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The future of energy generation and storage

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I can see gas as a future feed stock for future fuels such as syngas technology’s but as a raw energy needs for power stations and homes, gas exports will be made redundant some time in the future in my view. Why export a compressed gas that takes enormous amounts of energy to store when you can use syngas techniques to transport it in a liquid state and at a fare grater volume and and being carbon neutral at the same time.
 
Muckman said:
Why export a compressed gas that takes enormous amounts of energy to store when you can use syngas techniques to transport it in a liquid state and at a fare grater volume and and being carbon neutral at the same time.
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Natural gas is exported in a liquid state, it is not compressed.

We export LNG, (Liquified Natural gas) not CNG (compressed Natural Gas)

Natural gas is reduced in temperature until it is turned into a liquid, reducing its volume by 600 times, it is then stored as a liquid during shipping, and allowed to warm up and return to a gas at its destination.

Here is a short video explaining it.

 
sptrawler said:
When I installed the first solar system on my place 10 years ago, it was always tripping on over voltage and I did see over 250v, but I haven't seen those voltages for a long time.
As the person in the article said, there are things they can do to remedy the problem and steps are being taken everywhere.
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My car tells me the voltage of the power point I am plugged into, it seems to fluctuate above and below 240V, I have seen it go to 247V a fair few times, at first I was worried, but I called the energy company and they said fluctuations were normal, but that they had an accepted range, I can't remember what that accepted range was, but it does seem to be higher than 240V more often than not, but I am no expert, thats just what I see.
 
IFocus said:
Interesting obviously wants 7 media onside, but maybe makes sense to maintain local supply unlike the eastern states that pay more for domestic gas that the exporters do
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Yes it would also have been even better, if we were piping gas to the Kimberley's, rather than Darwin from the Browse basin.

The Ichthys gas field is a natural gas field located in the Timor Sea, off the northwestern coast of Australia. The field is located 220 km offshore Western Australia and 820 km southwest of Darwin, with an average water depth of approximately 250 metres.[1] It was discovered in 2000 and developed by Inpex in partnership with Total, Tokyo Gas, Osaka Gas, Chubu Electric Power, Toho Gas, Kansai Electric Power and CPC.
 
Smurf1976 said:
There's a simple explanation for it all. :)

Historically, pre-solar days, under normal circumstances in the context of supply to homes and small business voltage would only ever go down, not up, between the transformer and the consumer. Voltage rise can happen in the context of industry and long distances but not normally for small loads in the suburbs.

As such, if you've got a nominal voltage range of 216V - 253V then, since it was only going to go down never up, it made perfectly rational sense to intentionally aim at the upper end of that range. Aim for 250 and not much chance anyone's going be below 216.

Same with anything. If you're buying clothes for children and they're half way between sizes, well the kids are going to get larger not smaller so it's an easy choice to go a bit too large rather than a bit too small with the shoes, trousers or whatever. Give it a few weeks and it'll be just right.

The trouble is that with so much solar, it is indeed now the case that voltage can go up within the distribution network to exceed that at the transformer. All of a sudden the old approach not only doesn't work but it fails rather spectacularly to be aiming at the upper end and then it rises further. That's akin t saying that the kids do indeed get smaller at times, all past thinking has been turned on its head completely.

Just turning it down permanently isn't a solution however. At 6pm in Winter with everyone cooking dinner, running heaters etc and with no sun then the problem of voltage drop is as real as it always was. Send out, say, 230 at the transformer and someone's going to be complaining that it's 202 in their house. Can't get around physics there, that was always the reason for jacking the voltage up toward the upper end of the range, it gets around the problem that it will drop under load in the network.

There's really 3 solutions to this:

1. Put the electricity to use within the network at the time it's being produced. The old logic of heating water in the middle of the night, or using gas to do it, is very rapidly becoming obsolete.

SA now routinely sees minimum demand in the early afternoon, not overnight, with WA, Vic and parts of the NT rapidly heading to the same situation indeed at a local level some parts of those states already are. Other states will get there in due course and already are in some localised areas within them.

So shifting non-time critical electrical loads to the middle of the day makes massive sense, and increasingly so does shifting from the direct use of fuel to electricity where the end product (eg hot water) can be stored.

2. Do clever things in the network. That is, change transformer taps in relation to actual measured voltages or at least based on a reasonable proxy (eg weather and time of day will get it pretty close). That requires some investment but not dramatically.

3. Accept that ultimately there are limits to how much rooftop solar makes sense. The rationale behind it is that the land cost is zero and the electrical network is already there. That idea works to a point but fails if we have to spend $$$ upgrading the network, in which case the alternative option of building large solar farms is an alternative means to the same end result without adding stress to the distribution network.

Here's a 53,000 kW solar farm which if fully operational will in practice produce comparable output to around 10,000 household systems given that the latter will have issues with sub-optimal orientation, shading and so on which a large solar farm doesn't. Further, it does so more consistently through the day thus reducing the need for storage capacity:

https://www.google.com.au/maps/@-31.9877709,141.3908337,2659m/data=!3m1!1e3?hl=en

Now zoom that map out. Please don't anyone try and tell me that land's a problem - not in Australia it isn't. Even Victoria and Tasmania have far more land than they're going to need for solar farms.

Here's another one, 108 MW, again it's the proverbial drop in the ocean in terms of land use. https://www.google.com/maps/@-35.27469,139.4859376,2560m/data=!3m1!1e3?hl=en

So we won't sensibly put solar on literally every house, it's just not sensible to go beyond the point where the cost of doing it becomes uneconomic compared to the large scale alternative. That in itself means that distribution network upgrades only need go to a certain point beyond which further expenditure makes no sense. :2twocents
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So am I right in assuming that if my neighbour hood, is producing more solar than we can consume, there is no way to pass the excess back through the transformer and into another neighbourhood, or is my understanding of the issue wrong?

Also, are the transformers you are talking about those boxes you see up the power poles with 100 or so houses connected to them, or are you talking about the larger substation type things?
 
Value Collector said:
So am I right in assuming that if my neighbour hood, is producing more solar than we can consume, there is no way to pass the excess back through the transformer and into another neighbourhood, or is my understanding of the issue wrong?

Also, are the transformers you are talking about those boxes you see up the power poles with 100 or so houses connected to them, or are you talking about the larger substation type things?
Click to expand...

I found these video trying while trying to answer my own question.



 
sptrawler said:
Wow this could be a bit of a concern for Eastern States and its gas situation.
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I'll keep out of the lunacy (politics) and simply note the reality of the situation as it applies to south-eastern Australia (the whole of NSW, ACT, Vic, SA, Tas collectively):

In terms of consumption, for example (only) on 4 August 2020 it was 1983 TJ across the south-eastern states versus 794 TJ on the 24th of January (and that wasn't the lowest, it's just a random day I picked).

So there's a very clear seasonal pattern there hence, in the absence of some major incident, if supply copes through winter then it'll cope through the following summer without much drama.

Now to summarise what the industry, AEMO and everyone else is well aware of:

Supply will get through winter 2020, 2021 and 2022 so long as there are no major incidents etc.

Supply might be adequate through 2023 or it might not. Depends on exactly when certain fields stop producing which depends on the exact rate of consumption. That comes down to temperature (heating) as well as other things like the overall economy (business use), operation of gas-fired power generation (which would go up in the event of any major failure of coal / hydro / wind / solar) and so on.

Supply isn't adequate for winter 2024 with present infrastructure, gas fields and so on. Not much chance it'll make it that far unless we get consumption right at the low end of what's possible between now and then.

That's the crux of it. The rest is politics and so on.

Hence the various proposals to boost supply including, among others, the Santos gas field development in NSW (200 TJ / day), the new pipeline from the NT (124 TJ / day) and various ideas of importing LNG to NSW / Vic / SA and/or building a pipeline from WA or additional pipelines from Queensland or NT.

A key problem in all this which leaves many confused is that it's all somewhat instantaneous. Energy's basically the only thing where it's entirely possible to have an abundance of supply today and be in a crisis literally 24 hours later if the weather changes and demand goes up or something fails. That doesn't happen in terms of coal sitting in piles or fuel in tanks etc but it sure can in terms of gas actually in the distribution network or electricity that's actually available.

Eg mid-summer it's not unknown to see Victoria's total gas consumption over 24 hours at just ~20% of the peak winter daily consumption. Once you realise that point, it's then fairly easy to grasp that it just needs a change in the weather to go from surplus to shortage or vice versa in terms of gas that's been produced and is in the pipelines. Hence the focus on daily production capacity - that impacts the ability to supply consumers far more directly than does gas in the ground or annual production rates despite those all being related.

End of the world? No - but there's a looming supply gap and the options are either that something fills it (new supply) or consumption must be reduced. There's no way around that. I'll leave the politics to the politicians though. :2twocents
 
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Value Collector said:
So am I right in assuming that if my neighbour hood, is producing more solar than we can consume, there is no way to pass the excess back through the transformer and into another neighbourhood, or is my understanding of the issue wrong?
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Transformer can go both ways.

Where the issue arises is that due to the resistance of the wiring, there will always be some loss as current flows through it and that loss in practice means a drop in voltage.

Put a supply source at "A" and a load at "B" with however much wire between them. The voltage measured at "B" will be lower than that seen at "A" due to that loss.

If you've ever noticed that the cable of a high powered appliance gets warm then that's the reason why. It's the voltage drop within the cable due to the current flow and the resistance of the copper wire. That voltage drop will by its very nature produce heat.

Traditionally the only issue in the network was a loss of voltage between the transformer and consumers since power flow was in one direction only. Eg send out 250V at the transformer and it was a given that consumers would get no more than 250 and that most of them, due to that voltage drop, would get a bit less. It worked and nobody complained.

The problem now is that power flow is in two directions and under circumstances where a large portion of homes have solar, the transformer becomes the load on the low voltage (230 / 400V) network and the small solar systems are collectively the source of supply. That is, power flows from that street through the transformer and into the rest of the grid.

That can work but for it to do so requires that the solar systems can and do push the voltage to a level that's higher than the transformer. Same as anything involving pressure - to inflate a tyre requires that the pump can produce a pressure that's higher than what the tyre is already at. The higher the tyre's current pressure, the higher pressure the pump needs to apply to get more air into it. That's where the trouble starts.

If the transformer's at 250 then the solar needs to push it above that in order to get that power to flow into the network. End result is it goes too high and the inverters automatically trip due to excess voltage as they're required and designed to do. That's becoming an increasingly common problem.

Turning the voltage down at the transformer to, say, 230 fixes that problem since now the voltage can rise above that in the network and still be within specifications as such. So the solar inverters cause the voltage to rise to (say) 245 but no problem since the inverters are happy at that level and it all works.

Where that does cause a problem though is at ~6pm on a cold winter evening. Everyone's got their ovens, heaters etc going and we see considerable drop between the transformer and the customer furthest away. Send out 230 at the transformer and it's a given that the house furthest away will get considerably less than 230 V and if it's too low then they'll be complaining that the oven's taking ages to heat up, the lights are dim and so on. Overcoming that voltage drop in the network was the reason for running the transformers at ~250V in the first place.

So the change is from a situation where voltage always dropped as distance from the transformer increases to one where, if there's enough solar, it may either rise or fall at different times of the day.

The solution to that is to change the voltage at the transformer according to what's going in in the network. That is, drop it down for the middle of the day but be able to wind it back up for the evening peak. That allows the voltage to rise above the transformer voltage during daytime without tripping off the inverters but jacks the transformer voltage back up to avoid the problem of voltage dropping too low during times of high demand and no sun.

Trouble is - in many cases we don't have an easy method of actually doing that. Different transformers, different ages, not all of them have any taps which can be used to adjust voltage anyway and even if they did, doing so requires a site visit with a truck and so on.

Workaround to that problem is change it on the high voltage side instead. That then takes all the transformers on that HV line up and down with it. It's easier to set up since it becomes one change instead of a hundred and so on and whilst less tailored, in practice it's good enough given that a few volts either way won't really matter.

Note that there are differences in the manner in which different distribution networks are approaching the problem and that comes down to their having different equipment, different load profiles (eg heatwaves not really an issue in Tas for example) and different % of homes with solar.

The other issue is the prospect that small solar systems generate so much power that there's simply nowhere for it to go. That is, we can feed surplus from one street into the rest of the network no worries, we can even feed the surplus from a whole town(s) back into the transmission grid, but that relies on someone consuming that in real time.

SA is within sight of actually reaching that exact situation, a point where total small solar generation is so high that exceeds total consumption within the state from all consumers, and in due course Victoria, WA and parts of the NT are sure to get there too.

Conventional power system operation relies upon being able to vary the output of generation so as to match load but that obviously can't be done if all the generation is sitting on roofs and there's no control over it.

In that context SA is the world leader so far as any reasonably large power system is concerned and there's a lot of discussion as to how, exactly, to deal with the situation.

So long as SA is connected to Victoria and Vic hasn't yet reached the same situation then that's one workaround. Trouble is, relying on a single asset that has had major failures in the past (a section of that line was destroyed by extreme weather just a few months ago, since repaired) is too risky when failure could black out the whole state. Politically that would be a nightmare if it happened.....

Building a new SA - NSW line provides one workaround. Sure that could fail too but the chance that both fail at once is pretty slim.

Simply encouraging more use of electricity at midday is another workaround. Eg heating water is an obvious potential use, charging EV's and even just things like pricing incentives to encourage people to run the dishwasher at midday instead of 9pm. Etc.

Batteries, pumped hydro and any other form of storage is another solution. In practice it adds load to the system if it's charged during the middle of the day, thus keeping load up to a point where it always exceeds the output from small solar systems.

Finally, the "last resort" idea is one that won't be popular with consumers although it'll no doubt be more popular than a system collapse. It isn't being done now, and nobody's proposing it as an economic or ideological thing, but from an engineering perspective well if all else fails then intentionally jacking up voltage across the distribution network is one way that inverters could be forced offline. They won't all go off at once but slowly ramp it up and that'll cut solar output thus keeping load up to a point where the system is controllable. Not ideal but as a last resort measure if all else fails well then it would work yes.

As a broad comment there, the networks don't really care about all the ideological and political argument, it's just an engineering question of making it work. SA's the leader globally so there's nobody else to copy. Meanwhile some of the options available in SA, eg exporting the problem to Vic and NSW, aren't an option for WA which is heading down the same track. But it's an engineering issue not an ideological one.

Separate but related to that, it's a reality that quite a few present power stations simply weren't designed with the idea that they'd be operated intermittently. They were designed to run solidly for months at a time since, at the time they were designed and built, that was what they needed to do. Trying to adapt those to intermittent operation to accommodate wind and solar ranges from easy (some hydro and gas) through to impossible in practice (some of the coal plants) with rather a lot being able to go part way there.

That becomes a problem in a scenario when it's sunny and with moderate demand at midday but then the weather changes and demand is high during the evening. There's quite a bit of plant that simply can't get back on in that time frame or at least not without incurring $$$ in costs to do it.

To be clear though, some coal plant certainly can ramp up and down pretty easily and we're not yet at the point where we actually need to turn all of it off anyway. It's definite issue though. :2twocents
 
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Value Collector said:
I called the energy company and they said fluctuations were normal, but that they had an accepted range, I can't remember what that accepted range was
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216V to 253V is the accepted range however the "preferred" range is 225V to 244V.

The first one's the requirement as such, the latter is the goal but not always achievable.

Some distributors will act on anything outside that range, others will only act on a marginal breach of the standard only if it's for a specified duration. That said, any of them will jump real quick if it's something way outside the range to the point of being dangerous.

Frequency is nominally 50Hz with the normal operating range being 49.85Hz to 50.15Hz.

In the event of an incident, the goal is to contain frequency within the 49.50 to 50.50 Hz range. Not always achieved in practice depending on what's gone wrong but that's the aim. :2twocents
 
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On the same theme, Australia's biggest solar farm online, the good part is they are all starting to get their $hit together rather than just throwing them in. It is all coming together IMO, magic.:xyxthumbs
https://reneweconomy.com.au/austral...istered-with-two-big-spinning-machines-40203/
From the article:
Darlington Point – which was originally due to begin production earlier this year – is also located in an area of the grid known as the West Murray zone, which is considered weak, and where “system strength” have been identified, and where five big solar farms had their output cut in half for more than seven months because of potential voltage issues.

Darlington Point – despite being located in what it says is an “ideal” part of the grid, near Griffith in south-west NSW – has installed two synchronous condensers – large rotating machines that mimic the operations of coal or gas generators, to try and ensure that it is not penalised for any grid stability issues that may emerge.

Project developers in the region have been warned of extended delays to the congestions and commissioning, and AEMO has recently decided that projects will be connected one by one (sequenced), so that grid issues can be monitored.
 
basilio said:
This decision reflects the view of the role of fossil fuels in the longer term energy mix

Insurance giant Suncorp to end coverage and finance for oil and gas industry
Suncorp’s decision to pull out of industry by 2025 puts it at odds with government push for gas-led recovery
https://www.theguardian.com/environ...coverage-and-finance-for-oil-and-gas-industry
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Looks like the PC brigade has got into the insurance industry now.

Gas may be a fossil fuel but it's a lot cleaner than coal, and I'd rather trust Alan Finkel when he says gas should be an important part of our energy grid.

I suppose insurance companies can do what they like with their money , but I'd rather have scientists and engineers designing our essential services.
 
sptrawler said:
AEMO has recently decided that projects will be connected one by one (sequenced), so that grid issues can be monitored
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It's a scenario that's all too familiar to anyone who's had involvement with power generation and for that matter transmission too.

Something happens (a genuine problem) and that results in something else tripping which wasn't supposed to trip. Eg one generating unit fails or a single transmission line trips and then some other generator or line that has nothing wrong with it also trips due to the disturbance.

It's one of those things which shouldn't happen but does in practice, most easily understood by explaining that we're talking about a situation where a 1% change in frequency is problematic and once it's 4 - 5% then fair chance the whole lot goes down.

Hence the logic behind commissioning then seeing what happens in practice before going further. Engineering calculations are all well and good but experience says let's see what really happens - the danger being that the new thing doesn't play as intended with what's already there due to some unforeseen problem.

There's been a few dramatic incidents over the years which come to mind. Most obviously the SA system black in 2016. Triggered by physical failure of transmission lines but ultimately the system could've survived that with only localised blackouts. What brought the whole show down was things tripping which shouldn't have tripped which then overloaded everything remaining and caused that to trip as well.

That's not the only such incident, just the most dramatic one in recent times. Only yesterday there was a line trip in Victoria which resulted in the unintended trip of a solar farm. That it didn't make the news is because everything else worked as intended so the lights stayed on - AEMO are however following through to make sure the reasons are identified and resolved to prevent a recurrence.

For the avoidance of politics I'll point out that it certainly wouldn't be the first time that fossil fuel or hydro plant tripped when it shouldn't have. The situation isn't confined to wind or solar by any means. :2twocents
 
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SirRumpole said:
Gas may be a fossil fuel but it's a lot cleaner than coal, and I'd rather trust Alan Finkel when he says gas should be an important part of our energy grid.
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On one hand I'm pretty keen on the idea of renewables. It can be done yes.

On the other well realistically there's zero chance we won't be needing oil or gas 5 years from now. That the majority of it isn't used for power generation but for millions of consumer devices which have already been built ensures that. We're not going to see a complete replacement of cars, heaters etc in that time so we're going to need fuel that's a given. :2twocents
 
Smurf1976 said:
On one hand I'm pretty keen on the idea of renewables. It can be done yes.

On the other well realistically there's zero chance we won't be needing oil or gas 5 years from now. That the majority of it isn't used for power generation but for millions of consumer devices which have already been built ensures that. We're not going to see a complete replacement of cars, heaters etc in that time so we're going to need fuel that's a given. :2twocents
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We are not going to stop using fossil fuels in the next 5- 10 even 20 years. That's a given.
On the other hand the push to renewables is driven by economics and environment. They don't compete economically and represent a CC risk. In that context the financial risk of backing new fossil fuel projects is very significant.

It comes down to the risk of billions of dollars of stranded assets. Who wants to take that financial risk ? An insurance company? Private industries?

Hardly.
 
Not completely off topic. I think this is a thread for engineers so check out how a guy moves huge concrete blocks by hand.

No jacks. No modern technology.
Clever and interesting.
 

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