What Is Alternative Energy And Give Two Examples?
What is Alternative Energy?
Alternative energy refers to energy sources that are derived from natural processes and are continuously replenished. These energy sources are considered alternatives to fossil fuels like coal, oil and natural gas, which are non-renewable resources that emit high levels of greenhouse gases when burned.
Unlike fossil fuels that take millions of years to form, alternative energy comes from sources that are naturally replenished over short periods of time. The five main types of alternative energy are solar, wind, hydroelectric, geothermal and biomass.
The concept of harnessing energy from natural sources dates back to ancient times with the use of windmills and waterwheels. But the modern development of alternative energy technologies expanded in the 1970s during the oil crisis, as there was an urgent need to find substitutes to imported oil.
Since then, alternative energy has seen major advancements. While fossil fuels still dominate, adoption of renewables is rising due to concerns about climate change and energy independence. There is great potential for alternative energy to replace conventional fuels and provide clean, sustainable energy worldwide.
Why Alternative Energy Matters
Alternative energy sources provide substantial environmental benefits compared to fossil fuels like coal, oil and natural gas. By utilizing renewable energy sources like solar, wind and hydropower, we can significantly reduce air and water pollution. Burning fossil fuels releases greenhouse gases like carbon dioxide that contribute to global warming and climate change. Transitioning to clean energy helps mitigate these harmful emissions. According to the EPA, the U.S. electric power sector was responsible for 25% of the nation’s greenhouse gas emissions in 2019. Alternative energy has the potential to eliminate a significant portion of these emissions.
Developing alternative energy also enhances energy independence and national security for countries reliant on imported oil and gas. The more domestic clean energy sources like wind, solar and geothermal that can be developed, the less exposed a nation is to volatile fossil fuel markets and supply chain disruptions. Energy independence also reduces the strategic and economic influence of oil-exporting countries. With its abundant natural resources, the U.S. has the potential to generate much more of its own energy from renewable sources rather than relying so heavily on imported oil. Investing in alternative energy allows countries to take control of their own energy future.
Types of Alternative Energy
There are several major types of alternative energy that are gaining popularity and seeing increased usage as renewable alternatives to fossil fuels.
Solar Energy
Solar energy utilizes the power of the sun to generate electricity and provide power. Some examples of solar energy technologies include solar photovoltaic panels that convert sunlight into electricity, solar hot water systems that use the sun to heat water, and concentrating solar power plants that use mirrors to reflect and concentrate sunlight.
Wind Energy
Wind energy taps into the kinetic energy of wind, through the use of wind turbines to generate mechanical power or electricity. Wind farms consist of many wind turbines and generate power through the rotation of propeller-like blades when wind blows through them.
Hydroelectric Power
Hydroelectric power generates electricity through turbines that are powered by flowing water. Dams are constructed to store water and control its flow, which is then released to turn hydroelectric turbines connected to generators.
Geothermal Energy
Geothermal energy harnesses the internal heat of the earth to provide clean power. Technologies like geothermal heat pumps take advantage of shallow ground temperatures for heating and cooling buildings. Geothermal power plants utilize hot water reservoirs deeper below the earth’s surface to produce steam and generate electricity.
Biomass Energy
Biomass energy utilizes organic plant and animal waste to generate power. Types of biomass include wood, crops, landfill gas, and alcohol fuels. Biomass can be burned directly or converted to liquid biofuels for renewable power production.
Solar Energy
Solar energy is one of the most promising renewable energy sources available today. It converts energy from the sun into electricity through the use of photovoltaic (PV) panels or concentrated solar power plants.
PV panels work by absorbing photons from sunlight and converting them into an electric current. They are placed on rooftops or large solar arrays to capture as much sunlight as possible. The growth of the solar industry has been exponential in recent years, with global solar capacity reaching over 500 gigawatts in 2018, up from under 10 gigawatts in 2007. This is largely driven by dramatically falling costs for solar panels and supportive government policies.
The benefits of solar power include its renewable nature, reduction of greenhouse gas emissions, and energy independence. Once installed, the fuel source (sunlight) is free. Drawbacks are that solar only produces energy when the sun is shining, requiring storage or supplemental power sources for cloudy days and nighttime. Solar potential is also limited geographically to sunnier regions. However, panels can still be effective in less sunny areas.
Overall, solar energy is one of the most important technologies needed to transition away from fossil fuels. With continued advancements in energy storage and grid integration, solar has the potential to supply a substantial portion of the world’s electricity.
Wind Energy
Wind energy is one of the fastest growing renewable energy sources in the world. It harnesses the wind using large wind turbines to generate electricity. Multiple wind turbines are often grouped together in wind farms to produce energy on a utility scale.
In recent years, wind power capacity has expanded rapidly due to improvements in turbine technology and cost reductions. According to the Global Wind Energy Council, global wind power capacity increased by over 10% in 2020 alone. Many countries are investing heavily in wind power to reduce dependence on fossil fuels and meet climate change mitigation targets.
Wind turbines work by using the kinetic energy of wind to spin large blades connected to a rotor. As the blades turn, they spin a generator to convert the mechanical power into electricity. Modern wind turbines can be easily over 100 meters tall in order to capture stronger winds at higher altitudes.
Wind farms comprise multiple wind turbines spread out over large areas, often in areas with consistently high wind speeds like plains, shorelines and hilltops. Larger wind farms can have hundreds of wind turbines and generate hundreds of megawatts of power when operating at maximum capacity.
The main benefits of wind power are its decreasing costs over time, global availability, and position as a zero-emissions renewable energy source. Wind power produces no air pollution or carbon emissions during operation. Limitations include variability in generation depending on wind conditions, wildlife impacts, and aesthetic concerns related to turbine visibility.
Hydroelectric Power
Hydroelectric power is electricity generated using the power of water moving from higher to lower elevations. It is one of the oldest and most widely used renewable energy sources in the world. Hydroelectricity is generated in hydroelectric power plants where falling or fast-flowing water rotates large turbines that spin generators to produce electricity.
Most hydroelectric plants are built around dams that store water in reservoirs. When water is released from the reservoir, it flows through tunnels in the dam and turns the turbines. The most common type of hydroelectric plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. The amount of electricity that can be generated depends on how far the water drops and how much water moves through the system.
Globally, hydroelectric power continues to grow as an important source of renewable energy. In 2020, hydroelectricity accounted for over 16% of global electricity generation. The biggest hydroelectric power producers are China, Brazil, Canada, the United States, and Russia. Large scale hydroplants can generate thousands of megawatts of power and supply electricity to millions of people. However, building large dams and reservoirs often involves environmental and social impacts like habitat destruction, loss of land, and displacement of communities.
The main advantages of hydroelectricity are its renewable and clean nature, scalability to meet large energy demands, and low operating costs once facilities are built. It also offers storage capabilities to generate power on demand. However, high upfront infrastructure costs, geographic limitations based on water availability, and environmental impacts are key limitations. Overall, hydroelectricity remains a major renewable electricity source globally, but new projects must balance power generation goals with environmental sustainability.
Geothermal Energy
Geothermal energy is a renewable energy source that harnesses the natural heat beneath the earth’s surface to generate electricity and provide heating and cooling. The word “geo” means earth, while “thermal” means heat. So geothermal energy taps into the thermal energy created and stored within the earth.
Most geothermal energy comes from areas with active or geologically young volcanoes. Here, magma comes close to earth’s surface, heating groundwater that has percolated into fractured or porous rocks, or heating water that has been injected artificially into the earth through a well. Hot springs and geysers are examples of geothermal features created when water and magma interact.
Geothermal power plants are built over these hot spots to convert the heated water into electricity. Wells are drilled 1 or 2 miles deep into a geothermal reservoir to pump hot water or steam to the surface. The steam rotates a turbine that activates a generator, which produces electricity. Geothermal power plants run steadily for decades because the water is replenished in the reservoir.
Geothermal energy has several key benefits. It provides constant baseload power independent of weather conditions. It has a small carbon footprint and low emissions. It requires little land and few personnel to operate. However, geothermal power is limited to areas with adequate underground temperatures and fluid content. It can sometimes trigger small earthquakes or release gases. Overall, geothermal presents a reliable, renewable energy source with minimal environmental impact.
Biomass Energy
Biomass energy utilizes organic matter such as plants, wood, and waste to generate electricity and fuel. It is considered a renewable energy source because plants and trees can be replanted to regenerate the fuel source.
Some examples of biomass fuels include:
- Biofuels – Liquid fuels like ethanol and biodiesel that are derived from crops like corn and soybeans. They can replace gasoline and diesel in vehicles.
- Wood – Burning wood chips or pellets to heat buildings and generate electricity.
- Landfill gas – Produced by the natural decomposition of municipal solid waste. This gas can be captured and used to generate electricity.
- Agricultural residues – Using leftover materials like corn husks, nut shells, and stalks to create energy.
A key benefit of biomass energy is that it can reduce dependence on fossil fuels. It also makes use of waste materials that would otherwise decompose and release methane, a potent greenhouse gas. Limitations include potentially high costs for collection and transport of biomass fuel sources. There are also concerns that biofuels may divert crops and land from food production.
The Future of Alternative Energy
The future looks bright for alternative energy sources. As concerns grow over the environmental impacts of fossil fuels, many countries are accelerating investments into renewable energy research and adoption. The International Energy Agency predicts renewable electricity capacity will expand globally by over 60% between 2019 and 2024.
Solar and wind power are expected to lead growth as technologies improve and costs continue to fall. The share of electricity generated by renewables is projected to rise from 26% today to 30% by 2024. Developing countries are forecast to overtake developed countries in new renewable capacity added over the next five years.
Emerging technologies like floating wind farms, printed solar panels, and storage solutions will further enhance viability of renewables. With more funding and research, breakthroughs in areas like tidal power and geothermal energy will enable adoption in more locations globally. Alternative energy likely won’t completely replace fossil fuels in the near future, but the pace of growth ensures it will play a major role in the global energy mix going forward.
Conclusion
To summarize, alternative energy refers to power generated from renewable, sustainable sources as an alternative to fossil fuels. We discussed a few major types of alternative energy, including solar, wind, hydroelectric, geothermal, and biomass energy. The development of alternative energy is critical for reducing greenhouse gas emissions, mitigating climate change, improving public health, and transitioning to a more sustainable future. While fossil fuels currently dominate, alternative energy solutions are rapidly evolving and have enormous potential to transform our energy systems. By continuing to innovate and invest in renewable technology and infrastructure, we can realize an energy-efficient world powered by clean, abundant alternative energy.
