Energia

ARTICLE IN PRESS

Renewable and Sustainable Energy Reviews 12 (2008) 1789–1821 www.elsevier.com/locate/rser

Green energies and the environment
Abdeen Mustafa OmerÃ
17 Juniper Court, Forest Road West, Nottingham NG7 4EU, United Kingdom Received 10 April 2006; accepted 24 May 2006

Abstract Globally, buildings are responsible for approximately 40% of the total world annual energyconsumption. Most of this energy is for the provision of lighting, heating, cooling, and air conditioning. Increasing awareness of the environmental impact of CO2 and NOx emissions and CFCs triggered a renewed interest in environmentally friendly cooling, and heating technologies. Under the 1997 Montreal Protocol, governments agreed to phase out chemicals used as refrigerants that have the potential todestroy stratospheric ozone. It was therefore considered desirable to reduce energy consumption and decrease the rate of depletion of world energy reserves and pollution of the environment. This article discusses a comprehensive review of energy sources, environment and sustainable development. This includes all the renewable energy technologies, energy efficiency systems, energy conservationscenarios, energy savings and other mitigation measures necessary to reduce climate change. r 2006 Elsevier Ltd. All rights reserved.
Keywords: Green energy technologies; Sustainable development; Mitigation measurements

Contents 1. 2. 3. 4. 5. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Energy and population growth . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Energy saving in buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Energy use in agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Renewable energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 5.1. Solar energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1790 1792 1793 1795 1798 1798

ÃFax: +44 115 978717.

E-mail address: abdeenomer2@yahoo.co.uk. 1364-0321/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.rser.2006.05.009

ARTICLE IN PRESS
1790 A.M. Omer / Renewable and Sustainable EnergyReviews 12 (2008) 1789–1821

6. 7.

8. 9.

Efficient bio-energy use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1799 5.2.1. Briquette . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1802 5.2.2. Improved cook stoves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1802 5.2.3. Biogas . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1802 5.2.4. Improved forest and tree management . . . . . . . . . . . . . . . . . . . . . . . . . 1803 5.2.5. Gasification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1803 5.2.6. Major research gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 1804 5.2.7. Recent trends of research on biomass energy. . . . . . . . . . . . . . . . . . . . . 1805 5.2.8. Barriers to implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1805 5.3. Combined heat and power CHP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1805 5.4. Fuel cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 1807 5.5. Hydrogen production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1808 5.6. Hydropower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1809 5.7. Wind energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....