Clean, green and renewable energies: Welcome back to “Science For Everyone”, ABP Live’s weekly science column. Last week, we discussed what unidentified flying objects (UFOs) are, some interesting anecdotes of these mysterious phenomena, and how NASA aims to track them. This week, we explain the similarities and differences between clean, green and renewable energies. The impact of climate change on the global environment has reached the point where if everyone does not take immediate action to curb greenhouse gas emissions, the future generations will be forced to live in a dystopian world, similar to the post-apocalyptic scenarios shown in science-fiction movies.
If greenhouse gas emissions are made nil, a global net-zero economy will be achieved. For this, a transition to renewable energy is essential.
A global group of over 200 climate and energy organisations signed an open letter calling for world leaders and Parties to the Paris Agreement to agree at the 28th United Nations Climate Change Conference (COP28) to triple renewable energy by 2030. The open letter was published on September 18, 2023. In the G20 New Delhi Leaders’ Declaration, leaders pledged to triple renewable energy capacity by 2030, as part of efforts to accelerate a transition to clean energy, and mitigate climate change.
Clean, green and renewable energies are terms often used interchangeably. However, there are similarities as well as differences between these terms.
The meanings of clean energy, green energy, and renewable energy may overlap, but each word has a distinctive meaning. All green energy sources are renewable, but all renewable energy sources are not green. Also, nuclear energy is a type of clean energy. However, nuclear energy is neither green nor renewable.
Clean energy
An energy source that results in negligible pollution, and releases minimal greenhouse gases and chemical contaminants, is known as clean energy, according to Palmetto, a clean energy company.
The sources from which clean energy is derived do not release air pollutants and contaminants. Therefore, clean energy sources have minimal or zero impact on the surrounding environment.
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Green energy
A form of energy that comes from natural sources such as wind, sunlight, or water is called green energy. Therefore, wind energy, solar energy, and hydro-energy are types of green energy.
Green energy sources do not cause pollution, unlike fossil fuels. Also, green energy sources can be naturally replenished and avoid mining or drilling techniques that can damage the ecosystem, according to The Welding Institute, a Cambridge-based institute.
Renewable energy
The energy produced from sources like the Sun and wind, that are naturally replenished, and do not get extinguished, is known as renewable energy. These natural sources are replenished at a higher rate than they are consumed. One can use renewable energy to generate electricity, cool and heat water, and for transportation. According to the US Department of Energy, the six main types of renewable energy are solar energy, wind energy, hydropower, bioenergy, marine energy, and geothermal energy.
Non-renewable energy sources are the ones that take hundreds of millions of years to form, and when these sources are used to produce energy, they release harmful greenhouse gases into the atmosphere.
Meanwhile, renewable energy sources result in negligible greenhouse gas emissions. Also, renewable energy sources are considered inexhaustible, because of which they are a better option compared to coal and gas.
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How clean energy, green energy and renewable energy are similar to and different from each other
All forms of green energy are considered renewable. However, all renewable energy sources are not green. This can be explained through the example of hydropower. In order to build hydro dams, trees need to be cut, and factories built. In order words, deforestation and industrialisation are associated with the construction of hydro dams for the generation of hydro power. This is damaging to the environment. Another example is that of bioenergy, which is generated from wood waste, combustible organic agricultural waste, sawdust, and charcoal. Burning these materials produces greenhouse gases.
In order for something to be classified as clean energy, the source must not release air pollutants, and for something to be termed as green energy, it must be obtained from natural sources.
According to Palmetto, renewable energy, green energy, and clean energy can be differentiated based on creation, renewal and impact.
In terms of creation, renewable energy is obtained from naturally-occurring sources, and can be replaced naturally, during the average lifetime of a human being. Green energy is also obtained from natural sources, and allows sustainable development. Green energy has the smallest environmental footprint, and is a subset of renewable energy.
Clean energy produces negligible amounts of carbon dioxide and chemical contaminants.
In terms of renewal, renewable energy sources are inexhaustible, and are naturally replenished. For renewable energy sources, there is a limit to the amount that can be captured over time. For instance, one can harness only as much wind as already exists.
Green energy is obtained from the renewable energy sources that are naturally renewed, and have the least environmental impact.
While clean energy is created without emitting greenhouse gases, it is not necessarily naturally renewable.
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In terms of impact, renewable energy can have an impact on the environment, determined by the kind of process used to harness the energy.
Since green energy has little to no ecological impact, it is considered the most environmentally friendly energy source.
Clean energy does not have an adverse environmental impact.
A difference between renewable energy and clean energy is that the former is not always clean. Wind energy, solar energy, and geothermal energy are the cleanest renewable energy sources. Small hydro plants are clean and renewable, but large hydroelectric plants release some pollutants into the environment.
The difference between clean energy and green energy is that clean energy creates negligible or no emissions during creation, renewable, and regeneration, but some green energy sources, including biomass, release a bit of polluting substances into the atmosphere. However, green energy generation does not threaten habitat loss or plant extinction.
Clean energy can be associated with clean air, green energy with natural sources, and renewable energy with recyclable sources.
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Overall, one can conclude that renewable energy is obtained from natural resources that can be replenished, green energy is not only renewable but also has minimal ecological impact, and clean energy includes renewable sources as well as zero-emission non-renewable sources such as nuclear power.
“Although the terms ‘clean,’ ‘green,’ and ‘renewable’ energy are frequently used interchangeably, each has its own set of implications and impacts. Renewable energy comes from natural, constantly replenished sources such as wind, solar, and hydro. Green energy takes this further, being not only renewable but also minimally harmful to the environment—think solar and wind, as opposed to large-scale hydro projects that may disrupt ecosystems and displace communities. Clean energy is a broader term that includes both renewable and low- or zero-emission non-renewable sources, like nuclear power, which brings its own safety concerns and waste management issues. While all aim to curb greenhouse gas emissions, they differ in environmental effects and renewability. It is crucial to understand these distinctions as we navigate our path to a sustainable future,” Harjeet Singh, Head of Global Political Strategy, Climate Action Network International (CAN-I), a global network in over 130 countries working to combat the climate crisis, told ABP Live.
A net-zero world can become a reality if a proper combination of renewable, green and clean energy technologies is used.
Check all the stories appearing in ABP Live’s weekly science column here.