MCY Mercury NZ ( MRP Mighty River Power)

[turnip]

Let's rerun the calculation for FY2016 using the new lower equity accounted generation base

The geothermal generation capacity at Mercury is 334MW (table above). If run at 100% capacity for twelve months those five geothermal stations can generate

334MW x 24 hrs/day x 365 days/quarter = 2,925,840 MWh/year

So the Mercury geothermal stations, over FY2016, operated at: 2,830,000 / 2,925,840 = 96.7% capacity

What do you think? Could I be onto something? The only problem is that this 96.7% figure is even higher than the 95.5% figure that Mercury claim. Hmmmm

Would the Mercury availability figure be calculated that way, or is that just how you are estimating it because you don't have access to the actual data on how long each geothermal station was offline during the year?

I think geothermal generation is slightly seasonal: higher production in cold winter months than in hot summer months. If you calculated availability just by how long the station is offline in a year then that would not be affected by when in the year it was offline. But if you calculate from the total GWh output for the year as you are doing then you might get different results depending on whether the outage was in winter or summer. I don't know if that would be enough to account for the discrepancy though.

Edit: OK I see in the 2016 FY results presentation Mercury claim 95.5% availability, which is equivalent to downtime of 16.5 days out of 366 maximum. But your calculation is in terms of energy, i.e. a loss of 95.84 GWh out of 2925.84 GWh maximum. So to convert the energy figure to days of downtime would depend on whether the downtime was in winter or summer. A shorter winter outage might lose the same amount of power as a longer summer outage. (Due to the lower thermal efficiency during summer.)

And to complete the process, although there will likely be a large error due to rounding: 95.84 GWh / 16.47 days = 242 MW, so it seems to be in the realm of possibility that your calculation of 96.7% on a lost energy basis does work out equivalent to Mercury's 95.5% availability on a downtime basis, with the downtime occuring mainly during the summer months.

[Mr Slothbear]

[QUOTE=fish;863116]

I think you need to keep in mind Jantar's post on the cost structure of the industry below:



IMO the way the cost structure is set up in the industry, people who attempt to generate their own power are effectively screwed.

The gentailers will screw you because they can and want to
Both my houses have had solar installed .
My gentailer -contact energy -after months have still not installed the import/export meter .
So I am looking at changing to Flick who pay the wholesale price-Jantars post is very helpful in calculating the current wholesale price I would receive-or Genesis-who pay more than contact.
What I am enjoying is 5kw of free power during the day with aircondtioning,pumps,swimming pool etc operating-a lot more fun than exporting to our miserly gentailers !
I might sell my contact shares as well (definitely keeping Mercury)

i can highly recommend ecotricity.

i have been using them for quite some time and significantly better both as a consumer or for exporting as with solar than any of the gentailers.

https://ecotricity.co.nz/

[Jantar]

I think you’re on to something. 2016 was a leap year so 366 days not 365, which brings you down to 96.4% I think.

I also wonder if it’s as simple as on or off though. Perhaps more likely there’s a low, slow idle state that minimizes both stress and costs but doesn’t produce much output either.

Geothermal is either on or off. There is not really an between setting. When a geothermal machine is reduced in load the steam field is still trying to produce steam. That steam either has to be vented with noise and pollution issues, or one or more steam bores have to be shut down. When a bore is shut down, the pores fill with silica which precipitates out of the geothermal fluid and they block up. Once the bore is opened again it never gets back up to full production.

When I was a system controller, 30 odd years ago, we were told that any controller who instructed geothermal to reduce load, other than for an outage, would be sacked.

[turnip]

It was mentioned in the Infratil thread that Mercury could be one of the bidders for Infratil's stake in Tilt Renewables. I wondered if anyone knew anything more, such as whether Mercury would be bidding in its own right or as part of a joint venture?

Edit: I really hope Tilt won't be delisted, but if it is then perhaps better Mercury take it over than one of the big pension funds. Could make Mercury a more interesting company to own anyway. (MCY is my #2 holding, TLT #3.)

[Aaron]

Probably not an issue and I am unsure if there are any fault lines along the Waikato but I wonder what a major earthquake could do to Mercury? Potentially one broken dam taking out the others downstream. Suddenly the company is washed away, do the shareholders come up with the funds to rebuild?

The stuff of fiction and I guess no one could predict it, unless it happened, although engineers must have had a crack at some stage. Wild speculation on my part.

Just popped into my head this morning when reading about all the earthquakes going on in the North Island.

[Jantar]

Probably not an issue and I am unsure if there are any fault lines along the Waikato but I wonder what a major earthquake could do to Mercury? Potentially one broken dam taking out the others downstream. Suddenly the company is washed away, do the shareholders come up with the funds to rebuild?

The stuff of fiction and I guess no one could predict it, unless it happened, although engineers must have had a crack at some stage. Wild speculation on my part.

Just popped into my head this morning when reading about all the earthquakes going on in the North Island.

After the discovery of a fault line under the Clyde dam during construction, it was found that most rivers follow fault lines for at least part of their course. It would be extremely likely that some of mercury's dams do have fault lines under them. However the good news is that an earthquake under a dam is not likely to destroy that dam, and anything less than a magnitude 6 probably wouldn't even cause damage to the structure.

A large enough quake could cause damage, as shown in the Shih-Kang Dam failure due to an earthquake directly underneath. The good news is that in the event of such a failure it doesn't release all the water at once, and not enough to destroy all the downstream dams.

On the Waikato river, the ones most at risk would be Whakamaru and Waipapa, as they are earth dams rather than concrete, and once breached would soon wash away.

[Snoopy]

Probably not an issue and I am unsure if there are any fault lines along the Waikato but I wonder what a major earthquake could do to Mercury? Potentially one broken dam taking out the others downstream. Suddenly the company is washed away, do the shareholders come up with the funds to rebuild?

The stuff of fiction and I guess no one could predict it, unless it happened, although engineers must have had a crack at some stage. Wild speculation on my part.

Just popped into my head this morning when reading about all the earthquakes going on in the North Island.

Not a silly thought at all Aaron. Such an event may not happen for 5,000 years. But it might happen next week. I guess this is a reason not to put all your money in one company, no matter how 'safe' that investment might seem.

I am fairly sure that all of those dams were designed with earthquakes in mind. Although when you read stories of how the 'new' Wellington Library built in the 1980s is now regarded as a so unsafe that it will cost more to modify than building a whole new library, you do wonder about structures built to 'historic' earthquake standards.

Fortunately the major shareholder in Mercury is 'The Gummint'. So it should be easy to access new capital to rebuild in your disaster scenario, even if other shareholders end up being diluted. You would hope catastrophic damage would be restricted to just one dam, and the would be enough bypass flow channels to avoid downstream damage. But I guess nothing would be big enough to withstand 'the really big one'......

Then you have to consider that maybe Lake Taupo will erupt again before that (I think it is due in geologic time at least), and that could mean the end of the Waikato river in its current form, stranding all those Waikato dam assets. Just as well these scenarios are really unlikely within our lifetimes, isn't it Aaron?

SNOOPY

[peat]

After the discovery of a fault line under the Clyde dam during construction, it was found that most rivers follow fault lines for at least part of their course. It would be extremely likely that some of mercury's dams do have fault lines under them.

Do you mean

It would be extremely likely that some of mercury's dams do NOT have fault lines under them. ?

[101nick101]

Curious as to why nobody (media) or otherwise is talking about the Meridian Energy trading halt.

Edit Sharesies has since removed the trading halt... weird

[Jantar]

Do you mean

It would be extremely likely that some of mercury's dams do NOT have fault lines under them. ?

Both. It is extremely likely that some do and that some do not. The map of fault lines doesn't show exactly, but it appears that Ohakuri, Whakamaru and Maraetai are on fault lines.
https://www.waikatoregion.govt.nz/as...earthquake.pdf