The invention provides for a method for power optimized transmission scheduling in an energy harvesting machine to machine device, comprising an internal power storage and an internal energy harvesting source and being configured for communication with a mobile communications network via a wireless link. The method comprises receiving an event triggering a decision to send data to the mobile communications network, monitoring at least one power parameter of said internal power source and scheduling said data for transmission based on the at least one power parameter. The invention also relates to a corresponding M2M device, to a network node and to a computer program for performing the method.