The installed capacity, or ICAP, of a power system represents the maximum capacity that the system is designed to run at. It’s also known as “peak installed capacity” or “rated capacity.” For example, for a hydroelectric plant it refers to the maximum runoff that can be constantly maintained and utilized by the equipment at the plant. For wind turbines, it describes how much electricity can be generated by a turbine in optimal wind conditions. As with other forms of electricity generation, the installed capacity is typically measured in megawatts (=1 million watts). So a power plant with 10 MW of installed capacity produces 10MW at any instance of time.
Since conditions related to the natural resource that serve as the basis for renewable power fluctuate — the sun shines and the wind blows sometimes, and sometimes not — the actual power generated will be less than optimal at some times. This is less than the “installed capacity.”
Some further ideas to explore on Installed Capacity
See if you can find the rated capacity for an electrical appliance in your home.
Determine the total MW of installed capacity of wind power on the island of Ireland in a particular year, and the total actual energy generated by wind power for that same year.
Exploring Green Technology, “Installed Capacity Definition.” exploringgreentechnology.com/glossary/installed-capacity-definition/
US Energy Information Administration, “Generator nameplate capacity (installed),” www.eia.gov/tools/glossary/index.cfm?id=G#gen_nameplate
Winds-Energy Blog, “History of Wind Energy,” winds-energy.blogspot.com/search/label/History%20of%20Wind%20Energy