The topic of renewable energy is becoming increasingly important as concerns about climate change and the depletion of non-renewable resources continue to grow. Renewable energy sources, such as solar and wind power, have the potential to provide a clean and sustainable source of power for the world's growing population. One of the major advantages of renewable energy is that it is not limited by the same supply constraints as fossil fuels. Unlike oil, coal, and natural gas, which are finite resources that will eventually run out, renewable energy sources like solar and wind power will never run out. Additionally, renewable energy sources do not produce the greenhouse gases that are responsible for climate change, making them a much more environmentally friendly option. Despite the clear benefits of renewable energy, there are still significant challenges that need to be overcome in order for it to become a viable alternative to fossil fuels. One of the main challenges is the cost of renewable energy, which is currently higher than traditional fossil fuels. However, as technology continues to improve and economies of scale are achieved, the cost of renewable energy is expected to decrease. Another challenge is the need for reliable and efficient energy storage solutions, which are essential for the widespread adoption of renewable energy. Without effective energy storage solutions, renewable energy sources like solar and wind power can only be used when the sun is shining or the wind is blowing, which greatly limits their overall usefulness. Overall, renewable energy has the potential to play a critical role in addressing the world’s energy needs and reducing dependence on fossil fuels. While challenges remain, with continued research and development, renewable energy is likely to become increasingly viable and important in the coming years.

Select the most appropriate synonym of the given word from the passage.Stringent