P ECAN S TREET P ROJECT – A “G REEN ” D EVELOPMENT Center for Electromechanics Pecan Street, Inc. SWEDE 2013 May 5, 2013 Austin, Texas Dr. Fabian Uriarte Center for Electromechanics University of Texas at Austin

W HAT IS P ECAN S TREET, I NC.?  R&D organization UT Austin  Focus  Test advanced technology  Understand customer behavior  Flagship Efforts  Demonstration smart grid  Improve the way we use energy

S MART G RID L OCATION Pecan Street offices Mueller Community Texas Advanced Computing Center Ctr. for Electromechanics pecanstreet.org

Homes735 Transformers94 Solar panels200 Electric vehicles100

E LECTRICAL D ISTRIBUTION Mueller Community, Austin, Texas 735 homes (so far) 94 transformers 200 solar panels 100 electric vehicles

T RANSFORMER L OAD * 240/120V *One possible combination Circuit feed (7.2 kV) xfms. Homes per transformer: Maximum: 11 Mode: 8 Minimum: 4

L OAD D ISTRIBUTION BY P HASE (Electric Vehicles) (Photovoltaic Arrays)

C ASE S TUDY * Modeling in progress Center for Electromechanics

S IMULATION A PPROACH Use Recorded Data as Input Run Model Examine Results

R ECORDED D ATA P OOL >100 homes being measured (load and generation) 1 min. intervals Measurements start on different dates 24 hrs of data per CSV file Everyday a new CSV file is created (awaiting next data dump)

R ESIDENTIAL L OAD Real Data

PV G ENERATION Real Data MW of distributed PV generation daily

EV L OAD Mix of 120 V and 240 V charging > 4 PM

T RANSFORMERS T HROUGHPUT

T RANSFORMER U TILIZATION High PV/Load ratio causes reverse flows Can increase or decrease xfm. utilization After PVs and EVs Before PVs and EVs

C HANGE IN T RANSFORMER L OAD Example (blue areas): Usage before: 25 % (fwd. direction) Usage after: 5 % (reverse direction) Change: 20 % “-” or “<0” shows reduction in utilization “>0” means increase in utilization No change PVs produce 23% increase EVs produce 2% increase

L ATERAL P OWER 0.5 MW reduction in real power demand Equal reactive power demand Power factor drops After PVs and EVs Before PVs and EVs Vars Watts VA PF Vars Watts VA PF As seen from here

L ATERAL C URRENT Decrease in diurnal current unbalance Peak time unbalance unchanged After PVs and EVs Before PVs and EVs From here

D ISTRIBUTION L OSSES Increase due to EVs Xfm losses almost unchanged $45/day = $16k/year After PVs and EVs Before PVs and EVs Reduction due to PVs

C ONCLUSIONS Center for Electromechanics  Simulation Model  We have real data (1 m resolution )  Consumption  PV generation  Can simulate entire smart grid (735 homes)  Confidence in results  Transformers  Appear oversized already  Some operate ~80%  Can meet EV load (at Mueller community)  Power flow is forwards and backwards  Residential Solar Panels (PVs)  Inject power back into the grid  Injection is uncontrolled and unbalanced  Reduce lateral and transformer power factor  Provide voltage support  Electric Vehicles (Chevy Volts)  Uncontrolled charging exacerbates peak demand  Electrical impact appears small due to transformer sizing

A CKNOWLEDGEMENTS Pecan Street, Inc. Brewster McCracken executive director Bert Haskell technology director Ariane Beck program manager Chris Holcomb data analysis Dan Weisberg economic strategy UT Austin Dr. Kwasinski & Amir Toliyat solar arrays Dr. Baldick & David Tuttle electric vehicles Dr. Edgar, Wesley Cole, Robert Fares, and Akshay Sriprasad energy storage Austin Energy Kurt Stogdill utility strategist Charles Robinson distribution planning Sharon Bickford systems engineering Center for Electromechanics Robert Hebner director John Herbst program manager

Q UESTIONS Fabian Uriarte Center for Electromechanics The University of Texas at Austin utexas.edu/research/cem Burnet Road, Austin, TX Center for Electromechanics