Wave
and tidal energy devices are those which generate electricity from the natural motions
created in water by waves and tidal currents.
Wave energy devices can take forms such
as paddles that bob up in down with the water, or large jointed snake-like
devices which
rest along the water surface, bending and stretching as waves pass under
them. A third
method that is being developed is a pumping mechanism that turns a water
turbine.
Tidal
current energy devices are somewhat similar to conventional wind turbines,
except that
the turbine is submerged in water and moved by the constant ebbing and flooding
of tides
rather than the wind. Moving water has
much more kinetic energy per unit cross sectional
area than wind due to the higher density of water, and the innovation of tidal turbines
avoids the negative environmental impacts of damming a bay or estuary as is
done with
a tidal barrage plant such as the La Rance plant in France. A new effort is being pursued
to harness the ocean currents similar to tidal or in-stream technology.
The Hampton Roads area is a unique combination of
resources in the mouth of the Chesapeake,
the local rivers and the off shore ocean areas, and should be considered for research
and development focusing on secondary technology and market applications. The key
could be in developing complementary
wave, tidal and in-stream technologies that serve
to enhance other renewable technologies such as solar and wind or can be
applied to solving
unique environmental challenges in the Chesapeake Bay or similar key habitats.
Source: Mayor's Alternative Task Force Report