Nature-inspired synchronisation protocols have been widely adopted to achieve consensus within wireless sensor networks. We analyse the power consumption of such protocols, particularly the energy required to synchronise all nodes across a network. We use the model of bio-inspired, pulse-coupled oscillators to achieve network-wide synchronisation and provide an extended formal model of just such a protocol, enhanced with structures for recording energy usage. Exhaustive analysis is then carried out through formal verification, utilising the PRISM model-checker to calculate the resources consumed on each possible system execution. This allows us to investigate a range of parameter instantiations and the trade-offs between power consumption and time to synchronise. This provides a principled basis for the formal analysis of a broader range of large-scale network protocols.