Answers.comÂ® is making the world better one answer at a time. The element that makes the strongest material is carbon, and the material which is made is graphene. Thao Hg.
<br /><br /> Solar power is the cheapest renewable energy source for small-scale use, such as pocket calculators, LED lights, and remote (small) electrical appliances. Hydroelectric power is the cheapest renewable energy source for large-scale production. That is, it has the lowest cost to construct and maintain the generating facilities compared to the amount of energy produced.
Technical feasibility. Hydropower is the most energy efficient power generator. Currently, hydropower is capable of converting 90% of the available energy into electricity. This can be compared to the most efficient fossil fuel plants, which are only 60% efficient.