1. Power Consideration of CEPC
Weiren Chou
25 May 2018, Rome Workshop, Italy

2. CEPC Power Consumption – Pre-CDR
Efficiency
(AC to beam) = 20%
W. Chou
Rome Workshop, 5/25/2018

3. CEPC Relative Power Consumption (Pre-CDR)3% 2% 9%
10% 6%
16% 5%
48%
W. Chou
Rome Workshop, 5/25/2018

4. CEPC Power Consumption – as of 12/13/2017
Electric power demand estimated for CEPC
System
Location and electrical demand(MW)
Total (MW)
Ring
Booster
LINAC
BTL IR
campus
RF power source
160
7.68
1.75
169.43
Cryogenics
16.8
Converter for magnets
98.5
10.5
5.7 2
116.7
Experimental devices 14
Dedicated services 6 3 1
0.5
Utilities 40
45.5
General services 13
0.3 12
27.3
Total
334.3
20.18
11.45
3.3 18
400.23
W. Chou
Rome Workshop, 5/25/2018

5. CEPC Power Consumption – CDR
Table A3.9:
Saving = 134 MW
W. Chou
Rome Workshop, 5/25/2018

6. CERN/Fermilab Power Consumption (2012 data)
CERN: current average 183 MW (R. Saban)
Fermilab: 2010 average 58 MW (D. Wolff)

7. Collider SRF Efficiency – as of 12/13/2017
W. Chou
Rome Workshop, 5/25/2018

8. Collider SRF Efficiency – CDR
Klystron efficiency: to change from 50% to 70% (linear part)
Waveguide efficiency: to change from 90% to 95%
Overall efficiency: to change from 40% to 60%
Overhead power: to change from 15% to 5%
The total SRF power reduced from 173 MW to 104 MW
W. Chou
Rome Workshop, 5/25/2018

9. Magnet Power – CDR Table A3.4: Two changes in collider magnet design:
2-in-1 design for dipole and quadrupole – power reduced by half
Double the quadrupole coil cross section
Power reduced by another half
Construction cost increase minimal
The total magnet power reduced from 117 MW to 62 MW
W. Chou
Rome Workshop, 5/25/2018

10. Collider 2-in-1 Dipole
W. Chou
Rome Workshop, 5/25/2018

11. Collider 2-in-1 Quadrupole Design Change
W. Chou
Rome Workshop, 5/25/2018

12. FCC-ee
FCC-ee

13. Remind about ILC in Kitakami candidate site
Basic policy of the ILC construction: Staging scenario
20.5km ⇒
250GeV⇒
31km ⇒
500GeV⇒
50km 1 TeV
The Kitakami candidate site has an enough potential to accept the 50km ILC
Total MW
1313

14. CEPC Power Consumption – CDR Wall plug efficiency = 23%
Table A3.9:
Saving = 134 MW
Wall plug efficiency = 23%
W. Chou
Rome Workshop, 5/25/2018

15. Remind about ILC in Kitakami candidate site
Basic policy of the ILC construction: Staging scenario
20.5km ⇒
250GeV⇒
31km ⇒
500GeV⇒
50km 1 TeV
The Kitakami candidate site has an enough potential to accept the 50km ILC
Total MW
Beam power 5.28 MW, efficiency 5%
1515

16. Power consumption breakdown excluding the auxiliary systems.
PSI
The magnet system
consumes 2.6 MW;
The entire consumption of the RF system is 4.5 MW;
The Ohmic losses in the
cavies are about 1.2 MW;
Losses in the RF sources are 1.5 MW;
Losses in the rectifier are 400 kW.
Cooling circuit efficiency
is 94%.
The entire efficiency is 18%
The beam current increase up to 3 mA leads to the beam loading increase and
consequently, efficiency increase up to 24%.
5/19/2017 V.Yakovlev | IPAC 2017

17. SNS Breakdown of electric power consumption by
systems during 1.4 MW operation; 26.3 MW
SNS
LINAC efficiency is 8.6%
5/19/2017 V.Yakovlev | IPAC 2017

18. The RF power consumption breakdown for the J-PARC facility.
Linac and RCS: Power consumption: 32.6 MW; beam power: 1 MW
Efficiency ~3%
5/19/2017 V.Yakovlev | IPAC 2017

19. CEPC Operation Plan CEPC yearly run time assumption:
Particle
type
Energy (c.m.)
(GeV)
Luminosity per IP
(1034 cm-2s-1)
Luminosity per year
(ab-1, 2 IPs)
Years
Total luminosity
Total number
of particles H
240 3
0.8 7
5.6
1 x 106 Z 91 32 8 2 16
0.7 x 1012 W
160 12
3.2 1
1 x 107
CEPC yearly run time assumption:
Operation – 8 months, or 250 days, or 6,000 hrs
Physics (60%) – 5 months, or 150 days, or 3,600 hrs, or 1.3 Snowmass Unit.
Compared to known e+e- collider yearly run time:
KEK-B 11-year average ( , Y. Funakoshi):
Operation – 6,000 hrs
Physics (70%) – 4,200 hrs
PEP-II 6-year average ( , J. Seeman):
Operation – 6,500 hours
Physics (60%) – 4,000 hrs
BEPC-II 3-year average ( , Q. Qin):
Operation – 7,000 hrs
Physics (70%) – 4,800 hrs (BES 3,100 hrs, SR 1,700 hrs)

20. LEP1 and LEP2 Efficiency (J. Wenninger)

21. Electricity Bill For a 266 MW CEPC in China:
Fermilab (D. Wolff):
$ 440k per MW-year
$ 20M a year (~5% of lab budget)
(5 US cents per kWh)
CERN (R. Saban):
1,200 GWh /year
CHF 65M a year (~5% of lab budget)
(5 Swiss cents per kWh)
BEPC II: (Qing Qin)
Annual machine operation: 100M yuan
Electricity: 40M yuan a year (US$ 6M)
(~3% of lab budget)
For a 266 MW CEPC in China:
To reach the required integrated luminosity, we need about 6,000 hours for operation each year:
266 MW x 6,000 hours = 1.6 x 109 kW-hr
Annual electricity cost: RMB 1 billion (US$ 150M)
(RMB 0.6 yuan per kWh for industry, 2 times higher than in the US or France)
W. Chou
Rome Workshop, 5/25/2018

22. Summary
Future colliders, either circular or linear, require hundreds MW of power.
Circular ones more so because of synchrotron radiation.
But circular ones provide higher luminosity and more IPs, so the power per unit luminosity is actually lower.
The power suckers are RF and magnet.
Klystron efficiency is the key to reduce RF power.
2-in-1 design reduces magnet power by half
Quadrupole is the main consumer of power. Optimization between construction cost and operation cost has been carried out, but may have room for further improvement.
To make CEPC greener, permanent magnets will be employed in the two linac-booster transfer lines (similar to the Fermilab MI-8 line).
The required wall plug efficiency (23%) for CEPC is a tall order.
Innovative thinking and ideas are welcome.
W. Chou
CAS, 22/02/2018, Zurich

23. Questions?