No, this project doesn’t use water in the heat collection or storage. And the mirrors aren’t actively cooled at all.

The power generation loop does use water, turning it into steam in one heat exchanger and condensing it back to liquid in the other.

And the condenser uses water; a fair amount if it’s wet-cooled, much less if it’s dry-cooled.

No, this project doesn’t use water in the heat collection or storage. And the mirrors aren’t actively cooled at all.

The power generation loop does use water, turning it into steam in one heat exchanger and condensing it back to liquid in the other.

And the condenser uses water; a fair amount if it’s wet-cooled, much less if it’s dry-cooled.

No, this project doesn’t use water in the heat collection or storage. And the mirrors aren’t actively cooled at all.

The power generation loop does use water, turning it into steam in one heat exchanger and condensing it back to liquid in the other.

And the condenser uses water; a fair amount if it’s wet-cooled, much less if it’s dry-cooled.

the company’s application to the CPUC shows that there is NO water used. The heat storage is in molten salt. The mirrors are dry cooled.

“Liquid salt (The salt is a mixture of sodium nitrate, a common ingredient in fertilizer, and potassium nitrate, a fertilizer and food additive. These mineral products will be mixed onsite as received directly from mines in solid crystallized form and used without additives or further processing other than mixing and heating.), which has viscosity and appearance similar to water when melted, is circulated through tubes in the receiver, collecting the energy gathered from the sun.

The heated salt is then routed to an insulated storage tank where it can be stored with minimal energy losses.

When electricity is to be generated, the hot salt is routed to heat exchangers (or steam generation system).

The steam is then used to generate electricity in a conventional steam turbine cycle. After exiting the steam generation system, the salt is sent to the cold salt thermal storage tank and the cycle is repeated.

The salt storage technology was demonstrated successfully at the U.S. Department of Energy-sponsored 10-MW Solar Two project near Barstow, California, in the 1990s.”

the company’s application to the CPUC shows that there is NO water used. The heat storage is in molten salt. The mirrors are dry cooled.

“Liquid salt (The salt is a mixture of sodium nitrate, a common ingredient in fertilizer, and potassium nitrate, a fertilizer and food additive. These mineral products will be mixed onsite as received directly from mines in solid crystallized form and used without additives or further processing other than mixing and heating.), which has viscosity and appearance similar to water when melted, is circulated through tubes in the receiver, collecting the energy gathered from the sun.

The heated salt is then routed to an insulated storage tank where it can be stored with minimal energy losses.

When electricity is to be generated, the hot salt is routed to heat exchangers (or steam generation system).

The steam is then used to generate electricity in a conventional steam turbine cycle. After exiting the steam generation system, the salt is sent to the cold salt thermal storage tank and the cycle is repeated.

The salt storage technology was demonstrated successfully at the U.S. Department of Energy-sponsored 10-MW Solar Two project near Barstow, California, in the 1990s.”

“Once-through water cooling returns all of the withdrawn water to the source. Although it does not consume any water in the cooling process, it does increase the temperature and hence the evaporation rate from the body of water. This cooling method is limited in application and is not typically available for a solar power plant.” (p.12)

If you’re trying to dump your waste heat into the air, your wet-cooling (“Recirculating”) or dry-cooling system doesn’t *care* what the source of your heat is. It’ll take the same amount of water per unit of heat. The differences in water use come from the variation in efficiency of the different technologies, which come from the differing temperature of the steam they generate. Gas burns extremely hot, so it has the highest efficiency. Solar power tower and dish systems can reach much higher temperatures than parallel trough systems (See p.14.), hence the difference in water consumption.

Again, don’t take my word for it:

“Based on thermodynamic principles, a water-cooled linear Fresnel reflector plant which generates steam directly in the heat collection tube, is estimated to require somewhat more water than a trough plant owing to its lower operating temperature and reduced cycle efficiency (greater heat rejection per MWh of electricity). Conversely, a power tower with a conventional Rankine cycle would presumably use somewhat less water, approximately 600 gal/MWh similar to a coal plant, by virtue of its higher operating temperature and efficiency.” (p.11–12)

“Consider water-use information from the 2006 report Energy Demands on Water Resources, Report to Congress on the Interdependency of Energy and Water prepared by the U.S. Department of Energy: a coal fired plant uses 110 to 300 gallons per megawatt hour; a nuclear plant uses between 500 and 1100 gallons/MWh; and a solar parabolic trough plant uses 760-920 gallons/MWh.”

http://www.ag.arizona.edu/azwater/awr/septoct08/d3aa3f8e-7f00-0101-0097-9f6724822dfe.html

“Once-through water cooling returns all of the withdrawn water to the source. Although it does not consume any water in the cooling process, it does increase the temperature and hence the evaporation rate from the body of water. This cooling method is limited in application and is not typically available for a solar power plant.” (p.12)

If you’re trying to dump your waste heat into the air, your wet-cooling (“Recirculating”) or dry-cooling system doesn’t *care* what the source of your heat is. It’ll take the same amount of water per unit of heat. The differences in water use come from the variation in efficiency of the different technologies, which come from the differing temperature of the steam they generate. Gas burns extremely hot, so it has the highest efficiency. Solar power tower and dish systems can reach much higher temperatures than parallel trough systems (See p.14.), hence the difference in water consumption.

Again, don’t take my word for it:

“Based on thermodynamic principles, a water-cooled linear Fresnel reflector plant which generates steam directly in the heat collection tube, is estimated to require somewhat more water than a trough plant owing to its lower operating temperature and reduced cycle efficiency (greater heat rejection per MWh of electricity). Conversely, a power tower with a conventional Rankine cycle would presumably use somewhat less water, approximately 600 gal/MWh similar to a coal plant, by virtue of its higher operating temperature and efficiency.” (p.11–12)

“Consider water-use information from the 2006 report Energy Demands on Water Resources, Report to Congress on the Interdependency of Energy and Water prepared by the U.S. Department of Energy: a coal fired plant uses 110 to 300 gallons per megawatt hour; a nuclear plant uses between 500 and 1100 gallons/MWh; and a solar parabolic trough plant uses 760-920 gallons/MWh.”

http://www.ag.arizona.edu/azwater/awr/septoct08/d3aa3f8e-7f00-0101-0097-9f6724822dfe.html

Pretty cool…

Pretty cool…

That’s why nuclear plants got shut down in France in the heat wave drought and coal plants were shut down in Australia in 2007: drought.

Most coal plants here are older, and closer to the high end. Because they got grandfathered in. Nuclear has not been updated since the 70’s. Maybe in theory they could use less water, but in fact both use on the high side.

And to compare apples to apples I included the high side of solar thermal water use too: UP TO 1,000 gallons per megawatt hour.

I know dry cooling is less efficient. But even wet cooled solar thermal is not comparable to fossil plants. The fossil-funded Heartland Institute is claiming that solar thermal uses MORE water than fossil plants.

That’s why nuclear plants got shut down in France in the heat wave drought and coal plants were shut down in Australia in 2007: drought.

Most coal plants here are older, and closer to the high end. Because they got grandfathered in. Nuclear has not been updated since the 70’s. Maybe in theory they could use less water, but in fact both use on the high side.

And to compare apples to apples I included the high side of solar thermal water use too: UP TO 1,000 gallons per megawatt hour.

I know dry cooling is less efficient. But even wet cooled solar thermal is not comparable to fossil plants. The fossil-funded Heartland Institute is claiming that solar thermal uses MORE water than fossil plants.

That’s why nuclear plants got shut down in France in the heat wave drought and coal plants were shut down in Australia in 2007: drought.

Most coal plants here are older, and closer to the high end. Because they got grandfathered in. Nuclear has not been updated since the 70’s. Maybe in theory they could use less water, but in fact both use on the high side.

And to compare apples to apples I included the high side of solar thermal water use too: UP TO 1,000 gallons per megawatt hour.

I know dry cooling is less efficient. But even wet cooled solar thermal is not comparable to fossil plants. The fossil-funded Heartland Institute is claiming that solar thermal uses MORE water than fossil plants.

You’ve misread your source, which says,

“The majority of new fossil power plants use evaporative water cooling to reject the steam cycle heat. A typical coal plant or nuclear plant consumes 500 gallons of water per MWh (gal/MWh) of electricity generated.1, 3 This is similar to the water consumption by a power tower. A combined-cycle natural gas plant consumes about 200 gal/MWh.4 A water-cooled parabolic trough plant consumes about 800 gal/MWh.”

*Any* thermal plant can use dry cooling — if it’s willing to take the performance hit. The amount of water needed to get rid of a given amount of waste heat doesn’t depend on the source of the heat. But ordinarily, fossil-fuel and nuclear plants aren’t built in the middle of a desert, so they don’t have to.

You’ve misread your source, which says,

“The majority of new fossil power plants use evaporative water cooling to reject the steam cycle heat. A typical coal plant or nuclear plant consumes 500 gallons of water per MWh (gal/MWh) of electricity generated.1, 3 This is similar to the water consumption by a power tower. A combined-cycle natural gas plant consumes about 200 gal/MWh.4 A water-cooled parabolic trough plant consumes about 800 gal/MWh.”

*Any* thermal plant can use dry cooling — if it’s willing to take the performance hit. The amount of water needed to get rid of a given amount of waste heat doesn’t depend on the source of the heat. But ordinarily, fossil-fuel and nuclear plants aren’t built in the middle of a desert, so they don’t have to.