1. What is wave and tide energy?
Wave energy is energy that is powered by kinetic energy using the waves and tides. The energy is converted to electricity using buoys and turbines.
 It is the kinetic energy of wind interacting with water and creating waves.
The problem is that it's not easy to harness this energy and convert it into electricity in large amounts. Thus, wave power stations are rare

2. Its Beginning
 Research into wave power started around 20 years ago he says, originating in high-population, energy-hungry places like the UK and Europe that have few natural energy sources. Progress continued in wave-like spurts and lulls until recent times when the more urgent push for renewable energy sources stoked research and development funding. 
Mainly from harvesting the power of waves through turbines

3. How Does It Work?
Most designs now are experimental but some common type designs are currently
A point absorber 
Overtopping devices 
Attenuators
The names vary but are pretty much the same.
A Point Absorber a floating structure with components that move relative to each other due to wave action (e.g., a floating buoy inside a fixed cylinder). Point absorbers often look like floating oceanographic buoys. They utilize the rise and fall of the wave height at a single point for energy conversion.
Overtopping devices have reservoirs that are filled by incoming waves, causing a slight buildup of water pressure like a dam. The water is then released, and gravity causes it to flow back into the ocean. The energy of the falling water is used to turn hydro turbines to generate power. Specially built floating platforms can also create electricity by funneling waves through internal turbines and then back into the sea.

4. What are the specs? The average price in the U.S
Although the average price around is about 20 cents in some areas
While coal might be priced at five to 10 cents per kilowatt hour of energy, he said, wave energy costs reach 20 to 30 cents.

5. Wave energy Developments
Wave energy is becoming more and more accessible! Prominent companies in the wave energy business are
Pelamis Wave Power, a Scotland-based company
Ocean Power Technologies, a New Jersey company
Columbia Power Technologies, through a partnership with Oregon State University, this company develops wave energy harvesting devices
Pacific Gas and Electric Company, the California utilities company that is advancing theWaveConnect program, a pilot study to test various wave energy converter devices
AWS Ocean Energy, a Scotland-based company that develops ocean energy technology
Aquamarine Power, also in Scotland, this company developed a hydroelectric wave energy converter

6. Despite It’s Expensive Price Now
Wave energy is generally considered to be the most concentrated and least variable form of renewable energy. It is the high power density of wave energy that suggests it has the capacity to become the lowest cost renewable energy source.

7. Harvesting the waves
The World Energy Council has estimated that approximately 2 terawatts (2 million megawatts), about double current world electricity production, could be produced from the oceans via wave power. It is estimated that 1 million gigawatt hours of wave energy hits Australian shores annually and that 25% of the UK's current power usage could be supplied by harvesting its wave resource.
The United States receives 2,100 terawatt-hours of incident wave energy along its coastlines each year, and tapping just one quarter of this potential could produce as much energy as the entire U.S. hydropower system. Oregon and Washington have the strongest wave energy resource in the lower 48 states and could eventually generate several thousand megawatts of electricity using wave resources.2

8. Annual average wave energy flux in kW per metre of wave front

9. How Bad Can It Be? PROS CONS Renewable Environment Friendly
. Abundant and Widely Available
Variety of Ways To Harness
Easily Predictable
. Less Dependency on Foreign Oil Cost
No Damage to Land
Effect on marine Ecosystem
Suitable to Certain Locations
Source of Disturbance for Private and Commercial Vessels
Wavelength
Weak Performance in Rough Weather
Wavelength : Wind power is highly dependent on wavelength i.e. wave speed, wave length, wavelength and water density. They require a consistent flow of powerful waves to generate significant amount of wave power. Some areas experience unreliable wave behavior and it becomes unpredictable to forecast accurate wave power and therefore cannot be trusted as reliable energy source.
Weak Performance in Rough Weather : The performance of wave power drops significantly during rough weather. They must withstand rough weather.( why its so expensive)
Effect on marine Ecosystem : As clean as wave energy is, it still creates hazards for some of the creatures near it. Large machines have to be put near and in the water to gather energy from the waves. These machines disturb the seafloor, change the habitat of near-shore creatures (like crabs and starfish) and create noise that disturbs the sea life around them. There is also a danger of toxic chemicals that are used on wave energy platforms spilling and polluting the water near them.