The document discusses how nuclear energy can help enable the integration of renewable energy sources by providing flexible base load power. It makes three key points: 1. Flexible base load fleets like nuclear and coal, combined with energy storage and cogeneration, can help integrate intermittent renewables like wind and solar in a synergistic system. 2. Nuclear power plants are flexible enough to accommodate higher levels of renewables if system effects are addressed through coordinated solutions involving production, storage, and cogeneration. 3. Intermittency is a system issue that requires system solutions, primarily through the use of energy storage to balance supply and demand across the energy network.

1. The nuclear fleet : a decisive enabler
to integrate a share of Renewables.
(in the framework of a comprehensive system solution)
ATOMS FOR THE FUTURE
SFEN - october 21 - 2013
H. GRARD (CEA), J.-B. THOMAS (CEA)
V- 6 : 18/10 – 13h30
1 - System effects; production & storage back-up
2 - Flexible base-load fleets (coal, nuclear) + storage & cogeneration as
IREN integration enablers : a win-win deal
3 - Yes, NPP are flexible enough, if system effects are dealt with in a
synergistic system solution framework
4 - An overview of storage back-up contribution
5 - Going on with NPP improvements : some innovation and R&D issues
1

2. Summary (1/2)
•
•
•
An efficient and clean base-load production fleet complemented with a
powerful, 6 to 12 h. (typically) discharge duration storage back-up, is
the backbone of the mix.
The IREN are a (disruptive) « winger », up to 20% of total power
production. They need a large flexible baseload protecting the grid, the
consumer, the production fleet itself.
Baseload generation plants need a high capacity factor (low variable cost
/ high capital cost). A « win–win » deal is thus mandatory.
Flexible but lower merit order fleets
(gas, excepting domestic shale gas)
are receding (Spain, Germany) because
of a pincer movement made by IREN
on one side and by coal or by nuclear
and hydro on the other side, and thus
of a letal fall-back of their capacity
factor.
2

3. Summary (2/2)
• Baseload plants (coal, nuclear) need to keep a large installed power to
deliver the required power ramping capacity (LF + IREN).
This requirement would be contradictory with a high kp if smart storage
could not help (in France, currently, hydro dams and Pumped
Hydropower Storage (STEPS)).
•
Intermittency is a system issue and will be dealt with using system
solutions, involving primarily storage back-up.
•
Beyond the ultimate grid and plants adaptation effort, toxic surpluses
must be « stored or dumped » by the producer (detrimental production
of a commodity : no value).
3

4. The main IREN Drawbacks
1 - Week-long, “pan-European” failure :
winter solar hibernation, wind “naps”
IREN can’t remove more than 3 to 4 % of their installed power
(for a typically balanced fleet). France – 2030 : ~ 3 GW (not 20)
4
4% of the installed power means ~ 20% of their mean power.

5. The main IREN Drawbacks
2 – Threatening thermal commercial plants (gas, coal, nuclear) kp and flexibility
France–2030 : Prod # 550 TWh; Pi (IREN) = 70 GW, Pmean ~14 GW
Power prod. (IREN) # 120 TWh (not all dispatchable),
“Commercial thermal Production back-up” kp decrease :
•
little Pi reduction (3 to 4% Pi IREN),
•
But minus 100 to 120 TWh production (under “fatal” IREN assumption).
From Wagner :
capacity factor as a function of IREN
energy production/annual demand
5

6. The main IREN Drawbacks
3 – Summer “pan-European” solar flares (even without DESERTEC)
Le solaire Allemand, préfiguration du solaire Français
de 2030 ?
L’Allemagne possède un parc de production d’énergies intermittentes avec en puissance
installée, 33000 MW de solaire et 30000 MW d’éolien.
Production
solaire
Heure/heure du
16/06
Pic de production de la
journée : 20000 MW
14
15
6

7. Transposing to the French 2030 prospective
16/06/2013 : consommation vs, solaire et éolien "2030"
Killing the base-load fleet “softly”
Threatening the grid
50000
40000
Remedies ?
30000
MW
Consommation
éolien 2030
20000
solaire Ge
Flexible base-load (N/C)PP
10000
0
0
10
20
30
40
50
60
70
80
90
100
Flexible hydropower dams
Cogeneration
-10000
n°de quart d'heure
Smart* (see below) Storage back-up
base résiduelle en été en 2030 (données du 16 06 2013 Fce et Ge)
Reducing drastically the need for
“production back-up”
50000
45000
40000
35000
30000
MW
consommation
25000
Fatal total
QSP base
20000
15000
Making solar and wind energy useful,
by IREN production time-shift, at
the right location
Plus air conditioning and efficient
heat pump winter heating growth
10000
5000
0
0
10
20
30
40
50
n° de quart d'heure
60
70
80
90
100
7

8. “It’s the air conditioning, stupid !”
8

9. Typical anticipated German patterns (with storage) - Wagner
9

10. “The power flows from North
to South through lines of
least resistance, causing
parallel flows in Benelux
countries in the West (2006)
and in Poland and the Czech
Republic in the East”.
+ Limitless exchanges
between Germany and
Austria.
Europhysics News (2013)
10

11. The main IREN Drawbacks
4 – The “regular” wind intermittency
11

12. The main IREN Drawbacks
5 – Challenging the multi-scale space – time control of frequency and
voltage, supported by the patiently built consistency : production,
transmission and distribution.
The breaking down threshold is probably lower than in the previous sections
devoted to “scalar” issues
12

13. The main IREN Drawbacks
6 - Intermittency induced volatility
Towards restored margins through (much) higher prices for the consumer.
Challenging the availability + affordability criteria (WEF)
A panel of helpers (to be
coupled with a power production
fleet), including P2G
There is no clear cut between storage
and cogeneration, either.
13

14. “Wind Dumping” from “The limits of wind penetration” (USA).
“Excessive wind dumping imposes an upper economic limit on wind power”.
Toxic surpluses call for a dedicated regulation : “store or dump”.
Taking off around 20/30%. (see Wagner : 30/40% : “optimized” IREN mix)
14

15. Yes, NPPs are flexible enough. Implementation level variable, depending on
past needs, culture, improvements (hard, soft).
Related Requirements : EUR ; ALWRs : URD from EPRI.
Supporting (any time - any location) : frequency, voltage, through :
• Contracts (down to a few hours);
• Automatic control on flexible reserves
15

16. New “ramping” challenges from massive IREN penetration
LF requires fast and deep ramping up/down. In winter, between 6h and 7h
(a.m.), + 7 GW can be required in 1 h., and the total ∆P can be ~ +18 GW
in 3 h.
The present French mix can deal with such steps and ramping rates, every
morning.
The IREN hibernation (solar) and “naps” (wind) make it impossible to shrink
the nuclear base-load component (at most – 2 to GW around 2030).
Moreover, due to the intermittency, keeping a large nuclear installed power
is necessary. Dedicating 40% of the fleet to a 50% of its rated power
“step” at 1%/mn means + 12 GW in 1h. Adding 25% interruptible
cogeneration (long term energy time-shift : G2P ?), leads to + 18GW in 1h.
Supported by hydro dams and STEPS, this “enabler” can withstand a
significant level of IREN penetration before coming in trouble. Anyway, this
time might come sooner than expected.
The toxic system effects from intermittency are highly non-linear with
IREN installed power (see above : “dumping take-off point”).
A system solution involving a broader synergy between flexible production,
cogeneration and storage capacities, must be devised before over-investing
in the grid (but strengthening some transport lines will be unavoidable). 16

17. 17

18. 18

19. STORAGE Who ? How ? When ? Where ?
Electric Energy Storage Applications (SANDIA report)
Renewables Integration :
• Renewables Energy Time-shift ; (in the US : “buy low, sell high”)
• Renewables Capacity Firming;
Players :
• Solar and wind power producers (farms; residential & commercial)
• “utilities”;
• “grid”;
• “Consumers”;
• Private investors
Main parameters
• The discharge duration : excepting Short Term wind support (10 s. to
15 mn.), the typical discharge duration of interest ranges from 1 to 6 h
Obvious as for solar; helps also for wind.
• The unit power capacity involved. “Smart storage” will probably be
modular / distributed (1 MW to 100 MW), with a few high concentration
sources (~ 0.5 / 1GW).
19

20. STORAGE Who ? How ? When ? Where ?
Where ? Close to :
• Some wind (solar) farms : at the source of the intermittent supplies, for
various reasons : upstream grid protection; “capacity firming”,
“polluter/payer” or “pirate/corsair” mode; depending on the global
regulation framework and on the game played by the main actors;
• The main base-load plants, as auxiliary tools;
• The main consumption sites;
• The most fragile locations on the grid.
• The only locations where the implementation is easy, accepted, efficient
and low cost.
How (and how much – money - ?). Highly dependent on the way it is used,
as well as on potential synergies with other applications.
20

21. 21

22. Monotone éolien 40 GW
35 000
30 000
Store or dump
25 000
24 GW : 60% (Pinst.)
½ welcome / ½ undesirable
MW
20 000
creative solutions (cogeneration)
16 GW : 40% (Pinst.)
15 000
~ 10 TWh
Pumped
Turbined ~ 7 TWh
10 000
Mean value
Direct use (simplified)
5 000
0
0
1 000
2 000
3 000
4 000
5 000
6 000
7 000
8 000
9 000
10 000
heures
22

23. Solaire et STEP
25000
More Air Conditioning ? (with HP – power – heating in
winter and a leverage ratio of 2.5 to 3 ?)
20000
15 GW : 50% (Pinst.)
MW
15000
Pumped
~ 5 TWh
10000
5000
Mean value (kp # 14%)
Turbined ~ 3.5 TWh
Direct use
(incl. Air Cond.)
0
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
heures
Start from typical patterns of cooperation between a flexible production
fleet and an auxiliary storage “pool” dedicated to the grid optimisation. 23

24. CAES
24

25. STORAGE Who ? How ? When ? Where ?
For solar, peak storage during “summer sonny afternoons” means about the
same capital cost than building the solar plant. It makes solar power
dispatchable and useful, thus defining its very value.
Massive air conditioning : a profitable opportunity given by solar “pushers”
Compressed Air Energy Storage, High Temperature Stimulated Geothermal
Storage (with cogeneration) : specific SWOTs; a limited but valuable
potential.
The best suited tool seems to be the extension of Pumped Hydropower
Storage. France disposes of around 5 GW of STEP power production
potential (efficiency : about 70%), less than Germany, and Japan
disposes of around 25 GW.
In Germany, about 50 GWh are installed and about 20 GWh are in
construction. In France, a few more GW (before 2025) could be
beneficial to the grid.
In summary, storage increases the value of IREN by energy time-shift and
it curtails the LF burden for base-load workhorses. Up to 20% of IREN
power production (?), it enables :
• IREN firming by “filling” the dips during the production drop;
• Protecting the grid from failure or from huge irrational over-costs (grid
wizard);
• protecting nuclear and coal from over-ramping (up/down) as well as of
shutting down during wind storms and solar flares.
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• avoiding (partly) dumping toxic surpluses.

26. The continuous improvement process is going on.
Application to Gen-2, Gen-3, Gen-3+;
to the SMR, then to Gen-4 prospective.
Specifications and related R&D topics
1 – Defining the “flight envelope”
useful improvement criteria
2 – Some related R&D topics could be :
•
Improving the knowledge of the physical state of the core, of the fuel :
coupling the instrumentation to “numerical core simulation”, plus real time
optimisation of core control “planning” by advanced algorithms.
•
Ageing : technology, materials; anticipation thanks to the “virtual
reactor” monitoring and to extended operation feedback knowledge bases
•
Flexible, interruptible cogeneration : open questions about operation and
compatibility, about cogeneration process ramping rate capability, about
capacity factor (kp) and capital cost balance, etc.
3 – SMR; small core control, without boron; dedicated fuel …
4 - Gen-4.
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