APS operates 238 solar sites totaling 188 MWAC in Arizona, including 9 utility-scale sites totaling 170 MWAC, 59 school and government sites at 12 MWAC, 41 legacy sites between 5-15 years old at 4 MWAC, and 129 residential sites at 1 MWAC. Solar O&M involves monitoring sites in real-time for performance and security issues as well as preventative and corrective maintenance, with the biggest impacts on energy production coming from switchgear failures and degraded inverters.

1. Arizona Public Service Solar O&M
Jim Hansen

3. APS solar sites under O&M
• AZ Sun – (9) utility scale sites, 170 MWAC
– Allowed by utility commission
• Schools & Government – (59), 12 MWAC
– Allowed by utility commission
• Legacy – (41), 4 MWAC
– 5 to 15 years old
• Residential – (129), 1 MWAC
– Special DOE project

4. Solar O&M – AZ Sun Sites
• Operations (O)
– Monitoring site: real time data, alarms, check
against estimated performance, security, 24/7
– “Smart” meter data for smaller sites
• Maintenance (M)
– PM=Preventive Maintenance
• Weekly, semi-annual, annual
– CM=Corrective Maintenance
• Equipment down, soiling, erosion

5. Solar O&M Options
• Utility owned sites
– Contract w/original EPC on each site for O&M
• Can be expensive over life of plant
• Multiple contracts to manage
– Contract w/one supplier on all O&M
• Problems with communications, multiple parties
• Terms of contract are critical
– In-house O&M
• Some problems w/warranty response of EPC
• Could be most cost effective

6. Utility Scale Solar Sites
• Biggest impacts on energy production
– Switchgear, single point of failure
• Long lead time replacements
• MV fuses, early degradation
– Inverters, most events/issues
• Could be 1% to 11% impact for 1 inverter down

7. Thank You,
any questions?