Renewable Energy MCQs

Correct Answer: Flowing water

Hydropower is generated by flowing or falling water turning turbines, which drive generators to produce electricity.

Correct Answer: Solar energy

Solar energy is renewable because sunlight is continuously replenished, unlike coal, petroleum and natural gas, which are finite fossil fuels.

Correct Answer: Plant & animal waste

Biomass energy is obtained from organic matter such as plant and animal waste, wood and crop residues, which release stored chemical energy when burned or digested.

Correct Answer: Wind turbines

Wind turbines convert the kinetic energy of moving air into electricity: the wind turns rotor blades connected to a generator.

Correct Answer: Electricity

Solar (photovoltaic) cells convert sunlight directly into electricity through the photovoltaic effect in semiconductor material.

Correct Answer: Heat inside the Earth

Geothermal energy comes from heat stored inside the Earth, from the planet's interior and from radioactive decay in rocks.

Correct Answer: Photovoltaic cells

Solar panels are made up of photovoltaic cells, usually of silicon, which convert sunlight directly into electricity.

Correct Answer: China

China is the largest producer of solar energy, with the world's largest installed solar power capacity.

Correct Answer: Megawatt (MW)

Hydropower plant capacity is measured in megawatts (MW).

Correct Answer: Three Gorges Dam (China)

The Three Gorges Dam on the Yangtze River in China is the world's largest hydroelectric dam by installed capacity (about 22,500 MW).

Correct Answer: Sun

The Sun is the primary source of most energy on Earth: fossil fuels store ancient solar energy, and wind, water-cycle and solar power are all driven by the Sun.

Correct Answer: Bioenergy

Bagasse, the fibrous residue left after sugarcane juice is extracted, is burned or processed to produce bioenergy (heat, electricity and biofuel).

Correct Answer: Iceland

Iceland uses geothermal energy more than any other country as a share of its energy: it heats about 90% of Icelandic homes and supplies a large share of its electricity.

Correct Answer: Hydropower

Hydropower is the most used renewable energy source in the world, supplying the largest share of renewable electricity.

Correct Answer: Vegetable oils

Bio-diesel is produced from vegetable oils (such as soybean, rapeseed and palm oil) and animal fats by transesterification.

Correct Answer: China

China is the country where wind energy is growing fastest in installed capacity, adding more new wind capacity each year than any other country.

Correct Answer: Joule

The SI unit of energy is the joule (J); the watt is the unit of power, the rate at which energy is used.

Correct Answer: Watts per square meter

Solar energy intensity (irradiance) is measured in watts per square meter (W/m²), the power of sunlight falling on each square meter.

Correct Answer: Renewable energy

Hydroelectric energy is a renewable energy source, since it is driven by the continuously replenished water cycle.

Correct Answer: Tides & waves

Ocean energy is produced from tides and waves: tidal currents and wave motion drive turbines that generate electricity.

Correct Answer: Wind & solar

Wind and solar energy depend on weather: wind turbines need moving air and solar panels need sunlight, so their output varies with conditions.

Correct Answer: China

China is the world’s largest producer of hydroelectric power, with the largest installed hydropower capacity and generation.

Correct Answer: Anaerobic decomposition of waste

Biogas is produced by the anaerobic decomposition of waste: micro-organisms break down organic waste without oxygen, releasing methane-rich gas.

Correct Answer: Methane (CH₄)

The main component of biogas is methane (CH₄), typically about 50–75%, with carbon dioxide making up most of the rest.

Correct Answer: Electromagnetic radiation

Energy from the Sun reaches Earth as electromagnetic radiation, including visible light, infrared and ultraviolet radiation.

Correct Answer: Photovoltaic power

Electricity generated from sunlight is called photovoltaic power: solar cells convert sunlight directly into electricity.

Correct Answer: Fermentation

Fermentation converts biomass to ethanol: yeasts break down plant sugars into ethanol and carbon dioxide.

Correct Answer: California, USA

The world’s largest geothermal complex is The Geysers in California, USA.

Correct Answer: China

China has the most wind turbines installed, with the world’s largest installed wind power capacity.

Correct Answer: Renewable energy

Energy that can be replenished naturally is called renewable energy: solar, wind, hydro, biomass and geothermal energy.

Correct Answer: Appleton, Wisconsin, USA (1882)

The world's first hydroelectric central station began operation on 30 September 1882 at Appleton, Wisconsin, on the Fox River, lighting two paper mills and a residence.

Correct Answer: Silicon

A solar cell is usually made of silicon, a semiconductor whose photovoltaic effect converts sunlight directly into electricity.

Correct Answer: USA (California, 1980s)

The world's first wind farms were built in California, USA, in the 1980s, notably in the Altamont Pass area.

Correct Answer: Hydropower

Hydropower is the largest source of renewable energy worldwide by electricity generation, ahead of wind and solar power.

Correct Answer: Yangtze River

The Three Gorges Dam in China is located on the Yangtze River, the world's largest power station by installed capacity.

Correct Answer: Persia (Iran)

Windmills were first used in Persia (present-day Iran), where vertical-axis windmills ground grain and pumped water centuries ago.

Correct Answer: Greenhouse gases

Renewable energy reduces greenhouse gases: replacing fossil-fuel generation with wind, solar and hydro cuts carbon dioxide emissions.

Correct Answer: Kinetic energy of water

Hydropower converts the kinetic energy of moving water into electricity: flowing water spins turbines connected to generators.

Correct Answer: China

China is the largest wind power producing country, with the world's largest installed wind capacity and generation.

Correct Answer: Sugarcane & corn

Bioethanol is produced from sugarcane and corn: their sugars and starches are fermented by yeast into ethanol.

Correct Answer: Biogas

Energy generated from animal dung is called biogas: anaerobic digestion of dung and other organic waste produces a methane-rich gas used for cooking and power.

Correct Answer: Hydropower

Hydropower is the most efficient renewable energy technology by conversion efficiency: a hydro turbine converts around 90% of the water's energy into electricity, well above wind and solar conversion rates.

Correct Answer: Irregular supply

The main disadvantage of wind energy is irregular supply: wind is intermittent, so output varies with the weather and needs storage or backup generation.

Correct Answer: Dams

Hydropower stations require construction of dams in the booklet's conventional frame: a dam impounds water and creates the head that drives the turbines.

Correct Answer: Photovoltaic cells

Solar energy is harnessed using photovoltaic cells: the cells convert sunlight directly into electricity by the photovoltaic effect.

Correct Answer: Italy (1904)

The world's first geothermal plant was built in Italy in 1904, at Larderello in Tuscany, where geothermal steam first generated electricity.

Correct Answer: Biodiesel

Biodiesel is the fuel obtained from plant oils: vegetable oils and animal fats are converted (transesterified) into a diesel substitute.

Correct Answer: Three Gorges Dam, China

The world's largest hydropower dam is the Three Gorges Dam in China: its installed capacity of 22,500 MW on the Yangtze River is the largest of any hydroelectric station.

Correct Answer: Solar energy

Solar energy is the booklet's conventional answer for the cleanest renewable energy source: a solar panel produces no emissions at all while generating electricity.

Correct Answer: Tidal energy

The energy obtained from sea tides is tidal energy: the rise and fall of tides drives turbines, distinct from wave energy, which harnesses surface waves.

Correct Answer: Wave energy

The energy obtained from sea waves is wave energy: devices capture the motion of surface waves to generate electricity, distinct from tidal energy, which uses the rise and fall of tides.

Correct Answer: Ethanol & Biodiesel

Biofuels include ethanol and biodiesel: ethanol is an alcohol fuel made from crops, and biodiesel is made from vegetable oils or animal fats, both replacing or blending with petrol and diesel.

Correct Answer: Vegetable oils

Biodiesel is produced from vegetable oils (and animal fats): the oils are converted by transesterification into fatty-acid methyl esters that can run diesel engines.

Correct Answer: China

The country with the largest solar energy production is China: China has by far the world's largest installed solar capacity and generates more solar electricity than any other country.

Correct Answer: Photo voltaic cell

Solar panels are composed of photovoltaic (PV) cells, which convert sunlight directly into electricity.

Correct Answer: Solar and hydel

Solar and hydel power are renewable energy sources that do not pollute the environment like fossil fuels.

Correct Answer: Renewable energy resources

Renewable energy resources, such as solar and wind, are friendly to the environment because they do not pollute.