The Difference Between Clean and Renewable Energy Generation
When we consider how the generation and use of energy must change in pursuit of environmental goals, important questions arise. How can we ensure that the resources we rely on for energy generation will remain available for use in the future? How can we meet energy demand without emitting greenhouse gases and contributing to climate change? Although sustainability and climate change are often discussed together, certain methods of energy generation can emit zero greenhouse gases yet be unsustainable, and vice versa.
Using precise terminology -- like clean energy or renewable energy -- clarifies the different implications that various technologies have on the health of the environment and the public. Specifically, energy that is renewable comes from sources that replenish naturally and thus are not threatened with potential depletion, like wind, solar, and geothermal energy. In terms of the sustainability of natural resources, renewable energy is seen as a future-proof alternative to relying on nuclear fuels and fossil fuels, which are in finite supply. However, a major challenge with renewable energy generation is its natural variability: geothermal and hydropower systems are limited in suitable geographic locations, while the output of wind and solar energy systems is subject to transitory weather conditions.
It is important to distinguish between renewable and clean energy because certain renewable energies are not clean, meaning they emit greenhouse gases. A prominent example is hydropower. Because the water cycle is continual, hydropower offers a renewable source of energy. Hydropower is both cost effective and reliable due to the durability of its infrastructure as well as its ability to store energy for long periods of time in the case of pumped storage hydropower (PSH). However, it is not classified as clean energy because the dams it requires alter hydrologic processes such that the greenhouse gases naturally emitted from the water body are enhanced.
Transitioning to clean energy is critical to limiting climate change and its associated effects as well as air pollution, with 99% of today’s global population exposed to air that does not meet the quality standards set by the World Health Organization (WHO). With zero greenhouse gas emissions, nuclear power is a form of clean energy generation that is expected to play an important role in the transition away from fossil fuels because its output is stable and reliable. This complements the variable nature of renewable energy for a more balanced energy mix overall.
Notably, energy generation may be both clean and renewable: wind and solar energy, for example, do not emit greenhouse gases and come from sources that replenish naturally. Furthermore, the prices of these technologies have declined substantially in recent decades, such that they are now more affordable than using coal or natural gas. As we look to the future, investing in energy that is clean, renewable, or both brings us closer to achieving a healthier and safer environment.
