Whenever you turn the switch on, you connect to the power grid, and the power grid consists of many power generation methods: the power generation companies burn fossil fuels like coal and gas, use nuclear power or use renewable sources like wind power, solar power and hydro power.
When there is no wind - wind power is not produced, when the sky is dark - like at night - solar power is not generated and in drought seasons the dams are empty so hydro power is no effective. Reducing carbon emission means that you want to use power when renewable sources are available
elxn is collecting live data and thousands of other variables like weather conditions, generation methods, electricity demands and others, to give you the most sensible time to use electricity in order to reduce your carbon footprint, reduce carbon emission and fight global warming
1 The Terrace, Wellington, New Zealand