RenewableSolarPower - Revision history

WikiSysop: /* Summary */

2016-04-25T16:18:45Z

‎Summary

WikiSysop: /* Summary */

2016-04-25T16:17:40Z

‎Summary

WikiSysop: /* Summary */

2016-04-25T16:14:46Z

‎Summary

WikiSysop at 01:05, 8 November 2015

2015-11-08T01:05:14Z

DavidShaw: /* Solar Facts */

2015-10-22T16:43:40Z

‎Solar Facts

DavidShaw: /* Worked Example */

2015-10-22T16:41:48Z

‎Worked Example

DavidShaw: Rewrote some sections

2015-10-22T16:40:20Z

Rewrote some sections

DavidShaw: /* Summary */

2015-10-22T16:34:19Z

‎Summary

DavidShaw: New solar panels are more efficient

2015-10-03T17:06:01Z

New solar panels are more efficient

WikiSysop: /* Worked Example */

2015-08-31T16:18:01Z

‎Worked Example

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 * Solar
-* Hydrogen
+* [[FuelCell|Hydrogen]]
 Wind is a non-starter for propulsive power because, well, if you want to use wind power, get a sailboat! Right?

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 But still the headlines persist about the miracle of renewable wind and solar energy:
 * Holographic foil that is twice as efficient as typical photovoltaic (PV) solar cells, using light selection, deflection, and concentration. The Dresden-based company Apollon GmbH & Co claims this has 28% efficiency compared to a typical 17%.
 * Modern silicon and indium-tin-oxide-based solar cells are approaching the theoretical limit of 33.7% efficiency but a research team at Princeton has used nanotechnology to create a mesh that increases efficiency over organic solar cells nearly threefold.

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 == Summary ==
-There have been a lot of new developments on the renewable-energy front, and yet solar energy is not a good candidate for boat propulsion. A few years ago powering a trawler with solar energy would require towing a solar-barge larger than the boat, and in 2015 not much has changed.
+There have been a lot of new developments on the renewable-energy front, and yet solar energy is not a good candidate for boat propulsion. A few years ago powering a boat with solar energy would require towing a solar-barge larger than the boat, and in 2016 not much has changed.
 But still the headlines persist about the miracle of renewable wind and solar energy:

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 {{#TwitterFBLike:right|small|like}}
 = Renewable Solar Power =
 == Summary ==

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 In practice, for an 8-hour summer day, 40 degree latitude, the sun delivers an average [http://zebu.uoregon.edu/1998/ph162/l4.html 600 W/m²]. Currently the best commercial solar panels are ~16% efficient. At an efficiency of ~16% on a perfect sun day this is a yield of 96 W/m² averaged over 8 hours (0.768 kWh).
-(In 2015 solar panel company SolarCity announced [http://www.solarcity.com/newsroom/press/solarcity-unveils-world%E2%80%99s-most-efficient-rooftop-solar-panel-be-made-america commercial cells that are 22.5% efficient].)
+UPDATE: In 2015 solar panel company SolarCity announced [http://www.solarcity.com/newsroom/press/solarcity-unveils-world%E2%80%99s-most-efficient-rooftop-solar-panel-be-made-america commercial cells that are 22.5% efficient].
 Now, metric horsepower, widely used in the auto industry, is defined as 0.73549875 kilowatt (kW). Assuming we need 200 horsepower (hp) to drive a 70-ft boat, this is ~147kW. At 96 W/m² this equals 1,531 m² (16,472 ft2) of panel acreage [1 m² = 10.76 ft²]. And this is just for propulsion during daylight hours. There is no extra for storage in a battery for night operations.

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 Let’s cut to the chase with a real worked example. Assume a boat moored in Montreal’s Old Port at 45.5 degrees N and 73.35 degrees W. The sun’s azimuth angle varies between 20 and 68 degrees from winter to summer. Assume 365 perfectly sunny days and solar panels that are horizontal on the boat deck and do not track the sun’s azimuth and east-to-west travel. The average available energy over a year is 3.40 kW/m²/day. At 16% solar-panel conversion efficiency, this is only 0.56 kW/m²/day.
-Assume a solar field 10x3 m (30 m²). This would yield an average of 16.8 kW/day. In comparison 200 hp is equivalen to 150 kW (diesel fuel has a high energy density).
+Assume a solar field 10x3 m (30 m²). This would yield an average of 16.8 kW/day. In comparison 200 hp is equivalen to 150 kW.
 {| class="wikitable"

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 Here's the short version on solar energy.
-According to NASA, the earth's surface receives a maximum of 137 Watts per square meter (W/m²) at noon at the equator when the sun is perpendicular. At other latittudes and sun angles the energy is less.
+According to NASA, the earth's surface receives a maximum of [http://www.grc.nasa.gov/WWW/k-12/Numbers/Math/Mathematical_Thinking/sun12.htm 137 Watts per square meter] (W/m²) at noon at the equator when the sun is perpendicular. At other latitudes and sun angles the energy is less.
-In practice, for an 8-hour summer day, 40 degree latitude, the sun delivers an average 600 W/m². Currently the best commercial solar panels are ~16% efficient. At an efficiency of ~16% on a perfect sun day this is a yield of 96 W/m² averaged over 8 hours (0.768 kWh).
+In practice, for an 8-hour summer day, 40 degree latitude, the sun delivers an average [http://zebu.uoregon.edu/1998/ph162/l4.html 600 W/m²]. Currently the best commercial solar panels are ~16% efficient. At an efficiency of ~16% on a perfect sun day this is a yield of 96 W/m² averaged over 8 hours (0.768 kWh).
-<div style="background-color:orange">
+(In 2015 solar panel company SolarCity announced [http://www.solarcity.com/newsroom/press/solarcity-unveils-world%E2%80%99s-most-efficient-rooftop-solar-panel-be-made-america commercial cells that are 22.5% efficient].)
-−
-NEW!! Solar panel company SolarCity has announced commerical cells that are 22.5% efficient. <ref>http://www.solarcity.com/newsroom/press/solarcity-unveils-world%E2%80%99s-most-efficient-rooftop-solar-panel-be-made-america</ref>
-−
-</div>
 Now, metric horsepower, widely used in the auto industry, is defined as 0.73549875 kilowatt (kW). Assuming we need 200 horsepower (hp) to drive a 70-ft boat, this is ~147kW. At 96 W/m² this equals 1,531 m² (16,472 ft2) of panel acreage [1 m² = 10.76 ft²]. And this is just for propulsion during daylight hours. There is no extra for storage in a battery for night operations.

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 * Hydrogen
-Wind is a non-starter for propulsive power because, well, if you want to use wind power, get a sailboat! Right? Wind, like solar is useful for supplementary power.
+Wind is a non-starter for propulsive power because, well, if you want to use wind power, get a sailboat! Right?
-[[#top|Top]]
+[[WindEnergy|Wind energy]], like solar is useful for supplementary power; or, for supporting a minimal lifestyle on a sailboat.
 == Solar Facts ==

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 In practice, for an 8-hour summer day, 40 degree latitude, the sun delivers an average 600 W/m². Currently the best commercial solar panels are ~16% efficient. At an efficiency of ~16% on a perfect sun day this is a yield of 96 W/m² averaged over 8 hours (0.768 kWh).
 Now, metric horsepower, widely used in the auto industry, is defined as 0.73549875 kilowatt (kW). Assuming we need 200 horsepower (hp) to drive a 70-ft boat, this is ~147kW. At 96 W/m² this equals 1,531 m² (16,472 ft2) of panel acreage [1 m² = 10.76 ft²]. And this is just for propulsion during daylight hours. There is no extra for storage in a battery for night operations.
@@ Line 35: / Line 41: @@
 The highest density commercial solar cell has a capacity of 174W/m² or ~16W/ft². Assume this is feasible output, even though we only receive 137 W/m² at the equator and 96 W/m2 at 40 degrees latitude. For our 147-kW motor we would need 845 m² (9,092 ft²) of panels. At most a 70-ft yacht would have less than 1,000 ft² of surface area, so you can see why most boats using solar have hybrid diesel-electric propulsion systems.
 [[#top|Top]]
 == Solar at a Cost ==

← Older revision		Revision as of 16:18, 31 August 2015
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	The reality (do the math yourself) is that even with solar panels at 100% solar-conversion efficiency it isn't feasible -- for practical purposes -- to fully power a trawler only with a solar platform that is sized within the hull's boundary. It doesn't compute. Solar is best as a supplemental charging system for the boat's batteries.		The reality (do the math yourself) is that even with solar panels at 100% solar-conversion efficiency it isn't feasible -- for practical purposes -- to fully power a trawler only with a solar platform that is sized within the hull's boundary. It doesn't compute. Solar is best as a supplemental charging system for the boat's batteries.
		+
		+	== Links ==
		+
		+	[http://arstechnica.com/science/2015/08/the-solar-sunflower-harnessing-the-power-of-5000-suns/ Solar Sunflower]

	[[#top\|Top]]		[[#top\|Top]]