Challenges that once thwarted widespread solar thermal power generation — including cost, speed of deployment, and environmental sustainability — have now been met. eSolar delivers a new blueprint for solar energy in Cal

Sierra SunTower supplies 5 MW of clean, renewable energy to the grid. The full-scale power plant, the only commercial CSP tower in the United States, supplies electricity to Southern California Edison (SCE) and will power up to 4,000 homes.

Quick Facts

2 modules
20 acres
2 towers
2 65-ton natural recirculation thermal receivers
1 refurbished 1947 GE steam turbine generator
Steam temperature 440° C
Steam pressure 60 bar
24,000 mirrors reflecting the power of 20,000 suns
5 MW of clean, renewable energy supplied to 4,000 Southern California Edison households through a power purchase agreement
Only operating solar thermal power tower plant in the US


Southern California Homes – Sierra SunTower will produce 5 MW of electricity powering up to 4,000 homes.
Job Creation – The project created over 250 construction jobs and 21 permanent jobs.
Local Community – Sierra SunTower provides a new local tax base, as well as direct and indirect economic benefits during development, construction and operation.
Greenhouse Gases – 5 MW of clean solar power generation will offset more than 7,000 tons of CO2 each year.
Clean and Reliable – Efficient and clean solar power is reliably available during peak demand.

Environmental Facts

The 5 MW output of Sierra SunTower will reduce CO2 emissions by 7,000 tons per year. For perspective, Sierra SunTower’s annual impact is equivalent to:
Planting 5,265 acres of trees
Removing 1,368 automobiles from the road
Saving 650,000 gallons of gasoline

eSolar has developed a cost-effective utility-scale CSP power plant that is based on mass-manufactured components and designed for rapid construction, uniform modularity, and unlimited scalability. The eSolar approach marries a low-impact, pre-fabricated design with patent-pending computer software and elegant engineering solutions to provide solar electricity ranging from 46 MW to over 500 MW. The eSolar® solution delivers cost-competitive solar energy in response to growing worldwide energy demands.

1. How Their System Works

 Power Tower Technology

A field of sun-tracking heliostats reflects solar heat to a thermal receiver mounted atop a central power tower. The focused heat boils water within the thermal receiver and produces steam. The plant pipes the steam from each thermal receiver and aggregates it at the turbine, powering a power generator. The steam then reverts back to water through cooling, and the process repeats.

2. Patented Heliostat Design

 The eSolar Building Block

A small and mass-manufactured heliostat is the building block of the eSolar® solution. eSolar designed the heliostats for deployment in pre-fabricated "heliostat sticks" that can be installed easily with a minimum of training. Low wind profile design allows fields of eSolar® heliostats to be installed faster than any competitive CSP solutions.

3. Modular Field Layout

 Cost-Based Design

Thousands of systematically spaced heliostats combine to form the eSolar® modular field, comprised of north and south facing mirror sub-fields. Both mirror fields concentrate sunlight to a thermal receiver mounted atop a central tower. The sub-field design optically optimizes the layout to maximize the harvested thermal energy.

4. Scalable Units

 The eSolar Solution

A 46 MW eSolar® power unit consists of 12 towers (each with its own north-south heliostat sub-field), a turbine generator set, and a steam condenser. 46 MW power units fit on approximately 100 hectares (250 acres). eSolar can construct multiple 46 MW units scalable to any required size of output.