US PV Installations and Average System Price 2000 - 2013
Source: GTM Research, US Solar Market Insight Report 2013 Year-In-Review
Recent Installed PV Capacity by Market SegmentSource: GTM Research, US Solar Market Insight Report 2013 Year-In-Review
Ten Largest PV Systems in Operation - 2013
Source: GTM Research, US Solar Market Insight Report 2013 Year-In-Review
State PV Installation Rankings 2012-2014
Source: GTM Research, US Solar Market Insight Report 2013 Year-In-Review
PV Installations by State and Sector
Source: GTM Research, US Solar Market Insight Report 2013 Year-In-Review
Recent NC PV Installations by Market Segment
Source: GTM Research, US Solar Market Insight Report 2013 Year-In-Review
Average Installed Price by Market Segment
Source: GTM Research, US Solar Market Insight Report 2013 Year-In-Review
NREL Solar Radiation Manual - Raleigh, NC
• Fixed Tilt Optimal Annual Average Solar Radiation : 5 sun hours/day• 1-Axis Tracking: 6.2 sun hours/day ( 24% increase)• 2-Axis Tracking: 6.4 sun hours/day (28% increase)
DC Rating vs. AC Rating• PV System Ratings may be DC or AC so you need
clarification • AC Rated Capacity = DC Nameplate Capacity x
DC to AC Derate Factor• DC Nameplate Capacity is the sum of the module
nameplate nominal DC power ratings at Standard Testing Conditions (not real world)
• DC to AC Derate Factor takes into account real world operating conditions, system inefficiencies and conversion losses from DC to AC power.
• Typical DC to AC Derate factors for commercial and industrial scale PV systems are 85% to 90%
• Example: 6 MW DC PV Farm– 87% DC/AC Derate Factor– 5.22 MW AC Rated Capacity
DC to AC Derate Factor
• Today’s inverters have very high DC to AC conversion efficiencies
• Modules now have high nameplate power tolerance
Solar PV Capacity Factor
• Capacity Factor: Annual generation divided by generation that would result from system operating at full capacity all day everyday
• Capacity Factor = (AC Rated Capacity x Annual Solar Hours (kWh/m2 day) x 365 days) ÷ (AC Rated Capacity x 8760 hours/year)
• Example: Fixed-tilt 6 MW DC PV farm is 5.22 MW AC PV farm– CF = (5.22 MW AC x 5 kWh/m2 day x 365) ÷
(5.22 MW AC x 8760)– CF = 0.208
Real World PV Performance vs. PV Watts Simulation – A 2010 NC AE Study
Small PV is < 10 kW, Large is PV >10 kW Small PV system PVWatts simulations vs.
Actual generation analysis actual 24% less mostly due to shade
Large system PVWatts simulations vs. Actual generation analysis Actual is in line with PV Watts because
shading isn’t a large problem for large PV
PV Capacity Factor• Solar PV Capacity Factor is lower
than conventional power plant Capacity Factors due to Diurnal cycle, Weather and Season– Daily effect on PV
• No sun for about half of each day• Daylight sunshine equivalent to Full sun for
about 1/3 of day at best
– Seasonal effect on PV (Raleigh NC, Latitude tilt PV)
• Winter solar energy is 67% of summer solar energy
• Spring and fall solar energy are 95% of summer
PV Capacity Factor
– Weather effect on PV energy (kWh)• Sunny day generates 100%• Partly cloudy day generates 50 to 75%• Partly cloudy day generates 50 to 75%• Rainy day generates 10 to 25%
AE 2012 Large Solar PV Generation Study2011 Operation Study Results
Annual Capacity Factor is 19% (Tracking is 20%)
Summer Capacity Factor is 24% (Tracking is 28%)
Spring and Fall is 20% (Tracking is 20%) Winter is 13% (Tracking is 13%)
Solar Plant vs. Nuclear Plant with Capacity Factor of 90%
2500 MW Solar Plant will generate same Power as 2500 MW Nuclear Plant around noon hour in Summer
2500 MW Solar Plant will generate as much Annual Energy as 550 MW Nuclear Plant
In summer, Solar PV generation coincides well with grid load due to increased building cooling load in middle of day
Solar output is proportional to solar radiation so it doesn’t produce rated power except near noon on clear sunny days
Nuclear Plant has to run near full capacity 24/7 Daily load on Grid fluctuates widely over the day Nightime nuclear capacity may be unneeded Example: Duke Energy’s Bad Creek 1000 MW Pumped
Storage Hydro Power Plant is used to balance day and night load with Oconee 2500 MW Nuclear Plant
Renewable and Grid Scale Energy Storage We need large scale energy storage
integrated with solar and wind if we want to increase Renewables to exceed 25% of Grid Capacity Pumped Storage Hydro is one proven
technology Duke Energy’s Bad Creek 1000 MW Pumped
Storage Hydro Power Plant
Widely Distributed Utility Controlled Demand Management acts like Grid Scale Energy Storage
Smart Grid improvements promise to improve integration of renewables, energy storage and load management
Typical Daily, Weekly and Seasonal Utility Power Variation (Texas)
Hourly loads from ERCOT 2005 (NREL)
Load-Following Generators
• To mange highly fluctuating system loads, load-following generators such as hydroelectric and natural gas plants with fast power ramping rates are used
• Power Ramping Rate - the speed at which load-following generation units must increase and decrease power output
• Intermediate Load Plants – load following plants used to meet most of the day-to-day variable demand
• Peaking Units - load following plants which meet the peak demand and often run less than a few hundred hours per year.
Net Load Met By Load-Following Generation for Medium Wind Penetration
Dispatch with higher VG penetration (wind providing 16% of load)* *The Role of Energy Storage with Renewable Electricity Generation, NREL, January 2010
A Mix of Renewables Can Offset Each Other
• Wind generation tends to peak at night and in the cooler months
• Solar generation peaks during the day during the warmer months
• Solar generation peaks coincides air conditioning driven load in the summer