Humans can't live without energy - they have always used energy.
using their senses
Long before "we" were humans, when our early prehuman ancestors ate a piece of fruit. Also when they felt the sun warm them in the morning.
Electricity by converting it using wind turbines.
There are many sources that humans can get their energy from. Humans typically get their energy from different food sources.
Humans use food for energy.
They modify the habitat (using fossil energy usually) to suit their requirements.
thermal energy maybe?
That sounds as if you want to stop using energy. That's not possible - we need energy to survive. We (humans) can reduce our use of energy, and we can try to reduce the environmental impact of the energy we do use.
A solar panel collects energy from sunlight, just like windmills convert wind energy. The mechanics inside the solar panel and inside the building let humans use solar energy. There is no more harm to humans from solar energy than there is from using energy produced from the wind.
humans get there energy from minerals and carbohydrates . the stored energy is changed in muscular energy.
they break sugar down using enzymes which are proteins, into energy, oxygen is used as an energy supplier to the reaction which creates water and Co2
As we do not have endless supply of the traditional fuels, of course we have to research on alternative ones. Using the energy of sun or using bio-energy can be the future.