ASU Solar: Lessons Learned Presented by Robert W. Vandling

Introduction Here at the Tempe Campus, ASU is currently producing 1.88 MW of Solar power. PS1 = 880 kW DC PS2= 30 kW DC PS5= 711 kW DC Lattie Coor= 108 kW DC BioDesign= 150 kW DC

Introduction As you might have imagined, we had many challenges and obstacles to overcome to make this happen. The following is a brief overview of some of the lessons we learned from this endeavor.

Lessons Learned 1) The original RFP focused on rooftops for our Solar installations. Our parking structures proved to be a better place to start due to their high output as well as the age of our roofs were in question.

Lessons Learned 2) One of our more challenging issues proved to be Time. All of our projects, except for BioDesign, were originally set for completion by the end of Unfortunately, only Parking Structure 5 met this goal while PS1 and Lattie Coor each had challenges of their own. PS1 – Late start do to the construction of PS5 Lattie Coor – Personnel issues with the subcontractors BioDesign – Logistics of access to a secure facility. Per APSES: Different buildings have different challenges associated with them. Specifically, the available construction hours at BioDesign are subject to the security protocol of the building which only allows contractors to work 8 hours a day. This eliminates the possibility of accelerating the schedule through longer workday and/or overtime.

Lessons Learned 3) Electrical Feeders RADIAL Each Feeder has only one source energized at a time If the breaker opens, the feeders source is lost The Customer takes an outage until APS switching can occur NETWORK – Two Source Circuit A network is two or more sources operated in parallel to a common bus If a switch opens, then only one source is lost Power is still supplied to the load by the other source

Lessons Learned 3) Electrical Feeders… cont. APS had concerns of our generation be greater than our load. At the West Sub, a NETWORK fed sub, the concern was raised that we would generate more than the load of the sub. As such, we had to create a Trip Signal system wherein APS could signal ASU to drop any and all generation affecting that sub. RADIAL fed sub stations are not a concern to APS in regards to damaging their gear to necessitate a trip signal system.

Lessons Learned 4) Metering Issues ASU requires the use of their own metering system to verify energy production of solar array. The owner of the system also requires these numbers as does APS. Hence, 3 separate meters were installed since both APS and ASU try and secure access to their meters. Owner = pulls data right from the inverters & their meters APS = their own electric meter ASU = Veris CT meters

Lessons Learned 5) LEED Certification With the BioDesign facility, APSES noted that If the solar system has a certain system size criteria in order to qualify for LEED points, you want to double check the available roof space can support the system size.

Questions… ASU Home: ASU Energy Conservation: Campus Metabolism: GIOS: Links: