What are the pros and cons of alternative energy sources?

Pros

It is sustainable and so doesn't run out

Few waste products such a carbon dioxide and so reduced greenhouse gas emissions

Usually require less maintenance

Many economic benefits especially to local areas

Cons

Expensive

difficult to generate required amount of energy, say as much as you could with fossil fuels

reliability, e.g. solar-lack of sunlight, wind-no wind etc.

Also the classic, NIMBY- not in my back yard, often you get protests by local people who are "pro" renewable energy, but only if it is somewhere else.

HTH