Fossil fuels, an essential source of energy for modern life, are gradually depleting, and environmental pollution is becoming a serious problem. Renewable energy, which has emerged as an alternative, has the potential to replace fossil fuels in various forms, including solar, wind, geothermal, and marine energy. These renewable energies are environmentally friendly, and their efficiency and cost-effectiveness are improving as technology continues to develop, making them the energy source of the future.

Televisions, cars, cell phones, computers. All of these products make our lives more convenient and enriching. However, these products require energy to run. Until now, we have been using resources such as coal and oil to provide energy, but we can all agree that these resources are becoming increasingly depleted. In addition, most of the fuels we have been using are fossil fuels, which produce carbon dioxide and other pollutants and are a major source of environmental pollution. For this reason, renewable energy is being researched as an alternative. In this article, we’ll look at what renewable energy means, what types of energy there are, and what their characteristics, advantages, and disadvantages are.
First, let’s look at the concept of energy. Energy is the power underlying human activity, the ability to perform physical work. Everything we see, hear, touch, and use requires energy.
So what is renewable energy? In English, it’s called “new & renewable energy,” and it refers to energy that is either converted from conventional fossil fuels or harnessed from renewable resources such as sunlight, water, geothermal, and biomass. It is the future energy source for a sustainable energy supply system. In Korea, a total of 11 fields are designated as renewable energy, including 3 new energy and 8 renewable energy.

Types of renewable energy

Fuel cells

Fuel cells generate electricity by indirectly reacting different substances through a semi-permeable membrane, and hydrogen fuel cells are a typical example. Hydrogen and oxygen combine to create water, which is then converted into electricity. Unlike batteries, fuel cells do not require recharging because they are supplied with hydrogen and oxygen from the outside, and because they generate energy without a combustion reaction, they are pollution-free and can significantly reduce carbon dioxide emissions. It also has a high energy efficiency of 50% compared to conventional internal combustion engines (30%). However, it is not technically an alternative energy source because it converts and uses existing energy.

Hydrogen energy

Hydrogen energy is obtained by combusting hydrogen with oxygen. Hydrogen is converted into water by combining with oxygen, so there is no pollution from exhaust, and it produces about three times more energy than the same mass of oil. Interest in hydrogen energy as a clean fuel has increased since the 1970s oil crisis, when research into alternative fuels was revitalized. Hydrogen is difficult to produce and store, but researchers are working on ways to store and transport hydrogen by adsorbing it on some metal hydroxides, such as magnesium.

Coal liquefaction and gasification

Coal liquefaction and gasification is a method of liquefying or gassing solid coal or low-grade feedstock left over from refining and using it as an energy source. It is a highly efficient and environmentally friendly technology with low emissions of sulfur oxides and nitrogen oxides. It has the advantage of reusing low-grade raw materials and converting them into high-value-added products, but it requires a large investment in basic facilities.

Biomass energy

Biomass energy is the pyrolysis or fermentation of biological matter to produce methane, ethanol, hydrogen, etc. Biomass utilizes energy from the microbial decomposition of animal and plant organic matter or utilizes organic raw materials. We use biomass to generate heat by burning firewood or straw, or to make compost. However, efficient biomass production requires large areas of land, and energy production varies by region, making it difficult to commercialize.

Solar thermal energy

Solar thermal energy utilizes heat from the sun and is used for heating and power generation. It can be used to generate electricity by concentrating heat, or by boiling water and turning it into high-pressure water vapor in a turbine. It has the advantage of being pollution-free and less localized, but its use is limited on cloudy days and its unit cost of energy is relatively high.

Geothermal energy

Geothermal energy utilizes heat from deep underground to produce hot water or steam. This hot water is used for heating and power generation, and can also contribute to the local economy through tourism when hot springs are developed. However, there are limited areas where geothermal energy can be developed, and there are safety concerns due to tectonic movements.

Ocean energy

Ocean energy is energy that utilizes the ocean’s waves, tides, currents, and temperature differences. Tidal energy, in particular, harnesses the rise and fall of sea levels to generate electricity, making it ideal for places like the West Coast where there are large tidal differences. Tidal power is expensive to install, but it doesn’t require fuel, and it’s considered an environmentally friendly energy source. It’s not currently economically viable, but it could become competitive if fossil fuel prices rise.

Wind and hydropower

Wind power converts wind into electrical energy and is environmentally friendly, but its output fluctuates depending on the amount of wind, and the initial installation costs are high. Hydropower harnesses the potential energy of water and has a low unit cost of electricity generation and high density, but it can cause environmental damage due to flooded areas.

Conclusion

As you can see, renewable energy is gaining traction because conventional fossil fuels are dwindling and are expected to be depleted in the next 40 to 60 years, according to the Korea Institute of Energy Technology. Renewable energy is also environmentally friendly. In 1997, the Kyoto Protocol adopted the goal of reducing greenhouse gas emissions, and Korea has been required to reduce emissions since 2008. Korea, which ranks ninth in the world in annual carbon dioxide emissions, needs to invest more in renewable energy development.
Renewable energy still accounts for less than 10% of the world’s electricity generation, due to high production costs and difficulties in developing technologies. However, as institutional mechanisms such as voluntary renewable energy supply agreements (RPAs) and mandatory renewable energy quotas (RPSs) and technological developments are steadily progressing, the potential for renewable energy to replace fossil fuels is growing.