billiards said:
Nobody can give you a straight answer. Actually there's a lot of oil and gas and other things, but that isn't the important thing, they're only useful if we can get to them and the energy we spend getting them out is less than the energy returned after all is said and done. Economics.
The fact is there's a lot of energy from things like the sun and the wind and even the tides so we're always going to have electricity at our disposal. One thing seems fair to say though, if our population continues to grow along with our energy demands, unless we develop new sources we will not have enough to continue our consumerist ways. That is, we'll still have electricity but we won't be able to use it as much anymore.
Or use it in a more economical way...
Most of your energy for warming houses is simply wasted. Only a fraction is used to increase the temperature of the air in your building, the largest part is necessary to compensate for the loss of energy due to losses (the temperature gradient with the outside atmosphere).
So we might very well focus on techniques on how to keep the energy in and prevent the heated air from cooling down quickly.
In that way, we are going to need less energy, but with the same benefit.
Energy reduction/transition is a three way path:
1. Reduce the energy that is not used at all: heating your house when you are away, or all kinds of electric equipment that is consuming electricity without you using it.
2. Increase the energy efficiency in all energy transitions (from producing the electricity or fuel source to distribution and utilization). Also to regain energy from waste energy.
3. Transition from fossil energy sources to renewable energy resources. If you have done the first two steps extensively and exhaustively, there is less energy you have to produce to fulfill your needs, which then can be more easily replaced with all kind of resources (from water, geothermic, wind, solar, biofuels, etc.).
{The most common rebuttal that 'alternative energy sources' like water/wind/solar etc. can't fulfill all our needs are typically based on energy usage statistics which don't take into consideration the need of steps 1 and 2.
We can't replace fossil fuel usage with any other resource (unless we would have nuclear fussion, but that is still a long way, and not sure) , unless we extensively also take care of step 1 and 2.
Alternative / renewable energy is available in magnitudes of quantities larger then the current world energy consumption, but most of it we can not tap into, but if only that part would be used that would be achievable, this could fulfill all energy needs.
As an example: if we cover an area the size of France with solar panels, this would give us the equivalent of energy the world currently uses. }