By Steven Shackell
In 2001, 86% of the energy consumed in the United States originated from fossil fuels, while renewable energy sources generated only 5.3%. Fast forward to 2022, and fossil fuels' share dropped to 79%, while renewable sources grew to 13%, via Statista. As the world grapples with the impacts of climate change and greenhouse gas emissions, the quest for sustainable and alternative energy sources grows more critical.
Fossil fuel energy harvesting has historically consisted of mining coal and drilling for oil, both of which are limited resources. Alternative energy harvesting technologies are now a promising alternative. This article explores the various forms of sustainable, alternative energy harvesting methods, including familiar sources such as solar, wind and hydropower, as well as up-and-coming alternative sources such as geothermal, wave and vibration energy.
How is hydroelectric energy harvested?
Hydroelectric energy is, by far, the most productive renewable energy source. In 2020, hydropower produced over 4000 terawatt-hours, accounting for 17% of global electricity generation. Hydropower utilizes the gravitational potential energy of water to generate electricity by passing dammed water through hydroelectric turbines. For more information on how hydroelectric dams work, read our article on the advantages of hydroelectricity.
Today, China dominates the hydropower market. Hydropower supplies nearly 8% of China's overall power consumption, accounting for nearly 40% of the global hydropower capacity, per IEA. The largest hydroelectric dam in the world, the Three Gorges Dam, spans the Yangtze River in China. Additionally, nearly 70% of the planned hydropower expansion projects in sub-Saharan Africa, Southeast Asia and Latin America will be built, financed or owned by Chinese hydropower firms. In the next decade, hydropower will continue to grow its global contribution to renewable electricity generation far beyond its capacity today.
Wind energy generators
Wind energy generators convert the kinetic energy of moving air into electricity and can exist on both localized and vast scales. Wind energy harvesting is so widely adopted worldwide that it accounts for more energy production than solar systems.
Small-scale generators such as the Thames Kosmos Wind Power Kit can generate enough electricity to power an LED or charge a small battery. Meanwhile, the largest wind turbine in the world, which is as tall as a 50-story building, just set a new single-day wind power record, generating 384.1MWs. This single wind energy turbine generated enough power for nearly 170,000 homes in 24 hours. Globally, wind energy accounts for the second most energy production behind hydropower.
Solar energy
Solar energy generators convert solar radiation into usable DC electricity. The sun is now a mainstream source of electricity, with solar panels found atop commercial buildings, homes and in sprawling standalone arrays. Although it's likely the most visible renewable source to most Americans, solar currently ranks third worldwide among renewable sources of electricity.
Solar cells such as Panasonic's AM-5610CAR-T can be used on a small scale to generate energy to power small electronics assemblies. We're most accustomed to seeing solar cells combined into solar panels. Those panels can then be connected into photovoltaic (PV) solar grids that can be scaled to compete with fossil fuel power generation. Converting all that solar energy to the electrical grid are solar inverters that use power semiconductors such as onsemi’s NTH4L022N120M3S.
China is the global leader in solar power adoption, accounting for 37.5% of the global production per IEA. China also accounts for more solar generation than the next seven leading countries behind it: U.S., Japan, India, Germany, Australia, Spain, Italy.
Geothermal energy harvesting
Geothermal energy production utilizes the Earth's internal heat to generate electricity. Geothermal power plants pump water deep underground, which is naturally heated, converted to steam and passed through a steam turbine. This energy harvesting method emits minimal amounts of greenhouse gasses but is limited to locations with geothermal activity.
The U.S. leads the world in geothermal energy production, with California the top state for geothermal energy harvesting. Geothermal accounts for a significant share of total electricity demand in countries as diverse as Iceland, El Salvador, New Zealand, Kenya and the Philippines. In Iceland, geothermal energy meets over 90% of heating demand, albeit not through electricity production. However geothermal energy is not mainstream and only accounts for only 0.5% of renewables-based electricity generation around the globe.
Tidal and wave energy harvesting
In coastal countries, harvesting energy from ocean waves is a more recent frontier for renewable energy generation. Marine energy, which can utilize both underwater turbines or tidal buoys, saw only 524 MW of production in 2022. France and South Korea led the world, producing 211 and 256 megawatts, respectively.
However, the European Union plans to increase its wave and tidal electricity production to 1GW by 2030, with hopes of reaching 40GW by 2050. Some experts believe that energy generated by waves and tidal currents could supply over 10% of the world's electricity demand, but there are many concerns over these devices negatively impacting ocean ecosystems. Others believe that wave and tidal electricity generators can simultaneously act as micro-ecosystems for algae that can harvest CO2 from the atmosphere and shellfish that clean the oceans.
The evolution of alternative energy
The transition from fossil fuels to alternative and sustainable energy sources is well underway, with the adoption landscape varying widely from country to country. Countries with an abundance of one resource — geothermal heat in Iceland, waves in France — develop techniques that are mimicked and adopted elsewhere. The evolution of energy harvesting methods can be observed in the global commitment to reduce our dependency on finite and environmentally damaging fossil fuels. Wider adoption of alternative energy harvesting technologies will grow over the next several decades, paving the way for a more sustainable energy future.
