Tidal power system and methods

1. A hydropower generation method utilizing changing water levels, the method comprising:

collecting water percolating through a permeable substance into a first underground region as a water level is increased;

releasing water from the first underground region into a second underground region, and thereby operating a first hydro turbine and generator operatively coupled therebetween to generate power; and

releasing water from the second underground region as a water level is decreased, and thereby operating a second hydro turbine and generator operatively coupled therebetween to generate power; wherein the method is characterized by (1) wherein the permeable substance comprises a beach; or (2) wherein the changing water levels are due to a tide; or (3) both.

2. The method of claim 1 wherein the permeable substance comprises sand, gravel, rock, and mixtures thereof.

3. The method of claim 1 wherein the permeable substance comprises a beach.

4. The method of claim 1 wherein the changing water levels are due to a tide.

5. The method of claim 4 wherein the first underground region is located at substantially the same elevation as the second underground region and wherein water is collected in the first underground region to a level up to about a high tide level.

6. The method of claim 4 wherein the first underground region is located at substantially the same elevation as the second underground region and wherein water is released from the second underground region at or about low tide.

7. The method of claim 1 , further comprising releasing water from the first underground region into the second underground region through an inflow pipe.

8. The method of claim 7 , further comprising opening one or more pipe valves in the inflow pipe at an increased water level.

9. The method of claim 1 , further comprising releasing water from the second underground region to a decreased water level through an outflow pipe.

10. The method of claim 9 , further comprising opening one or more pipe valves in the outflow pipe at the lower water level.

11. The method of claim 1 , further comprising closing one or more pipe valves in the inflow and outflow pipes while collecting percolating water in the first underground region.

12. The method of claim 1 , further comprising storing or transmitting at least a portion of any power generated.

13. A tidal power system comprising:

a first underground region for collecting water percolating through a coastal area medium at a higher tide level;

a second underground region capable of fluid communication with the first underground region;

an inflow pipe through which water is released from the first underground region to the second underground region, the inflow pipe further comprising a first hydro turbine and generator operatively coupled thereto to generate power; and

an outflow pipe through which water is released from the second underground region, the outflow pipe further comprising a second hydro turbine and generator operatively coupled thereto to generate power;

wherein the system is configured to release water at separate times from the first underground region and the second underground regions to operate the hydro turbines and generators and thereby produce electricity and wherein the system is characterized by (1) the first underground region comprising a mesh or screen for filtering water percolating through the coastal area medium; or (2) the second underground region being insulated from water infiltration through the coastal area medium; or (3) both.

14. The system of claim 13 , wherein the first underground region further comprises a mesh or screen for filtering water percolating through the coastal area medium.

15. The system of claim 13 , further comprising one or more pipe valves in the inflow pipe configured to allow release of water from the first underground region to the second underground region.

16. The system of claim 13 , further comprising one or more pipe valves in the outflow pipe configured to allow release of water from the second underground region.

17. The system of claim 13 , wherein the second underground region is insulated from water infiltration through the coastal area medium.

18. The system of claim 13 , further comprising an operable connection to an apparatus configured to use produced electricity.

19. A hydropower generation method utilizing changing water levels, the method comprising:

collecting water percolating through a permeable substance into a first underground region as a water level is increased;

releasing water from the first underground region into a second underground region, and thereby operating a first hydro turbine and generator operatively coupled therebetween to generate power; and

releasing water from the second underground region as a water level is decreased, and thereby operating a second hydro turbine and generator operatively coupled therebetween to generate power which method comprises providing a filter around at least a portion of the first underground region for filtering water.

20. The method of claim 19 , wherein the filter comprises a material selected from a mesh, screen, net, or combination thereof.

21. The method of claim 19 , wherein the permeable substance comprises a beach.

22. The method of claim 19 wherein the changing water levels are due to a tide.

23. The method of claim 22 wherein the first underground region is located at substantially the same elevation as the second underground region and wherein water is collected in the first underground region to a level up to about a high tide level.

24. The method of claim 22 wherein the first underground region is located at substantially the same elevation as the second underground region and wherein water is released from the second underground region at or about low tide.

25. The method of claim 19 , further comprising releasing water from the first underground region into the second underground region through an inflow pipe.

26. The method of claim 25 , further comprising opening one or more pipe valves in the inflow pipe at an increased water level.

27. The method of claim 19 , further comprising releasing water from the second underground region to a decreased water level through an outflow pipe.

28. The method of claim 27 , further comprising opening one or more pipe valves in the outflow pipe at the lower water level.