Introduction

Sustainable development means meeting present needs without harming the ability of future generations to meet theirs. Electrical energy supports it because it can be produced from renewable sources (in Nepal mainly hydropower, also solar and wind), is clean at the point of use, and can replace imported fossil fuels in almost every end use.

Role through the main areas of utilization

1. Domestic sector

• Electric cooking (induction stoves, rice cookers) replaces LPG, kerosene and firewood, reducing indoor air pollution, deforestation and LPG imports.
• Lighting, refrigeration, water heating and communication raise living standards, health and education (students can study at night, digital learning).

2. Industrial sector

• Electric drives (motors), electric furnaces, arc welding and electrolysis give efficient, controllable, pollution-free production.
• Cement, steel, food processing and textile industries can run on domestic hydropower instead of diesel or coal, creating jobs and adding value locally.

3. Commercial and service sector

• Hotels, hospitals, offices, banks and IT services depend on electricity; tourism (Nepal's key sector) needs reliable supply.

4. Transport (electric traction and e-mobility)

• Electric vehicles, trolley buses, electric railways and cable cars use hydropower instead of imported petroleum, cutting the trade deficit and urban air pollution. Nepal's large EV import growth is an example.

5. Agriculture

• Electric pumps for irrigation, cold storage, agro-processing raise productivity and rural income.

6. Social services

• Water supply pumping, street lighting, health posts, schools and telecommunication need electricity.

Dimensions of sustainability

 Hydro/solar/wind (renewable)
          |
     Electricity
          +--> Domestic    --> living standard
          +--> Industry    --> GDP, jobs
          +--> Transport   --> less oil import
          +--> Agriculture --> food security
          +--> Export      --> revenue

What is needed

• Increase per-capita consumption (still low in Nepal) by promoting electric cooking, EVs and electricity-intensive industry.
• Reliable, quality supply: strong transmission and distribution, reduced losses.
• Efficient utilization: energy-efficient motors, LED lighting, demand side management and suitable time-of-day tariffs.
• Rural electrification through grid extension and micro/mini hydro.

Thus wider and more efficient utilization of clean electrical energy drives economic growth while protecting the environment, which is the core of sustainable development.

Electrical energy is the energy carried by the flow of electric charge, i.e. the work done by electric power over time: $E = P \times t$, measured commercially in kilowatt-hours (kWh, a "unit"). It is produced by converting other forms (hydro, thermal, solar, wind, nuclear), transmitted over lines, and converted back at the consumer into mechanical work (motors), heat, light, sound or chemical energy.

Classes of electrical consumers and their demand

Utilities group consumers by the nature of their use, load pattern and supply voltage. The main classes (also the basis of NEA tariff categories) are:

1. Domestic (residential) consumers

• Loads: lighting, fans, TV, refrigerator, water heater, induction cooker, iron, pumps.
• Demand: small connected load (typically 0.5 to 10 kW), single-phase 230 V (three-phase 400 V for large houses).
• Peak in the evening (about 5 to 10 pm); low load factor (about 10 to 20 %), high diversity.

2. Commercial consumers

• Shops, offices, hotels, hospitals, banks, malls, cinemas.
• Loads: lighting, air-conditioning, lifts, computers.
• Demand: medium; peak during working hours; load factor about 25 to 40 %; supplied at 400 V or 11 kV.

3. Industrial consumers

• Small industries (up to about 50 kW): 400 V three-phase.
• Medium industries (about 50 kW to 1 MW or more): 11 kV.
• Large industries (MW range: cement, steel, paper): 33 kV, 66 kV or 132 kV.
• Loads: motors (largest share), furnaces, welding, electrolysis.
• Demand: large; high load factor (60 to 80 % for continuous-process plants); reactive power demand due to induction motors.

4. Agricultural (irrigation) consumers

• Pumps for irrigation, agro-processing.
• Demand: seasonal (dry season), low load factor.

5. Public services

• Street lighting: night only, fixed hours; predictable load.
• Water supply and sewage pumping: fairly continuous.
• Traction (trolley bus, electric railway, EV charging stations): fluctuating load.

6. Others: temples and religious places, community consumers, government institutions, bulk supply to other utilities.

 Load (MW)
   |           industrial ______________
   |   ____/~~~~~~~~~~~~~\        /\ <- domestic
   |__/                    \______/  \_ evening peak
   +---------------------------------------> hour
   0     6      12      18     24

Knowing each class's demand helps the utility forecast load, size generation and network, set tariffs, and apply demand side management to flatten the evening peak.

Benefits of electrical energy over other sources

1. Easy and cheap transmission: transmitted over long distances by lines; no transport of fuel by truck or pipeline.
2. Easy conversion: readily converted to mechanical (motors), heat (heaters, furnaces), light (lamps), chemical (electrolysis, battery charging) and sound energy.
3. Easy control: switching on/off, speed control of motors, temperature control of heaters are simple, accurate and can be automated or remote.
4. High efficiency at the point of use: electric motors 85 to 97 %, induction heating far better than open flame.
5. Clean: no smoke, ash or fumes at the point of use; silent operation.
6. No storage of fuel needed at the consumer; available instantly at the switch.
7. Flexible: from mW (electronics) to hundreds of MW (smelters) with the same supply.
8. Safe and reliable when properly protected; renewable generation (hydro, solar) makes it sustainable.
9. Economical in Nepal: hydropower is an indigenous resource, while petroleum and LPG are fully imported.

Limitation: cannot be stored cheaply in bulk; generation must match demand instantly.

Electrical power utilization in Nepal by consumer and voltage level

The Nepal Electricity Authority (NEA) supplies consumers in tariff categories according to use and supply voltage.

 Generation (hydro) 11 kV
     | step-up
 Transmission 400 / 220 / 132 kV
     |
 Sub-transmission 66 / 33 kV ---> large industries
     |
 Primary distribution 11 kV  ---> medium industries,
     |                            large commercial
 Secondary 400/230 V ---------> domestic, small
                                industry, commercial,
                                street light, irrigation

Pattern of use. Domestic and industrial consumers together account for most energy sold (roughly comparable shares, each around 40 %), with commercial and others making up the rest (as per NEA annual reports; shares change each year). Domestic load causes a sharp evening peak, while industry gives a steadier base load. Per-capita consumption is still low compared with the world average, so the government promotes electric cooking, EVs and industrial load to use the growing hydropower surplus, especially in the wet season, alongside power export to India.

Significance of classifying consumers

Consumers are grouped (domestic, commercial, industrial, agricultural, street lighting, etc.) because each group has a different load pattern. Classification helps the utility to:

1. Forecast load: each class grows differently; class-wise forecasting is more accurate for generation and network expansion planning.
2. Plan the network and voltage level: domestic loads are fed at 230/400 V, medium industries at 11 kV, large industries at 33 kV and above.
3. Use diversity: different classes peak at different times (industry by day, domestic in evening), so the system maximum demand is less than the sum of individual demands; this reduces the installed capacity needed.
4. Design tariffs: energy and demand charges, time-of-day rates and power-factor penalties are set class-wise to recover cost fairly.
5. Demand side management: targeted programmes (peak shifting for industry, efficient lighting for households).
6. Operation and load dispatch: knowing which classes are on-line helps unit commitment, load shedding priority and reliability (hospitals and water supply get priority).
7. Reactive power and quality planning: industrial motor loads need capacitor compensation; commercial loads produce harmonics.

Factors influencing demand

Residential

• Household size and income; number and type of appliances.
• Weather and season (heating in winter, fans and AC in summer).
• Time of day: evening lighting and cooking peak.
• Electricity price and availability of substitutes (LPG, firewood).
• Urban vs rural location, awareness of efficient appliances (LED, inverter AC).
• Government programmes, e.g. promotion of induction cooking.

Commercial

• Type and size of business (hotel, hospital, mall, office).
• Business hours and occupancy; tourist season.
• Air-conditioning, lighting and lift loads; building design.
• Weekends and holidays; tariff level.

Industrial

• Type of process (continuous, batch) and number of shifts.
• Production level and market demand, economic conditions.
• Rating and efficiency of motors, furnaces and other equipment; power factor.
• Tariff structure (time-of-day, demand charge) and supply reliability; captive generation.
• Automation and technology level.

Power supply structure in industries

An industry receives power from the utility grid at a voltage depending on its size and distributes it internally through substations, switchboards and feeders to motors, heaters and lighting.

   Utility grid 132/66/33/11 kV
            |
     [Metering + CB/isolator]
            |
     [Main step-down transformer]
        33 or 11 kV / 0.4 kV
            |
   ==== Main LV switchboard (PCC) ==== <- capacitor
     |           |           |       |   bank (PFC)
   [MCC-1]    [MCC-2]    [Lighting  [Standby
   motors     motors      DB]        DG set +
    |  |        |  |       |          ATS]
    M  M        M  M     lamps,
                         sockets

Main parts

1. Incoming supply: from the utility at 11 kV (medium), 33 kV or 66/132 kV (large industries), with metering (energy, maximum demand, reactive energy).
2. HV switchgear: isolator, circuit breaker, lightning arrester, protection relays.
3. Main transformer: steps down to 400 V (or 6.6/3.3 kV for large HV motors).
4. Power control centre (PCC) / main LV switchboard: busbars and ACBs/MCCBs feeding sub-boards.
5. Motor control centres (MCC): starters, contactors, overload relays, VFDs for groups of motors.
6. Distribution boards for lighting, sockets and small loads.
7. Power factor correction capacitors (fixed or automatic) at PCC or near motors, to avoid PF penalty.
8. Standby supply: diesel generator with automatic transfer switch (ATS); UPS for critical control.
9. Earthing system and lightning protection.

Radial distribution is used in small plants; ring or duplicate feeders in large or continuous-process plants for reliability.

Possibilities of industrialization in Nepal

Favourable factors (present scenario)

• Surplus hydropower, especially in the wet season; installed capacity has grown rapidly and supply interruptions due to load shedding ended around 2018.
• Raw materials: limestone (cement), agro and forest products, herbs, minerals, water.
• Market access to India and China; growing domestic demand.
• Government policies: Industrial Enterprises Act, special economic zones (SEZs) and industrial estates, investment board, energy-intensive industry promotion.
• Young labour force.

Promising industries

Challenges: weak transmission and distribution at industrial corridors, voltage and reliability problems, dry-season shortage, high tariff and demand charges for some categories, poor road infrastructure, labour issues, policy instability and limited capital.

Measures: dedicated industrial feeders and substations, concessional tariff for energy-intensive industries during the wet season, time-of-day tariffs, improved infrastructure and investment-friendly policies. With these, Nepal can use its hydropower internally for industrial growth instead of relying only on power export.

Electrical energy in Nepal is used mainly in the domestic, industrial and commercial sectors, with smaller shares in irrigation, water supply, street lighting and transport. Since nearly all power comes from hydropower, increasing its use replaces imported petroleum and LPG.

Present areas of utilization

1. Domestic: lighting, fans, TV, refrigerators, rice cookers, water heaters, increasingly induction cooking. Largest number of consumers (over 90 % of all connections) and a large share of energy; causes the evening peak.
2. Industrial: cement, steel rolling, textiles, food and beverage, pharmaceuticals, paper. Mostly motor loads; supplied at 400 V to 132 kV. Second largest (roughly comparable) energy share.
3. Commercial: hotels, shopping centres, hospitals, banks, offices, telecom towers, IT companies.
4. Agriculture/irrigation: electric pumps (shallow and deep tubewells, especially in the Terai), mills.
5. Water supply: drinking water pumping in towns (e.g. Melamchi distribution).
6. Street lighting: municipal lighting in cities and highways.
7. Transport: electric vehicles and charging stations (rapidly growing), cable cars, earlier the Kathmandu trolley bus.
8. Others: temples, community and government institutions.

How to increase or improve consumption

Domestic

• Promote electric cooking (induction stoves) to replace LPG through lower tariff blocks, subsidies and awareness.
• Promote electric water heating and space heating with heat pumps.
• Reliable 24-hour supply and stronger distribution transformers in villages.

Industrial

• Concessional tariffs for energy-intensive industries during the wet (surplus) season.
• Dedicated industrial feeders and substations, reliable supply to SEZs and industrial estates.
• Replace diesel boilers and furnaces with electric boilers, induction and arc furnaces.

Transport

• Expand EV use (tax incentives already exist), public charging stations, electric buses for public transport, electric railway and trolley buses.

Agriculture

• Grid-connected irrigation pumps replacing diesel pumps, cold storage and agro-processing in rural areas.

Commercial

• Electric cooking and heating in hotels and restaurants, data centres, green buildings.

Improving quality of use (efficiency)

• Reduce technical and non-technical losses in transmission and distribution.
• Efficient equipment: LED lamps, high-efficiency motors, VFDs, power-factor correction.
• Demand side management and time-of-day tariffs to flatten the evening peak and use off-peak energy.
• Smart meters for monitoring.

 Surplus wet-season hydro
        |
   +----+-----+---------+----------+
 cooking   industry   EV/transport  export
 (replace  (replace   (replace      (revenue)
  LPG)      diesel)    petrol)

Increasing domestic consumption in these productive ways raises per-capita consumption, reduces the trade deficit and supports economic development.

Electrical energy is the most convenient and widely used form of energy in modern society. Practically every activity, from lighting a home to running a factory or a hospital, depends on it, so per-capita electricity consumption is often used as an index of a country's standard of living and development.

Roles in different areas

1. Domestic life

• Lighting, cooking (induction, microwave), refrigeration, washing machines, water heating, fans and air-conditioning.
• Entertainment and communication: TV, mobile phones, internet.

2. Industry

• Electric drives (motors) run pumps, compressors, conveyors, machine tools, rolling mills; they account for most industrial electricity use.
• Electric heating and melting: arc and induction furnaces, welding.
• Electrochemical processes: electroplating, electrolysis, refining of aluminium and copper.
• Automation, robotics and process control.

3. Commercial and service sector

• Offices, banks, shopping malls, hotels, lifts and escalators, air-conditioning.

4. Transport

• Electric traction: electric railways, metros, trams, trolley buses.
• Electric vehicles and charging infrastructure; airport and port operations.

5. Communication and information technology

• Telephone exchanges, mobile towers, data centres, broadcasting, satellite ground stations. Without electricity, no digital economy is possible.

6. Health care

• X-ray, MRI, ventilators, operating theatres, vaccine refrigeration.

7. Agriculture

• Irrigation pumping, cold storage, food processing, greenhouses.

8. Public services

• Street lighting, traffic signals, water supply and sewage treatment.

9. Education and research

• Computers, laboratories, e-learning.

10. Defence and security

• Radar, communication, surveillance.

Why electrical energy suits modern society

           Electrical energy
   +-------+-----+-----+------+--------+
 Home  Industry Transport  ICT  Health/Agri

Social and economic impact

• Raises productivity, creates employment and drives GDP growth.
• Improves health (clean cooking, hospital equipment) and education.
• Reduces drudgery, especially for women in rural areas.
• With renewable generation, supports climate goals and energy security.

For a country like Nepal with large hydropower potential, increasing electricity use in cooking, industry and transport is a key route to modernisation.

Electrical energy is used by three main consumer groups. In each, a large part of the load is electric drives (motors driving machines), whose type depends on the load's needs.

Domestic use

• Lighting (LED, CFL), fans, TV, computers, refrigerators, washing machines, water pumps, mixers, vacuum cleaners, rice cookers, induction stoves, water heaters, irons.
• Supply: 230 V single-phase (400 V three-phase for large houses).

Features of drives used

• Small fractional-kW motors, mostly single-phase induction motors (capacitor-start, capacitor-run, shaded pole) for fans, pumps, refrigerator compressors.
• Universal (series) motors for mixers, vacuum cleaners, drills: high speed, high starting torque, work on AC and DC.
• BLDC motors in modern ceiling fans and inverter compressors: high efficiency, speed control.
• Requirements: low cost, quiet operation, maintenance-free, reliable.

Commercial use

• Lighting, air-conditioning and heating (HVAC), lifts and escalators, water pumping, refrigeration in shops and hotels, computers and servers, kitchens.
• Supply: 400 V three-phase, or 11 kV for large buildings.

Features of drives used

• Three-phase induction motors for pumps, fans, compressors (simple, robust).
• Lifts and escalators: induction motors with variable-frequency drives (VFD); smooth acceleration, accurate stopping, regenerative braking; earlier DC (Ward-Leonard) drives.
• HVAC with VFDs on fans and pumps for energy saving at part load.
• Requirements: smooth, quiet operation, safety, energy efficiency.

Industrial use

• Machine tools, rolling mills, cranes and hoists, conveyors, pumps, compressors, crushers, textile and paper machines; electric furnaces, welding, electrolysis; lighting.
• Supply: 400 V (small), 11 kV (medium), 33 kV and above (large).

Features of drives used

• Squirrel-cage induction motors: most common; constant-speed loads like pumps, fans, compressors.
• Slip-ring induction motors: high starting torque (cranes, crushers, hoists), speed control by rotor resistance or slip-power recovery.
• Synchronous motors: constant speed, large compressors, power-factor improvement.
• DC motors (series for traction and cranes, shunt for machine tools): wide speed range, now often replaced by VFD-fed induction motors.
• Stepper and servo motors: precise positioning in CNC and robotics.
• Requirements: correct torque-speed match, starting and braking, speed control, duty cycle, overload capacity, protection, efficiency.

Nepal's economically feasible hydropower potential is commonly quoted as about 42,000 to 45,000 MW (theoretical about 83,000 MW), but only a small fraction (a few thousand MW) has been developed. The barriers can be grouped into macro (national/policy/economic level) and micro (project/local level) factors.

Macro factors

1. Policy and institutional instability: frequent changes of government and policies; slow licensing and approval; overlapping authorities (DoED, NEA, Investment Board, ministries).
2. Lack of capital and investment: hydropower is capital intensive; limited domestic capital markets, high interest rates, perceived country risk for foreign investors.
3. Limited market and power trade: small domestic demand, low per-capita consumption; wet-season surplus but dry-season deficit; power trade with India/Bangladesh depends on cross-border agreements and transmission.
4. Weak transmission infrastructure: delays in building transmission corridors, so completed plants cannot evacuate power (spill of energy).
5. Power purchase agreement (PPA) issues: delays and limits on PPAs by NEA, take-or-pay concerns.
6. Geopolitical and regional issues: dependence on neighbouring countries for market and equipment.
7. Lack of integrated water resource and energy planning; preference for run-of-river (ROR) plants, few storage projects, causing seasonal mismatch.
8. Natural factors at national scale: monsoon-dependent flow, climate change, glacier lake outburst floods (GLOF), earthquakes.

Micro factors

1. Land acquisition and compensation disputes; local protests and demands for shares, jobs, royalties.
2. Difficult geography and access: lack of roads to remote sites raises cost and time.
3. Geological problems: weak young Himalayan rock, landslides, tunnelling difficulties; sediment load damaging turbines.
4. Environmental and social issues: forest clearance, resettlement, fish migration, EIA delays.
5. Lack of skilled manpower and local technology; imported equipment, foreign contractors.
6. Contractor and management problems: cost and time overruns (e.g. delays in some large projects).
7. Inadequate hydrological and geological data for design.
8. Local security issues, strikes and bandhs.

Remedies (brief)

One-window approval, stable policy, cross-border transmission and export agreements, more storage and pumped-storage projects, domestic investment through public shares, better local benefit sharing and timely transmission construction.

Electrical energy plays a central role in almost every activity of modern life, and its advantages over other forms of energy (coal, oil, gas, firewood, direct mechanical power) are the reason it is chosen for most applications.

Roles of electrical energy

1. Industry: electric drives for machines, furnaces, welding, electrolysis, automation; industrial production depends on reliable power.
2. Domestic: lighting, cooking, heating, cooling, appliances, communication.
3. Commercial: offices, hotels, hospitals, banks, lifts, air-conditioning, IT.
4. Transport: electric railways, metros, trolley buses, electric vehicles.
5. Agriculture: irrigation pumps, processing, cold storage.
6. Communication and IT: telecom, internet, broadcasting.
7. Public services: water supply, street lighting, health and education.
8. Economic development: per-capita electricity use is closely linked with GDP and human development.

Advantages over other forms, by application

General advantages

• Transmission: carried over long distances by wires, unlike coal or oil transport.
• Control: simple and precise, suitable for automatic and remote control.
• Conversion: easily into any other form.
• Cleanliness: no smoke, ash or flue gases at the point of use.
• Efficiency: high conversion efficiency at the load.
• Safety and convenience: no fuel storage, no fire hazard from fuel handling.
• Renewable generation: hydro, solar, wind make it sustainable; for Nepal it reduces imported fuel.

Limitation: bulk storage is costly, and failure of supply stops all dependent activities, so a reliable supply system is essential.

Electrical energy is a basic infrastructure for national development: industries, services, transport, health and education all depend on it. A rise in per-capita electricity consumption usually goes with a rise in GDP and living standard.

Roles of electrical energy in developing a country

1. Industrialisation: powers motors, furnaces, welding, electrolysis and automation, enabling manufacturing and value-added products (cement, steel, food processing) and creating jobs.
2. Agricultural growth: electric irrigation pumps, cold storage, agro-processing raise productivity and farmers' income.
3. Better living standards: lighting, clean cooking, refrigeration, water supply and appliances improve health and comfort.
4. Education and health: lighting for study, computers, e-learning; hospital equipment and vaccine storage.
5. Transport: electric vehicles, railways and trolley buses reduce petroleum imports and urban pollution.
6. Communication and IT: mobile networks, internet, data centres support banking, e-governance and the service economy.
7. Commerce and tourism: hotels, offices, shopping centres, airports.
8. Rural development: rural electrification (grid and micro-hydro) brings small industries and reduces migration to cities.
9. Foreign exchange: for Nepal, export of surplus hydropower earns revenue and reduces the trade deficit; domestic use replaces imported LPG and petroleum.
10. Environment: clean renewable electricity reduces deforestation and greenhouse gas emissions.

  More electricity --> industry, agriculture, services
         |                       |
         v                       v
  jobs + income  ---->  higher GDP, better health,
                        education  ---> development

Benefits of electrical energy over other forms

Limitation: cannot be stored economically in large quantity; generation must follow demand continuously.

Electrical energy is preferred over other forms (fuel, steam, direct mechanical, chemical) in most applications because it is easy to transmit, convert and control, and is clean at the point of use.

General advantages

1. Easy transmission and distribution: by overhead lines and cables over long distances at low cost; no transport of coal or oil.
2. Easy conversion to mechanical, heat, light, chemical and sound energy.
3. Simple and precise control: switching, speed and temperature control, automation and remote control.
4. High efficiency at the point of use.
5. Cleanliness: no smoke, ash, fumes; better working environment.
6. No storage of fuel needed by the user; always ready.
7. Compact equipment, low maintenance, long life.
8. Safety when properly installed and protected.
9. Generation from renewable sources (hydro, solar, wind).

Advantages in different applications

1. Electric drives (motive power)

• Motors are available from fractions of a watt to many MW, start instantly, can be reversed and braked (including regenerative braking) and speed-controlled easily.
• No fuel, exhaust or warm-up; compact and quiet. Compared with steam or diesel engines: higher efficiency, lower maintenance, suitable for automation.

2. Electric heating

• Accurate and automatic temperature control, uniform heating, high efficiency.
• Heat can be produced inside the material (induction, dielectric), useful for melting, hardening, drying wood and plastics.
• No contamination of the product by combustion gases; clean furnaces.

3. Electric welding

• Arc and resistance welding are faster, give strong joints, and are easier to control and automate than gas welding.

4. Electric traction

• High starting torque and acceleration, regenerative braking, no smoke in tunnels and cities, lower maintenance and running cost than steam or diesel locomotives.

5. Lighting

• Electric lamps are bright, safe, efficient and controllable compared with oil lamps or gas lighting.

6. Electrochemical processes

• Electrolysis, electroplating, electro-refining (aluminium, copper) are only practical with electricity.

7. Communication and electronics

• All modern communication and computing need electricity.

Limitation: bulk storage is difficult and supply failure stops all work; a reliable grid is needed.

Electrical consumers are classified according to the purpose of use, size of load and supply voltage. Each class has a typical demand pattern, load factor and peak time, which the utility uses for planning and tariff setting.

Classes of consumers

1. Domestic (residential)

• Loads: lights, fans, TV, refrigerator, water heater, cooker, iron, pumps.
• Demand: small (about 0.5 to 10 kW); 230 V single-phase or 400 V three-phase.
• Peak in the evening; low load factor (about 10 to 20 %); high diversity among households.

2. Commercial

• Shops, offices, hotels, restaurants, hospitals, cinemas, banks.
• Loads: lighting, air-conditioning, lifts, computers.
• Demand: medium; peak during business hours; load factor about 25 to 40 %; 400 V or 11 kV.

3. Industrial

• Small-scale (up to about 50 kW, 400 V), medium-scale (about 50 to 1000 kW, 11 kV), large-scale (above about 1 MW, 33 kV and above).
• Loads: motors, furnaces, welding, electrolysis, lighting.
• Demand: large and steady; high load factor (60 to 80 % for multi-shift plants); needs reactive power, so power-factor correction.

4. Agricultural (irrigation)

• Pumps, threshers, mills. Seasonal, mostly daytime; low load factor (about 15 to 25 %).

5. Street lighting

• Fixed night-time load (dusk to dawn); load factor about 40 to 50 %; predictable.

6. Public utilities and others

• Water supply and sewage pumping (fairly continuous), traction and EV charging (fluctuating), temples, community, government institutions, bulk supply.

Comparison of demand

 kW
  |                          domestic
  |      commercial _____     /\
  |   industrial ___/~~~~\___/  \__
  |__/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  +-------------------------------- hour
  0     6     12     18     24

Because the classes peak at different times, the diversity factor of the system is greater than 1, so the generating capacity required is less than the sum of the individual maximum demands. The values above are typical textbook ranges and vary from system to system.

Electrical energy is used in domestic, commercial and industrial sectors. The supply voltage increases with the size of the load: small loads at low voltage (LV), larger loads at medium (MV) or high voltage (HV), to keep current and losses low. Voltage levels given below are those used in Nepal (NEA).

Domestic use

Examples:

• Lighting: LED, CFL lamps.
• Heating: water heater, room heater, electric iron, induction cooker, rice cooker.
• Motors: fans, mixer-grinder, washing machine, water pump, refrigerator compressor.
• Electronics: TV, computer, mobile chargers, internet routers.

Voltage: 230 V single-phase, 50 Hz; houses with large load (over about 10 kW) may get 400 V three-phase.

Commercial use

Examples:

• Lighting and signboards in shops, offices, malls.
• Air-conditioning, ventilation, refrigeration (cold stores, supermarkets).
• Lifts and escalators, water pumps.
• Computers, servers, ATMs; hospital equipment (X-ray, MRI); commercial kitchens in hotels.

Voltage: 400/230 V three-phase for most; large buildings (hotels, malls, hospitals) take 11 kV with their own transformer.

Industrial use

Examples:

• Electric drives: pumps, compressors, conveyors, cranes, machine tools, rolling mills, crushers.
• Electric heating: arc and induction furnaces (steel), resistance ovens, dielectric heating.
• Welding: arc, resistance welding.
• Electrochemical: electroplating, electrolysis, battery charging.
• Process control, lighting.

Voltage:

• Small industries (workshops, mills): 400 V three-phase.
• Medium industries: 11 kV.
• Large industries (cement, steel): 33 kV, 66 kV or 132 kV.
• Large motors inside a plant may run at 3.3 kV, 6.6 kV or 11 kV.

Summary table

 Grid 132/66/33 kV --> large industry
     |
   11 kV ------------> medium industry, big commercial
     |
  400/230 V ---------> homes, shops, small industry