Alternative Elements for Renewable-Energy

[Alpine]

What I want to ask is as simple as the topic says

 

Can we use some other natural elements as a substitution for the ones we use at present as a source of renewable-energy?

 

For example

 

Substitute water with sand in hydro-electric power?

Or

Use volcanoes for geothermal power stations?

 

The list might go on and on...but is it possible to substitute various natural elements for generating electricity? :rolleyes:

[JMJones0424]

Can we use some other natural elements as a substitution for the ones we use at present as a source of renewable-energy?...Substitute water with sand in hydro-electric power?

 

I envision a number of problems with this approach right up front.

 

1) Solar energy causes evaporation of water from low-land areas and a portion of that water falls as rain on higher elevation areas. We trap this water and control it's decent back to low areas while using the energy it releases as it falls to drive turbines which generate electricity. I know of no free (to us) cycle that moves sand from areas of low energy potential to areas of higher energy potential. This is by no means an "efficient" use of energy, but since the energy required to move the water from a low gravitational potential to a higher potential is not expended by us, where it takes place naturally, this is an efficient means of capturing energy that would otherwise go un-utilized (if you don't mind the destruction of habitat caused by damming rivers)

 

2) Sand does not flow as freely as water, and it seems to me that sand is naturally moved only by wind or tides. I think it makes more sense to tap into these sources directly, rather than to use accumulated sand to drive turbines. Sand is also terribly abrasive against metal parts, and I would think that sand falling at a velocity fast enough to drive a turbine would also cause damage to the turbine.

 

I think it would be interesting to know what the prospects are for storing energy by moving sand to a higher gravitational potential rather than water. I suspect that like water, it would be terribly inefficient, and would still be harder to generate electricity from falling sand rather than falling water.