Yes, renewable energy can be used again and again. This is because renewable energy sources, such as solar, wind, hydro, and geothermal, are naturally replenished. For example, sunlight is available every day, wind blows constantly, and water flows continuously. This means that renewable energy can be used to generate electricity, heat homes, and power vehicles without producing greenhouse gas emissions.

The amount of renewable energy needed to stop global warming depends on a number of factors, such as the rate of population growth, economic development, and technological advancements. However, it is estimated that we need to generate at least 80% of our electricity from renewable sources by 2050 in order to limit global warming to 1.5 degrees Celsius.

Achieving this goal will require a significant investment in renewable energy technologies. However, the cost of renewable energy has been falling rapidly in recent years, and it is now cost-competitive with fossil fuels in many parts of the world. As the cost of renewable energy continues to fall, it is becoming increasingly clear that renewable energy is the key to a sustainable future.

In addition to generating electricity, renewable energy can also be used to heat homes and power vehicles. For example, solar thermal collectors can be used to heat water for homes, and electric vehicles can be powered by renewable energy sources. As we transition to a renewable energy future, we will need to invest in these and other technologies in order to reduce our reliance on fossil fuels.

The transition to a renewable energy future will not be easy, but it is essential if we want to stop global warming. By investing in renewable energy technologies, we can create a cleaner, healthier, and more sustainable future for all.

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Dr Murtadha Shukur thank you for your contribution to the discussion

Yes, renewable energy can be used again and again. Renewable energy comes from sources that replenish naturally and continually within a human lifetime. Major renewable energy sources include solar, wind, hydroelectric, tidal, geothermal, and biomass energy. These sources are called renewable because they can be used repeatedly without depletion.

As for how much renewable energy we need to stop global warming, it is suggested that all countries must reduce their fossil fuel use substantially, extend access to electricity, improve energy efficiency, and increase the use of alternative fuels, according to United Nations sources. To reach net zero emissions by 2050, annual clean energy investment worldwide will need to more than triple by 2030 to around US$4 trillion, according to the IEA. The roadmaps call for countries responsible for 99.7% of global CO2 emissions to switch to 100% clean, renewable wind, hydro, and solar power no later than 2050, with at least 80% renewables by 2030. This is critically important in tackling the climate crisis.

Dr Jorge Morales Pedraza thank you for your contribution to the discussion

Renewable energy refers to any energy source that can be utilized more than once as; fossil fuels like coal can only be burned once to create energy. Renewable resources are those resources that continue to exist despite being consumed or can replenish themselves over a period of time even as they are used. They include the sun, wind, water, geothermal, and biomass. The disadvantage of renewable resources is that they may not be available for use when needed. Renewable energy is energy produced from sources like the sun and wind that are naturally replenished and do not run out. Renewable energy can be used for electricity generation, space and water heating and cooling, and transportation. 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. Renewable energy sources are delineated as “renewable” since they do not run out the way that fossil fuels, oils, and gasses do. Renewable energy is then used to power electricity, space heating, cooling systems, and even transportation. Renewable energy is sometimes say clean energy or reusable energy. Combined Heat and Power (CHP) is a form of energy recycling, where processes and equipment are designed to produce power and also supply heat rather than waste it. Energy recycling and CHP can be implemented at industrial sites, manufacturing facilities and large institutions such as hospitals and universities. The main difference between renewable and nonrenewable energy is that there is a finite amount of nonrenewable energy while renewable energy is unlimited because the source of its power is regenerative. Annual energy-related CO2 emissions need to decline 70% below today's levels by 2050 to set the world on a pathway toward meeting the climate goals. Renewable energy and electrification alone can deliver 75% of energy-related CO2 emissions reductions needed. As per the study conducted in Finland's LUT University (LUT) and the Energy Watch Group (EWG), a global 100% renewable energy system can be a reality with zero GHG emissions before 2050 and more cost-effectively than the current fossil fuel and nuclear-based energy system. Non-bioenergy renewable need to increase their share of total energy supply from close to 5% today to approximately 17% by 2030 in the NZE Scenario. To achieve this, annual renewable energy use must increase at an average rate of about 13% during 2023-2030, twice as much as the average over the past 5 years.

Dear colleagues

Sorry to inform you that NO, the renewable energy sources cannot be used again and again. First, most of it comes from the conversion of solar radiation, and the amount of solar radiation the earth receives is limited to 347 W/m² outside the atmosphere, and most of it is reflected or re-emitted as thermal radiation to the space. Converting all that power into usable energy will provide 1,734 × 1017 W or 173 PW. It is about 8'600 times the average energy use of mankind, i.e about 20 TW, but it is nevertheless limited.

Another source acknowledged as "renewable" is geothermal energy. This results form radioactive decay of elements in the earth, and is therefore limited. The available power is only about 44.3 TW today, that is only twice the energy use of mankind.

However, the most severe limitation is that any energy conversion and use ends into heat. Efficient solar collectors are black, and absorb more solar radiation than the common environment. Therefore, using more and more solar energy will heat the earth and hence change the climate.

The same for geothermal energy: the heat taken form deep underground ends into heat in the atmosphere.

Therefore, renewable energy sources cannot be used again and again without limits. However, it is absolutely necessary to use only them to reduce the climate change, and replacing fossil fuels by solar energy will indeed reduce, in the long term, the global temperature, as long as our energy use is only a negligible part of the solar radiation.

The final, absolute limit is the amount of hydrogen to be converted in helium by nuclear fusion in the sun. Astrophysicists tell us that there are about 5 billion years left...