Failure of gas supply infrastructure
| Impact | 5 |
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| 2 |
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| Likelihood | |||||||||||||||||||||||||||||||||||||||||||||||||||
| ID | 27 |
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| Risk theme | Accidents and system failures |
Impact & Likelihood
| 5 | Catastrophic |
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| 4 | Significant |
| 3 | Moderate |
| 2 | Limited |
| 1 | Minor |
| 5 | >25% |
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| 4 | 5-25% |
| 3 | 1-5% |
| 2 | 0.2-1% |
| 1 | <0.2% |
Background
The UK has a diverse and highly resilient gas network. Industry works to continuously minimise the risk of unplanned disruption while taking the risk of such outages into account in forward planning. Natural gas is a crucial fuel source that is used to heat homes and businesses, generate electricity or act as a feedstock for industrial processes across the UK. Though unlikely, a failure of gas supply infrastructure may result from a technical issue or accident, with serious impacts on human welfare, essential services and the economy.
Scenario
The reasonable worst-case scenario is based on a technical failure or accident causing a significant loss of UK gas supplies in winter. Domestic gas customers in the region would lose their gas supply. If the loss of supply led to a gas shortfall, emergency procedures could be required to safely balance and maintain pressure on the network by stopping supply to large industrial users, including a proportion of gas-fired power stations (as the largest users). Disconnecting gas supply to electricity generator stations could cause a shortfall in electricity supply. In the event of a prolonged electricity supply shortfall, rolling power cuts lasting 3 hours a time may be required to balance supply and demand. Within this process, some critical sites would be protected from disruption, with the remaining disconnections being evenly distributed across Great Britain.
Further information on established emergency procedures for a gas or electricity emergency can be found in the National Emergency Plan for Downstream Gas and Electricity.
There would be casualties and fatalities from a lack of heating, access to necessary medical treatment, exacerbation of an existing condition, or limited ability to use gas-fired cookers safely. However, impacts would depend on the scale of disruption. Priority of gas supply would be given to domestic users (as they take longer to reconnect following disconnection for safety reasons). Within this process, some critical sites would be prioritised for supply.
Key assumptions
The scenario assumes that impacts would be greatest during a severe winter that sees high consumer demand and low supplies from other sources.
Response capability requirements
There would need to be preparations in place to support wider recovery and the continued operation of multiple sectors. This includes functioning telecoms, emergency services and fuel distribution. Additional support could be provided via mutual aid agreements.
Recovery
Restoration of the affected gas infrastructure could take approximately 3 months, at which point rolling power cuts would no longer be required, as gas supplies to electricity power stations would resume. It would take a further week for industrial gas customers to be fully restored and weeks or months for some sites to return to service. It would take several months to restore domestic gas customers impacted by the initial loss of supply.