📖 Chapter 6 of 8 · Green Energy - Basic 2 · Class 7
Chapter 6: How Do We Store and Share Clean Energy?
In this chapter
- The Sun sets and the wind stops — now what?
- Batteries: our energy piggy banks.
- The power grid: a giant web that shares electricity.
- India’s green energy journey, and meet Iba from Meghalaya and Aditya from Kerala.
The Big Idea
The Sun does not shine at night, and the wind does not always blow. So we need ways to store clean energy for later. Batteries are like energy piggy banks. We also share electricity through the power grid — a giant web of wires and stations that connects power plants to homes across the country.
Did You Know?
A pumped storage plant works like a giant water battery. When there is extra electricity, water is pumped up into a high lake. Later, when power is needed, the water flows down and spins turbines again.
Story Time — Iba’s School That Glows After Dark
Iba, age 10 · A village in the West Khasi Hills, Meghalaya
Iba lives in a misty village in the Khasi Hills of Meghalaya, where it rains a lot. During storms, trees sometimes fall on the power lines, and the whole village goes dark.
This year, her school put solar panels on its roof and built a small room full of batteries. During the day, the panels run the fans and computers, and any extra energy fills up the batteries.
One stormy evening, the village lights went out again. But the school windows kept glowing! Families walked over with their phones to charge them, and the older students held an evening study class.
“How are our lights still on?” asked Iba’s friend Daniel. The headmaster pointed to the battery room. “The Sun filled these batteries today. Now we are spending that saved energy, just like money from a piggy bank.”
“But in a cloudy week, the batteries may not fill completely,” he added, “so we must still use energy wisely.” Iba nodded. She made a sign for the classroom door: “Saved sunshine — please switch off!”
Story Time — Aditya and the Sunshine Airport
Aditya, age 9 · Kochi, Kerala
Aditya lives in Kochi, Kerala. He was flying to Delhi with his mother to visit his grandparents. As the taxi reached the airport, he saw fields of shining blue panels stretching far away.
“Amma, why are there so many solar panels here?” Amma smiled. “In 2015, Cochin International Airport became the first airport in the world to run fully on solar power. And look — in some places, vegetables grow in the shade under the panels!”
“But planes fly at night too,” said Aditya. “How does the airport get power then?”
“Good thinking!” said Amma. “During the day, the panels make more electricity than the airport needs, so the extra is sent into Kerala’s power grid for other people to use. At night, the airport takes power back from the grid. The grid works a bit like a bank.”
As the plane rose into the sky, Aditya pressed his face to the window. The panels sparkled below like a blue carpet. “When I grow up,” he said, “I will build a sunshine airport too!”
Storing and Sharing Clean Power
Clean energy works best when we can save it and share it.
- Batteries store electricity as chemical energy and give it back when we need it — in phones, e-buses and solar homes.
- The grid links power plants, tall towers, substations and homes. India connected all its regions into one national grid in 2013, often called “One Nation, One Grid”.
- Sharing helps: when it is sunny in Rajasthan or windy in Tamil Nadu, that power can travel to other states.
- India’s journey: In 2021, India set a goal of 500 gigawatts of power capacity from non-fossil sources by 2030, and to reach net zero by 2070. In June 2025, India reached a big milestone: half of its power-plant capacity now comes from clean, non-fossil sources.
- Still more to do: Plants that burn coal still make most of the electricity we actually use, so India is building more storage and clean power every year.
Solved Examples
Think first, then read the answer.
1. Why do we need to store solar energy?
Show answer
Answer: Solar panels make power only when the Sun shines. Storing it lets us use clean power at night and on cloudy days.
2. What is the power grid?
Show answer
Answer: A huge network of power plants, transmission towers, cables and substations that carries electricity to homes, schools and factories.
3. A school battery stores 10 units. The school uses 2 units each evening. For how many evenings will it last?
Show answer
Answer: 10 ÷ 2 = 5 evenings, if the battery is not recharged.
4. How does the grid help Cochin airport at night?
Show answer
Answer: The airport sends extra solar power into the grid during the day and takes power back from the grid at night.
5. India reached 50% clean power capacity in 2025. Does that mean half of all our electricity now comes from clean sources?
Show answer
Answer: Not yet. Capacity means how much power the plants can make. Sun and wind do not work all the time, so coal still makes most of the electricity we use. That is why storage matters so much.
✎ Now You Try!
A home battery stores 12 units. The family uses 3 units each night. For how many nights will the battery last without recharging?
Check Your Understanding
A. Fill in the blanks
- Batteries are like energy banks.
- The giant web of wires that shares electricity is called the power .
- Cochin airport in was the world’s first fully solar-powered airport.
- India’s goal is 500 gigawatts of non-fossil power capacity by .
- In a storage plant, water is pumped up and released later.
B. True or False
- Solar panels make electricity at night. ( ___ )
- The grid can carry power from one state to another. ( ___ )
- Iba’s school batteries never run low. ( ___ )
- India aims to reach net zero by 2070. ( ___ )
C. Choose the correct option
- Iba’s school lights stayed on because of (a) batteries (b) candles (c) a diesel bus
- At night, Cochin airport gets power from (a) the grid (b) the Moon (c) the sea
- “One Nation, One Grid” was completed in (a) 1947 (b) 2013 (c) 2030
D. Answer in two or three sentences
- Why is a battery called an “energy piggy bank”?
- How does sharing power through the grid help the whole country?
- Write two things India is doing to grow clean energy.
Brain Buster
Count the devices in your home that have a battery. Which one do you charge most often?
Check your understanding
Tap an answer to see if it is correct. This is just for fun — nothing is saved.
1. Why do we need to store solar energy?
- The Sun does not shine at night
- Panels get too heavy
- To make smoke
Show answer
A. The Sun does not shine at night
2. What is the power grid?
- A game
- A web of power lines and stations that shares electricity
- A kind of battery
Show answer
B. A web of power lines and stations that shares electricity
3. A battery stores 10 units. A school uses 2 units each evening. How many evenings will it last?
- 2
- 5
- 20
Show answer
B. 5
4. In June 2025, what did India reach?
- Half of its power-plant capacity from clean, non-fossil sources
- No more coal at all
- Net zero
Show answer
A. Half of its power-plant capacity from clean, non-fossil sources