This is largely because we are replacing coal plants with fracked natural gas plants, which we are doing because fracked gas is cheap and plentiful.
Fracked gas is way better from an air pollution point of view and a little better from a direct carbon emission point of view. But when you consider the methane leaks from wellheads and pipelines and facilities it is roughly as bad as coal for climate. This is overall not a good story for climate as we lock in gas plants for decades.
Renewables and nuclear deployments did not factor in much to this decrease.
Fracked gas is way better from an air pollution point of view and a little better from a direct carbon emission point of view. But when you consider the methane leaks from wellheads and pipelines and facilities it is roughly as bad as coal for climate. This is overall not a good story for climate as we lock in gas plants for decades.
Renewables and nuclear deployments did not factor in much to this decrease.