Hydropower actually has strong carbon-related undesirable environmental consequences, but probably not to such an extent in California as it does in Africa and

Hydropower actually has strong carbon-related undesirable environmental consequences, but probably not to such an extent in California as it does in Africa and South America. You'd have to find dam-specific data to verify that for Californian dams, though. It's not like with coal where burning 1 kg releases 3.6 kg of CO₂ no matter where you burn it. Emissions of a dam per kWh produced depend at the very least on its surface area, depth, water temperature, biomass inflow etc., all of which are dam-specific.