Introduction to Renewable Generation
Renewable generation includes sources of energy that renew themselves constantly through natural processes and will never run out during normal human time-scales. Renewable energies come from three primary sources: the Sun, heat from the inner Earth, and tidal power. The Sun, in turn fuels the wind and, indirectly, most biomass resources.
Concentrated Solar Power Efficiencies
Concentrated solar power (CSP) collects sunlight over a large surface area and relies on mirrors to concentrate the solar radiation into a small area to produce heat. The heat, in turn, is used to drive a steam boiler and turbine to produce power. There are four different CSP systems with different efficiencies.
|Linear Fresnel System||8 to 12%|
|Parabolic Trough||14 to18%|
|Power Tower||14 to 19%|
|Dish sterling||18 to 23%|
Solar Photovoltaic Efficiencies
Solar radiation may also be converted directly to produce electricity (photovoltaic or PV effect). Solar energy is of major importance because it is non-polluting and renewable. At the same time, the price of solar PV power systems have fallen 65% in the 5 year period 2010 to 2014, and are expected to continue to fall significantly. The efficiency values of PV modules is a function of the materials used. The measured efficiency is defined as the ratio of the electrical energy produced by the modules to the energy of the incident solar radiation striking the plane of array. The numbers reported below define the range for commercially available modules, plus the best research efficiency by type.
|Monocrystalline PV Modules||17 to 21%
|Policrystalline PV Modules||14 to 18%
|Thin Film PV Modules||12 to 16%
Wind Turbine Efficiencies
Wind turbines start operating or cut-in at wind speeds of 3-5 metres per second (m/s) and reach maximum power output at around 12-15 m/s, where output levels off. At very high wind speeds, around 25 m/s, wind turbines shut down or cut-out. A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs depending on the wind speed and the shape of the turbine power curve. As a result, wind turbines have a wide efficiency range.
|Large Wind Turbine||Up to 45%|
Hydro Turbine Efficiency
Hydroelectric power station performance depends on the type of water turbine…be it large or micro-power plants. Hydroelectric capacity is normally applied to peak-load demand, because it is so readily stopped and started, except in countries where there is an abundant hydro resource for baseload demand. Hydro is among the most efficiency generation sources. The conversion process captures kinetic energy and converts it directly into electric energy. There are no inefficient intermediate thermodynamic or chemical processes and no heat losses.
|Large Hydro Power Plant||Up to 95%|
|Small and Micro Hydro Power Plants||Up to 90%|
|Tidal Power||Up to 90%|