Comments on: The Physics and Economics of Wind Turbines http://www.windpowerengineering.com/policy/the-physics-and-economics-of-wind-turbines/ Thu, 09 Feb 2012 11:44:45 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: How to calculate wind power output : Small Wind Tips http://www.windpowerengineering.com/policy/the-physics-and-economics-of-wind-turbines/#comment-9854 How to calculate wind power output : Small Wind Tips Fri, 20 Jan 2012 06:27:23 +0000 http://www.windpowerengineering.com/?p=1548#comment-9854 [...] The Wind Energy Payback Period Workbook from the National Renewable Energy Labs is a spreadsheet tool that can help you analyze the economics of a small wind electric system and decide whether wind energy will work for you. It asks you to provide information about how you’re going to finance the system, the characteristics of your site, and the properties of the system you’re considering. It then provides you with a simple payback estimation in years. If it takes too long to regain your capital investment—the number of years comes too close or is greater than the life of the system—wind energy will not be practical for you. Read here for more on the physics and economics of wind turbines. [...] [...] The Wind Energy Payback Period Workbook from the National Renewable Energy Labs is a spreadsheet tool that can help you analyze the economics of a small wind electric system and decide whether wind energy will work for you. It asks you to provide information about how you’re going to finance the system, the characteristics of your site, and the properties of the system you’re considering. It then provides you with a simple payback estimation in years. If it takes too long to regain your capital investment—the number of years comes too close or is greater than the life of the system—wind energy will not be practical for you. Read here for more on the physics and economics of wind turbines. [...]

]]> By: Pramod Jain http://www.windpowerengineering.com/policy/the-physics-and-economics-of-wind-turbines/#comment-553 Pramod Jain Wed, 09 Dec 2009 00:58:12 +0000 http://www.windpowerengineering.com/?p=1548#comment-553 The author states that wind energy is 11 to 13c per kWh. This is much higher than cost numbers we have seen. Range should be 7c to 11c. See WindPower Monthly's January 2009 article http://www.windpower-monthly.com/, and http://www.iea.org/Papers/2009/Wind_Roadmap.pdf. The author states that wind energy is 11 to 13c per kWh. This is much higher than cost numbers we have seen. Range should be 7c to 11c. See WindPower Monthly’s January 2009 article http://www.windpower-monthly.com/, and http://www.iea.org/Papers/2009/Wind_Roadmap.pdf.

]]> By: Jonathan Nieuwsma http://www.windpowerengineering.com/policy/the-physics-and-economics-of-wind-turbines/#comment-466 Jonathan Nieuwsma Fri, 06 Nov 2009 22:14:23 +0000 http://www.windpowerengineering.com/?p=1548#comment-466 To the editor: There's a common physics mistake in this article: confusing energy with power. They're closely related but not the same thing. Energy, whether it's measured in kilowatt-hours, ergs, foot-pounds, or joules, is a fundamental physical concept measuring the amount of work that can be done. Energy comes in various forms: electric, kinetic, and thermal, etc. Power is the rate at which work is performed or energy is used, and is measured in units of energy per time: joules per second or watts (1 watt is defined as 1 J/s), foot-pounds per second or horsepower (1 horsepower is defined as 500 ft.lbs/sec.), etc. The first equation for kinetic energy, Ek = 1/2 MV ^2, is correct. However, the second equation shows energy per time -- power -- so it's not accurate to call that kinetic energy. It's power. Sincerely, Jonathan Nieuwsma President KBN Industries To the editor:

There’s a common physics mistake in this article: confusing energy with power. They’re closely related but not the same thing.

Energy, whether it’s measured in kilowatt-hours, ergs, foot-pounds, or joules, is a fundamental physical concept measuring the amount of work that can be done. Energy comes in various forms: electric, kinetic, and thermal, etc.

Power is the rate at which work is performed or energy is used, and is measured in units of energy per time: joules per second or watts (1 watt is defined as 1 J/s), foot-pounds per second or horsepower (1 horsepower is defined as 500 ft.lbs/sec.), etc.

The first equation for kinetic energy, Ek = 1/2 MV ^2, is correct. However, the second equation shows energy per time — power — so it’s not accurate to call that kinetic energy. It’s power.

Sincerely,
Jonathan Nieuwsma
President
KBN Industries

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