# A wind turbine generates electricity and supplies it to a small village. Not all of the energy from the wind is transferred to useful electrical energy. Explain why the wind turbine cannot be 100% efficient, and describe TWO ways in which the efficiency of any energy transfer device can be increased.

> Edexcel A-Level Physics (9PH0) — 3.2 EMF, resistance and circuits · Explain · 5 marks

> A wind turbine converts kinetic energy from moving air into electrical energy. In practice, some energy is always wasted during this process. The efficiency of the turbine is 35%.

## Mark scheme (5 marks)

1. Energy cannot be created or destroyed (conservation of energy) but some energy is transferred to non-useful forms / wasted
2. Waste energy is transferred as heat and/or sound, which does not serve the purpose of generating electricity
3. Efficiency can be increased by lubrication of moving parts
4. Efficiency can be increased by using thermal insulation to reduce heat loss to the surroundings
5. Efficiency can be increased by recycling / recovering waste energy output and using it as an input to the device

## Key terms

- [efficiency](https://www.gradenine.co.uk/glossary/efficiency)

## Related

- [Revision notes for Edexcel A-Level Physics (9PH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-wind-turbine-generates-electricity-and-e972bd0b) · Published by Druglandscape Ltd.