Electricity generation and consumption are inevitably part of the same system. Electricity should not only be used as efficiently as possible, consumption should also ideally be shifted to times when production is abundant and cheap– a constraint gaining in importance with the growth of variable renewable energy sources.
Taking a systems approach to energy use includes assessing whether particular electrically driven functions in a building are flexible enough to be shifted in time, either to maximise the self-consumption of local renewable energy generation, or to participate in a utility company’s demand side management programme, or both.
Another strategy can be to lay additional emphasis on energy efficiency measures that realize peak load reductions. One example is a waste water heat recovery (WWHR) system that recuperates the heat from shower water to pre-heat the cold water flowing to the water heater. Since showers are usually taken in the morning or the evening, the resulting efficiency gain does not only reduce primary energy use, but also mitigates the need for expensive peak hour electricity.
Electricity consumption should ideally be to times when production is abundant.