Space Zoo Patrol – Concentrating Solar Power

By Dr. Craig Turchi, National Renewable Energy Laboratory

Background

What is this technology called?

Concentrating Solar Power (CSP) or Concentrating Solar-Thermal Power (CST)

How does it work?

See information at: https://www.energy.gov/eere/solar/concentrating-solar-thermal-power-basics

What is concentrating solar-thermal power (CSP) technology and how does it work? CSP technologies use mirrors to reflect and concentrate sunlight onto a receiver. The energy from the concentrated sunlight heats a high temperature fluid in the receiver.

This heat – also known as thermal energy – can be used to spin a turbine or power an engine to generate electricity. It can also be used in a variety of industrial applications, like water desalination, enhanced oil recovery, food processing, chemical production, and mineral processing.

Concentrating solar-thermal power systems are generally used for utility-scale (utility power company) projects. These utility-scale CSP plants can be configured in different ways. Power tower systems arrange mirrors around a central tower that acts as the receiver. Linear systems have rows of mirrors that concentrate the sunlight onto parallel tube receivers positioned above them.

Smaller CSP systems can be located directly where power is needed. For example, single dish/engine systems can produce 5 to 25 kilowatts of power per dish and be used in distributed applications (closer to the need for electricity).

Who invented it? And when and where?

The first commercial CSP plants were built in California in the late 1980s. Those plants operated for decades, getting upgrades and serving as a testbed for newer technology. Collectively these were known as Solar Electric Generating Stations (SEGS) I through IX. In the 1980s and 90s the U.S. Department of Energy undertook the Solar One and Solar Two projects in California to demonstrate the next generation in CSP technology—the Power Tower. Solar Two was the first large-scale Power Tower to use molten salt as a fluid to move and store heat in a CSP plant. This is now the current state-of-the-art in commercial CSP plants.

Advantages

What are the environmental advantages?

CSP has no exhaust and therefore has no pollution of air, land, or water.

What are the life cycle financial advantages?

Constructing a large facility is expensive up-front, but the low cost of generating energy on a daily basis shows that the initial expense will pay for itself over time. Current price of electricity from CSP is 18 to 10 cents per kilo Watt hour but with research and development these costs may be cut in half by 2030.

What jobs are created?

Like many types of utility-scale power plants, CSP plants have a staff of administrators, operators, and maintenance teams. A CSP plant may employ 20-40 people for operations, while hundreds of workers help with construction of the plant, which can take 2-4 years.

Energy Production

How efficient is this technology?

Unlike solar photovoltaics (PV), CSP collects heat from the sun. The most efficient CSP system converted about 31% of incoming sunlight to electricity. A typical commercial plant will convert about 20% – 25% to electricity. This is a little higher than commercial PV systems. PV systems cost less than CSP, but CSP systems can store the solar energy in the form of heat and use the heat later, for example after sunset, to make electricity. This is the primary advantage of CSP vs. Solar PV.

How many units are needed for 1 house, 1 school, 1 community?

CSP plants are utility-scale systems that feed power into the electric grid. They are too large for individual homes or small communities.

What percentage of total energy usage (US) does this technology provide today?

The U.S. has 1.5 GWe of operating CSP plants. This is about 0.1% of total capacity.

What percentage of total energy usage (US) could this technology provide in the future?

While CSP is most effective in the southwestern part of the United States, studies have shown that CSP could contribute up to 25% by 2050.

What geographical areas can this be used in?

CSP is best suited for dry, sunny regions around the world. Se map at:

https://www.solarpaces.org/csp-technologies/csp-potential-solar-thermal-energy-by-member-nation/

Countries with excellent CSP conditions include the southwestern USA and northern Mexico; Chile; Morroco, North Africa, and Middle East; Spain; western China; South Africa; Australia and others.

https://www.solarpaces.org/csp-technologies/csp-projects-around-the-world/

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