Energy transition with renewable energies
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Renewable energies reached an estimated share of 42 percent of gross electricity consumption in 2021 - significantly less than in 2020. In 1990, the share was still 3.4 percent.
Although renewable energy is often seen as a new technology, the power of nature has long been used for heating, transport, lighting and other purposes. But over the last 500 years, people have increasingly turned to cheaper, dirtier energy sources like coal. In the future, the integration of technological development could make the global energy transition possible. However, for the development of the global renewable energy sector, it is crucial to consider the different factors such as environment, society, economy, technology, politics and geographical location. Natural sources such as sunlight, wind, biomass, water, waves, tides and geothermal energy are the green energy sources. Unlike fossil fuels, these energy sources are renewable, unlimited and naturally replenished.
Renewable energies are an alternative to conventional energy based on fossil fuels, and they tend to be much less harmful to the environment. Europe is a leader in wind and solar energy. In fact, 50 countries (26%) generated more than a tenth of their electricity from wind and solar power in 2021, with seven countries reaching this milestone for the first time: China, Japan, Mongolia, Vietnam, Argentina, Hungary and El Salvador.
Solar energy as an environmentally friendly energy source
Sunlight, the source of solar energy, is constantly available and renewable on Earth. Today, we use the sun's rays in many ways - to heat homes and businesses, to heat water and to power appliances. Solar cells, or photovoltaic cells, are made from silicon or other materials and convert sunlight directly into electricity. Solar farms can generate enough electricity to power thousands of homes by using mirrors to concentrate sunlight onto a large area of solar cells. In 2022, photovoltaic systems generated 12.1 percent of Germany's electricity so far. These active solar technologies use sunlight to generate electricity that we use to power lamps, heating systems, computers and televisions. Passive solar energy does not use any devices. Instead, energy is generated from the way sunlight naturally changes throughout the day.
You can find projects on the topic of photovoltaics here.
The use of solar energy has many advantages. PV cells have a long lifetime, about 20 years. However, there are reasons why solar energy cannot be used as the only energy source in a community. It can be expensive to install PV cells or to build a building with passive solar technology. Solar radiation is also difficult to predict. It can be obscured by clouds, and the sun does not shine at night. Different parts of the earth receive different amounts of sunlight depending on location, season and time of day.
Even more environmentally friendly is "floatovoltaics" - solar modules installed on bodies of water. The lure of floating solar panels lies in the potential cost savings and power generation efficiency associated with these systems. Since they do not take up valuable land, the cost of floating solar systems is lower than conventional land-based systems. In addition, floating solar systems eliminate some of the additional labour required for land-based installations, such as tilling the soil or removing obstacles. The floating solar installations make their contribution to climate protection. By shading the water, they limit algae growth and reduce evaporation.
Solar energy systems do not produce air pollutants or greenhouse gases, and as long as they are installed in a suitable location, most solar modules have little environmental impact beyond the manufacturing process. Picture
Solar energy as an environmentally friendly energy source
Flowing water can be converted into electricity with generators. Most hydroelectric power plants are located at large dams that control the flow of a river. Dams block off the river and create an artificial lake or reservoir. A controlled amount of water is forced through tunnels in the dam. As the water flows through the tunnels, it turns huge turbines and generates electricity.
Rivers flow all over the world, making the energy source accessible to millions of people. Hydroelectric power plants are a great help, but they also have massive disadvantages. Not only is the fauna disturbed by the turbine plants, but the flora also suffers from the interference with nature. In addition, it can happen that the water below the power plant becomes scarce and thus has a massive impact on the environment. For hydropower, a flowing water source must be dammed up. If the water stops flowing, the habitats on the river banks disappear. This can even lead to animals no longer having access to the water.
The potential of hydropower in Germany is largely exhausted. Image. Picture
Wind energy plays a significant role in the energy transition
Today, turbines as tall as skyscrapers and almost as large in diameter can be found all over the world. Wind energy or wind power is generated with a wind turbine, a device that uses kinetic energy from the wind to generate electricity. The wind blows the blades of the turbine, which are attached to a rotor. The rotor then drives a generator, which produces electricity.
Here you can find sustainable projects in the category wind energy.
Small, single wind turbines can generate 100 kilowatts of power, enough to supply a house with electricity. Small wind turbines are also used for places like water pumping stations. Slightly larger wind turbines sit on towers that are up to 80 metres high and have rotor blades that are about 40 metres long. These turbines can generate 1.8 megawatts of power. Once the electricity is generated, it can be used, connected to the grid or stored for later use. The largest offshore wind farm in the world is called Walney Extension. This wind farm is located in the Irish Sea about 19 kilometres (11 miles) west of the northwest coast of England. The Walney Extension covers a huge area of 149 square kilometres (56 square miles), making the wind farm larger than the city of San Francisco in California or Manhattan Island in New York.
Wind is a free, inexhaustible and sustainable energy source available almost everywhere in the world. Image
Did you know?
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The total capacity of all wind turbines worldwide has exceeded 840 gigawatts, which is enough to cover more than 7 % of the world's electricity demand. In 2020, the figure was 742.5 gigawatts.
Bioenergy with positive and negative impact on the environment
Biomass is organic material that comes from plants and animals, e.g. crops, wood waste and trees. When biomass is burned, the chemical energy is released as heat and can generate electricity with a steam turbine. A major advantage of biomass is that it can be stored and used when needed. However, growing crops for biofuels requires large amounts of land and pesticides. The land could be used for food instead of biofuels. Some pesticides could pollute the air and water. Biomass energy can also be a non-renewable energy source. Biomass energy is based on biomass feedstocks - plants that are processed and burned to produce electricity. Biomass feedstocks can include plants such as corn or soybeans as well as wood. If people do not replant the biomass feedstocks as quickly as they consume them, biomass energy becomes a non-renewable energy source.
Biogenic waste and residues from agriculture, forestry, households and industry are used to generate bioenergy. Picture
Bioenergy with positive and negative impact on the environment
The thermal energy stored in the earth's crust is called geothermal energy and can be used for heating, cooling and electricity generation. However, most of the earth's heat remains underground and only very, very slowly reaches the outside. We can use underground geothermal energy in a number of ways. One way to use geothermal heat is "ground source heat pumps". This involves laying a water pipe between a building and holes dug deep in the ground. The water is heated by the geothermal energy underground and brings the heat above ground into the building. Geothermal heat pumps can be used to heat houses, pavements and even car parks.
Geothermal energy is only available in certain parts of the world. Picture
Another way to use geothermal energy is to use steam. In some areas of the world, there is underground steam that naturally rises to the surface. The steam can be piped directly to a power plant. In other parts of the world, however, the ground is dry. To produce steam, water has to be forced underground. When the steam comes to the surface, it is used to drive a generator and produce electricity. There are large underground water reservoirs in Iceland. Almost 90% of the Icelandic population uses geothermal energy as a source of energy to heat their homes and businesses. Advantages and disadvantages. One advantage of geothermal energy is that it is clean. It does not require fuel and does not emit harmful pollutants into the air. Another disadvantage of geothermal energy is that in areas where there is only dry heat underground, large amounts of fresh water are needed to produce steam. There may not be much fresh water. People need water for drinking, cooking and bathing. According to an evaluation of the environmental effects of generating electricity with deep geothermal energy, it can contribute to a sustainable energy supply at present and in the future.
More on renewable energies: Renewable energies, Solar and Wind Power, Federal Environment Agency