Hydropower is easily the most firmly established, most efficient, mature and largest renewable energy known to humanity. It spans over 100 countries and provides about 17% of global electricity, while accounting for 100% electricity in Lesotho, Paraguay, Bhutan, Albania, Mozambique, Zambia, Congo Kinshasa, and Zambia. With one of the best conversion efficiencies, it directly captures and converts both potential and kinetic energy into electricity, with insignificant heat losses, and needs neither subsidies for profitability nor fuel for operations. Of the 3 main categories, reservoir damming remains the most controversial. Accounting for more than 70% of global renewable electricity, it is grossly underrepresented in institutional investment portfolios, because of its controversial nature mainly due to negative externalities from its environmental and social impacts. It also has high CAPEX, low OPEX, greater site adaptation requirements, as well as higher complex technical specialist knowledge and active management skill requirements, along with multiple co-benefits such as drinking and irrigation water storage, drought-preparedness, aquaculture, flood control protection, and recreational opportunities and it can support more intermittent renewable sources like wind and solar, creating portfolio balance and rapid-response power. Dam failure is a structural catastrophic breakdown resulting in the sudden, rapid, and uncontrolled discharge of impounded water, killing many. Reservoir safety is especially critical as large reservoirs hold back huge water volumes. Its failures can occur as a result of sabotage, poor construction, or natural disasters as they can be disastrous to downstream settlements and infrastructure. Under international humanitarian law, dams are recognized as "installations containing dangerous forces" due to the huge impact of a possible destruction on the host population and the environment. The Chinese Three Gorges Dam can store 22 cubic kilometres of floodwaters on the Yangtze River. A 1954 flood on this river killed 33,000 people and forced the relocation of 18 million, while a 1998 flood caused 4000 deaths and affected 180 million people. The reservoir flooding led to the relocation of more than one million people. Similarly, the Kainji dams' excess water release chronically floods many states in Nigeria. This is worsened by the additional release of excess water from Cameroon's Lagdo dam through River Benue, flooding already heavily impacted communities, killing many people, destroying properties and forcing relocations, and as is the case this year, it is preventing the dead from resting in peace, as many of the buried, were 'flooded' out of their graves. The IHA Sustainability Assessment Protocol assesses hydropower performance across over 20 criteria. Although, water release objectives include power generation, flood protection, drinking and riparian ecosystems water supply, reservoir and downriver water/fish quality survival, aquatic weeds and disease vectors control, irrigation and recreation, yet global institutions like the IFC, the World Bank, the International Hydropower Association, the World Commission on Dams, the International Commission on Large Dams and the IRENA, along with NGOs, CBOs and CSOs must ponder if this is what clean energy has to be and ensure that Hydropower ESIA, ESMS, ESG, the Equator Principles & the IFC Performance Standards move the industry towards greater sustainability. Topograhy, geology, hydrology along with design, EPC, E & M, operations, maintenance, especially human resettlement and flooding, economics and funding challenges are addressed within the context of sustainability. Since clean electricity is mandatory for green hydrogen production, and the latter uses huge amounts of electricity; stakeholders should consider the possibility and feasibility of establishing green hydrogen and hydropower co- production facilities at the same location.
