Utility Scale Rooftop Solar Ability of neighborhood solar to
defer new electrical facilities 1
Slide 2
Describe Rocky Mountain Powers in-depth study of neighborhood
solar to offset the need to build new infrastructure (power plants,
substations and lines) Outline Rocky Mountain Powers progress on
Utah carbon reduction goal Describe Rocky Mountain Powers support
of customer-owned renewable energy Purpose of presentation 2
Slide 3
Customer use on the rise Rocky Mountain Power residential
customers use about 26% more electricity than 20 years ago To meet
our obligation to serve, additional power supply resources,
substations and power lines are needed to meet growing customer use
New facilities are expensive and difficult to permit Advocates want
different solutions 3
Slide 4
Can rooftop solar defer new facilities? Study Area Boundary
Customers questioned substation expansion in an established
neighborhood Public opposition delayed conditional use permit
Undertook subsequent study of rooftop solar to determine its
ability to meet customer use SOUTH TEMPLE UNIVERSITY STREET 1100
EAST400 SOUTH 900 EAST 4
Slide 5
Scope of the solar opportunity CategoryType of Building Median
Roof Footprint Median # of PV Panels Minimum # of PV Panels Maximum
# of PV Panels Average Usable Roof Area ResidentialSingle Family
Residential171 m 2 25011913.81% Multi-ResidentialApartments,
Condos, etc.173 m 2 32039719.88% Sm. CommercialRestaurant,
Commercial Retail349 m 2 136634031.31% Lg. CommercialOffices,
Hospitals, Churches430 m 2 1601691732.74% UnknownUnknown Land
Use196 m 2 26226214.57% 20 ft. 40 ft. 60 ft. 80 ft. 5
Slide 6
Determining panel location 176 Panels 97.79kWh/day 19.8% usable
roof 9:30am 12:30pm 6:30pm Evaluated roof shading on every
structure Determined solar exposure Locate solar panels where they
produce the most energy 6
Slide 7
Two-thirds of rooftops are suitable for solar panels (237 of
356 ) Total number of panels 13,304 Study uses high efficiency
panels; solar energy to electricity = 19% Study aims to maximize
solar output 7
Slide 8
Customer Use Solar Production Here comes the sun 8
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Customer Use Solar Production 9
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Here comes the sun Customer Use Solar Production 10
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Here comes the sun Customer Use Solar Production 11
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Here comes the sun Customer Use Solar Production 12
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Here comes the sun Customer Use Solar Production 13
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Here comes the sun Customer Use Solar Production 14
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Here comes the sun Customer Use Solar Production 15
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Here comes the sun Customer Use Solar Production 16
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Here comes the sun Customer Use Solar Production 17
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Here comes the sun Customer Use Solar Production 18
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Here comes the sun Customer Use Solar Production 19
Slide 20
Estimated solar production Solar Energy Conversion: 2,210 MWh
annual energy production 1,560 MWh during summer months (May-Sept.)
Maximum Solar Power Output as calculated June 21 = 1.52 MW (summer
solstice) Temperature Corrected = 1.45 MW at 76 o F Solar Output on
Circuit Peak August 2 = 0.54 MW (2010 circuit peak) Temperature
Corrected = 0.48 MW at 93 o F Projected 2011 Circuit Peak = 4.6 MVA
20
Slide 21
Solar contribution to peak Solar output at ideal conditions
Actual customer load Circuit Peak 21
