Good question. Temperature is a funny thing. When a system is far from equilibrium, the notion of temperature becomes a little unfamiliar. The thermodynamic te

Good question. Temperature is a funny thing. When a system is far from equilibrium, the notion of temperature becomes a little unfamiliar. The thermodynamic temperature of the radiation is connected to the entropy of its power spectrum. LEDs and especially lasers emit very low-entropy light, which can be focused and heat a surface up to very high temperatures. (Sunlight focused onto a surface cannot heat that surface above the temperature of the sun). Thermodynamically speaking, a low-entropy power source like a laser -- and whatever is driving it -- must have a very high exergy, which is equivalent to behaving like a high temperature heat source, even though it might feel cold to the touch. Some more details here: https://en.wikipedia.org/wiki/Exergy#Quality_of_energy_types https://en.wikipedia.org/wiki/Exergy#Quality_of_energy_types Stored electricity's equivalence to a high-temperature heat source is one of the things that makes it so useful. It's intrinsically connected to why it takes a lot of low-grade heat to produce a small amount of electricity in the first place, and also why electric furnaces can produce such high temperatures. So while a battery can drive an LED that shines on a PV panel that generates power with everything feeling equally warm to the touch, a temperature gradient is still necessary; it's just been moved outside the boundaries of the system, to the process that distilled the entropy out of the energy that became the battery's stored charge. We can reversibly recreate this temperature gradient by driving a Carnot engine with that battery, instead of a laser.