Band 6+: The diagram shows the consumption of renewable energy in the USA from 1949-2008. Write a 150-word report for a university lecturer identifying the main trends and making comparisons where relevant.

The line chart displays the use of renewable energy sources in the United States in the 1949 – 2008 period. The total consumption of such resources has shown a remarkable growth throughout the defined timeframe, from nearly three quadrillion Btu up to somewhere close to seven quadrillion.

Hydroelectric power and wood have shown a relatively estable behavior with minor fluctuations. In the case of water based energy sources there has been higher peaks around the half of the 80s and and 90s, closing with just above two quadrillion Btu, while wood increased its usage in the 70 and mantantained a levels just below two quadrillion Btu.

Energy coming from biofuels and wind emerged at the beggining of the 80s decade and despite of its exponential growth, its contribution is not as big as the previously referenced energy sources, as their levels have not reached the two quadrillion Btu mark. In that scenario biofuels have a larger share than wind.