|The UK’s electricity transmission and distribution systems have little spare capacity to accommodate the widespread changes in volume and location of power flows arising from planned changes in generation type and characteristics, and from major changes in demand patterns. Gaining consents for the construction of new overhead lines is extremely time-consuming and costly. Without action, this will increasingly constrain the necessary changes in generation and demand.
The ‘Network Capacity’ project has assessed the feasibility of using new technologies now emerging in the marketplace or in development, including multi-terminal HVDC systems, in novel ways in order to provide increased Transmission & Distribution system capacity and improved management of network power flows, in order to facilitate increased renewable energy installation levels in the UK.
This document contains two reports:
- Appendix A.Barriers to Development of FACTS Devices in UK Grid (Task 4; begins on page 11)
- The FACTS (Flexible AC Transmission Systems) devices considered in this report, SVCs, STATCOMs and TCSCs, do not appear to have any major technological barriers to further utilisation and development. The major barriers for further utilisation are cost and footprint.
- Historically in the UK, the advantages offered by the FACTS devices have not, generally, been deemed to merit the high costs and large footprints required. However, this may change as more generation is sited far away from load centres.The requirement to control greater power flows over a larger transmission network will necessitate more voltage and power flow control equipment.
- It does not appear that cost of the systems will diminish greatly but some of the alternatives, such new lines, are increasingly more expensive and problematic. These drivers and the likely expansion of HVDC may put a strain on the small core of engineers competent to design FACTS and HVDC devices.
- Each of the active network management technologies discussed have individual barriers to development but the largest general concern expressed by network operators is that of creating niche pockets of non-standard technology around the network and causing legacy problems. To overcome these issues it will be necessary to develop and demonstrate modular solutions that will allow staff to plan, design, maintain and operate ANM systems across the network in a standard manner, preferably not too dissimilar to current methods. The use of ANM has the potential to change the operation of the transmission and distribution networks in the UK but it will be necessary to develop and adopt flexible industry standards and frameworks to allow this to occur.
- Appendix B.Environmental and Social Impacts of FACTS Devices in UK Grid (Task 5; starts page 37)
- This report is focussed on the potential environmental and social impacts associated with the application of FACTS (Flexible AC Transmission Systems) in the UK transmission and distribution network to provide enhanced network power flows and as a result release more capacity within the T&D systems.
- The assessment was done in terms of ecology, designated sites, noise, overhead lines, substations, mitigation options, construction noise, landscape and visual impact, air quality, cultural heritage, hydrology, land contamination, land use, waste, access and traffic management, socio-economic factors (such as employment, benefits to local businesses during construction, loss of recreational areas) EMF exposure and impacts on carbon balance.
- When considering each candidate technology the characteristic that appears to have the most influence on the potential for environmental impacts is the associated footprint. Another important consideration is that all but one of the options would be sited alongside an existing substation while the other requires the development of an entirely new site.
- With these factors in mind the two preferred candidate options from an environmental perspective are:
- Static synchronous compensators (STATCOMs); and
- Thyristor Controlled Series Compensators (TCSCs) at either end of the selected line