Cars which emit no greenhouse gases or create no pollution...
Cell phones and laptops working for a long time with a single cartridge without the necessity of recharging...
The sun, the wind or the water from the river used for heating and lighting even at night or when there is no wind and the river is dry...
Using energy from the sun, the wind, the rivers or nuclear reactors to run car engines...

Is it possible?

In other words, can we use energy in a way that it can be stored, be renewable, respects the environment and does no harm to health?

- what is energy?
- why do we need it?
- where does it come from?
- what are the consequences of its use?