Renewable, Sustainable and the Grail
Environmentalists are tantalized by sustainability. We’ve developed renewable fuels, but sustainable fuels remain just out of reach.
The terms “renewable energy” and “sustainable energy” are not synonymous. Renewable fuels are potentially sustainable fuels, but sustainability is a broad, lofty concept. Hydroelectric power, for example, is a form of renewable energy, but fails to meet the specifications of a sustainable energy source.
A sustainable fuel source provides clean, renewable energy today, and will not compromise the ability of future generations to generate clean, renewable energy. A sustainable energy source consumes no fossil fuels at any time during its production or storage. It does no harm to the soil, water or air. Sustainable fuels neither disrupt ecosystems nor damage habitats.
Hydroelectricity was touted as sustainable, but it has not proved to be. Hydropower is renewable. It can reuse water, and the water is replenished through natural cycles. However, hydropower as now configured is not fully sustainable. Current hydroelectric plants emit methane, which is even worse than carbon dioxide for the atmosphere. Hydropower plants wreak havoc in the local ecosystem.
Sustainable, renewable fuels are the holy grail for environmentally conscious chemical engineers. Biofuels and hydrogen fuels are renewable fuel sources that seem to approach sustainability.
Biofuels, however, currently fail to meet the criteria for sustainability. Biofuel production often falls far short of carbon neutrality; it consumes more energy than it produces, and much of the energy it consumes derives from fossil fuels. All first generation biofuels compete with other crops for soil and water, although algae biofuel farms may hold the potential to overcome this obstacle.
Scientists persevere to resolve the issues but, at present, no renewable fuel source is ready for crowning as an economically viable, environmentally sustainable fuel source. Still, many renewable fuels appear to have the potential to become sustainable under the right conditions, and are therefore worthy of continued research and development.
Hydrogen fuel cells are one of the most intriguing areas of research. Fuel cells filled with hydrogen extracted from its source by equipment that runs on electricity generated by wind turbines or solar power may one day prove a viable sustainable, renewable fuel.