Scenarios for Large-Scale PV Deployment

There are many possible scenarios for large-scale PV deployment in the UK, covering a range of scales, technical solutions, timescales, geographical bias and end-use markets. Examples of possible scenarios include:

1. The use of grid-connected PV systems within the facade of a commercial building

   Issues to consider are the likely output power levels of such systems as compared with the likely on-site load. These systems are likely to be small in number, but relatively large in size (i.e. possibly larger than are covered by the current PV connection guidelines, >5kW). The sort of issue that may be raised is what happens at the weekend, especially on summer Sundays, when the building is unoccupied (therefore electricity consumption is likely to be very low), but the PV system is still generating and exporting electricity to the network.

2. The retro-fit of PV systems to existing houses.

   This scenario is likely to offer geographical diversity, but some clustering is likely to occur due to both the "copycat effect" and local influencing factors (e.g. remote rural location, local incentives). The fitting of retro-fit systems to existing houses also implies that the existing network will be expected to cope with the effects of the embedded generator with the minimum of additional cost (ideally zero additional cost). Generically, there are different types of electricity network in existence in the UK. These can be loosely classified as urban (i.e. cable networks) and rural (i.e. overhead line networks). There are sub-classifications within these two definitions which could interact differently with the connection of embedded generation (i.e. interconnected/non-interconnected, radial/mesh, hybrid networks).

3. The use of PV systems on new housing

   In this scenario the PV system is fully integrated as part of the architectural design of the house. Houses specifically designed to accommodate PV systems are likely to have other novel features, such as high thermal efficiency and low overall energy consumption. This is likely to impact on the load profile of the house and therefore on the ratio of electricity imported and exported to the network.