Biofuels, Solar and Wind as Renewable Energy Systems David Pimentel Editor Biofuels, Solar and Wind as Renewable Energy Systems Benefits and Risks 123 Editor Dr. David Pimentel Cornell University College of Agriculture and Life Sciences 5126 Comstock Hall Ithaca, NY 15850 USA
[email protected] ISBN: 978-1-4020-8653-3 e-ISBN: 978-1-4020-8654-0 Library of Congress Control Number: 2008931413 Chapter 5 c The Authors c 2008 Springer Science+Business Media B.V. No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Cover Images Dutch windmill (Courtesy of Schoen Photography, www.schoenphotography.com) c Schoen Photography, Colorado, USA Wind turbine c 2008 JupiterImages Corporation Printed on acid-free paper 987654321 springer.com Preface The petroleum age began about 150 years ago. Easily available energy has sup- ported major advances in agriculture, industry, transportation, and indeed many diverse activities valued by humans. Now world petroleum and natural gas sup- plies have peaked and their supplies will slowly decline over the next 40–50 years until depleted. Although small amounts of petroleum and natural gas will remain underground, it will be energetically and economically impossible to extract. In the United States, coal supplies could be available for as long as 40–50 years, depending on how rapidly coal is utilized as a replacement for petroleum and natural gas.