>If a module is only 5% efficient in converting heat into electricity, the other 95% comes out as heat again. If the stove is used for space heating, this heat cannot be considered an energy loss, because it still contributes to its original purpose. Total system efficiency (heat + electricity) is close to 100% – no energy is lost.

So if you need a ton of heat and a tiny bit of electricity, this is perfect for you. Otherwise, it doesn't sound like a replacement for solar panels as much as a complementary technology for certain situations.