The growing demands for electricity in the contemporary world, fueled by burgeoning individual and industrial needs, underscores the urgency to optimize the efficiency and reliability of electric power transmission systems. Efficient electricity production and transmission are critical to achieve renewable energy targets.
The Basics of Electricity Transmission
Any power supply system consists of three broad components, namely, generation, transmission, and distribution. Electricity is generated at power plants along with smaller renewable-energy installations. It is then transmitted using a distributed network comprising stations, substations, switches, overhead and underground cables, transformers, among others. The transmission’s efficiency largely depends on the voltage and current; the lower the current and higher the voltage, the more efficient the transmission.
Resistance in Transmission Cables and the Role of AC
Despite their importance, cables used for transmission do have some resistance, which can lead to energy loss. To control this loss, the thickness of the cable can be manipulated; thicker cables lose less energy but incur higher costs. Alternating Current (AC) is the preferred mode for transmission due to its high efficiency and ease of modification using transformers. AC power, where voltage continuously changes polarity causing alternating current flow, is widely used for electricity transmission.
State of Global Electricity Generation Capacity as of May 2023
As of May 2023, the total installed capacity (Fossil Fuel & Non-Fossil Fuel) is 417 GW. Of this, fossil fuel (including Coal) accounts for 56.8%, Nuclear fuel holds 1.60% share, and Non-Fossil fuel comprises 41.4%.
Power Transmission Infrastructure and Substation Network
In power transmission, a three-phase AC circuit is utilized. Each wire carries AC current in different phases. These wires, originating from a power station, are routed to transformers that boost their voltage. The transmission architecture includes safety features such as insulators for surge protection and circuit-breakers for overload protection. Substations of different types facilitate power distribution with each playing a unique role in the system.
Grid Operation and Resilience
Grids, composed of production, transmission, and distribution components, are complex systems essential for electrical power distribution. Grids must be resilient to prevent network-wide failures. They also need to manage voltage levels to meet varying demands and ensure stable and reliable power supply. Storage facilities within grids store surplus electricity, releasing it when demand exceeds supply.
Wide-Area Synchronous Grids and Their Challenges
A wide-area synchronous grid is one where all connected generators produce AC current at the same frequency. These grids lower power costs due to shared resources but necessitate measures to prevent cascading failures in case of a local power supply shutdown. The North Chinese State Grid and India’s national grid are examples of such grids.
The Electric Grid of India
Also known as the National Grid, India’s electric grid is a high-voltage electricity transmission network connecting power stations and major substations nationwide. Owned, maintained, and operated by state-owned corporations, it ensures that electricity generated anywhere in India can be used to meet demand elsewhere. As of 31 May 2023, it is one of the largest operational synchronous grids globally, with an installed power generation capacity of 417.68 GW.
Questions from Previous Year UPSC Civil Services Examination
For reference, here are some questions about renewable energy from previous years’ UPSC Civil Services Examinations:
Prelims Question: “With reference to the Indian Renewable Energy Development Agency Limited (IREDA), which of the following statements is/are correct? (2015)”
Mains Question: “Access to affordable, reliable, sustainable and modern energy is the sine qua non to achieve Sustainable Development Goals (SDGs)”. Comment on the progress made in India in this regard. (2018)”
