission line from Swanbank to Lismore is ~130 km and could add 1000 MW to the NSW network. Queensland has the youngest coal fleet, and with the additional renewable generation there will be looking for a market.

    • David leitch

      There is a lot of support for new interconnectors. they do not preclude distributed generation but complement it.

    • Mike Westerman

      I agree Malcolm, but including a second Basslink at 2GW so cover Vic. Also not sure why you wouldn’t include 1GW or so of PHES in NSW with a levelised cost of storage of $70-80/MWh – cheaper than combined cycle at the start of the analysis period and getting cheaper as costs of RE drop. Take your pick of sites: off stream version of Apsley (FS done in 1981 for ECNSW used onstream Apsley but alternatives quite feasible) or Brown Mountain in NSW, Dartmouth in Vic, Mt Byron in Qld (but needs QNI reinforcement).

    • Greg Hudson

      ”heatwaves in Sydney are typically a day later than heatwaves in Melbourne”
      Spanner in the works… Heatwaves in Melbourne can last a lot longer than one day, so it is not uncommon for Sydney and Melbourne to be under pressure at the same time (IMO)

  • RobertO

    For Bass Link 2 (BL2) the costing is about $1 billion but if you add King Island the costs go up by 5% to 10% but you add 1000+ MW wind plus you delete 2.6 Million litres of Diesel. All electrical cable buried or sea can have optical fibre added about $600 per Km as opposed to fibre only sea cable of $60,000 per Km. The problem with Transmission is that we need to start now and the current plan for BL2 is to wait until SA gets a new interconnect or Wind in Tasmania gets more that 700 MW new wind. Build it and the Wind will come form both Tasmania and King Island

  • Peter F

    I hate to go on but
    1.Germany with lots of cloud and old solar panels, poor wind resources away from the north coast and a smaller share of hydro than us, are generating 200TWr from renewables in 350,000 sqkm. If you draw overlapping circles 180 km radius around the main population centres down the east cost and up to Port Augusta, they enclose about 1,300,000 sqkm of land area.
    We can locate all the generation we need within 200km of the load.

    2.The latest generation 4MW class wind turbines generate 12-20GWhrs vs the current German average of 3.4GWhr per year. i.e. you can replace Liddell’s entire generation with 600 of them. If they are running at 35% of rated capacity they will produce more power than Liddell did during February’s peak.

    3.NREL did a study of the rooftop capacity of the US and found 14% of the small roofs could meet peak power and 15-20% of all roofs would supply all the electricity of the US at 16% panel efficiency. They have worse average insolation, less roof space per person, use more power and new panels are already beating 16%. We should be able to generate 200-300Twhr from rooftop solar alone.

    4. We use 20% more electricity per head as California and 40% more than Germany we should be aiming to cut energy use by 1-2% per year roughly 5-10% by 2022 or two to three times the lost output from Liddell

    4. In the short term while it might be advantageous to make some small grid reinforcement eg the Swanbank to Lismore line, heavy duty high voltage transmission is not generally required.

    At the current state of play,the best investment it is a trade-off between demand response, extra wind and solar generation, local storage particularly for heat and ice, batteries, some gas and last of all large scale transmission enhancements
    a.demand response

    Thus there may be a case for more interconnects

  • RobertO

    Hi David, Liddell mines coal, is any of the old mine sites worth considering a Pump Hydro site like the Kidston project. Is this part of what AGL is thinking about using at the end of Liddell?. They use vast amounts of H2O already so they have licences already.