Criticism of the current electricity market, inconsistency and prospective for renewable energies

[SebastianL]

Hello,

I wanted to write a long article on the European electricity market, its lack of coherence in terms of renewable energy, in particular on the absence of an economic model for energy storage, which is absolutely necessary if we are serious about doing renewable!
I therefore presented a proposal for a "virtual distributed battery" status, explaining what would change.
To expose a concrete and applied case I unveiled a technical prospective of thermal mass storage around a new nuclear complex to be built to show that it is highly probable that this is the future of the subsidiary.

if I speak of nuclear it is only because it is capable of making an ultra-efficient battery for ENRs.
This is essentially due to the fact that a nuclear power plant has a poor primary energy efficiency, 34%, which can be greatly improved with thermal storage heated by renewable energies, thus thanks to an increase in the primary efficiency by an increase in the temperature of the hot source, we can restore all of the ENRs that have been injected into the heating of the storage, which is really not trivial!

This is an important reflection to have, quickly, before the new nuclear sites begin!
It is decisive for the development of renewable energies but also for the profitability of nuclear power to have safety


Downside, it's very technical, surely boring to read and moreover I write badly I didn't do a bac letter so it's up to you to see, in any case there is something to surprise more than one with my vision of the transition energetic!

https://medium.com/@nonoceb/paradoxe-du-marché-de-lelectricité-europeen-b8c2eceb0dfb

The article can still be modified in order to have a physically and economically realistic prospective, among others.
Nevertheless technically I believe that it is stable and that it will not move fundamentally.

Good reading!
Sebastien

[sicetaitsimple]

if I speak of nuclear it is only because it is capable of making an ultra-efficient battery for ENRs. 
Sebastien

My God!
I have read your article.
Beyond the fact that it is technically impossible to operate a turbine over such a temperature range, have you just calculated the storage volume that would be necessary to go from a power of 1000MW (pure nuclear) to a power of 1600MW (nuclear + storage), this 24/24? Which storage would be heated with renewable electricity, to then be reconverted into electricity with a yield of 30 to 40%? With which renewable electricity, produced when?

Well...I think you're dreaming, and you don't know much about it. Sorry.

[SebastianL]

Hi sicetaitsisimple

Thank you first of all for your interest, we go directly into the usually divisive subjects and it is technically complicated.

Concerning what is possible to reach in steam hot spring temperature I chose a fairly realistic value of 500°c, some steam turbines for coal power plants operate at 550°c. In fact, the limitation of the temperature essentially comes from the ability not to oxidize the metal used by the turbine and concerns only the high pressure stage.
For the low pressure stages the limitation comes from the centrifugal force on the last very low pressure expansion blades, we even went from turbine at 3000rpm to 1500rpm to meet this limit despite the increased costs to manufacture the AC generator which is heavier and more expensive than the 3000rpm version.

Here we even talk about a water steam turbine at 610°c https://www.tlv.com/global/FR/steam-the ... steam.html

Regarding the volume of thermal storage, yes the calculation has been made the order of magnitude is ten GWh in the short term 24H-48H, there is no difference between an ENR electricity input or an electricity input of nuclear origin. This also allows a massive clipping power of the nuclear power plant in situations where renewable energy exceeds demand.
Obviously the storage discharge is not 24 hours a day, there are charging phases and discharging phases, but the genius is that it is technically possible to restore all of the electricity stored by improving the efficiency. nuclear during the discharge, at this stage we use nuclear thermal energy better and this compensates for the losses of the steam cycle of the destocking... You have to look at this closely, I know it's complicated

[Obamot]

Hello and welcome Sebastian,

Don't take offense at the scathing reactions of certain members (known here for that and who often count for cream), and thank you for having accepted the game of confrontation of ideas By your original approach and its inventive aspect.

If we understand well and if we extend your idea, why not install heat storage sites, to make eg. a new kind of WWTPs — i.e. pumped energy transfer stations (in this case heat pumping during off-peak hours — and adjoining the power stations with additional dedicated turbines, and would clearly make it possible to increase (or even double ?) their capacity to respond to the load factor of the network, and thus to increase the production fleet of renewable energies... (proportionally)

For calculations, the optimum will be found! What does it matter! But the idea is very good, thanks to its proximity to a heat source, we immediately understand why... And why not include geothermal storage in the same perspective?

One even wonders why the idea would not already be concretized? Perhaps because of the historical opposition between nuke VS EnR...?

[SebastianL]

I have just made a more precise calculation of the electrical efficiency of thermal storage-retrieval, it is 88.6%

From saturated steam 70bar 285.80°c 
Specific enthalpy of liquid water 1267.48kj/kg 
Specific enthalpy of steam 2773.51kj/kg 
Latent heat of vaporization 1506.03kj 
Specific heat 5.0348kj/kg
steam at 70bar at 500°C has an enthalpy of 3411.4kj/kg, so we must add 638kj/kg out of a total of 3411kj/kg = 18.7% of superheated heat.
Primary power for 1GW at n=34% = 2.94GW
Primary power for 1.6GW at n=44.2% = 3.62GW
Superheat power 3.62Gw x 18.7% = 0.677GW
Reactor power 3.62Gw x 81.3% = 2.94GW
So we have an overall efficiency of thermal discharge (excluding dissipative losses of the HT tank) towards electricity of 600MW/677MW = 88.6%
If there is, it will be even better, since there will be less racking to recycle thanks to really dry steam at the start of the cycle.

[SebastianL]

If we calculate the increase in the volume of superheated steam at 70bar with PV = nRT, that is a ratio of 773K/558K or 38.5% more work available at the turbine, by injecting 18.7% of superheated energy.
We also know that the actual efficiency of the steam turbine is 34% at 285°C, but it is difficult to estimate precisely the efficiency at 500°C overheated.

We can calculate the ratio of Carnot yields at the 2 hot temperature points:
1-323/558=42%
1-323/773=58%
That is a ratio of increase in efficiency of 38%, a value which corresponds to the increase in the volume of steam in ideal gas. Logic.
We can then roughly estimate the new yield at 0.34 x 1.38 = 46.9% and redo the balance sheet:

Primary power for 1.6GW electrical at n=46.9% = 3.426GW
Superheat power 3.426Gw x 18.7% = 0.64GW
Reactor power 3.426Gw x 81.3% = 2.785GW

So if we injected 640MW into the thermal storage previously, we recover 600MW, i.e. a storage efficiency of 93.75%, that's phew

[sicetaitsimple]

From the variable geometry turbine.....

If I understood correctly, the turbine is used:
- at 70bar and 286°C for 1000MW in ""nuclear only" mode
- at 70bar and 500°C for 1600MW in "nuclear + destocking" mode
What scenario? Let's say 90% of the time in nuclear mode alone and 10% of the time for the rest?

What's wrong is that the turbine and the rest of the water-steam cycle will have to be sized for the highest conditions, ie 500°C and 1600MW.
So when you send it steam at 70bar 286°C, the turbine will be completely mismatched and operate with poor efficiency (compared to the 34% cycle efficiency you mention for a turbine adapted to values ​​of 70bar 286° VS). This only under the thermodynamic aspect, it would still have to work over time.
Significant degradation 90% of the time, for 10% of the time it will be a little better.
Except to invent the 1600MW turbine with variable geometry....

[Obamot]

Didn't I modestly suggest a dedicated turbine?
Is it so hard to argue in a constructive/inventive/positive sense, making technique 'at the service of ideas and objectives' (as far as their own limits go without saying) and not a bit systematically against them?

[sicetaitsimple]

Didn't I modestly suggest a dedicated turbine?

Bah, modestly, if you go on a dedicated turbine, you fall back on the classic efficiency of a water-steam cycle at fairly usual temperature/pressure, say between 35 and 40% efficiency.
But as you rightly said a little above, the real question is "One even wonders why the idea would not already be concretized? "
It's a mystery....

[Obamot]

Well yes, storing energy by phase shift, in the form of heat, is done and it works!

You will not force us into yet another syllogism!
[if they didn't do it "So it's good THAT]:"
(blah-blah-blah)

You are not answering the bottom of my post, since you are making NO effort to be CONSTRUCTIVE (I also suggested coupling it to geothermal energy* and it exists under the CCF concept => heat-force coupling => produced simultaneously heat and electricity. It is therefore not until they have thought of it that the concept of cogeneration must be extended / adapted...
(even if it's not exactly what we thought until then) I salute the "inventive effort" expressed by Sébastien.


*) What do you know? maybe in times of plenty designers didn't think of it or for a matter of cost. Whereas today it is necessary to find other solutions in the available energy mix?