Post by LancedDendrite on Sept 10, 2012 0:22:40 GMT 9.5
Splitting this discussion from another topic, as it seems like it might be needed for those of us that wish to develop more concrete plans for decarbonising individual regions.
Summary of discussion points:
In closing, it should be remembered that a 30MW unit was considered to be large about 60 years ago. By 30 years ago, 660MW units were at the small end of standard sizes for baseload applications. Doubling or even tripling the unit size to 2GW is a technical, cost-benefit issue and is in no way related to the topic of this thread. Let's have the debate!
I'm not sure as to what the probability of an individual turbogenerator unit tripping compared to a switchyard fault occuring, which is why I'm being cautious in saying that ~750 MWe is about the upper limit for a single turbogenerator. If you had a 1600 MWe unit on such a small grid (the NEM is loosely interconnected at present, it's pretty much still split along state boundaries) you might have some issues with generator intertia if there's a frequency transient.
(Of course, I may be quite wrong - I'm only an EE student and not a practising power engineer)
Agreed. I would put a 2000 MWe per switchyard limit on such plants. I hear that AEMO had an interesting time dealing with the 2000+ Mwe Bayswater switchyard tripping back in 2007.
I think the issue there will be water constraints (unless we go for air-cooled reactors such as LFTR), so I would advise against siting any possible reactors inland. Olympic Dam could pull it off it there was a dedicated transmission line from Ceduna or Port Augusta.
That's 7 potential sites for NSW alone, each with excellent grid connection, existing local workforces experienced in construction, maintenance and operation of power plant and with access to cooling water.
The Lake Macquarie area would be excellent for nuclear reactors, I agree. Access to existing switchyards, transmission easements and a decent source of saltwater for cooling are all great things to have available.
Summary of discussion points:
- How big can you make an individual generator/reactor before there are reliability issues stemming from the loss of large amounts of supply from the grid?
- How large can you make a power plant (defined as one or more generators with a common switchyard and transmission line) before transmission line and switchyard reliability comes into play?
- Is there a 'sweet spot' generator & power station size for an individual grid where economies of scale and reliability issues balance each other out?
Let's not get too hung up about unit size - there's more than enough range available right now, from a bunch of suppliers and with more coming.
In closing, it should be remembered that a 30MW unit was considered to be large about 60 years ago. By 30 years ago, 660MW units were at the small end of standard sizes for baseload applications. Doubling or even tripling the unit size to 2GW is a technical, cost-benefit issue and is in no way related to the topic of this thread. Let's have the debate!
Australian loads and systems are suited to 500 - 750 MW units. However, a unit double that size would not present major hurdles.
I'm not sure as to what the probability of an individual turbogenerator unit tripping compared to a switchyard fault occuring, which is why I'm being cautious in saying that ~750 MWe is about the upper limit for a single turbogenerator. If you had a 1600 MWe unit on such a small grid (the NEM is loosely interconnected at present, it's pretty much still split along state boundaries) you might have some issues with generator intertia if there's a frequency transient.
(Of course, I may be quite wrong - I'm only an EE student and not a practising power engineer)
Single units equal to two of the above are thus perhaps not ideal from a fault management perspective, but are not out of the question, either.
Agreed. I would put a 2000 MWe per switchyard limit on such plants. I hear that AEMO had an interesting time dealing with the 2000+ Mwe Bayswater switchyard tripping back in 2007.
1. One or two designs in the range 50 to 100 MW for local loads, eg as support to mines and to enable feed from remote-ish locations to reduce the transmission losses. EG: Broken Hill? Tamworth?
I think the issue there will be water constraints (unless we go for air-cooled reactors such as LFTR), so I would advise against siting any possible reactors inland. Olympic Dam could pull it off it there was a dedicated transmission line from Ceduna or Port Augusta.
2. 700MW and 1000MW units, which offer lower whole-of-life unit costs and will fit quite well onto or near existing sites. Example: In NSW, the four power stations mentioned above, plus Vales Point, Munmorah and Wallerawang.
That's 7 potential sites for NSW alone, each with excellent grid connection, existing local workforces experienced in construction, maintenance and operation of power plant and with access to cooling water.
The Lake Macquarie area would be excellent for nuclear reactors, I agree. Access to existing switchyards, transmission easements and a decent source of saltwater for cooling are all great things to have available.