Question

Power generation plant based on energy of natural gas

Answer 1

Answer:

There are two types of natural gas power plants: Simple cycle gas plants and combined cycle gas plants. The former consists of a gas turbine connected to a generator and the latter consists of a simple cycle plant, combined with another external combustion engine, operating on the Rankine cycle—hence its name "combined cycle".

The simple cycle is simpler but less efficient than the combined cycle. However, simple cycle plants are able to dispatch faster than coal-fired power plants or nuclear plants. This means they can be turned on or off faster in order to meet societies electricity needs.[4] Often needed on the grid with wind power and solar power, its purpose is to meet the fluctuating electricity needs of society, known as peaking power. Combined cycle plants are more efficient because it makes use of the hot exhaust gases that would otherwise be dispelled from the system. These exhaust gases are used to boil water into steam—which can then spin another turbine and generate more electricity. The thermal efficiency of the combined cycle can get up to 60%.[5] Moreover, these plants produce one third of the waste heat of a plant with a 33% efficiency (like a typical nuclear power plant or an older coal power plant). See the thermal efficiency page for more information on this.

The cost of a combined cycle plants is generally higher since they cost more to build and run. The EIA estimated that for a simple cycle plant the cost is about US$389/kW, whereas combined cycle plants are US$500-550/kW.[6]

The use of natural gas accounts for around 23% of the world's electricity generation (see the data visualization below). This is second only to coal, and the fraction that is natural gas is expected to grow in coming years. This means that natural gas's contribution to climate change will continue to grow.