In this blog post, we will look at how renewable energy can overcome the limitations of fossil fuels and create a sustainable future.

 

Renewable energy, the power to light the future

Televisions, cars, mobile phones, computers. All of these products make our lives more convenient and richer. However, using these products requires “energy.” So far, we have been using resources such as coal and oil to supply energy, but most people agree that these resources are gradually running out. In addition, most of the fuels we have been using are fossil fuels, which generate carbon dioxide and other pollutants and are the main cause of environmental pollution. For this reason, renewable energy is being studied as an alternative. In this article, we will look at the meaning and types of renewable energy, and the characteristics, advantages, and disadvantages of each energy source.
First, let’s look at the concept of “energy.” Energy is the power that is the source of human activity, that is, the ability to perform physical work. Energy is essential for all the things we see, hear, touch, and use.
So, what is new and renewable energy? It is also called “new & renewable energy” in English and refers to energy that is converted from existing fossil fuels or that uses renewable resources such as sunlight, water, geothermal energy, and biomass. It is a future energy source for a sustainable energy supply system. In Korea, a total of 11 areas have been designated as new and renewable energy, including three new energy sources and eight renewable energy sources.

 

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. The energy that is released when hydrogen and oxygen combine to form water is converted into electricity. Unlike batteries, fuel cells do not require charging because they receive hydrogen and oxygen from the outside. They generate energy without combustion, so they do not emit pollutants and can significantly reduce carbon dioxide emissions. They also have a high energy efficiency of 50%, compared to 30% for conventional internal combustion engines. However, strictly speaking, they are not a complete alternative energy source because they are a method of converting and using existing energy.

 

Hydrogen energy

Hydrogen energy is a method of obtaining energy by burning hydrogen with oxygen. Since hydrogen combines with oxygen and is reduced to water, there is no environmental pollution from exhaust gas, and it produces about three times more energy than the same mass of petroleum. After the oil crisis in the 1970s, research on alternative fuels was activated, and interest in hydrogen energy as a clean fuel increased. Hydrogen has the disadvantage of being difficult to manufacture and store, but research is being conducted on a method of storing and transporting hydrogen by adsorbing it on some metal hydroxides, such as magnesium.

 

Coal liquefaction and gasification

Coal liquefaction and gasification is a method of using solid coal or low-grade raw materials left over after oil refining as an energy source by liquefying or gasifying them. It is highly efficient and an environmentally friendly technology with low emissions of sulfur oxides and nitrogen oxides. Although it has the advantage of being able to reuse low-grade raw materials and turn them into high-value products, it requires a lot of money for basic facilities.

 

Biomass energy

Biomass energy is a method of obtaining methane, ethanol, hydrogen, etc. by pyrolysing or fermenting living organisms. Biomass uses the energy generated when microorganisms decompose plant and animal organic matter or uses organic raw materials. Biomass is used to generate heat by burning firewood or straw, or to make compost. However, large areas of land are required for efficient biomass production, and there are differences in energy generation depending on the region, making commercialization difficult.

 

Solar thermal energy

Solar thermal energy is a method of using the heat radiated from the sun and is used for heating or power generation. It uses the high heat obtained by concentrating heat or produces electricity by boiling water and turning a turbine with high-pressure water vapor. It has the advantages of being a pollution-free energy source and having little regional bias, but its use is limited on cloudy days and the energy unit price is relatively high.

 

Geothermal energy

Geothermal energy is a method of obtaining hot water or steam by using heat deep underground. Such thermal water is used for heating or power generation, and it can contribute to the local economy through the development of hot springs and the resulting tourism effect. However, the areas where geothermal energy can be developed are limited, and there are safety issues due to crustal movements.

 

Ocean energy

Ocean energy is energy that uses the waves of the sea, the ebb and flow of the tide, ocean currents, and temperature differences. In particular, tidal energy is a technology that produces electricity using the rise and fall of the sea level, and is suitable for places with large tidal differences, such as the west coast. Tidal power generation has a high installation cost, but it does not require fuel costs and is considered an eco-friendly energy source. Although it is currently uneconomical, it can become competitive when fossil fuel prices rise.

 

Wind power and hydroelectric power

Wind power is a method of converting wind into electrical energy, which is environmentally friendly, but the amount of power generated varies greatly depending on the amount of wind, and the initial installation cost is high. Hydroelectric power is a method of using the potential energy of water, which has a low power generation cost and high density, but there is a risk of environmental damage due to flooding.

 

Conclusion

As seen above, the reason why various renewable energy sources are attracting attention is that existing fossil fuels are decreasing and are expected to be depleted within the next 40 to 60 years, according to the Korea Institute of Energy Research. In addition, renewable energy is environmentally friendly. The Kyoto Protocol adopted the goal of reducing greenhouse gas emissions in 1997, and accordingly, Korea has been required to reduce emissions since 2008. As Korea, which ranks ninth in the world in terms of annual carbon dioxide emissions, needs to invest more in the development of new and renewable energy.
The reason why renewable energy still accounts for less than 10% of the world’s total energy consumption is due to the high production cost and the difficulty of developing technology. However, as institutional mechanisms such as the Renewable Portfolio Agreement (RPA) and the Renewable Portfolio Standard (RPS) and technological development are steadily progressing, renewable energy is increasingly becoming a viable alternative to fossil fuels.