Developing tidal power generators vary greatly in size, scale and design. Technologies themselves range from helical turbines to biologically inspired systems that mimic the motion of algae, or even a whale's tail. For a more in depth report on the generators themselves, please read our State of Technology report.

    1. A Huge Resource: Locally, nationally and globally.

    2. Environmentally Friendly: miniscule impact per unit energy

    3. Invisible: completely silent and submerged underwater

    4. Highly Predictable: the tides are precisely calculated

    5. Material Efficient: water is 1,000 times denser than air (see above illustration)

In contrast to conventional hydropower, which utilizes the vertical drop or "head" of water, tidal power harnesses the lateral flow. This horizontal flow is an entirely distinct component of the energy in water, and is virtually untapped. Innovative hydropower is a huge and varied global resource, extraction coming from tides, waves, rivers or streams.

This huge resource has a very high power density because water is 1,000 times as dense as air. Another great advantage is our ability to precisely predict the tides, which is key since the value of utility-scale power generation depends on temporal cycles in power load (see above illustration). In comparison to other renewable energies and possible future large-scale power generation, tidal power takes the lead (see Figures 1 and 2).