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renewable

/rɪˈnuːəbl/·adjective

drawn from a source that nature replenishes faster than it is used
Fig. 1 — Two power sources share one afternoon.
01Definition

Renewable describes a resource that nature refills on a human timescale — sunlight, wind, flowing water, heat from the ground, wood if it is regrown. The contrast is with a stock: coal and oil took millions of years to form, so every tonne burned is gone from the account. Renewable sources behave like a flow instead: tomorrow brings more wind whether or not today's was used. The word also keeps a plainer life in contracts and passports, where renewable means simply able to be renewed when it expires.

02In use
  • iDenmark now draws most of its electricity from renewable sources.
  • iiFirewood is renewable only if the forest is replanted as fast as it is cut.
  • iiiThe licence is valid for three years and renewable on request.
03Collocations
  • renewable energy
  • renewable sources
  • invest in renewables
  • renewable resources
  • 100% renewable

Family renew (verb) · renewal (noun) · renewables (plural noun)

04Relations

=replenishable, regenerating, green, clean, self-replenishing

≠finite, non-renewable

06TOEFL & IELTS

Environment prompts are this word's home ground: renewable energy/sources/resources, 'a shift to renewables', 'non-renewable fossil fuels' — the standard furniture of a Task 2 energy paragraph. Note the noun trick English allows: renewables, plural, means the sources themselves ('investment in renewables rose'). Four syllables with stress on -new-, rih-NEW-uh-bul (British rih-NYOO-). Keep it distinct from sustainable: renewable is about the source refilling, sustainable about the whole practice lasting.

07Asked
What does renewable mean in renewable energy?
That the source refills naturally at least as fast as we draw on it: sun, wind, water, geothermal heat, and regrown biomass. The scene above draws the distinction as two meters — the coal meter slides one way to empty, while the wind meter dips and refills all afternoon. Renewable is a claim about the source, not about the technology being clean, cheap, or well sited.
What is the difference between renewable and non-renewable resources?
Timescale. Non-renewables — coal, oil, natural gas, uranium — formed over millions of years, so on any human horizon the stock only shrinks. Renewables are flows: today's wind and sunlight arrive whether or not yesterday's were captured. The practical consequence is scarcity logic — a non-renewable resource can be used up, while a renewable one can only be under-harvested or over-harvested.
Is nuclear energy renewable?
Conventionally no: uranium is mined and finite, so nuclear is classed as non-renewable even though it is low-carbon — a reminder that renewable and clean are different labels. The picture has arguments at the edges (breeder reactors stretch fuel enormously; seawater uranium is debated), so careful writing says nuclear is low-carbon but not renewable rather than lumping it in either camp.
Is wood or biomass renewable?
Conditionally — and the condition is the whole point. Wood counts as renewable if forests are replanted and regrow at the rate they are cut; harvest faster than that and the same fuel becomes a shrinking stock. That is why 'renewable' claims for biomass are audited by regrowth rates and why the same firewood can be renewable in one country's forestry system and not in another's.
What does 'renewables' mean as a noun?
The renewable sources themselves, treated as a plural noun: 'renewables now supply a third of demand', 'investment in renewables'. English does this with a handful of adjectives (valuables, disposables), and in energy journalism it is now the default shorthand. Handy for Task 1 reporting, where 'renewables overtook coal in 2020' is shorter and sharper than any full paraphrase.
Does renewable always mean environmentally friendly?
No — a renewable source can still be harvested destructively, sited badly, or built at a heavy carbon cost. Hydropower floods valleys, poorly managed biomass can emit more than it saves, and a wind farm still has to be built out of steel and concrete.