Hydro & Ocean

Top countries developing Hydro power (IPCC)

Hydro power generation is the most extensively used renewable source, converting flowing or falling water to kinetic energy via turbines and then to electricity via generators. It advantages compared to other renewable sources due to the availability of continuous electricity production and energy storage. Based on the facility type hydro power is classified to two different types:
1.Run off river: Hydro power exploits the natural flow of a river and by controlling a portion of the river flow through a channel/pipe adjusted with a turbine the turbine is then forced to rotate producing kinetical energy.
2.Reservoir hydropower: A dam is manufactured to control the flow of the water from a differential height. The water then led to flow downstream through a turbine. Pumps are connected to recycle the falling water back to the reservoir tank, leading to a continuous electricity production.

 

Three gorges dam yagtze river China 18GW

Applying the reservoir hydropower technology can be eligible for energy storage whereas pumped hydro power generator consists of two reservoirs (upper and lower), pump turbine, motor generator set and connection lines. At off demand meets the supply. Then the water flows through a hydraulic turbine driving an electric generator.

PROS
-Continuous and reliable power production
-Eligible for energy storage/ back up load for high demand times
-Simple methodology and high efficiency
CONS
-Depending on the size of the plant Impacts on habitat areas of people and livestock, landscape and biodiversity of the location

 

OCEAN POWER

Sihwa Tidal Power

Tidal power is a highly predictable energy source but variable. Tidal range is the difference between high and low tide and the concept of tidal Power generation is based on altering the oscillation of the basin water level. This can be achieved by building barriers or dams where the water flow is controlled. Gateways or pumps increase the water`s kinetic energy which generates an adjusted turbine producing mechanically power. Tidal power can be obtained using tidal barrages or dams, tidal lagoons, tidal fences and tidal turbines in higher water deep levels designed to operate in both flow dimensions
Examples
-La Rance Power station – 240 MW (1966)
-Sihwa – 254MW (2011)
Open sea currents such as the Gulf Stream are explored for development.

PROS
-Predictable energy cost
-Utilizes both dimensional current flows

CONS
-Environmental concerns (wildlife trapping)
-In some locations high impact on landscape
-Suitable Locations are rare (100 on the planet, 50 may be used)
-In the sea water high corrosion of the turbines, high maintenance cost

Palamis Wavepower

Wave Power: Wave movement consist of wide range of frequencies and amplitudes complicating the utilization of wave energy. Nevertheless there are more than 50 proposed methods of utilizing wave power where most of them are at early experimental stage. Some examples of applied wave power generating devices are: Coast attached oscillating water column device (Portugal 1999) where water as a piston is used to push air column through a turbine, while the most impressive wave power extracting device is Palamis wavepower device (750 kW, Portugal) which floats allowing wave snake-like movement, while connected to a cable converting kinetic energy to electric power.
The most recent wave power projects are:
-Oyster (EMEC , 2009)
-Waveroller (Portugal 2012)

PROS
-Potentially vast reserves

CONS
-Early development stage
-Expensive capital cost

Both Wave and Tidal Energy are at early development stage due to the ineffectiveness on capital cost.