GRIDLOCK project is an NGED led project delivered in partnership with the PNDC and the University of Strathclyde. The project will investigate the impact of DC injection from inverter-based LCTs, including solar, battery storage and Vehicle-to-Grid, on LV distribution network assets. Through a staged programme of research, laboratory testing and real-time simulation, the project will assess potential impacts on transformers, cables, protection systems and power quality. The project aims to develop an evidence base to support future engineering standards, network planning and asset management decisions, whilst determining whether current UK DC injection limits remain appropriate under DFES scenarios. Harmonising the standards, would provide benefits to customers by reducing inverter costs for all LCTs, this is a direct result of reducing testing and certification requirements.

Benefits

GRIDLOCK is classified as a research project and therefore the primary benefit is the generation of new knowledge and evidence. The project will improve understanding of the impact of DC injection on low-voltage distribution networks and associated assets, including transformers, underground cables, protection systems and monitoring equipment. 

Benefits expected from this project include:

• Reduced uncertainty for future engineering standards and network planning decisions.
  Improved asset management and evidence-based investment decisions.
• Reduced inverter compliance and certification costs if harmonisation with international standards is demonstrated to be technically feasible.
• Increased deployment of low-carbon technologies.
• Increased flexibility participation.
• Potential deferral of conventional network reinforcement.
• The recipients of these benefits would include electricity customers, Distribution Network Operators, equipment manufacturers, DER installers, standards bodies and regulators.

These benefits will be dependant on successfully harmonising standards, this would therefore reduce inverter costs for installation of LCTs.

Based on NGED's Future Energy Scenarios (DFES), rooftop solar deployment across NGED licence areas is forecast to increase by an average of approximately 7.5% per annum through to 2050. Starting from a baseline of around 600,000 domestic solar installations by the end of ED2, derived from approximately 6GW of installed solar generation and an assumed average domestic installation size of 5kW, the number of connected solar customers is expected to grow significantly over the coming decades.

The project has the potential to reduce the cost of solar inverter deployment by harmonising standards and reducing UK-specific certification and testing requirements. A conservative saving of £300 per inverter installation has been assumed. Applying this saving to the forecast uptake of domestic solar installations across NGED's licence areas results in a cumulative customer benefit of approximately £714 million by 2050.

In addition to the direct benefits realised by NGED customers, harmonisation of UK inverter standards and certification requirements will enable the same cost reductions to be realised across other UK distribution network operators. As manufacturers and installers adopt a common set of requirements, customers throughout Great Britain will benefit from lower inverter costs, reduced certification burdens, and more efficient deployment of domestic solar generation, increasing the overall customer value delivered by the project.