Short answers, pulled from the story.
Coal emerged as the worst emitter with a median value of 820 grams of carbon dioxide equivalent. This figure represents the highest emission rate among major electricity sources analyzed by the Intergovernmental Panel on Climate Change.
Wind farms are estimated to last thirty years before repowering becomes necessary. Extending plant lifetimes reduces the carbon footprint per unit of generated electricity and lowers overall emissions.
Geothermal research in Italy found emissions higher than previously thought during the 2020s. Individual studies after 2014 reveal wide ranges of estimates due to differing methodologies and varying assumptions about energy usage.
Larger dams like the Hoover Dam and Three Gorges Dam intend to last forever through maintenance. This indefinite lifespan creates a quantification problem for future decommissioning estimates and adds global warming potential when dismantling occurs.
Germany declared preservation of coal-based power until 2038 during its Energiewende transformation. Immediate shutdown of nuclear plants increased dependency on fossil gas within that nation and highlights tensions between different low-carbon strategies.