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

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

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

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

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

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

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

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

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

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

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

FCC-ee FCC-ee

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 117.3 MW 1313

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

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 117.3 MW Beam power 5.28 MW, efficiency 5% 1515

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

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

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

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 (2000-2010, Y. Funakoshi): Operation – 6,000 hrs Physics (70%) – 4,200 hrs PEP-II 6-year average (2003-2008, J. Seeman): Operation – 6,500 hours Physics (60%) – 4,000 hrs BEPC-II 3-year average (2015-2017, Q. Qin): Operation – 7,000 hrs Physics (70%) – 4,800 hrs (BES 3,100 hrs, SR 1,700 hrs)

LEP1 and LEP2 Efficiency (J. Wenninger)

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

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

Questions?