Why renewable energy sources are also called alternative energy sources?

Renewable energy sources are often referred to as alternative energy sources because they provide alternatives to traditional fossil fuels, which are finite and contribute to environmental issues like climate change. These renewable sources—such as solar, wind, hydro, and geothermal energy—are sustainable and can be replenished naturally. As the world seeks to reduce carbon emissions and dependence on non-renewable energy, these alternatives are increasingly recognized as viable solutions for a cleaner energy future.