  This paper investigates how spatiotemporal heterogeneity in inflexible
residential heat pump loads affects the need for storage and generation in the
electricity system under business-as-usual and low-carbon emissions budgets.
Homogeneous and heterogeneous heat pump loads are generated using
population-weighted average and local temperature, respectively, assuming
complete residential heat pump penetration. The results of a storage and
generation optimal expansion model with network effects for spatiotemporally
homogeneous and heterogeneous load profiles are compared. A case study is
performed using a 3-bus network of London, Manchester, and Glasgow in Britain
for load and weather data for representative weeks. Using heterogeneous heating
demand data changes storage sizing: under a business-as-usual budget, 26% more
total storage is built on an energy and power basis, and this storage is
distributed among all of the buses in the heterogeneous case. Under a
low-carbon budget, total energy storage at all buses increases 2 times on an
energy basis and 40% on a power basis. The energy to power ratio of storage at
each bus also increases when accounting for heterogeneity; this change suggests
that storage will be needed to provide energy support in addition to power
support for electric heating in high-renewable power systems. Accounting for
heterogeneity also increases modeled systems costs, particularly capital costs,
because of the need for higher generation capacity in the largest load center
and coincidence of local peak demand at different buses. These results show the
importance of accounting for heat pump load heterogeneity in power system
planning.
