Emerging Voices: Exploring the “Forgotten” Renewables

Solar, wind, and hydropower — the heavy hitters of renewable energy — are becoming increasingly common. Solar panels cover rooftops, wind turbines line highways, and hydroelectric dams cut across rivers. These energy sources are increasingly visible, yet renewable energy comprises only 20% of the power supply in the U.S. (1). Critics of renewable energy sources are quick to bring up their intermittency; the energy grid cannot only supply power during periods of sun and wind. Focusing on only one renewable energy source at a time implies that any green energy system would be as erratic and inconsistent as Mother Nature. Diversifying renewable energy sources is vital.

For decades, renewable energy sources entirely separate from the “big three” have been reliably and sustainably delivering power to society. Here are two renewables that might be critical to making energy grids more sustainable.

Tidal energy. The oft-forgotten tidal energy is absent from many lists of renewable energy forms. Tidal power extracts energy from the ocean’s natural tidal cycles (2). Unlike wind and solar, tidal power is consistent and predictable, and different systems can be fitted to match a location’s geography. In the case of tidal stream systems, turbines placed in shallow shoals along coastlines rotate as currents pass through them. Although tidal stream energy systems can potentially disrupt tidal flows, the slow...