Concentrated solar power (CSP), also called concentrating solar power or concentrated solar thermal, uses systems that gather sunlight to create heat. This heat can be used for tasks such as cooking, removing salt from seawater (desalination), or generating electricity. Mirrors are used to focus sunlight from a large area onto a receiver.

Electricity is made when the focused sunlight is changed into heat (solar thermal energy). This heat powers a machine, such as a Stirling engine or a steam turbine, which are similar to those used in traditional power plants. The heat also moves through an electrical generator or helps in chemical reactions that produce energy.

When combined with thermal energy storage, CSP can generate electricity even at night. This allows it to compete with battery storage systems that work with photovoltaic (solar panel) technology, which is the most common type of solar power. In 2022, photovoltaics had about 1 terawatt of global power capacity. By comparison, in 2021, CSP had less than 1% of that, with only 6.8 gigawatts of global capacity. As of 2023, CSP reached 8.1 gigawatts, including three new projects under construction in China and the United Arab Emirates. The U.S.-based National Renewable Energy Laboratory (NREL), which tracks CSP plants worldwide, reports 6.6 gigawatts of operational capacity and 1.5 gigawatts of projects currently being built.

Comparison between CSP and other electricity sources

Concentrated Solar Power (CSP) is a type of power station that uses heat, similar to power stations that use coal, gas, or geothermal energy. CSP plants can store thermal energy in two ways: as sensible heat or as latent heat, such as by using molten salt. This storage allows CSP plants to produce electricity whenever it is needed, even during the night. This ability to supply electricity on demand makes CSP a dispatchable form of solar energy. Dispatchable renewable energy is especially useful in areas with many solar panels, like California, where electricity demand often rises near sunset, just as solar panels generate less power (a situation called the duck curve).

CSP is often compared to photovoltaic (PV) solar energy because both use sunlight to create electricity. While PV solar grew quickly during the 2010s due to lower costs, CSP growth has been slower because of technical challenges and higher costs. In 2017, CSP made up less than 2% of the world’s solar electricity capacity. However, CSP can store energy more easily at night, which helps it compete with other power sources that can supply electricity continuously.

In 2017, the DEWA project in Dubai, which was under construction in 2019, set a world record for the lowest CSP cost at $73 per megawatt-hour (MWh). The project included 600 MW of trough technology and 100 MW of tower technology, with 15 hours of thermal energy storage daily. In 2017, a CSP project in the very dry Atacama region of Chile had a base-load price below $50 per MWh.

History

A story from later centuries says that Archimedes not only used the Claw of Archimedes but also a "burning glass" to focus sunlight on the Roman fleet during the Siege of Syracuse (213–212 BC). In 1973, a Greek scientist named Dr. Ioannis Sakkas tested whether Archimedes’ heat ray could have burned the Roman ships. He had nearly 60 sailors hold long mirrors to reflect sunlight toward a ship-shaped object 49 meters (160 feet) away. The object caught fire after a few minutes, but historians still question whether Archimedes actually used this method.

In 1866, Auguste Mouchout used a curved mirror to create steam for the first solar steam engine. The first patent for a solar collector was given to Alessandro Battaglia in Genoa, Italy, in 1886. Later, inventors like John Ericsson and Frank Shuman created solar-powered devices for tasks such as watering crops, cooling things, and moving trains. In 1913, Frank Shuman completed a solar thermal energy station in Maadi, Egypt, that produced 55 horsepower (41 kW) for irrigation. In 1929, Dr. R.H. Goddard, known for rocket research, claimed that challenges with solar-powered systems had been solved.

In 1968, Professor Giovanni Francia built the first concentrated-solar plant in Sant'Ilario, near Genoa, Italy. This plant used a design similar to modern power tower plants, with a central receiver surrounded by mirrors. It produced 1 megawatt of electricity using superheated steam at 100 bar and 500 °C. In 1981, the 10 MW Solar One power tower was built in Southern California. In 1995, Solar One was changed to Solar Two, which used a mixture of molten salt (60% sodium nitrate, 40% potassium nitrate) to store heat. Solar Two worked well until it closed in 1999. Meanwhile, the parabolic-trough technology used in the Solar Energy Generating Systems (SEGS), started in 1984, was more practical. SEGS became the world’s largest solar plant until 2014.

No large concentrated solar plants were built between 1990 and 2006, when the Compact linear Fresnel reflector system at Liddell Power Station in Australia was completed. Few other plants used this design, though the 5 MW Kimberlina Solar Thermal Energy Plant opened in 2009.

In 2007, the 75 MW Nevada Solar One was built using a trough design and was the first large plant since SEGS. Between 2010 and 2013, Spain built over 40 parabolic trough systems, each no larger than 50 MW. In other countries, plants have reached up to 200 MW, with costs being lowest around 125 MW.

After Solar Two’s success, a commercial power plant called Solar Tres Power Tower (later renamed Gemasolar Thermosolar Plant) was built in Spain in 2011. Gemasolar’s results helped create more plants of its type. Ivanpah Solar Power Facility was built at the same time but did not store heat, using natural gas to warm water each day. Most concentrated solar plants use parabolic troughs instead of power towers or Fresnel systems. Some trough systems combine solar energy with traditional fossil fuel systems.

At first, concentrated solar power (CSP) was seen as a competitor to photovoltaics (PV). Ivanpah was built without energy storage, but Solar Two had several hours of thermal storage. By 2015, PV plants had become much cheaper, selling for one-third the cost of CSP. However, CSP plants now often include 3 to 12 hours of thermal storage, allowing them to supply power when needed. This makes CSP increasingly competitive with natural gas and PV with batteries for flexible, reliable energy.

Current technology

Concentrated Solar Power (CSP) is used to make electricity, often called solar thermoelectricity, by using heat from sunlight. CSP systems use mirrors or lenses that move to follow the sun and focus sunlight onto a small area. This focused light is used to create heat, which powers a traditional power plant or provides heat for industrial processes, like solar air conditioning.

There are four main types of CSP systems: parabolic trough, dish, concentrating linear Fresnel reflector, and solar power tower. Parabolic trough and concentrating linear Fresnel reflectors are called linear focus collectors, while dish and solar power tower systems are point focus collectors. Linear focus collectors can concentrate sunlight up to about 50 times the normal sunlight (50 suns), and point focus collectors can concentrate it over 500 times (over 500 suns). These systems are not as efficient as the maximum possible concentration, but more advanced designs using nonimaging optics may improve performance.

Different CSP systems create different temperatures, which affects how efficiently they produce electricity. New improvements in CSP technology are making these systems more cost-effective.

In 2023, Australia’s CSIRO tested a CSP system where tiny ceramic particles absorbed heat from concentrated sunlight. These particles can store more heat than molten salt and do not need a container to hold them, which improves heat transfer.

A parabolic trough uses a curved mirror to focus sunlight onto a tube filled with a working fluid, like molten salt. The mirror tracks the sun along one axis, heating the fluid to 150–350 °C (302–662 °F). This hot fluid is then used to generate electricity. Parabolic trough systems are the most developed CSP technology. Examples include the Solar Energy Generating Systems (SEGS) plants in California, Nevada Solar One in Nevada, and Andasol in Europe.

Some CSP systems are built inside greenhouse-like structures with glass walls. This protects the mirrors from wind and dust, helping them reach higher temperatures. Mirrors inside the structure track the sun and focus sunlight onto pipes filled with water. The water is heated to create steam, which generates electricity.

GlassPoint Solar, the company that designed this system, claims it can produce heat for oil recovery at a lower cost than other solar technologies.

A solar power tower uses many mirrors (heliostats) to focus sunlight onto a tower where a heat-transfer fluid, like molten salt, is heated to 500–1000 °C (773–1,273 K or 932–1,832 °F). This heat is used to generate electricity or store energy. Solar power towers are less developed than parabolic troughs but offer better efficiency and storage. Examples include Solar Two in California and the Ivanpah Solar Power Facility in the Mojave Desert, which uses three towers. Ivanpah generated about 63% of its electricity from sunlight and 37% from burning natural gas.

Supercritical carbon dioxide can be used instead of steam to improve efficiency, but it is difficult to cool below its critical temperature in hot, dry areas. Scientists are working on new blends of carbon dioxide that can handle higher temperatures.

Fresnel reflectors use flat mirrors to focus sunlight onto tubes with working fluid. These mirrors are cheaper and capture more sunlight than parabolic reflectors. Some newer models use Ray Tracing technology to improve performance.

A dish Stirling system uses a parabolic mirror to focus sunlight onto a receiver at its focal point. The receiver heats a working fluid, which powers a Stirling engine to generate electricity. These systems are highly efficient (31–32%) and can be scaled up. Examples include systems at the University of Nevada, Las Vegas, and the Australian National University. A dish Stirling system in South Africa achieved 34% efficiency in 2015.

CSP with thermal energy storage

In a Concentrated Solar Power (CSP) plant with storage, sunlight is first used to heat a special type of salt or synthetic oil. This heated material is stored in insulated tanks to keep it hot for later use. When needed, the hot salt or oil is used in a steam generator to create steam, which turns a turbine to produce electricity. This allows solar energy, which is only available during the day, to generate electricity continuously throughout the day and night, similar to how power plants that run on coal or gas operate, but without pollution. The amount of thermal storage is measured by how many hours of electricity the plant can produce at its maximum capacity. Unlike solar panels or CSP plants without storage, CSP plants with thermal storage can provide electricity whenever needed, making them reliable and self-sufficient. These plants can also supply both electricity and heat for industrial processes around the clock. As of December 2018, the cost to generate electricity from CSP plants with thermal storage ranged between 5 cents and 7 cents per kilowatt-hour, depending on the amount of sunlight received at a location. Unlike solar panels, CSP plants with thermal storage can also produce heat for industrial processes 24/7, reducing the need for polluting fossil fuels. CSP plants can also be combined with solar panels to work more efficiently together.

Some CSP plants with thermal storage use air-based generators instead of steam to produce electricity and heat. These plants use gas turbines to make electricity and are smaller in size (less than 0.4 megawatts), requiring only a small area of land to install. Heat waste from the power plant can also be used to create process steam or support heating and cooling systems. If land is not limited, many of these small units can be combined to create larger power plants, up to 1,000 megawatts, with lower costs per unit compared to larger solar thermal plants.

Concentrated solar thermal storage plants can also be used to provide centralized heating for entire communities continuously throughout the day and night.

Deployment around the world

An early plant for concentrated solar power (CSP) was built in Adrano, Sicily. The United States began using CSP plants in 1984 with the SEGS plants. The final SEGS plant was finished in 1990. Between 1991 and 2005, no CSP plants were built anywhere in the world. From 2004 to 2013, global CSP capacity increased almost ten times. During the last five years of that period, capacity grew by an average of 50% each year as more countries started using CSP. In 2013, worldwide CSP capacity rose by 36%, or about 0.9 gigawatts (GW), reaching more than 3.4 GW. The highest CSP capacity was added in 2014, reaching 925 MW. However, this was followed by a decline due to changes in policies, the 2008 financial crisis, and lower costs for photovoltaic (solar) cells. By 2021, total global CSP capacity reached 6,800 MW.

Spain had nearly one-third of the world’s CSP capacity, 2,300 MW, even though no new CSP projects started operating in the country after 2013. The United States had 1,740 MW of CSP capacity. Interest in CSP has also grown in North Africa, the Middle East, China, and India. A trend shows increasing use of CSP in developing countries and regions with high sunlight, with many large projects under construction in 2017.

At first, most CSP plants used parabolic-trough technology, which made up 90% of all CSP plants at one time. Since around 2010, new CSP plants have mostly used central power tower technology because it can operate at higher temperatures—up to 565°C (1,049°F)—compared to the maximum of 400°C (752°F) for parabolic-trough systems. This higher temperature may improve efficiency.

Some of the largest CSP projects include the Ivanpah Solar Power Facility in the United States, which has a capacity of 392 MW and uses solar power tower technology without thermal energy storage. Another major project is the Ouarzazate Solar Power Station in Morocco, which combines parabolic-trough and tower technologies to produce a total of 510 MW, with energy storage for several hours.

Cost

In 2011, the fast drop in the cost of photovoltaic systems led to predictions that concentrated solar power (CSP) would no longer be a cost-effective option. By 2020, the cheapest large-scale CSP plants in the United States and globally were five times more expensive than the cheapest large-scale photovoltaic (PV) plants. The most advanced CSP plants had a projected minimum cost of 7 cents per kilowatt-hour, while the lowest cost for large-scale PV was 1.32 cents per kilowatt-hour. This five-times cost difference has stayed the same since 2018. Some hybrid PV-CSP plants in China tried to make money by using the local coal price of 5 US cents per kilowatt-hour in 2021.

Although the use of CSP is still limited in the early 2020s, the average cost of electricity from commercial-scale CSP plants has decreased since the 2010s. With a learning rate of about 20% cost reduction for every doubling of capacity, CSP costs were getting closer to the higher end of fossil fuel costs at the start of the 2020s. This was supported by programs in countries like Spain, the United States, Morocco, South Africa, China, and the UAE.

Some researchers believe that CSP combined with thermal energy storage (TES) could become cheaper than PV with lithium batteries for storage lasting more than 4 hours per day. However, others, such as NREL, predict that by 2030, PV with 10-hour lithium battery storage will cost the same as PV with 4-hour lithium battery storage did in 2020. This would mean CSP would not have a cost advantage in energy storage. Despite these predictions, energy storage remains important because it helps keep the power system stable and reliable by reducing problems caused by the unpredictable nature of renewable energy and power factor mismatches.

Efficiency

The efficiency of a concentrating solar power system depends on several factors, such as the technology used to change solar power into electricity, the temperature of the receiver, how heat is released, and any other losses in the system. The optical system that focuses sunlight also adds extra losses.

Real-world systems report a maximum efficiency of 23-35% for "power tower" systems, which operate at temperatures from 250 to 565 °C. Higher efficiency numbers assume a combined cycle turbine. Dish Stirling systems, which operate at 550-750 °C, claim about 30% efficiency. The highest recorded solar-to-grid efficiency is 31.25%, achieved by Sandia in 2008. A slightly higher efficiency of 31.4% was reported by the U.S. Department of Energy.

Because sunlight changes throughout the day, average conversion efficiency is usually lower than these maximum numbers. Pilot power tower systems have a net annual efficiency of 7-20%, while demonstration-scale Stirling dish systems have 12-25%.

The solar-to-electrical conversion efficiency depends on three factors: how much sunlight is captured (including losses in the optical system), how well the receiver converts sunlight into heat, and how effectively heat is changed into electricity.

The maximum efficiency of any thermal-to-electrical system is called the Carnot efficiency. This is a theoretical limit set by the laws of thermodynamics. Real systems do not reach this maximum.

The efficiency of converting sunlight into electricity depends on the properties of the solar receiver and the heat engine, such as a steam turbine. Sunlight is first focused onto the receiver by an optical system. The receiver converts sunlight into heat with a certain efficiency. The heat is then changed into mechanical energy by the heat engine, following Carnot’s principle. Mechanical energy is finally converted into electricity by a generator.

For systems with a solar receiver and a mechanical converter (like a turbine), overall efficiency is calculated by multiplying several factors: the fraction of light focused onto the receiver, the efficiency of converting light into heat, the efficiency of converting heat into mechanical energy, and the efficiency of converting mechanical energy into electricity.

The efficiency of converting light into heat depends on the receiver’s properties. The efficiency of converting heat into mechanical energy is limited by the Carnot efficiency, which depends on the receiver’s temperature and the temperature of the heat sink (where heat is released).

Real-world engines typically achieve 50-70% of the Carnot efficiency due to losses like heat loss and friction in moving parts.

When sunlight is concentrated onto a receiver, the amount of energy absorbed depends on the receiver’s temperature, the concentration level, and the receiver’s ability to absorb and emit heat. At very high temperatures, the receiver loses more energy as heat, which reduces its efficiency.

There is an ideal temperature for maximum efficiency, where the benefits of higher heat engine efficiency balance the losses from increased heat emission. This temperature depends on how much sunlight is concentrated.

In practice, real-world concentrating solar power systems often produce 25-60% less energy than predicted, partly because of losses not included in theoretical models, such as those from the Carnot cycle.

Incentives and markets

In 2008, Spain started the first large-scale commercial concentrated solar power (CSP) market in Europe. Until 2012, solar-thermal electricity generation was eligible for payments called feed-in tariffs (Article 2 of Royal Decree 661/2007). This led to the creation of the largest CSP fleet in the world, which had 2.3 gigawatts (GW) of installed capacity and provided about 5 terawatt-hours (TWh) of power to the Spanish grid each year. The initial rules for plants receiving feed-in tariffs were:

• Systems registered before September 29, 2008: 50 megawatts (MW) for solar-thermal systems.
• Systems registered after September 29, 2008: only photovoltaic (PV) systems.

Capacity limits for different system types were updated every quarter during reviews (Article 5 of Royal Decree 1578/2008, Annex III of Royal Decree 1578/2008). Before each application period ended, the maximum capacity allowed for each system type was published on the website of the Ministry of Industry, Tourism and Trade (Article 5 of Royal Decree 1578/2008). Due to cost concerns, Spain stopped accepting new projects for feed-in tariffs on January 27, 2012. Projects already accepted were affected by a 6% "solar-tax" on feed-in tariffs, which reduced the payments.

In this context, the Spanish Government passed Royal Decree-Law 9/2013 in 2013 to ensure the economic and financial stability of the electricity system. This law laid the foundation for the new Law 24/2013 of the Spanish electricity sector. In 2014, Royal Decree 413/2014 was introduced, replacing the previous rules from Royal Decree 661/2007 and Royal Decree 1578/2008. This new law set a new payment system for these projects.

After a period of slow growth for CSP in Europe, Spain announced in its National Energy and Climate Plan a goal to add 5 GW of CSP capacity between 2021 and 2030. To achieve this, bi-annual auctions for 200 MW of CSP capacity, starting in October 2022, are expected, though details are not yet confirmed.

Several CSP systems have been built in remote Aboriginal communities in the Northern Territory, including Hermannsburg, Yuendumu, and Lajamanu.

No large-scale CSP projects have been completed in Australia so far, but some have been proposed. In 2017, an American company called SolarReserve, which later went bankrupt, was given a contract to build a 150 MW CSP project in South Australia. The project would have produced electricity at a very low cost of AUD$0.08 per kilowatt-hour (kWh), or about USD$0.06 per kWh. However, the company could not find funding, and the project was canceled. Other CSP projects in Australia are being considered for mines that need electricity around the clock but have no connection to the power grid. A startup company called Vast Solar planned to build a 50 MW CSP and PV facility in Mt. Isa, North-West Queensland, by 2021, and a 30 MW CSP system near Port Augusta, with funding from the Australian Renewable Energy Agency and other sources after 2025.

At the federal level, under the Large-scale Renewable Energy Target (LRET), which is part of the Renewable Energy Electricity Act 2000, large-scale solar thermal electricity generation from approved power stations may earn large-scale generation certificates (LGCs). These certificates can be sold to electricity retailers to help them meet their obligations under the certificate system. However, since this law applies to all technologies equally, it often favors more established renewable energy sources, like large-scale wind power, which have lower costs to produce electricity. At the state level, renewable energy feed-in laws usually have limits on the maximum electricity generation capacity and are only open to small or medium-scale projects. In some cases, these laws apply only to solar photovoltaic (PV) systems. This means that large-scale CSP projects may not qualify for feed-in incentives in many states and territories.

In 2024, China is offering second-generation CSP technology to compete with other electricity generation methods that rely on renewable or non-renewable fuels, without direct or indirect subsidies. In the current 14th Five-Year Plan, CSP projects are being developed in several provinces alongside large-scale solar PV and wind projects.

In 2016, China announced plans to build 20 diverse CSP demonstration projects as part of the 13th Five-Year Plan, aiming to develop a globally competitive CSP industry. The first plants were completed in 2018, and electricity generated from these plants with thermal storage is supported by an administratively set feed-in tariff of RMB 1.5 per kWh. By the end of 2020, China operated a total of 545 MW of CSP capacity across 12 plants: seven plants (320 MW) used molten-salt towers, two plants (150 MW) used the Eurotrough 150 parabolic trough design, and three plants (75 MW) used linear Fresnel collectors. Plans to build a second batch of demonstration projects were not carried out, and further support for CSP in the upcoming 14th Five-Year Plan is unclear. Federal support for the demonstration projects ended by the end of 2021.

In March 2024, SECI announced that a request for proposals (RfQ) for 500 MW of CSP capacity would be issued in 2024.

Solar thermal reactors

Concentrated Solar Power (CSP) can be used for purposes other than generating electricity. Scientists are studying solar thermal reactors to create solar fuels, which could make solar energy a portable energy source in the future. These researchers use the heat from CSP to help chemical reactions that break apart water molecules (H₂O) into hydrogen gas (H₂). This process uses solar energy and produces no carbon emissions. By splitting both water and carbon dioxide (CO₂), other fuels like jet fuel used in airplanes could be made using solar energy instead of fossil fuels.

Heat from the sun can be used to create steam, which makes heavy oil less thick and easier to pump. This process is called solar thermal enhanced oil recovery. Solar power towers and parabolic troughs can produce the steam directly, without needing generators or creating electricity. This method can help extend the life of oil fields with very thick oil that would otherwise be too expensive to extract.

Producing carbon-neutral synthetic fuels using concentrated solar thermal energy at temperatures close to 1500°C is possible and may become practical in the future if the cost of CSP plants decreases. Additionally, carbon-neutral hydrogen can be made using solar thermal energy (CSP) through methods like the sulfur–iodine cycle, hybrid sulfur cycle, iron oxide cycle, copper–chlorine cycle, zinc–zinc oxide cycle, cerium(IV) oxide–cerium(III) oxide cycle, or other similar processes.

Gigawatt-scale solar power plants

From around the year 2000 to about 2010, many ideas were proposed for large solar power plants that use concentrated solar power (CSP). These included the Euro-Mediterranean Desertec project and Project Helios in Greece (10 gigawatts), but both were canceled. A study from 2003 found that the world could produce 2,357,840 terawatt-hours of electricity each year using large solar power plants that cover 1% of the world’s deserts. In 2003, total global electricity use was 15,223 terawatt-hours per year. The large-scale projects would have been made up of many standard-sized plants. In 2012, the U.S. Bureau of Land Management made 97,921,069 acres (39,627,251 hectares) of land in the southwestern United States available for solar projects, enough for 10,000 to 20,000 gigawatts of power. The largest single plant currently operating is the 510 megawatt Noor Solar Power Station. In 2022, the 700 megawatt CSP fourth phase of the 5 gigawatt Mohammed bin Rashid Al Maktoum Solar Park in Dubai will become the largest solar complex using CSP.

Areas with the highest direct sunlight are typically dry, at high altitudes, and in the tropics. These places have greater potential for CSP than areas with less sunlight. Abandoned open-pit mines, gentle hill slopes, and crater depressions may be useful for power tower CSP systems, as the power tower can be placed directly on the ground next to the molten salt storage tank.

Environmental effects

Concentrating solar power (CSP) plants use water and land, which can affect the environment. Water is often used to cool the plants and clean the mirrors. Some projects are trying to reduce water and cleaning chemical use by using barriers, non-stick mirror coatings, water misting systems, and other methods.

CSP plants with wet-cooling systems use more water than most other types of power plants. Only fossil-fuel plants with carbon-capture and storage may use more water. A 2013 study found that CSP plants with wet cooling used about 3.1 cubic meters of water per megawatt-hour (810 US gallons per MWh) for power tower plants and 3.4 cubic meters per MWh (890 US gallons per MWh) for trough plants. This was more than nuclear (2.7 cubic meters per MWh, 720 US gallons per MWh), coal (2.0 cubic meters per MWh, 530 US gallons per MWh), or natural gas (0.79 cubic meters per MWh, 210 US gallons per MWh) plants. A 2011 study by the National Renewable Energy Laboratory found similar results: CSP trough plants used 3.27 cubic meters per MWh (865 US gallons per MWh), CSP tower plants used 2.98 cubic meters per MWh (786 US gallons per MWh), coal plants used 2.60 cubic meters per MWh (687 US gallons per MWh), nuclear plants used 2.54 cubic meters per MWh (672 US gallons per MWh), and natural gas plants used 0.75 cubic meters per MWh (198 US gallons per MWh). The Nevada Solar One trough CSP plant uses about 3.2 cubic meters per MWh (850 US gallons per MWh). Water use is a major concern because CSP plants are often built in dry areas where water is limited.

In 2007, the US Congress asked the Department of Energy to find ways to reduce CSP water use. The report said dry cooling systems, which are more expensive but use less water, could reduce water use by 91 to 95 percent. Hybrid systems, which mix wet and dry cooling, could reduce use by 32 to 58 percent. A 2015 report found that of 24 CSP plants in the US, 4 used dry cooling systems. These included the three plants at the Ivanpah Solar Power Facility near Barstow, California, and the Genesis Solar Energy Project in Riverside County, California. Of 15 CSP projects under construction or development in the US as of March 2015, 6 used wet systems, 7 used dry systems, 1 used a hybrid system, and 1 was not specified.

Although older power plants with once-through cooling or cooling ponds use more water than CSP plants, most of the water used by these plants is returned to the environment. For example, a typical US coal plant with once-through cooling uses 138 cubic meters per MWh (36,350 US gallons per MWh), but only 0.95 cubic meters per MWh (250 US gallons per MWh) is lost through evaporation.

Bright lights from CSP plants can attract insects, which may draw birds that hunt them. Birds flying near the focused light can be burned, harming or killing them. This can also affect birds of prey that hunt other birds. Federal wildlife officials described the Ivanpah power towers as "mega traps" for wildlife.

Some media have reported that CSP plants have injured or killed many birds due to the intense heat from concentrated sunlight. Some claims may be exaggerated.

According to detailed reports, during the first six months of operation, 321 bird deaths were recorded at Ivanpah, with 133 linked to sunlight reflecting onto boilers. Over a year, 415 bird deaths were recorded from known causes, and 288 from unknown causes. Adjusting for how many dead birds were found, total bird deaths were estimated at 1,492 from known causes and 2,012 from unknown causes. Of the known causes, 47.4% were burned, 51.9% died from collisions, and 0.7% died from other causes. Actions like limiting the number of mirrors focused on one area during standby, as done at the Crescent Dunes Solar Energy Project, can reduce these numbers. Between 2020 and 2021, 288 bird deaths were directly recorded at Ivanpah, a number similar to previous reports. A 2016 study suggested that bird deaths per megawatt of power were similar for CSP and wind plants but higher for fossil fuel plants.