First, not having any definition, use of qualitative-only words such as "clean", "green", ... is unlikely in any scientific document. Secondly, and evidently too, there is none action issued from human activity that would result in zero energy consumption and/or zero pollution.

Regarding your other question, "why is green energy important in sustainable development?", renewable's main benefit is their ability to collect and transorm a free primary source, namely solar energy, into some end-use energy. Of course, such process is neither energy/ environmaent free. then, avoiding use of fossil fuels and limiting polution. They are better from a SD viewpoint!

Sincerely yours

Dr Jacques Roturier

Dr Jacques Roturier thank you for your contribution to the discussion

Renewable energy, often referred to as clean energy, comes from natural sources or processes that are constantly replenished. For example, sunlight and wind keep shining and blowing, even if their availability depends on time and weather. Green energy comes from renewable energy resources that can be renewed naturally and have the least environmental impact. Clean energy is created without emitting greenhouse gases, though it isn't necessarily naturally renewable. Green energy' and 'renewable energy' are often used interchangeably, but there is one essential (and sometimes confusing) difference between them. While most green energy sources are also renewable, not all renewable energy sources are considered entirely green. Renewable energy sources which are available in abundance all around us, provided by the sun, wind, water, waste, and heat from the Earth are replenished by nature and emit little to no greenhouse gases or pollutants into the air. The energy sources such as sunlight, wind, rain, tides, etc. can be called as green energy. This is because these are readily available on Earth, can be naturally replenished and do not even harm the environment much. Both biomass and large hydropower are renewable energy sources because they can be naturally replenished over time. They are not green though because they produce greenhouse gas emissions upon generation. Our world runs on the energy we produce. Clean energy production allows us to generate the energy we need without the greenhouse gas emissions and negative environmental effects that come with fossil fuels, in turn helping to reduce climate change. For instance, when compared to coal-fired power plants, electricity from renewable energy sources emits between 90 and 99% less greenhouse gases (GHGs) and produces 70 to 90% less pollutants. These technologies also create jobs and stimulate economic growth, which is essential for sustainable development.The most important aspect of clean energy is the environmental benefits as part of a global energy future. While clean, renewable resources also preserve the world's natural resources, they also reduce the risk of environmental disasters, such as fuel spills or the problems associated with natural gas leaks. Sustainable energy development involves the harnessing of energy resources for human use in a manner that supports lasting development. Environmental and economic benefits of using renewable energy include: Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution. Diversifying energy supply and reducing dependence on imported fuels. Exposure of such pollution can contribute to severe health related diseases. In this case, non- combustion based green energy is able to produce very less amount of pollution compared to the fossil fuels as well as conserve the factors that affect sustainable development. Renewable energy technologies, such as solar, wind, and hydropower, can play a critical role in promoting sustainable development in India by reducing greenhouse gas emissions, increasing energy security, and promoting rural electrification.