Wind turbine - Revision history

Michel Lamontagne: /* Emergency use */

2021-12-29T17:21:30Z

Emergency use

Michel Lamontagne: /* Emergency use */

2021-12-29T17:20:47Z

Emergency use

Michel Lamontagne: /* Wind turbine mass */

2021-12-29T17:19:39Z

Wind turbine mass

Michel Lamontagne: /* Wind turbine mass */

2021-12-29T17:15:49Z

Wind turbine mass

Michel Lamontagne: /* Wind turbine mass */

2021-12-29T17:14:10Z

Wind turbine mass

Michel Lamontagne: /* Wind turbine mass */

2021-12-29T15:50:48Z

Wind turbine mass

Michel Lamontagne: /* Wind turbine mass */

2021-12-29T15:48:21Z

Wind turbine mass

Michel Lamontagne: /* Wind turbine mass */

2021-12-29T15:38:16Z

Wind turbine mass

Michel Lamontagne: /* Example calculation */

2021-12-29T15:32:58Z

Example calculation

Michel Lamontagne at 22:40, 11 November 2021

2021-11-11T22:40:50Z

@@ Line 39: / Line 39: @@
 ==Emergency use==
-One of the prime cases for wind turbine use on Mars is to use them during storms, when solar does not function.  However, this case must be compared to the possibility of [[Nuclear power]], [[Flow battery]], or adding more solar and using the excess capacity to produce methane.  Methane could then be burned in a conventional gen-set to generate emergency power during a storm.  A 150 kW gen-set burns about one tonne per day of methane.  As all the modern Mars settlement plans include in-situ fuel production, the back-up methane can be part of the normal production process.  A 150 KW gen-set might mass about 2 tonnes, while a 150 kW wind turbine array would mass at least 20 tonnes, possibly more.
+One of the prime cases for wind turbine use on Mars is to use them during storms, when solar does not function.  However, this case must be compared to the possibility of [[Nuclear power]], [[Flow battery]], or adding more solar and using the excess capacity to produce methane.  Methane could then be burned in a conventional gen-set to generate emergency power during a storm.  A 150 kW gen-set burns about one tonne per day of methane.  As all the modern Mars settlement plans include in-situ fuel production, the back-up methane can be part of the normal production process.  A 150 KW gen-set might mass about 2 tonnes, while a 150 kW wind turbine array would mass at least 16 tonnes, possibly more.
 ==References==
 [[Category:Sources]]
 <references />

@@ Line 39: / Line 39: @@
 ==Emergency use==
-One of the prime cases for wind turbine use on Mars is to use them during storms, when solar does not function.  However, this case must be compared to the possibility of [[Nuclear power]], [[Flow battery]], or adding more solar and using the excess capacity to produce methane.  Methane could then be burned in a conventional gen-set to generate emergency power during a storm.  A 150 kW gen-set burns about one tonne per day of methane.  As all the modern Mars settlement plans include in-situ fuel production, the back-up methane can be part of the normal production process.  A 150 KW gen-set might mass about 2 tonnes, while a 150 kW wind turbine array would mass at least 20 tonnes, and likely more.
+One of the prime cases for wind turbine use on Mars is to use them during storms, when solar does not function.  However, this case must be compared to the possibility of [[Nuclear power]], [[Flow battery]], or adding more solar and using the excess capacity to produce methane.  Methane could then be burned in a conventional gen-set to generate emergency power during a storm.  A 150 kW gen-set burns about one tonne per day of methane.  As all the modern Mars settlement plans include in-situ fuel production, the back-up methane can be part of the normal production process.  A 150 KW gen-set might mass about 2 tonnes, while a 150 kW wind turbine array would mass at least 20 tonnes, possibly more.
 ==References==
 [[Category:Sources]]
 <references />

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 Both solar and wind require back up batteries that will add significantly to the system mass.
-On Earth, the steel tower is anchored in a foundation of more than a thousand tons of concrete and steel rebar, 30 to 50 feet across and anywhere from 6 to 30 feet deep. Shafts are sometimes driven down farther to help anchor it. Mountain tops must be blasted to create a level area of at least 3 acres. The foundation is critical to stabilizing the weight of the turbine assembly and resisting the force of the wind.(https://www.wind-watch.org/faq-size.php)  A similar foundation would be required on Mars.  The fondation might require the need to produce in situ concrete or some form of structural sintered regolith.
+On Earth, the steel tower is anchored in a foundation of more than a thousand tons of concrete and steel rebar, 10 to 15 meters across and anywhere from 2 to 10 meters deep. Shafts are sometimes driven down farther to help anchor it. Mountain tops must be blasted to create a level area of at least 1,2 hectare (12 000 m2 or 3 acres). The foundation is critical to stabilizing the weight of the turbine assembly and resisting the force of the wind.(https://www.wind-watch.org/faq-size.php)  A similar foundation would be required on Mars. The fondation might require the need to produce in situ concrete or some form of structural sintered regolith.  Rebar (steel bars for reinforced concrete) will add significantly to the mass of the tower.
 ==Emergency use==

@@ Line 36: / Line 36: @@
 Both solar and wind require back up batteries that will add significantly to the system mass.
-On Earth, the steel tower is anchored in a foundation of more than a thousand tons of concrete and steel rebar, 30 to 50 feet across and anywhere from 6 to 30 feet deep. Shafts are sometimes driven down farther to help anchor it. Mountain tops must be blasted to create a level area of at least 3 acres. The foundation is critical to stabilizing the weight of the turbine assembly and resisting the force of the wind.(https://www.wind-watch.org/faq-size.php)
+On Earth, the steel tower is anchored in a foundation of more than a thousand tons of concrete and steel rebar, 30 to 50 feet across and anywhere from 6 to 30 feet deep. Shafts are sometimes driven down farther to help anchor it. Mountain tops must be blasted to create a level area of at least 3 acres. The foundation is critical to stabilizing the weight of the turbine assembly and resisting the force of the wind.(https://www.wind-watch.org/faq-size.php)  A similar foundation would be required on Mars.  The fondation might require the need to produce in situ concrete or some form of structural sintered regolith.
 ==Emergency use==

@@ Line 35: / Line 35: @@
 The average power of wind turbines depends on the wind availability. If the same power to mass ratio can be built on Mars, with a wind availability of 100%, wind outperforms solar on an energy to mass basis.  If the availability is lower, for example 30% as on Earth, then wind power has less than half the energy/mass ratio of solar.  There might be areas, for example a base near the poles, where wind power outperforms solar.
 Both solar and wind require back up batteries that will add significantly to the system mass.
 ==Emergency use==

@@ Line 32: / Line 32: @@
 ==Wind turbine mass==
-On Earth, wind turbines are fairly massive objects:  In the GE 1.5-megawatt model, the nacelle alone weighs more than 56 tons, the blade assembly weighs more than 36 tons, and the tower itself weighs about 71 tons — a total weight of 164 tons. The corresponding weights for the Vestas V90 are 75, 40, and 152, total 267 tons; and for the Gamesa G87 72, 42, and 220, total 334 tons.(https://www.wind-watch.org/faq-size.php).  Or about 9W of power/kg of mass.  Solar power is about 30 W/kg.  However, solar availability is in the order of 25% so the average power is about 8W/kg.
+On Earth, wind turbines are fairly massive objects:  In the GE 1.5-megawatt model, the nacelle alone weighs more than 56 tons, the blade assembly weighs more than 36 tons, and the tower itself weighs about 71 tons — a total weight of 164 tons. The corresponding weights for the Vestas V90 are 75, 40, and 152, total 267 tons; and for the Gamesa G87 72, 42, and 220, total 334 tons.(https://www.wind-watch.org/faq-size.php).  Or a power to mass ratio of about 9W/kg.  Solar power is about 30 W/kg.  However, solar availability is in the order of 25% so the average power is about 8W/kg.
-The average power depends on the wind availability. If the same power to mass ratio can be built on Mars, with a wind availability is 100%, wind outperforms solar on an energy to mass basis.  If the availability is lower, for example 30% as on Earth, then wind power has less than half the energy/mass ratio of solar.  There might be areas, for example a base near to the poles, where wind power outperforms solar.
+The average power of wind turbines depends on the wind availability. If the same power to mass ratio can be built on Mars, with a wind availability of 100%, wind outperforms solar on an energy to mass basis.  If the availability is lower, for example 30% as on Earth, then wind power has less than half the energy/mass ratio of solar.  There might be areas, for example a base near the poles, where wind power outperforms solar.
-Both solar and wind require back up batteries, that will add significantly to the system mass.
+Both solar and wind require back up batteries that will add significantly to the system mass.
 ==Emergency use==

@@ Line 29: / Line 29: @@
 For the same size of turbine, as the air on Earth is 50 times more dense, the same turbine will produce 50 times more power.  However, the Martian wind turbine could be built much lighter as it handles much less power, and possibly have similar overall efficiencies and power/mass ratios.  A 2012 study<ref>https://pdfs.semanticscholar.org/2691/3339453d63ac462d90152bdf68e7a67c02ff.pdf</ref> found that the cord length for a Martian wind turbine would be three times longer than on Earth for a 1.5 chord ratio, and that the power and strain on the tower would be one tenth of an equivalently sized tower on Earth.
 Airborne wind turbines have been studied<ref>https://newatlas.com/nasa-airborne-wind-power/23200/</ref> with similar parametric changes from Earth to Mars.  The same reliability challenges apply to Martian airborne turbines.
 ==Emergency use==

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 ==Example calculation==
-[[File:300 kW wind turbine.jpg|thumb|600x600px|A speculative 84m wind turbine, with Spacex Starships in the background for scale.  Blade width is tripled for the low air density, and the blade thickness increased by 1.5 times compared to the Earth equivalent.  This might produce from 120 to 300 kW, while the Earth equivalent might produce 1,5 GW and need to be reduced in power at high wind velocities.  Mass is a big unknown.]]
+[[File:300 kW wind turbine.jpg|thumb|600x600px|A speculative 84m wind turbine, with Spacex Starships in the background for scale.  Blade width is tripled for the low air density, and the blade thickness increased by 1.5 times compared to the Earth equivalent.  This might produce from 120 to 300 kW, while the Earth equivalent might produce 1,5 MW and need to be reduced in power at high wind velocities.  Mass is a big unknown.]]
 ''P = ½*n*p*As*v3'' , where ''n'' is turbine efficiency, ''p'' is atmospheric density (kg/m3), ''As'' is swept area of the turbine (m2), and ''v'' is wind speed (m/s). The maximum efficiency is 16/27 (60%) as given by Betz’ law.  For a small 10m diameter turbine As=78m2, an efficiency of 31% , air density of 0,02 kg/m3 and a wind speed of 10 m/s, P= 487W.  A larger, 40m blade turbine might achieve between 150 and 300 kW of power.