I could be wrong but I think she means briquettes made from olive waste after the oil has been pressed out. I know that there are central heating boilers that run off this but they use a form of the waste in pellet form that is fed in through a hopper. I have been to a Tsikoudia still near Chania that uses a combination of heating oil and olive waste pellets to distil the fermented grape residue. I also know that there are barbecue briquettes made from the same source. I wasn't aware that they were available for wood burning stoves.
Thanks for posting the information, Mouche. Personally I don't intend to use it but it could be useful to somebody. I agree with you that wood is probably better. Unfortunately Annabanana is at the other end of the island so she needs someone down that end to reply.
Try the Olive Oil Mill in Pirgos Kalo Chorio, Lasithi. I have seen their mountain of waste, they must do something with it as within a short period at the end of production the waste mountain disappears. Why not try one of the Mills in Sitia.