Page 15 - Fundamentals of Ocean Renewable Energy Generating Electricity From The Sea

Introduction Chapter | 1 7

FIG. 1.7 Global electricity consumption of hydroelectricity, solar, and wind from 1965 to 2015.
(Data from British Petroleum, BP Statistical Review of World Energy, British Petroleum, London,
2016.)

this increased by a factor of 4 to around 4000 TWh in 2015. Although solar and
3
wind energy technologies have existed for a long time, these power sources did
not really have an impact on the world stage until the 21st century. However,
there has been high growth of these technologies over the last decade, with
wind (and solar) contributing around 850 TWh (and 250 TWh), respectively, to
the global energy mix in 2015.

1.2 CLIMATE CHANGE AND SUSTAINABILITY

The Earth’s climate varies over many timescales, as a response to both natural
processes and human influences. The global climate is governed by the planet’s
radiation balance, and there are three main ways in which this balance can be
altered:
1. changes in the incoming radiation (e.g. changes in the Earth’s orbit);
2. changes in the reflected radiation (albedo); and
3. changes in long-wave radiation emitted from the Earth (changing greenhouse
gas concentrations).
The ice ages that have occurred periodically over the geological past have
been linked to regular variations in the Earth’s orbit around the Sun, known

3. For example, the world’s first wind turbine originates from 1887.