Randolph Kinney
Elite Member
- Joined
- Apr 7, 2005
- Professional Status
- Retired Appraiser
- State
- North Carolina
Which Is Cheaper -- Rooftop Solar Or Utility-Scale Solar?
The Brattle Group,with support from the Edison Electric Institute, just released a study concluding that utility-scale solar photovoltaic (PV) systems in the United States are more cost effective than residential-scale (rooftop) PV systems in achieving the economic and policy benefits we all expect to come from the widespread use of solar energy.
The study was commissioned by First Solar, one of the largest solar companies in America. Titled Comparative Generation Costs of Utility-Scale and Residential-Scale PV in Xcel Energy Colorado’s Service Area, this study is the first to focus on a “solar to solar comparison of equal amounts of residential-scale and utility-scale PV solar deployed on an operating utility system.”
The study found that the cost of generating energy from 300 MW of utility-scale PV solar is roughly one-half the cost per kWh of electricity produced from an equivalent 300 MW of 5kW residential-scale systems when deployed on the Xcel Energy XEL +0.00% Colorado grid. Utility-scale solar remained more cost effective in all scenarios considered in the study, scenarios having different tax credits, monetizations, and inflation rates.
The study also concluded that 300 MW of PV solar deployed in a utility-scale configuration avoids approximately 50% more carbon emissions than an equivalent amount of residential-scale PV solar.
The large difference in costs between utility- and residential-scale systems was attributed to economies of scale and greater solar electric output resulting from optimized panel orientation and tracking assumed for utility-scale systems. The improved orientation and tracking of utility-scale solar resulted in a higher capacity factor than for rooftop solar.
The study found that projected utility-scale PV power costs will range from 6.6¢/kWh to 11.7¢/kWh across all scenarios, while projected power costs for a typical, customer-owned rooftop PV system will range from 12.3¢/kWh to 19.3¢/kWh.
Warren Buffet recently purchased the world’s largest photovoltaic solar array in Bakersfield, California. It is a 5-square-mile 579 MW PV array that cost a little over $2.2 billion. Assuming a capacity factor of 25% over the expected 25-year lifespan, this utility-scale PV will generate 32 billion kWhs in total:
579 MW x 1000 kW/MW x 8766 hours/year x 0.25 x 25 years = 32 billion kWhs
There are no obvious fuel costs, but PV solar has O&M costs of about 1.3¢/kWh, which comes to about $400 million over the life of this array. So to produce 32 billion kWhs at about $2.3 billion means a life-cycle cost of 7¢/kWh. This is getting close to the range of normal baseload providers like coal, nuclear and hydro, which have life-cycle costs of 5.1¢/kWh, 4.1¢/kWh and 2.7¢/kWh, respectively.
http://www.forbes.com/sites/jamesco...cheaper-rooftop-solar-or-utility-scale-solar/
The article leaves out that utilities have to supply electricity 24 hours a day, rain or shine, according to the demand load. That means the cost to build and operate a gas fired power plant needs to be added to the cost of solar because that will supply power 24 hours a day, rain or shine. You need that generation capacity to supply power when solar can't.
The Brattle Group,with support from the Edison Electric Institute, just released a study concluding that utility-scale solar photovoltaic (PV) systems in the United States are more cost effective than residential-scale (rooftop) PV systems in achieving the economic and policy benefits we all expect to come from the widespread use of solar energy.
The study was commissioned by First Solar, one of the largest solar companies in America. Titled Comparative Generation Costs of Utility-Scale and Residential-Scale PV in Xcel Energy Colorado’s Service Area, this study is the first to focus on a “solar to solar comparison of equal amounts of residential-scale and utility-scale PV solar deployed on an operating utility system.”
The study found that the cost of generating energy from 300 MW of utility-scale PV solar is roughly one-half the cost per kWh of electricity produced from an equivalent 300 MW of 5kW residential-scale systems when deployed on the Xcel Energy XEL +0.00% Colorado grid. Utility-scale solar remained more cost effective in all scenarios considered in the study, scenarios having different tax credits, monetizations, and inflation rates.
The study also concluded that 300 MW of PV solar deployed in a utility-scale configuration avoids approximately 50% more carbon emissions than an equivalent amount of residential-scale PV solar.
The large difference in costs between utility- and residential-scale systems was attributed to economies of scale and greater solar electric output resulting from optimized panel orientation and tracking assumed for utility-scale systems. The improved orientation and tracking of utility-scale solar resulted in a higher capacity factor than for rooftop solar.
The study found that projected utility-scale PV power costs will range from 6.6¢/kWh to 11.7¢/kWh across all scenarios, while projected power costs for a typical, customer-owned rooftop PV system will range from 12.3¢/kWh to 19.3¢/kWh.
Warren Buffet recently purchased the world’s largest photovoltaic solar array in Bakersfield, California. It is a 5-square-mile 579 MW PV array that cost a little over $2.2 billion. Assuming a capacity factor of 25% over the expected 25-year lifespan, this utility-scale PV will generate 32 billion kWhs in total:
579 MW x 1000 kW/MW x 8766 hours/year x 0.25 x 25 years = 32 billion kWhs
There are no obvious fuel costs, but PV solar has O&M costs of about 1.3¢/kWh, which comes to about $400 million over the life of this array. So to produce 32 billion kWhs at about $2.3 billion means a life-cycle cost of 7¢/kWh. This is getting close to the range of normal baseload providers like coal, nuclear and hydro, which have life-cycle costs of 5.1¢/kWh, 4.1¢/kWh and 2.7¢/kWh, respectively.
http://www.forbes.com/sites/jamesco...cheaper-rooftop-solar-or-utility-scale-solar/
The article leaves out that utilities have to supply electricity 24 hours a day, rain or shine, according to the demand load. That means the cost to build and operate a gas fired power plant needs to be added to the cost of solar because that will supply power 24 hours a day, rain or shine. You need that generation capacity to supply power when solar can't.