Renewable Energy
Renewable energy is energy derived from naturally replenishing sources that are virtually inexhaustible on human timescales, including solar, wind, hydroelectric, geothermal, and biomass energy. Unlike fossil fuels, renewable sources produce little to no greenhouse gas emissions during operation, making them essential for decarbonising the global energy system. India aims to achieve 500 GW of renewable energy capacity by 2030 under its Nationally Determined Contributions to the Paris Agreement.
Comparison of Major Renewable Energy Sources
| Energy Source | Capacity Factor (%) | CO₂ Emissions (g/kWh) | Land Use (m²/MWh/yr) | India Potential |
|---|---|---|---|---|
| Solar PV | 15–25 | 20–50 | 5.5–16.5 | Very High (748 GW estimated) |
| Wind (onshore) | 25–40 | 7–15 | 72–141 | High (302 GW estimated) |
| Hydroelectric | 35–60 | 4–30 | Low–High | Moderate (145 GW) |
| Geothermal | 80–95 | 15–55 | 0.1–1 | Low (limited zones) |
| Biomass | 50–90 | 230–490 | High | Moderate (17 GW+) |
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Related Terms
Carbon Footprint
A carbon footprint is the total amount of greenhouse gases, primarily carbon dioxide and methane, emitted directly or indirectly by an individual, organisation, event, or product, expressed as CO₂ equivalent (CO₂e). It is a widely used metric to quantify human contribution to climate change, encompassing energy use, transportation, food consumption, and manufacturing processes. Reducing carbon footprints is central to climate mitigation strategies outlined in international agreements such as the Paris Accord.
Sustainability
Sustainability is the capacity to meet the needs of the present generation without compromising the ability of future generations to meet their own needs, as defined in the 1987 Brundtland Commission report "Our Common Future." It integrates three interconnected pillars — environmental protection, social equity, and economic development — often referred to as the triple bottom line. In practice, sustainability science guides policy, urban planning, corporate strategy, and resource management to ensure long-term viability of human and ecological systems.
Ecological Footprint
The ecological footprint measures how much biologically productive land and water area an individual, city, country, or activity requires to produce the resources it consumes and absorb the waste it generates, expressed in global hectares (gha). It is compared against the planet's biocapacity — the actual supply of productive area — to determine whether humanity is living within ecological limits or in overshoot. Developed by Mathis Wackernagel and William Rees in the early 1990s, it is one of the most comprehensive single indicators of human demand on nature.
From Latin "renovare" (to renew, restore) and Old French "energie," from Greek "energeia" (activity, operation), from "en" (in) + "ergon" (work). The concept of harnessing inexhaustible natural forces dates to ancient water mills and windmills, but the term "renewable energy" gained technical currency in the 1970s during the global oil crisis.