Renewable energy, with its seemingly endless supply from nature, is becoming the pillar for a sustainable future. Switching to renewable energy not only helps protect the environment, mitigate climate change, but also creates many new job opportunities and promotes economic development. Let's join GREEN IN Find out what renewable energy is and the common types of renewable energy in the content below!
1. What is renewable energy?
Renewable energy comes from natural sources that are replenished at a rate greater than they are consumed. Examples include solar, wind, hydroelectric, biomass, ocean, and geothermal energy.
Renewable energy is not only an alternative to fossil fuels but also the future of the energy industry, promising a clean, sustainable and diverse energy supply for applications ranging from electricity generation, water heating to transportation and rural off-grid energy systems.
2. Types of renewable energy
Currently there are many types of renewable energy, of which the most popular and effectively applied are the following 8 forms:
2.1. Solar energy
Solar energy is a priceless gift from nature, not only providing light and heat but also an endless source of clean energy. For thousands of years, humans have known how to take advantage of sunlight to grow crops and dry food. However, it was not until the advent of photovoltaic cell technology that we had the opportunity to exploit part of the potential of this energy source.
Solar panels, also known as solar cells, are based on the photovoltaic effect and are capable of directly converting sunlight into electricity.
Solar energy is a clean energy. Solar energy causes almost no environmental pollution, does not emit greenhouse gases, and contributes to protecting the earth. In addition, solar energy also helps reduce dependence on fossil energy sources, ensuring national energy security.
2.2. Geothermal energy
Geothermal energy is a clean and sustainable source of energy that harnesses the immense heat from the Earth’s core. The process of generating electricity from this source occurs when steam or hot liquid deep underground is brought to the surface, creating high pressure and high temperature. This steam turns turbines, which in turn generate electricity.
Geologically active areas such as Iceland, New Zealand, or volcanic regions are ideal locations for exploiting geothermal energy. Here, underground temperatures can reach hundreds of degrees Celsius, providing an abundant and stable source of energy.
Compared to fossil energy sources, geothermal energy does not cause greenhouse gas emissions, significantly reducing negative impacts on the environment. In addition to electricity generation, geothermal energy is also widely used in fields such as air heating, hot water, and even farming.
2.3. Hydroelectric power
Hydroelectric power, or hydropower, harnesses the power of flowing water to generate electricity. Humans have been harnessing this energy source for thousands of years, and by the early 21st century, hydropower had become the world’s largest source of renewable energy, accounting for more than 18% of global electricity generation capacity in 2019.
The principle of hydroelectric power is based on the conversion of potential energy of water into electrical energy. Water is led from a certain height to a lower height through turbines. During this process, the potential energy of the water is converted into kinetic energy, rotating the turbine and activating the generator to produce electricity. After passing through the turbine, the water is discharged back to the original water source with almost zero velocity and lower potential energy.
The outstanding advantage of hydropower is its ability to reduce greenhouse gas emissions, contributing to environmental protection. In addition, hydropower also plays an important role in regulating the power system, providing stable energy and supporting other renewable energy sources such as wind and solar.
Hydropower is classified into two main types based on installed capacity: large hydropower and small hydropower. Large hydropower plants are those with a capacity of over 30 MW, while small hydropower plants have a capacity below this threshold. This division is not based on the size of the river but is entirely based on the power generation capacity of the plant.
For example: Da Nhim Hydropower Plant is built on a very small river of the same name, with a capacity of 160 MW, and is classified as a large hydropower plant.
2.4. Wind energy
The process of generating electricity from wind is quite simple: when wind blows on the blades of a wind turbine, they spin and transfer kinetic energy to a generator. The generator then converts this kinetic energy into clean, pollution-free electricity.
Compared to fossil energy sources, wind energy has the outstanding advantage of almost no greenhouse gas emissions, contributing to the mitigation of climate change. However, wind energy also has certain limitations. Due to the erratic nature of wind, the electricity output from wind power plants can fluctuate depending on the wind speed. To overcome this limitation, weather forecasting systems and smart grids are being developed to optimize the use of wind energy.
2.5. Biofuels
Biofuel is a form of renewable energy produced from renewable organic sources such as plants, animals and waste. These sources include vegetable oils (soybean, sunflower), animal fats, cereals (corn, wheat), agricultural waste (straw, bagasse) and even organic waste from industrial plants.
In the past, biofuels were mainly used as a small-scale alternative energy source. However, in the context of increasingly depleted fossil fuel resources and concerns about climate change, biofuels have become a potential renewable energy solution. Many countries around the world have invested heavily in research and development of biofuel production technology, aiming to reduce dependence on fossil fuels and minimize greenhouse gas emissions.
2.6. Wave energy
The potential of wave energy globally is huge, with an estimated 29.500 TWh/year that can be exploited. Many countries in the world, especially European countries, have pioneered the research and application of wave energy exploitation technology. Wave power stations with capacities ranging from several tens of kW to several MW have been successfully built and operated, providing electricity to residential areas, remote islands and other applications.
Vietnam, with more than 3000 km of coastline, possesses abundant wave energy potential. Exploiting this energy source not only contributes to ensuring national energy security but also promotes socio-economic development, especially in coastal and island areas.
Wave energy conversion technology is currently very diverse, classified based on installation location: onshore, nearshore and offshore.
- Onshore equipment: Placed directly on shore or in fixed structures such as dams, they are easy to maintain but energy harvesting efficiency is often low due to weaker waves.
- Nearshore equipment: Located in medium-deep water, they can be floating or fixed structures. These types of devices make better use of wave energy but face challenges in terms of durability and installation costs.
- Offshore equipment: Located in deep water, it can exploit the most powerful wave energy but requires high technology, high cost and difficult maintenance.
Each type of equipment has its own advantages and disadvantages, requiring appropriate technical solutions to optimize performance and minimize costs. The choice of equipment will depend on the geographical and hydrological conditions and energy exploitation goals of each area.
2.7. Tidal energy
Tidal energy is generated from the rise and fall of tides due to the gravitational interaction between the Earth, the Sun and the Moon, and is considered a potential renewable energy source. As tides flow through straits or estuaries, the kinetic energy of the water can be converted into electricity through special hydroelectric turbines. Ideal locations for harnessing tidal energy are areas with large tidal ranges and strong currents.
Compared to other renewable energy sources such as wind, tidal energy has a distinct advantage: water is denser than air, so the same size turbine can produce much more power. This means that tidal energy can provide a more stable and reliable source of electricity.
According to the US Department of Energy, the total energy potential from waves, tides and ocean currents worldwide is huge, enough to provide electricity to millions of households. However, the exploitation of tidal energy still faces certain challenges such as high initial investment costs, environmental impacts and complex technical factors.
2.8. Ocean current energy
Central Vietnam has 7 out of 12 points with the strongest currents in the West Pacific. The ocean current speed here is from 1,05 to 1,26 m/s, strong enough to provide energy for an entire country. With an ocean current length of up to 1.000km, an average depth of 10-35m and a width of about 24km, Vietnam can fully exploit this energy source to change the face of the economy.
One of the most promising technologies to exploit ocean currents is the "rotating drum" model. A hollow cylindrical turbine using Archimedes thrust will automatically rotate with the flow, converting kinetic energy into mechanical energy with an efficiency of up to 99,6%.
Compared to current technologies such as wind turbines (70% efficiency), the "rotating drum" turbine is expected to achieve 63% efficiency in converting mechanical energy into electricity. This figure shows that Vietnam possesses a breakthrough technology that can provide a clean, sustainable and abundant source of renewable energy for the future.
Conclusion
Renewable energy is increasingly asserting its important position in the global energy transition. Thanks to its stability and increasingly competitive prices, renewable energy has become a significant source of green investment. Through this article, GREEN IN hopes to help readers better understand renewable energy and the popular types of renewable energy today.