BEYOND RADIOACTIVITY. “Radiation in the form of photons is the primary way by which solar energy is transferred to living systems. The energy of a typical photon is between 2 and 3 eV (visible red, 1.8 eV and visible blue, 3.1 eV), and an abundant supply of such photons makes it convenient for life to utilize it for metabolic purposes. Even though most of the energy is lost in heat, the overall efficiency of 0.1–8% is sufficient to power metabolism.”
https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459