Power plant

A power plant/power station is an industrial facility that generates electricity.

AC and DC power applications

DC voltages couldn't be easily increased/converted into different voltages (step up) with the technology back then. Transmission lines must always use high voltage (155kV-765 kV) (before being stepped down to customers) to cause lower current flow (Joule heating effect) for efficient transmissions, and lower heat (melt wires and damage insulation) and energy loss. Whereas, lower voltages caused higher current, which caused more heat in wires and more energy loss. Power heat is mathematically represented by Joule's law of heating Iheat = P ∝ I²R, depicting that heat increases by 4x.

So at low DC voltage, current traveled less farther, causing dimmer lights in homes, leading to more power stations being scattered. Thus thick wires were used everywhere to reduce energy loss, and infrastructures were bulky and expensive. 

The introduction of AC power by Nikola Tesla solved this. AC voltage is easily increased/decreased by transformers due to its alternating behavior of changing direction. The frequency it changes is 60 times per second (60 Hz) in North America. 

Power plants' AC voltages are generated by big electromechanical generators (alternators), which convert mechanical energy into electrical energy via electromagnetic induction. A turbine (driven by steam, water, or wind) spins a magnetic field within coils of wire, inducing an alternating current (AC).

Functions

[2.1] Most modern power plants use programmable logic controllers (PLCs) or distributed control system (DCS). The ability to condition monitoring all plant items allows us to know what's running efficiently and what could fails and fix them in advance.

In a control room, a supervisory data acquisition sytem (SCADA) can monitor and control temperature; speed and pumps motors; and open and close valves; which can be useful in burning fossil fuel plants, where precise system control can increase the plant availability (the amount of time a plant can produce electricity in a time interval divided in the time in the period, being often a key Performance Indiactor (KPI), ensuring the most efficient use of the plant to maximize power generation.

[2.1] By tracking which time of a day demand is the highest, plants can adjust pumps' speeds automatically according to the time, which is impossible without automation control systems.

Types

Fossil Fuel Power Plants

Fossil fuel power plants burn fuels to generate heat, produce steam, and spin turbines.

🔹 Coal Power Plants

Burn coal to produce steam

Once the backbone of grids worldwide

Pros: Reliable, steady output (good for “baseload” power)

Cons: High CO₂ emissions, pollution

Hydroelectric power plant

[2.1] A hydroelectric power plant generates power by converting water's forces to turn large generators.

They have 3 types:

1. Impoundement: An impoundement facility often uses stored river water from reservoir's dam. As water is released there, it flows through a turbine to create motion, which activates the generator to create electricity.

2. Diversion: Diversion works like impoundement but without a dam. It channels a part of a riverthrough a canal/penstock.

3. Pumped storage stores its energy uphill to a reservoir at higher elevation. If there's power demand, water is released from elevated resevoir to a lower one, creating electricity if it flows a turbine.

Thermal power plant

[2.1] A thermal power plant generates electricity by converting heat to electricity, often by burning fuels. E.g., Nuclear power plants use reactor heats to turn water to steam, which is sent to a turbine which generates movement of a generator to create electricity.

They work akinly, but IO heating water, the burning coal's heat powers a steam turbine.

Solar power plant

[2.1] A solar power plant uses the Sun's energy to convert into electricity via photovoltatic (PV panels) made of semiconductor cells that release electrons when they're warmed by the Sun. Solar energy is one of the cleanest ways to generate electricity. The panels connect to the grid and used to supplement a thermal power plant resource and be used domestic environments. They can reduce household energy consumption drastically without burning fossil fuel.

Wind power plant

[2.1] A wind power plant or wind turbines receive energy from winds by connecting a generator to their blades, whose rotation movement caused by the winds powers a generator. Wind energy is clean but needs more hardware to work effectively and uses more parts.

References

• [1] Wikipedia

• [2] How does a Thermal power plant work? - Sabin Civil Engineering (YouTube)

  • [2.1] Power Plant Explained | Working Principles - RealPars

• [3]

• [4]