Course: REEC 120 Sustainability and Renewable Energy

Unit 5 Overview

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In Unit 5 we are going to explore materials from the book Sustainable Energy Without the Hot Air by David Mackay. You are expected to read three sections:

- “Wind” pages 32-34
- “Wind II” pages 263-268
- “Offshore Wind” pages 60-67

The rest of this unit has been adapted from a presentation by Timothy Wilhelm, from Kankakee Community College.

When exploring wind energy, let us look at how it relates to energy production. Keep in mind the concept we have been observing from reading Mackay's text: the resources used in consumption versus the energy produced. While his book is geared to the UK, the situation is not that much different from us in the U.S.
Roughly calculated, the UK total daily energy production from a realistic conversion of wind energy to usable energy is about 20kWh/d. This is a substantial amount of energy that can be harvested from the wind. The critical problem is that on average, the consumption of energy used per person is 40kWh/d. As a whole, people in the UK are using twice the amount of energy in the use of cars than what could every realistically be achieved in wind energy production.

If one takes nothing more away from the lessons in wind then take this:

Important equation: 1/2 * air density * Area * velocity cubed

What this means that to convert wind into usable energy we take half of the energy produced (using the density of air past a wind turbine blades area of rotating at a velocity) The velocity is multiplied by itself * multiplied by itself * multiplied by itself.