7.3.1: Renewable Energy History and Consumption

Renewable Energy: History and Consumption

Renewable energy comes from sources that are naturally replenished on human timescales. Major renewable energy sources include solar energy, wind energy, hydropower, geothermal energy, biomass energy, and tidal energy.

Although these energy sources appear very different, most can be traced to just three fundamental sources of energy. The sun provides energy for solar power and drives many other renewable energy sources. Solar heating of Earth's surface creates the temperature differences that generate wind, drives the water cycle that powers rivers and hydropower systems, and fuels photosynthesis, which produces biomass. Geothermal energy comes from heat within Earth's interior, and tidal energy comes from the gravitational pull of the Moon and Sun on Earth's oceans (figure \(\PageIndex{a}\)). 

The Sun is also the ultimate source of energy stored in fossil fuels because coal, oil, and natural gas formed from ancient organisms that captured solar energy through photosynthesis. However, fossil fuels require millions of years to form and are therefore considered nonrenewable.

Most renewable energy sources produce little or no greenhouse gas emissions during operation and generally cause less air pollution than fossil fuels. However, renewable energy technologies can still affect the environment. For example, hydropower dams can alter river ecosystems and fish migration, large solar and wind facilities can require substantial land area, and biomass combustion releases air pollutants and carbon dioxide. As a result, renewable energy sources are often considered more sustainable than fossil fuels, but they are not entirely impact free.

Interest in renewable energy increased during the energy crises of the 1970s, when oil shortages and rising fuel prices highlighted the risks of depending heavily on fossil fuels. During the following decades, countries expanded their use of different energy sources based on local conditions. For example, Iceland developed geothermal energy, Scandinavian countries expanded hydropower and wind energy, and many regions invested in solar energy as costs declined.

In recent decades, concerns about climate change, air pollution, and energy security have accelerated the growth of renewable energy worldwide. Improvements in technology and falling costs have made solar and wind power among the fastest-growing sources of electricity. Together with hydropower, geothermal energy, biomass, and emerging technologies such as tidal energy, renewable energy is playing an increasingly important role in the global transition to lower-carbon energy systems.

 

Use the interactive map below to explore the global transition to renewable energy (figure \(\PageIndex{b}\)). Compare the electricity mixes of the United States and one additional country of interest. What energy sources dominate electricity production in each location? How have the contributions of fossil fuels, nuclear power, and renewable energy changed over time? Press the play button to view shifts in electricity generation through the years.

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