Depending on who you ask, pumped hydro energy storage is either the future of the clean energy industry and the key to decarbonizing the global economy, or it's an ecological disaster that needs to be stopped. The truth, of course, lies somewhere in between – but friends and enemies of pumped hydro tend to espouse either one narrative or the other with inadequate attention to the nuanced trade-offs and potential synergies that pumped hydro storage presents to the renewable energy industry. The issue is this: building dams is good for…