Type of Power Plant

Broadly, Power plant loads can be categories into two categories.
1. Base load power plant
2. Peak load power plant

Base load is the minimum amount of power that power producer must make available to its commercial and industrial customers. Base load power plant is an energy plant devoted to the production of base load supply. Base load power plant are the power plant used to meet some or all of given region continuous energy demand and produce energy at a constant rate, usually at low cost relative to other production facilities available to the system. Base load power plant can be categories as below.
1. Coal fired power plant
2. Nuclear power plant
3. Geothermal power plant
4. Waste to energy power plant
5. Biomass power plant

These base load power plant may take many hours, if not days, to achieve a steady power output. On the other hand, they have low fuel costs. Because they require long time to heat up to the operating temperature, these kind of power plant are best suited to handle large amount of continuous base load demand. Coal fired power plants are cycled over the day to meet the demand at a particular time of the day, while output Nuclear power plants run at their peak load generation capacity except at the time of maintenance, refueling etc.

Broadly, Base load power plant do not change their output according to the demand curve since it is economical for them to keep running at a constant output. Therefore, typically these kinds of power plants are large and provide a majority of power used by a grid.

Peak load is define as surge in demand at a particular time period during day. Peak load generally occur during 5 to 10 PM when people return home from offices and switch on the home appliances i.e TV, Air Conditioners, cooking appliances etc. A peak load power plant, also known as Peaker plant, is power plant that generally runs when demand in the Grid system is high. 

Peak load power plants are generally gas based turbine power plants that burn natural gas. Gas turbine plants use the dynamic pressure from flowing gases to directly operate the turbine. Natural gas based power plant can start production of power in a quick time. But the cost involve in these kind of power plant are on higher side of economy. For example, erstwhile Enron company started the work on Enron Dabhol Power Plant (2000-2400MW as MoU signed between Maharashthra Government And Enron) in year 1992 which was fueled by Liquefied Natural Gas(LNG). The cost of the project was exorbitant $3.1 billion in year 1992. Although the official figure was not disclosed by the MSEB, a 10% partner of power plant, it was perceived to be Rs. 8-10 per unit. With such a high rate of generation of power, power plant was very unviable economically.