Introduction

Renewable energy (sources) or RESare a diverse group of technologies that extract energy from existing on-going natural processes, such as sunshine (to make electricity or to provide heating), wind, flowing water, biological processes, and geothermal heat flows. Neither fossil fuels nor nuclear power are renewable forms of energy.

The question of energy provision is essentially linked to the issue of climate change: much of the current energy economy relies on the combustion of fossil fuels, resulting in massive emissions of CO 2. In 2004, 25.9% of greenhouse gas emissions came from the supply of energy, with transport and industry respectively accounting for another 13.1% and 19.4% of emissions (IPCC AR4, WG3)

(c) Katherine Watts

The global energy challenge is to tackle the threat of climate change, meet the rising demand for energy and to safeguard secure energy supply to all groups of society. Renewable energy technologies are proven energy sources that are ready for large-scale deployment on a quantity- and time-scale that can help reduce atmospheric greenhouse gas loading.

Increasing use of renewable energy reduces carbon dioxide emissions, cuts local air pollution (including NO x, SO x and troposphere ozone, which itself is a powerful, if short-lived, greenhouse gas), creates high-value jobs and allow access to modern energy forms in parts of the world where it would be uneconomic to extend a grid-based electricity system: an estimated 2 billion people who currently lack access to modern energy services. It also increases energy security and, being decentralized, is less vulnerable to overall disruption of the system if one part fails.

The cost of renewable energy has already fallen significantly, and some technologies are cost effective, even when the external costs of fossil fuel-sourced energy are not taken into account. Nuclear and fossil fuels currently receive massive subsidies that distort the market against sustainable energy forms. If these subsidies were removed, and the external costs (climate and health impacts, for example) were accounted for, renewables become even more cost-effective as energy sources.