Ian Richardson

Assessing heat pumps as flexible load

In a future power system featuring significant renewable generation, the ability to manipulate domestic demand through the flexible operation of heat-led technologies such as heat pumps and micro-combined heat and power could be a critical factor in providing a secure and stable supply of electrical energy. Using a simulation-based approach, this study examined the linkage between the thermal characteristics of buildings and the scope for flexibility in the operating times of air source heat pumps. This was assessed against the resulting impact on the end-user’s comfort and convenience. A detached dwelling and flat were modelled in detail along with their heating system in order to determine the temporal shift achievable in the heat pump operating times for present-day and future dwellings. The simulation results indicated that the scope for shifting heat pump operating times in the existing building stock was limited, with time shifts of only 1–2 h achieved before there was a serious impact on the comfort of the occupant. However, if insulation levels were dramatically improved and substantial levels of thermal buffering were added into the heating system, sizable time shifts of up to 6 h were achievable without a significant impact on either space or hot water temperatures.

Integrated simulation of photovoltaic micro-generation and domestic electricity demand: a one-minute resolution open-source model

Domestic photovoltaic generation can partially offset the electricity demand within an individual dwelling. The net demand may be readily estimated on an annual basis, but modelling its import and export with respect to time, is more complex. A key issue is that domestic electricity demand, particularly lighting, is significantly influenced by the outdoor light level, which of course also has a direct effect on photovoltaic generation. Thus, realistic time-step simulation of the net demand requires that the two components are modelled with respect to a common representation of the solar irradiance. This article presents the construction of an integrated model that provides data at a one-minute time resolution, built upon a fully validated high-resolution electricity demand model. An open-source software implementation of the integrated model in VBA within Microsoft Excel is described and is available for free download.

A modelling framework for the study of highly distributed power systems and demand side management

This paper presents an approach to the modelling and simulation of highly distributed power systems, in the context of existing UK distribution networks. The model is part of a framework to assess the network impact of high-penetrations of micro-generation, as well as demand side management (DSM) measures. This framework supports the representation of the 11 kV and low voltage distribution network within a geospatial model, together with an integrated load-flow computational capability. A domestic electricity demand model is incorporated within the framework that generates synthetic demand profiles within the network. The framework is used to investigate the impact of distributed generation for a case study of a regional UK town, together with the surrounding villages and rural locale. The scope includes primary distribution substations, 11 kV feeders and a low-voltage distribution network, serving approximately 35 000 domestic properties and commercial premises. This case study also includes the measurement of minute-by-minute residential electricity usage within a number of individual domestic houses and distribution sub-stations.