Hi there!
Wind Power:
Wind power is a good alternative to fossil fuels. Wind turbines can be placed almost anywhere where there is space (and plenty of wind). The energy from the spinning wind turbine can be collected, stored, and used.
Solar Power:
Like wind power, solar power is also a great alternative. The sun gives a lot of energy in the form of heat and light off onto earth. By collecting this heat and light and converting it into energy, we can also store this and use it later.
Hope this helps!