The previous article introduced the concept and relationship between resources and energy, energy and renewable energy, and we will introduce the concept and characteristics of renewable energy in detail below.
The basic concept of renewable energy
In the energy field, people call renewable energy sources such as hydropower, solar energy, wind energy, ocean energy, and biomass energy that can be used continuously by humans. Compared with traditional fossil energy, renewable energy has significant advantages such as large reserves, wide distribution, easy on-site utilization, and lighter environmental hazards.
With the continuous development of science and technology, the total global consumption of renewable energy has been increasing in recent years. In the world’s primary energy consumption, renewable energy accounts for about 18%, and the growth rate is also increasing. Looking at the global energy layout in the 21st century, all countries in the world have placed the development and utilization of renewable energy in a very important position. From a national perspective, the countries with the largest installed capacity of renewable energy power generation other than hydropower are China, the United States, Germany, Spain, Italy, India, and Japan. The total installed capacity of non-aqueous renewable energy power generation in these seven countries exceeds 70% of the world.
At present, the European Union has clarified its renewable energy development plan, and is expected to increase the use of renewable energy to 59% of its total primary energy consumption by 2050. Although the United States has a vast territory and abundant resources, it is also deeply aware of the importance of the development of renewable energy, and relevant policies to encourage the production of renewable energy are becoming more and more powerful; countries in Latin America, Southeast Asia, Central Asia and other regions have also expressed a very positive attitude towards the development of renewable energy.
In terms of the current technological development, among all renewable energy utilization technologies, water energy utilization technology and biomass energy utilization technology are the most mature; wind energy utilization technology and solar energy utilization technology are developing rapidly; geothermal energy utilization technology is also developing rapidly in some areas; ocean energy utilization technology is not yet available for large-scale commercial application, related technical problems have yet to be overcome, and costs need to be further reduced.
In short, renewable energy is an energy source with abundant reserves and huge development potential in the world, and it will surely become the main energy source for mankind in the future. However, due to the different R&D capabilities of countries in the world, the government’s support is also different, and the development speed of renewable energy utilization in different countries in the world is different, but strengthening the development layout of renewable energy has become the consensus of all countries in the world.
Characteristics of renewable energy
From the perspective of sustainable development, renewable energy has the following common characteristics:
(1) The annual mining capacity of renewable energy is huge. The global renewable energy can be extracted every year is very large, of which solar energy is 25.533TJ, which is equivalent to 87Ttce; water energy is 2.26TW, which is equivalent to 540Etce; wind and ocean energy is 37.30TW, equivalent to 370Gtce; geothermal energy is 640TW, equivalent to 60Etce; biomass energy is 162GW, equivalent to 115Ztce, of which solar energy accounts for the vast majority. Although the amount of renewable energy is huge, the distribution is relatively scattered. Compared with fossil fuels, its energy density is low (less energy can be obtained per unit mass or unit area), and some are intermittent and changeable, which brings great inconvenience to collection or mining.
(2) Renewable energy has no or little impact on the environment. There is no pollutant discharge during the development and utilization of renewable energy such as wind, hydro, solar, and geothermal energy, which will not cause any impact on the environment, and can even bring additional benefits to sustainable development. Taking biomass energy as an example, the CO2 absorbed by biomass during the growth process is basically equal to the CO2 emitted during combustion, achieving zero CO2 emissions.
(3) Renewable energy is widely distributed and can be used locally. Renewable energy is diverse and widely distributed. There are one or several renewable energy resources in various parts of the world, and people can mine and use them on the spot as needed. So far, there are still more than 2 billion people in underdeveloped areas in the world who have no access to electricity. Most of them still live a life of poverty and backwardness, far away from modern civilization, working at sunrise and resting at sunset. There are also some special areas such as high mountain weather station, earthquake observation station, forest fire alarm monitoring station, optical cable communication relay station, microwave communication relay station, border guard post, cathodic protection station of oil and gas pipeline, maritime navigation mark, etc., where conventional power sources are generally not available, and the development of renewable energy is an important way to solve the power supply problem. The development and utilization of renewable energy is more beneficial to remote areas, mountainous areas, areas that are not covered by power grids, and areas with scattered residents, backward and poor, and inconvenient transportation. It can not only solve the problem of energy supply, but also help increase employment opportunities and help improve the quality of life of residents there.
(4) The initial investment of renewable energy is relatively high, but the operating cost is relatively low. It is a one-time investment and long-term benefit.