I certainly consider them to be green and wish that environmentalists would get behind them. I agree that they cause problems for spawning fish and have disturbed fish populations but in comparison to the huge environmental damage being done by the oil, gas and coal industry they are wonderful. The dams can be updated to produce 100 times the energy that the old equipment does and they produce no emissions, create no waste and in many cases the dams are already in place. Damage to the fish has already been done. We can spend a little money on new updated equipment and add a great deal of renewable energy to the mix. I would like to hear more talk along these lines.

Simple answer is YES!!!!!!

Daming a water system can change the local environmental conditions, but IMHO they are almost ALWAYS improvements. You create large(r) bodies of water and create ecosystems that would not exist without the dams. Some species can be negatively impacted and for most we can engineer workarounds. Fish ladders etc have helps with spawing etc.

Some species are greatly helped by creating the dams.

Given that I beleive we need to support humanity first with minimal negative impact I believe dams are the best solution we have available to us at this time.

Renewable? Yes. Green? Eh... sort of. Dams require blocking water which can greatly affect fish migrations. In addition it can also hurt wildlife when flooding areas to create dams. To a degree, it is green. It does not create admissions, but it can hurt wildlife.

Not-so-green hydroelectric dams give off more methane than anyone thought

Hydro dams could jeopardise 'Grand Canyon of the east', say green ... long considered hydropower an antidote to the country's overwhelming

There is much thinking that dams cause earthquakes because of the added water weight. That doesn't sound green.