Why we need "Net zero"

[Beelbeebub]

3 hours ago, SteamyTea said:

They extend the life of them, at great expense.

 

https://www.imeche.org/policy-and-press/from-our-perspective/energy-theme/nuclear-power/about-nuclear-power/the-future-of-nuclear/plant-life-extension

 

 

Absolutely, I played a small part in the magnox life extensions (Wylfa in particular) 

 

I'm sure the reactors will be kept running well beyond 2060 - which only compounds the uncertainty that EDF or it's successor will be around to honour it's commitment to decommissioning. 

 

There is a huge list of giant engineering companies that were around 50 years ago and aren't now. 

[saveasteading]

1 hour ago, scottishjohn said:

hydro scheme on the river Dee in s.w scotland -uses same water 3 times 

Interesting. Does this mean there are three dams of relatively low output rather than one huge one? 

Like in earlier centuries,  having several flour mills along a stretch of river?

[SteamyTea]

3 minutes ago, saveasteading said:

I hadn't heard of that. Do you know why it can't remain as a base

Possibly because when a windfarm is retooled, they put larger turbines on them.

Or it is just made up, like the 'million pounds of concrete needed'.

Offshore turbines use a lot less concrete and they drill a large hole and grout a steel base in (there is a company down here that makes the rigs to do this).

 

Maybe @Gus Potter can give some insight as to the design.

I get a bit stuck when converting the forces for, say, a 5MW turbine that is 125m heigh.  I think 1 Nm.s^-1 = 1W.

The diameter of the base will make a difference.

[Beelbeebub]

3 hours ago, -rick- said:

 

Well quite, it's why I'd expect a new plant to be designed to last at least as long without the expensive life extension.

 

Obviously maintenance, even fairly expensive maintenance, will be required to last that long. But if planned for upfront it's a lot cheaper than just building for 30 years and dealing with extension at a later date.

You don't want to know how little planning for decommissioning was done for the early reactors (magnox, agr etc).

 

Lots of stuff inaccessible, an unbelievable amount of stuff undocumented or not to the plans!

 

We did design work for robotic decommissioning - really expensive special purpose robots and manipulator ms to go in and undo a nut or grind off a weld. The sort of thing a man with a spanner or grinder could do in an hour - which I think was the orginal plan when they designed some of these in the late 50's and 60's!

 

[Beelbeebub]

2 hours ago, -rick- said:

 

Sure. I would expect that for a plant opening today that very few of the components would be original in 30 years time. But that to me is maintenance. If our existing fleet is running for 50 years, it just seems like we should design new plant to have the same life (with the expected maintenance).

 

It's the parts that can't easily be swapped out that need to be designed to live the longest. And if we have managed to get parts that we built 40-50 years ago to live until today then we should be able to design the new parts to do the same. Not maintenance free for 50 years, but to last 50 years with planned and scheduled maintenance. Most importantly with a design that allows for all the maintenance tasks we have found necessary on the old plant to be possible and planned for on the new plant.

This is part of thr high running costs.

 

Nobody can design such a critical bit of equipment not to fail ever. What we can do is have an inspection and testing regime to catch any failure before it is catastrophic. So when they design a weld or a pipe or a valve, it's limits for fatigue, temp cycling, corrosion, embrittlemnt etc are all calculated and an inspection regime is decided. Then the item is inspected to make sure it is to spec, then it"s inspected using all sorts of expensive stuff and the results fed back into the simulations to check it's "on track" and adjustments to inspection regime made on light of the actual performance. 

 

It's a huge undertaking 

[SteamyTea]

13 minutes ago, Beelbeebub said:

I played a small part in the magnox life extensions

Did you have a hearty breakfast to start the day.

 

 

Edited 1 hour ago by SteamyTea

[Beelbeebub]

2 hours ago, scottishjohn said:

wind power --who in their right mind would sign a contract that says they get paid if they turn them off

I would love to have run a company  where i got paid if I did not produce anything 

If you were contracted to produce cakes for wedding, you produced them and the customers courier couldn't make the lick uk because their vans were all busy - would you want to be paid? I suspect yes. 

 

The curtailment payments are due to the grid not being able to transport the contracted for power - which is a separate issue that is being addressed - and happens to gas (and once upon a time coal) plants as well

 

 

2 hours ago, scottishjohn said:

if you work out how much pollution is caused making the things and the amount of c02 in the huge concrete bases 

and when they get replaced they need a new base --it just don,t stack up 

This is false. The meme was popularised by the series "landman" where billybob Thornton goes on a (wrong) rant about wind turbines. 

 

The carbon payback for wind turbines varies from 6-18months.

 

The bases vary depending on ground conditions but typically 100m3 per MW - so between 100-600m3 per turbine. 

 

But concrete is not unique to wind turbines. Hinckley C has over 40,000m3 in just one of the two reactor foundations. 

 

The turbine blade problem is real but more a function of composites not yet generally being recycled. This is changing but the current best practice it to recycle the blades by grinding them into particles and (you'll like this) using them in concrete..... 😁 

[LnP]

2 hours ago, scottishjohn said:

wind power --who in their right mind would sign a contract that says they get paid if they turn them off

I suppose anybody who wants wind turbines to be built and for the electricity they produce to be affordable. CfDs reduce risk for the generators. Without them, generators would be asking higher prices for their electricity to reflect the risks they would be required to take on.

2 hours ago, scottishjohn said:

and if you work out how much pollution is caused making the things and the amount of c02 in the huge concrete bases 

and when they get replaced they need a new base --it just don,t stack up 

Yes, it does stack up, hugely. The parameter you need to look at is the life cycle greenhouse gas emissions, measured in grammes of CO₂e, per kWh of energy produced over the life of the asset. Results as follows (median values of the assets they studied):

• Coal: 1004 g
• Natural Gas: 458 g
• Solar PV: 53 g
• Offshore wind: 18 g
• Onshore wind: 12 g
• Nuclear: 6 g

(Clearing the Air, Hannah Ritchie, data source UN Economic Commission for Europe, 2021)

 

2 hours ago, scottishjohn said:

 

we have hydro scheme on the river Dee in s.w scotland -uses same water 3 times and was built in1937

 still running now --that is the right way 

hydro and tidal barages 

According to Drax Group who operate the Lanark and Galloway run-of-river hydro schemes, located in south-west Scotland, it generates 126 MW. Yes, that's nice but it's not going to get us far in the energy transition. The latest allocation round for offshore wind (AR7) procured 70 times that capacity, 8.4 GW.

2 hours ago, scottishjohn said:

the desert in america is full of old wind turbine blades that they cannot recycle economically - so they just lie there 

 

So what? The embedded CO₂ in the blades is taken into account in the above life cycle numbers. It's just a waste disposal issue. Same or worse for end of life fossil assets, many of which contain far worse materials - asbestos, mercury and other heavy metals, spent catalysts, etc.

[Beelbeebub]

47 minutes ago, SteamyTea said:

Did you have a hearty breakfast to start the day.

 

 

Ha! 😁 

 

No but I did have to "bunny suit up" amd wear a dosimeter for working on the lab and go through a radiation scanner on the way out each shift. Was an interesting job. 

[SteamyTea]

10 minutes ago, Beelbeebub said:

Was an interesting job

I still find this a harrowing scene.