"Radiant energy" refers to the energy that travels in waves or rays. It includes visible light, heat from the sun, and other forms of electromagnetic radiation. Full definition
It is that interruption in the flow of radiant energy in and out which gives rise to a warming effect. (newclimatemodel.com)
They subsequently contract on a time scale of tens of millions of years, the main source of radiant energy in this phase being the release of gravitational energy. (britannica.com)
That is one of the reasons that clouds get ignored as they generally are not widespread or dense enough to be considered to have a significant impact on incoming solar radiant energy. (realclimate.org)