In this blog post, we will learn about the definition, types, advantages, and disadvantages of renewable energy, as well as its current usage and potential.
Since the Industrial Revolution began in England in the 18th century, humanity’s energy consumption has increased rapidly. Coal, which fueled the Industrial Revolution, and fossil fuels such as oil and natural gas, which were discovered later, were the main sources of energy for the rapid growth of the 20th century. During this period, humanity developed industry and technology based on abundant energy resources, which laid the foundation for modern society. However, problems such as environmental pollution and limited reserves were discovered in these fossil fuels, and humanity began to search for new energy sources to solve these problems. Nuclear energy was the first alternative, but its use is gradually declining due to the risk of accidents such as the recent Fukushima nuclear disaster and the difficulty of disposing of nuclear waste. Recently, renewable energy, which is environmentally friendly and renewable, has been gaining attention as an alternative to nuclear energy. In this article, we will look at what renewable energy is, the types and advantages and disadvantages of renewable energy, the current status of renewable energy use, and the future of renewable energy.
The classification and definition of renewable energy vary from country to country, so this article will use the terms defined in Korea. Korea defines renewable energy as “energy that is converted from existing fossil fuels or from renewable sources such as sunlight, water, geothermal energy, precipitation, and biological organisms,” and it can be broadly divided into two categories: new energy and renewable energy. New energy refers to energy from new technologies such as fuel cells, coal liquefaction and gasification, and hydrogen energy, while renewable energy refers to natural energy that is not subject to depletion, such as solar heat, solar power, biomass, wind power, small hydro power, geothermal energy, marine energy, and waste energy. Within the above definitions, renewable energy in a broad sense refers to energy that replaces petroleum, while in a narrow sense, it refers to renewable energy sources.
Renewable energy sources are clean energy sources that are not subject to depletion, and each energy source has its own advantages and disadvantages. First, solar power generation is a technology that absorbs solar radiation and generates electricity through a heat engine, or uses the heat directly for heating. Since it uses energy from the sun, the energy source is unlimited and there is no pollution. Since it uses high-temperature heat, it can be linked to other industries such as metal processing, seawater desalination, and hydrogen production. In addition, energy can be stored through heat engines, enabling large-scale power generation. However, its disadvantages are low energy density and high initial investment and power generation costs.
Solar power generation is a technology that directly converts the sun’s light energy into electrical energy. Like solar heat, it is an unlimited energy source and does not cause pollution. After installation, power plants are easy to maintain and generally have a long service life. However, low energy density requires a large installation area, which can destroy the environment, and solar power is greatly affected by solar radiation. In addition, high system costs meant that initial investment costs and power generation costs were high, but recent advances in technology and a steady decline in component prices have made solar power more economical, leading to a significant increase in demand.
Biomass technology is a technology that uses organic organisms directly or through biochemical and physical conversion processes to produce liquid, gas, solid fuels, electricity, or heat energy. Biomass is renewable, so there is no concern about depletion, and carbon dioxide can be recovered from the atmosphere, which can help curb global warming. However, it requires a large area of land, which may destroy existing ecosystems, and its low productivity makes it inefficient. In addition, there are large variations in reserves depending on the region, and there is controversy over its use as an energy source because it is a resource that can be used as food.
Wind power generation is a technology that converts the kinetic energy of wind into electricity. Since it uses wind, it is an unlimited energy source and does not cause pollution. The cost of power generation facilities is low, making it economical, and power generation facilities can be used for agriculture and livestock farming, resulting in efficient land use. However, there are noise issues, and it can damage the natural landscape and ecosystem. Recently, offshore wind power generation has been gaining attention as a way to reduce these problems.
Small-scale hydroelectric power generation is a technology that uses the potential energy of water to generate electricity, with a capacity of 10,000 kW or less. Since it uses the fall of water, it does not cause pollution, has a high energy density compared to other energy sources, and is economical due to its low power generation unit price. In addition, power plants have a long service life and contribute to agricultural water supply and flood control in addition to power generation, ensuring a stable supply. However, there is a possibility of environmental problems such as damage to the natural landscape, ecosystem changes, and eutrophication of rivers, and there are large regional differences and difficulties in mass production, making it less competitive.
Geothermal energy refers to the heat energy emitted from the earth’s interior. It is mainly used directly for heating, but the use of steam or hot water to generate electricity is becoming more common. Although it is not renewable, it is an unlimited energy source inherent to the earth and does not cause pollution. Compared to other renewable energy sources, it is inexpensive and relatively easy to utilize. However, the areas where geothermal power can be generated are limited, and there is a risk of land subsidence around power plants.
Ocean energy is a technology that converts ocean tides, waves, currents, and temperature differences into electricity or heat. Among these, tidal power generation, which utilizes the difference between high and low tides to generate electricity, is currently being commercialized. The periodicity of tides makes it possible to predict changes in local water levels, and power generation is periodic, but power cannot be generated during periods when the water level is constant, and it poses a threat to coastal ecosystems. In the case of wave power generation, which utilizes wave energy, there are technical difficulties in constructing power plants on the sea, and the facility costs are high. Tidal power generation does not have a significant impact on the ecosystem as it utilizes the flow of seawater. Temperature difference power generation is a technology that generates electricity by utilizing the temperature difference between warm water on the sea surface and cold water in the deep sea. It enables the utilization of deep sea water and provides stable power generation.
Waste energy is energy generated using fuel obtained through the thermal decomposition and gasification of waste. It is mainly used in power generation using incineration heat and fuel obtained from the thermal decomposition of waste plastics and tires, and most of the renewable energy currently used is waste energy. It is economical because the raw materials are inexpensive and prevents environmental pollution caused by waste landfill. However, advanced treatment technology is required as new environmental pollution may occur during the waste treatment process.
Fuel cells are a technology that converts chemical energy generated by the chemical reaction between oxygen and hydrogen into electrical energy. Heat is generated during the process of producing electricity, and utilizing this heat greatly increases efficiency and produces almost no pollutants. Fuel cells are quiet, can be installed in urban areas, and can use a variety of fuels. However, the construction cost of power plants is high, and economic efficiency is somewhat low due to issues with the lifespan and reliability of fuel cells.
Coal liquefaction is a technology that converts solid coal into liquid fuel at high temperatures and high pressures to produce synthetic crude oil that is easy to transport and store. Coal gasification is a new technology that generates electricity by driving turbines with gas produced through the incomplete combustion and gasification of coal. Coal liquefaction and gasification technology is a form of combined power generation that produces electricity using synthetic gas obtained from coal with almost no emissions of pollutants. This technology compensates for the shortcomings of existing coal-fired power plants.
Unlike conventional fossil fuels, hydrogen energy is a clean energy source that does not emit pollutants after use, and is expected to be the most ideal energy source in the future. Hydrogen is the lightest element in the universe and is an infinite resource found in the Earth’s oceans and underground. It can solve the problem of fossil fuel depletion and, when used with fuel cells, increases energy efficiency. However, there are difficulties in storing and transporting hydrogen, and there is a risk of explosion, so technological improvements are needed to solve these problems.
Currently, the share of renewable energy is increasing significantly worldwide, with regional differences in its use. In Korea, the share of renewable energy is lower than the OECD average, with waste energy accounting for the majority. Globally, solar and wind energy account for a high share, while biomass accounts for a large share in Europe. Recently, the use of renewable energy has been expanding due to active government support and technological advances.
The future of renewable energy is bright. With technological advances, economic efficiency is improving, and renewable energy is gaining attention as an environmentally friendly energy source. However, there are still many challenges to be addressed before renewable energy can replace fossil fuels. First, the instability and low efficiency of energy sources must be improved, which requires continuous research and investment. In addition, energy storage technology must be developed to increase the stability of energy supply. Finally, policy support and international cooperation are necessary to expand the use of renewable energy and solve environmental problems.
This article looked at the types, advantages, disadvantages, current use, and future of renewable energy. Renewable energy has unlimited potential and is an essential energy source for the sustainable development of humankind. We hope that interest and investment in renewable energy will continue so that we can use cleaner and safer energy in the future.
