Renewable Energy Sources: How Solar and Wind Power Work

By Eduminate

Pastel desk scene with a paper pinwheel, a small fan, a glass jar and a plant on a blue background.

Renewable energy sources are sources of power that nature replaces or that keep arriving, and this guide explains how five of them work in plain language. It also compares them with fossil fuels and ends with classroom ideas for upper elementary readers.

Renewable energy sources

The word “renewable” means something can be renewed, or replaced. A renewable energy source is either replaced by nature in a fairly short time or is available again and again. Sunlight arrives every day. Wind keeps blowing. Rain keeps filling rivers.

This guide covers five sources: solar, wind, hydropower, geothermal and biomass. The first four get their own sections that explain how the energy becomes electricity. Biomass gets a short entry in the list of types.

What is renewable energy

Renewable energy is energy from sources that nature replaces or that keep coming, such as sunlight, wind and moving water. People use these sources to make electricity, to heat buildings and to run machines.

Electricity usually starts with something that turns. A turbine is a wheel with blades, and when it spins it turns a generator. The generator is the device that makes the electricity. Wind, steam and falling water can all turn a turbine. Solar panels are the exception, because they make electricity from light with no turning parts.

Energy changes form as it moves along. In a wind turbine, the energy of moving air becomes the energy of a turning shaft, and the generator changes that into electricity. In a solar panel, the energy of light becomes electricity directly. Students can follow this chain from source to electricity for each type, and it gives them a pattern to use for every source in this guide.

Renewable vs nonrenewable

Renewable and nonrenewable resources differ in how fast they are replaced. Coal, oil and natural gas are fossil fuels. They formed from the remains of ancient plants and animals over a very long time, and they cannot be replaced quickly. Once people burn them for energy, they are used up.

Here is a side-by-side look, written as two lists.

Renewable sources:

Sunlight
Wind
Moving water
Heat from inside the Earth
Plant material that can be regrown

Nonrenewable sources:

Coal
Oil
Natural gas

Types of renewable energy

There are several types of renewable energy. These five are the ones children meet first:

Solar: energy from sunlight.
Wind: energy from moving air.
Hydropower: energy from moving water.
Geothermal: energy from heat inside the Earth.
Biomass: energy from plant material, such as wood or leftover crop parts, which can be burned for heat or turned into fuel.

How does solar energy work

A solar panel is a flat sheet made of many small photovoltaic cells. A photovoltaic cell turns light into electricity. When sunlight hits the cell, it makes tiny electric charges move, and moving charges are an electric current.

The current from the panels then passes through a device called an inverter. The inverter changes the electricity into the form that lights and outlets in a building use.

Solar energy facts

The sun is a star, and its light reaches the Earth every day.
Solar panels have no turning parts.
Panels can sit on roofs or in open fields.
A battery can store some of the electricity for later.

Panels can be small or large. A small panel can run a calculator, and a large group of panels can supply a building. The idea is the same in both cases.

Advantages of solar energy

Sunlight costs nothing to collect, and a working panel does not burn fuel to make electricity. There is one honest limit. A panel makes less electricity when the light is weaker, and none at night. That is why many solar systems pair panels with batteries or with other sources of power.

Some reading packs go deeper into solar science. The solar energy reading packet for grades 6 to 8 has 10 texts, tasks and answer keys across 64 pages, and it covers renewable power and photovoltaic science.

How do wind turbines work

Wind is moving air. Air moves when the sun heats some parts of the Earth more than others, so wind is another form of solar energy at work. A wind turbine catches that moving air with its blades. The blades are shaped so that the air pushes them around.

The blades are attached to a shaft. When the blades turn, the shaft turns too, and the shaft is connected to a generator. Inside the generator, magnets and coils of wire move past each other, and that movement makes electricity. The turbine stands on a tall tower, because wind is usually stronger higher up.

Wind energy facts

A wind turbine does not burn any fuel.
It needs wind to turn. When the air is still, the blades stop.
Many turbines are placed in open areas where wind blows freely.

How do windmills work

Windmills and wind turbines both use blades that turn in the wind. Older windmills used that turning to grind grain or to pump water. Modern wind turbines connect the turning blades to a generator, so they make electricity.

Two reading packs focus on wind. The wind energy passages for grades 2 to 8 contain 10 texts with text dependent questions, a structured lesson plan and answer keys, in 63 pages. The windmill energy passages for grades 2 to 6 cover the history and science of wind power in 10 texts across 64 pages, with leveled texts, questions, a lesson plan and answer keys.

How does geothermal energy work

The inside of the Earth is hot. In some places that heat is close enough to the surface to use. People drill wells down to hot water or steam. The steam rises to a power plant, where it spins a turbine connected to a generator.

Hot springs show the idea in nature. Water warmed by heat underground rises to the surface, and the water in a hot spring is warm or hot as a result.

The geothermal passages for grades 3 to 7 cover underground heat, steam turbines, power plants and renewable electricity in 10 science passages across 64 pages.

How does hydropower work

Hydropower uses moving water. A river flows downhill, and flowing or falling water has energy. At a dam, water collects behind a wall. When it is released, it rushes through pipes and pushes against the blades of a turbine. The turbine turns a generator, and the generator makes electricity.

The water supply is renewable because of the water cycle. The sun warms water so that it rises into the air as vapor, and later it falls again as rain and snow and fills rivers. A river can run low if rain is scarce, so how much power it makes can change.

Geothermal and hydropower share something with wind: all three end with a turbine turning a generator. Only the thing that turns the turbine changes. For wind it is moving air, for geothermal it is steam or hot water, and for hydropower it is moving water. Putting those three side by side on one chart helps students see the pattern.

Simple ways to teach it

Sort energy cards into renewable and nonrenewable

Write the names of energy sources on blank cards: sunlight, wind, moving water, hot rock, wood, coal, oil and natural gas. Students sort them under two labels and explain their choices. Biomass is a good one to discuss, because plants can be regrown but only if people plant more.

Label a diagram of a turbine

Give students a plain diagram of a wind turbine and ask them to label the tower, the blades, the shaft and the generator. Then they write one sentence that traces the energy from the wind to the electricity.

Make a paper pinwheel

Cut a square of paper from each corner toward the middle, stopping before the center. Fold every other corner point into the middle and fasten them with a paper fastener to a straw or a pencil. When a student blows gently on it or holds it in a breeze from an open window, the pinwheel turns. The wind is pushing on the blades, which is the same idea a wind turbine uses. Only scissors are needed.

Trace the energy on paper

Give each student a strip of paper for each source. They write the source on the left and the electricity on the right, then fill in the steps between, such as blades, shaft and generator. Comparing strips shows which steps repeat from one source to the next.

A small model discussion

Place the pinwheel on the table and ask what is missing before it could make electricity. Students should reach the idea that a generator would need to be connected to the turning part. Then ask what other things could turn a turbine, such as steam or falling water. It makes a good quiet task for early finishers, and the post on early finishers activities has more ideas like it.

Practice material

These are reading passage packs with questions, so they suit a science block or a reading block. The post on reading comprehension strategies lists ways to use passages like these with a class.

Besides the wind, solar and geothermal packs above, two more packs are about energy topics. The solar paint passages for grades 4 to 7 make a 63 page packet in which students explore quantum dots, hydrogen generation, perovskite minerals and renewable energy. The waste to energy passages for grades 4 to 7 form a 72 page packet of ten environmental science passages. Students explore municipal waste combustion, steam power generation, pollution scrubbers and global recycling.

Frequently asked questions

Can renewable energy run out?

A source such as sunlight or wind keeps arriving, so it does not run out the way a fossil fuel does. A given day can still bring less of it. A cloudy day means less sunlight, a calm day means little wind, and a river can run low in a dry spell.

What is the difference between a windmill and a wind turbine?

Both have blades that the wind turns. Older windmills used the turning to grind grain or pump water. A wind turbine uses it to turn a generator that makes electricity.

Does solar energy work on cloudy days?

Yes, but with less output. Clouds let some light through, so panels still make some electricity. They make less than on a clear day, and they make none at night.

What grade learns about energy?

The reading packs linked in this article cover grades 2 to 8, and each product page lists its own range. The wind and windmill packs start at grade 2, the geothermal pack is for grades 3 to 7, and the solar energy pack is for grades 6 to 8.