Under pressure from multiple sources - of legislation, compliance, public opinion, the monitoring power unleashed by new technologies - the era of looking at energy efficiency purely in terms of cooling or distribution losses may have passed.  New measures and questions around network and storage efficiency, utilisation and optimisation will define future efficiency strategies. As embedded energy, the profile of energy sources, the recycling of waste heat and the environmental impact of the data center outside its walls increase in prominence so the strategy will need to incorporate sustainability objectives.. As in other areas of design and operation, hyperscale is setting new benchmarks in terms of efficiency and sustainability. But how feasible are these learnings and practices for everyone?