What are the qualities of an ideal source of energy?

(N/A) An ideal source of energy must possess the following qualities:
$I.$ It should be economical and easily accessible.
$II.$ It should be easy to store and transport.
$III.$ It should perform a large amount of work per unit mass or volume.
$IV.$ It should be safe to handle and use.
$V.$ It should be smoke-free and cause minimal pollution.