Definition
Energy efficiency — the cheapest energy is the energy not used
Energy efficiency encompasses all measures that reduce the amount of energy needed to deliver a given service. It is consistently the cheapest form of "energy supply" — every unit of energy saved avoids the cost of generating, transmitting, and distributing that unit. The IEA calls energy efficiency the "first fuel."
40%
Share of clean energy progress needed from efficiency (IEA NZE)
36%
Energy intensity improvement pledged at COP28 by 2030
$0.03
Approximate cost of saving 1 kWh via efficiency vs $0.10+ to generate it
~30%
Global building energy that could be saved with known technologies (IEA)
Sector by sector
Energy efficiency across buildings, industry, and transport
Buildings (largest opportunity):
Buildings consume approximately 40% of global energy (IEA 2023). Key measures: insulation (reducing heating/cooling loads by 40–80%), efficient glazing (triple-pane windows), heat pumps (deliver 3 units of heat per 1 unit of electricity consumed, vs 0.85–0.95 for gas boilers), LED lighting (80% less energy than incandescent), building energy management systems. India's Energy Conservation Building Code (ECBC) mandates efficiency standards for commercial buildings >500 m². India's BEE (Bureau of Energy Efficiency) star ratings for appliances (ACs, refrigerators, fans) have driven significant efficiency improvements — India's 5-star ACs use approximately 50% less electricity than 1-star models. Source: IEA Buildings · BEE India Annual Report 2023.
Buildings consume approximately 40% of global energy (IEA 2023). Key measures: insulation (reducing heating/cooling loads by 40–80%), efficient glazing (triple-pane windows), heat pumps (deliver 3 units of heat per 1 unit of electricity consumed, vs 0.85–0.95 for gas boilers), LED lighting (80% less energy than incandescent), building energy management systems. India's Energy Conservation Building Code (ECBC) mandates efficiency standards for commercial buildings >500 m². India's BEE (Bureau of Energy Efficiency) star ratings for appliances (ACs, refrigerators, fans) have driven significant efficiency improvements — India's 5-star ACs use approximately 50% less electricity than 1-star models. Source: IEA Buildings · BEE India Annual Report 2023.
Industry (hardest to decarbonise):
Industry consumes approximately 37% of global energy (IEA 2023). Steel, cement, chemicals, and aluminium are the most energy-intensive. Key efficiency measures: process heat recovery (capturing waste heat from furnaces), motor efficiency (premium efficiency motors use 3–5% less electricity than standard — trivial per motor but huge at scale since motors consume approximately 45% of all electricity globally), variable speed drives (reducing pump/fan energy by 30–60%), and energy management systems. India's Perform Achieve and Trade (PAT) scheme sets energy intensity targets for 13 large industries — trading energy saving certificates between over- and under-achievers. Source: BEE India PAT scheme reports.
Industry consumes approximately 37% of global energy (IEA 2023). Steel, cement, chemicals, and aluminium are the most energy-intensive. Key efficiency measures: process heat recovery (capturing waste heat from furnaces), motor efficiency (premium efficiency motors use 3–5% less electricity than standard — trivial per motor but huge at scale since motors consume approximately 45% of all electricity globally), variable speed drives (reducing pump/fan energy by 30–60%), and energy management systems. India's Perform Achieve and Trade (PAT) scheme sets energy intensity targets for 13 large industries — trading energy saving certificates between over- and under-achievers. Source: BEE India PAT scheme reports.
Transport:
Transport consumes approximately 28% of global final energy. The EV transition is the primary efficiency driver — EVs convert approximately 85–90% of input electricity to motion vs 25–30% for internal combustion engines. At the grid level, an EV charged from solar electricity has a well-to-wheel efficiency of approximately 25–30% vs 14–20% for a petrol car. Aviation fuel efficiency: modern aircraft (Boeing 787, Airbus A350) use approximately 20–25% less fuel per seat than their predecessors. Shipping: slow steaming (reducing vessel speed from 25 to 18 knots reduces fuel consumption approximately 50%). Source: IEA Transport · ICAO aircraft emissions.
Transport consumes approximately 28% of global final energy. The EV transition is the primary efficiency driver — EVs convert approximately 85–90% of input electricity to motion vs 25–30% for internal combustion engines. At the grid level, an EV charged from solar electricity has a well-to-wheel efficiency of approximately 25–30% vs 14–20% for a petrol car. Aviation fuel efficiency: modern aircraft (Boeing 787, Airbus A350) use approximately 20–25% less fuel per seat than their predecessors. Shipping: slow steaming (reducing vessel speed from 25 to 18 knots reduces fuel consumption approximately 50%). Source: IEA Transport · ICAO aircraft emissions.
Electricity grid efficiency:
Transmission and distribution (T&D) losses in India average approximately 18–20% (CEA 2023) — compared to approximately 6% in the UK and 5% in Germany. India's high T&D losses are the result of ageing infrastructure, theft (non-technical losses), and long transmission distances from coal-belt generation to coastal/southern demand. Reducing India's T&D losses to European levels would be equivalent to building approximately 80 GW of new generation. The National Smart Grid Mission (NSGM) targets smart meters for 250 million consumers by 2025. Source: CEA India Annual Report 2023 · NSGM India.
Transmission and distribution (T&D) losses in India average approximately 18–20% (CEA 2023) — compared to approximately 6% in the UK and 5% in Germany. India's high T&D losses are the result of ageing infrastructure, theft (non-technical losses), and long transmission distances from coal-belt generation to coastal/southern demand. Reducing India's T&D losses to European levels would be equivalent to building approximately 80 GW of new generation. The National Smart Grid Mission (NSGM) targets smart meters for 250 million consumers by 2025. Source: CEA India Annual Report 2023 · NSGM India.
Questions
Questions about energy efficiency
What is the "rebound effect" and does it undermine energy efficiency?
The rebound effect (also called the Jevons Paradox, after William Stanley Jevons who described it for coal in 1865) occurs when improved energy efficiency makes energy services cheaper, which causes people to consume more of them — partially or completely offsetting the efficiency gain. Example: LED lights use 80% less electricity, so people install more lights and leave them on longer. More fuel-efficient cars are driven more miles. More efficient factories produce more goods. The "direct rebound" for household energy services is estimated at 10–30% (i.e., a 30% efficiency improvement results in 21–27% net energy savings after rebound). The "economy-wide rebound" through GDP growth effects can exceed 100% (called "backfire") in rapidly industrialising economies. India, where access to energy services is still expanding rapidly, likely experiences higher rebound than advanced economies. However, the consensus view (IEA, IPCC AR6) is that rebound does not eliminate the net savings from efficiency improvement — it reduces them. Source: IPCC AR6 WG3 Chapter 9 · IEA Energy Efficiency Indicators.
Why does India have such high transmission and distribution losses?
India's T&D losses of approximately 18–20% (CEA 2023) are among the highest of any major economy. The causes are: (1) Technical losses: Long transmission lines from coal-rich states (Jharkhand, Odisha, Chhattisgarh, MP) to distant load centres (Mumbai, Delhi, Bangalore) cause significant resistive losses. Ageing transformers and conductors with higher resistance than modern equipment. (2) Non-technical losses (theft): Estimated at approximately 8–10% of total T&D losses — illegal hook-ups, meter tampering, billing irregularities. This is particularly prevalent in agricultural connections where flat-rate or heavily subsidised tariffs reduce the incentive to meter accurately. (3) Poor metering: Many rural and agricultural feeders in India are un-metered, making loss measurement itself impossible. (4) DISCOM financial stress: India's state electricity distribution companies (DISCOMs) are financially weak — their aggregate losses were approximately ₹75,000 crore in 2021–22 (Ministry of Power). Financially stressed DISCOMs defer infrastructure investment. The RDSS (Revamped Distribution Sector Scheme, approved 2021, ₹3.03 lakh crore) aims to reduce AT&C losses to below 12% by 2025. Source: CEA India · Ministry of Power RDSS documentation 2021.
Provenance
Attribution and citation
- Sources
- IEA Energy Efficiency 2024 · BEE India Annual Report 2023 · CEA India Annual Report 2023 · IPCC AR6 WG3 · Ministry of Power India RDSS
- Cite as
- "Energy Efficiency — Demand-Side Management · The Energy Codex", The Energy Codex, https://thecodex.expert/energy/efficiency/, last updated .