Where does all this energy come from, and how can we use it better?

Question: Where does all this energy come from, and how can we use it better?
- Keywords:
  environment,
  power,
  renewable
Asked by 116enec32 to Hilly, Lee, Liz, Tadhg, Yasmin on 14 Jun 2015.
- Lee Margetts answered on 14 Jun 2015:
  
  @deighton The truth is that nobody knows where energy comes from. That is a philosophical question studied by physicists who are interested in the Big Bang and beginning of the Universe. Wherever it comes from, engineers help convert it from a natural form (stored in the wind, waves, coal, oil, heat in the ground or radioactive minerals) into a form we can use (electricity or petrol or gas).
- Yasmin Ali answered on 14 Jun 2015:
  
  If you track it back, it comes from the sun. For example… oil and gas started life out as tiny plants and animals that died and got buried and decomposed. They got their energy from the sun when they lived.
  
  We can use it better by being more efficient – so only use what we really need. I walk and cycle as much as possible because it’s more fun but also it’s better for the environment.
- Tadhg O'Donovan answered on 15 Jun 2015:
  
  Did you know that the sun delivers more energy to the earth in 1 hour than humanity uses in 1 year. The engineering challenges are in efficient conversion and storage.
  
  I believe we need more solar hot water systems in the UK as approximately 70% of the energy we use at home is in heat. We’d cut out waste heat and transmission losses that way.

Question: Where does all this energy come from, and how can we use it better?