Humans have relied on renewable energy as a source of power for thousands of years. The Chinese burned wood for heating and cooking as far back as 2000 BCE, and developments in water energy and wind power occurred throughout Asia and Europe over the ensuing centuries and millennia. Prior to the Industrial Revolution, in fact, the majority of energy that humans used for heating and lighting came from renewable sources.
This began to change in the 17th and 18th centuries when the rise of coal sparked and later fueled the Industrial Revolution. Subsequent advancements in oil mining made fossil fuels more prominent and eventually led to the development of our modern world, one in which fossil fuels—specifically oil—remain our primary energy source.
In recent decades, however, concerns about dwindling petroleum resources, climate change, and other factors have resulted in an increased focus on renewable energy. Defined as being generated from natural sources that replenish faster than they are exhausted, renewable energy exists in a variety of types. Keep reading to learn about some of the most common forms, as well as their pros and cons.
Perhaps the most well-known source of renewable energy, solar power has evolved considerably since the development of the first solar-powered system in 1860. Owing to ongoing investment in the technology since the late 1970s, solar power is employed today for everything from large-scale energy production to single-home power generation.
The advantages of solar power begin with its availability. Driven by a virtually unlimited energy source (i.e., the sun), solar systems also produce little pollution and require minimal maintenance. Other advantages include solar power’s flexibility; in addition to generating electricity, solar can heat water and provide light.
Solar panels have been shown to be less effective in cloudy weather and in less sunny climates. Panels will also deteriorate over time and do require some upfront investment. That said, the amount of energy savings a solar power system creates more than makes up for the initial installation costs.
While most widespread in Europe, where nations like Denmark use it to cover a significant portion of their energy needs, wind power has become increasingly popular in the United States. As of 2015, wind energy installations delivered electricity to approximately 19 million American homes.
As is the case with solar power, wind-generated energy draws on a virtually unlimited source. In addition, when placed and operated efficiently, wind farms create power at a cost lower than most or all other renewable energy sources.
Wind farms work best when located out at sea or on expansive plains; thus, they are not a practical option for many parts of the world. Because wind installations should also sit as far from human-built developments as possible, setting up the infrastructure to deliver the energy to those who need it requires a significant investment. Other factors to consider include the danger that spinning turbines may pose to certain wildlife.
The history of using water to generate electricity dates back to at least the 1880s. Today, about 10 percent of the energy produced in the United States comes from hydroelectric power. This percentage will continue to grow in the years to come, according to experts.
Unlike other forms of energy generation, the production of hydroelectricity, which involves flowing water through a dam, can be easily controlled based on evolving energy needs. When up and running, dams also operate at a minimal cost, making the technology accessible for countries with strong or weak economies.
Dams will emit some carbon, though the level of emissions does not approach the amount seen in the burning of fossil fuels. A greater concern is the effect these unnatural constructions have on local environments. Besides disturbing the landscape, a dam will alter animal and plant life downstream.
Geothermal power involves extracting heat from below the earth’s surface as a way to create energy. Humans have drawn on the planet’s heat for centuries, and today the understanding of this natural process has birthed an industry that has undergone significant growth in recent years. According to the World Bank, approximately 40 nations could employ modern geothermal technology to cover a significant portion of their energy needs.
Geothermal power emits no greenhouse gas beyond what the planet would already naturally produce through geologic processes. As such, it is an especially clean source of energy. Once installed, geothermal power systems also generate energy more cheaply than most or all other sources.
While consumers can purchase simple, home-based geothermal power systems, the upfront costs associated with the technology remain high. The other major barrier involves geography. To use the systems most efficiently, consumers typically need to live in the vicinity of active volcanoes or near tectonic plate boundaries. For everyone else, investing in a geothermal power system may not be a sensible choice.