Keeping Electricity for Later

Electricity—what makes lights and many machines work—can come from the sun. But we need it at night too. How can we keep it for later?

One answer is a battery, a box that keeps energy for later use. Some homes and businesses already use batteries. Very big batteries help many people get electricity when they need it.

Another way uses water. Electricity moves water up a hill. Later, the water comes down and makes machines turn. This makes electricity again. Both ways lose some energy. They do not make extra energy.

In the coming years, we may keep more electricity from the sun for the evening. But keeping enough for a few hours is not the same as keeping enough for several days.

People are working on new ways. Some use heat. We do not know which ways will work best or cost less. Different places and needs will probably need different answers, not one special box.