Short answer: Energy and the environment recur constantly in IELTS Writing and Speaking, so precise words such as renewable, intermittent, decarbonisation and the grid are one of the quickest ways to lift your Lexical Resource band. The 30 words below include meanings, natural collocations and example sentences you can adapt straight into an answer.
Energy is one of the most dependable IELTS themes, feeding prompts on climate change, pollution, transport, government spending and how countries should power their future.
Because the subject recurs so often, the vocabulary is worth preparing in advance — and a candidate who reaches for renewable, decarbonisation and intermittent supply instead of "green power", "cutting carbon" and "not always available" reads at once as a higher-band writer.
This guide gives you 30 genuine Band 7+ renewable energy words, each with the collocation that makes it usable and an example sentence in an essay-style context.
Why topic vocabulary lifts your Lexical Resource band
In both Writing and Speaking, Lexical Resource is one of four marking criteria, each carrying equal weight — so it accounts for a full quarter of your mark on those papers.
The public band descriptors are explicit that reaching Band 7 requires "a sufficient range of vocabulary to allow some flexibility and precision" and the use of "less common lexical items… with some awareness of style and collocation", as set out in the official IELTS Writing Task 2 band descriptors.
Preparing topic vocabulary in advance is the most efficient way to reach that standard, because a predictable subject lets you plan precise language rather than improvise under pressure.
The honest caveat is that the descriptors reward accurate use, not decoration. A less common word dropped into the wrong collocation ("produce a clean energy", "a big dependence of oil") reads as reach without control and can pull your band down rather than up.
That is why every entry below is paired with its natural partners — the collocation is the unit to learn. For a structured month of building this kind of active, in-context vocabulary across topics, follow our 30-day vocabulary plan.
30 Band 7+ renewable energy words
Read down the table for the meaning, then across to the collocation and example — the example shows the word doing the job it would do in a real answer.
| Word | Meaning | Collocation / common usage | Example sentence |
|---|---|---|---|
| renewable | (of energy) drawn from sources that are naturally replenished | renewable energy, renewable sources | Renewable energy from wind and sunlight now supplies a growing share of electricity. |
| photovoltaic | converting sunlight directly into electricity | photovoltaic panels, photovoltaic cells | Falling prices for photovoltaic panels have put solar power within reach of ordinary households. |
| turbine | a machine that converts the movement of wind or water into electricity | wind turbine, drive a turbine | A single modern wind turbine can power hundreds of homes. |
| grid | the network that distributes electricity across a region or country | the national grid, feed into the grid | Surplus solar power can be fed back into the national grid for others to use. |
| intermittent | occurring at irregular intervals rather than continuously | intermittent supply, intermittent generation | The intermittent nature of wind power makes reliable storage essential. |
| baseload | the constant minimum level of electricity a grid must always supply | baseload power, baseload demand | Critics argue that renewables alone cannot yet meet baseload demand. |
| decarbonisation | the process of reducing carbon emissions from the energy system | decarbonisation of the economy | The decarbonisation of the electricity supply is the first step towards net zero. |
| geothermal | (of energy) derived from the natural heat within the earth | geothermal energy, geothermal power | Iceland meets much of its heating needs with cheap geothermal energy. |
| hydroelectric | (of power) generated from the force of flowing water | hydroelectric dam, hydroelectric power | A hydroelectric dam can supply clean power for decades once it is built. |
| capacity | the maximum amount of power a plant or system can generate | generating capacity, installed capacity | The country has doubled its installed solar capacity in just five years. |
| subsidy | financial support given by a government to encourage an activity | government subsidy, renewable subsidies | Generous subsidies helped the offshore wind industry become established. |
| feed-in tariff | a guaranteed payment to small producers of renewable electricity | a feed-in tariff, offer a feed-in tariff | A feed-in tariff rewards households that generate more electricity than they use. |
| storage | the retention of generated energy for later use, typically in batteries | energy storage, battery storage | Cheaper battery storage is the key to using solar power after dark. |
| biomass | organic material such as wood or crop waste burned as fuel | biomass energy, biomass boiler | A biomass boiler can heat a building using waste wood from local forestry. |
| carbon-neutral | producing no net addition of carbon dioxide to the atmosphere | carbon-neutral, become carbon-neutral | The company aims to make its factories carbon-neutral within a decade. |
| emissions | gases, especially carbon dioxide, released into the atmosphere | carbon emissions, cut emissions | Switching to renewables sharply cuts the emissions produced by generating power. |
| sustainable | able to be maintained long-term without depleting resources | sustainable energy, sustainable supply | A sustainable energy supply must not rely on fuels that will eventually run out. |
| dependence | reliance on a particular source or supplier | dependence on fossil fuels, energy dependence | Investing in solar power reduces a nation’s dependence on imported fuel. |
| transition | the gradual process of changing from one system to another | energy transition, transition to renewables | The transition to renewables will reshape the labour market as well as the grid. |
| efficiency | the ratio of useful energy produced to the energy put in | energy efficiency, improve efficiency | Improving the energy efficiency of homes reduces the demand that renewables must meet. |
| offshore | located at sea, away from the coast | offshore wind farm, offshore turbines | Offshore wind farms catch stronger, steadier winds than those built on land. |
| viable | capable of working successfully in practice | commercially viable, a viable alternative | Solar power is now a commercially viable alternative to gas in many regions. |
| harness | to capture and put to use a natural source of energy | harness solar power, harness wind energy | Coastal nations are racing to harness the energy of the tides. |
| output | the amount of energy or power that a source produces | energy output, power output | The output of a solar farm falls sharply on cloudy days. |
| clean | (of energy) producing little or no pollution | clean energy, clean technology | Investment in clean energy has accelerated as the cost of pollution becomes clear. |
| decentralised | distributed across many small sources rather than one central plant | decentralised generation, decentralised grid | A decentralised grid of rooftop panels is harder to disrupt than a single power station. |
| retrofit | to fit an existing building with new, more efficient systems | retrofit homes, energy retrofit | Grants are available to retrofit older homes with insulation and heat pumps. |
| carbon capture | technology that traps carbon dioxide before it reaches the atmosphere | carbon capture and storage | Some argue that carbon capture will be needed alongside renewables to reach net zero. |
| incentive | something that encourages a particular course of action | financial incentive, tax incentive | Tax incentives persuaded many households to install solar panels. |
| non-renewable | (of a resource) from a source that cannot be replaced once it is used | non-renewable resources, non-renewable fuels | Because coal and oil are non-renewable, the shift to clean power is inevitable. |
How to turn these words into marks
Learn each word inside its collocation, not on its own: memorising "intermittent" alone does little, but "intermittent supply" gives you a ready-made phrase you can place in an essay without a grammar risk.
Meet the words again in real reading so the partnerships become intuitive, then use them — that recognise-then-produce loop is what turns a list into active vocabulary.
Practise them in context with our renewable energy reading practice, which generates Cambridge-style passages on this exact theme, and build a daily habit with the IELTSbiz Word Coach, which gives you a word a day with practice in using it.
Keep accuracy ahead of ambition and your Lexical Resource band will follow.