This still relies on a heat differential, as described in the Details section of your linked article: https://en.wikipedia.org/wiki/Thermophotovoltaic_energy_co

This still relies on a heat differential, as described in the Details section of your linked article: https://en.wikipedia.org/wiki/Thermophotovoltaic_energy_conversion#Details https://en.wikipedia.org/wiki/Thermophotovoltaic_energy_conv...