The Details

The United States power sector has become increasingly dependent on natural gas pipeline networks to provide gas-fired power plants with the fuel needed to deliver flexible generation. Their dependence on this supply results in electricity and gas network coupling, requiring careful planning of both systems to ensure that electricity and natural gas outages are avoided. These outages, especially if prolonged, can cause loss of life, economic loss, and long-lasting damage to infrastructure.

Unlike coal and nuclear power plants, most gas-fired power plants do not store extra fuel on-site. They rely on pipeline deliveries to meet their fuel needs. A key value they bring is the ability to quickly ramp up to meet changes in electricity demand and gaps in available generation, and their fuel demand can change very quickly as a result. In order to avoid interruptions in gas supply, the pipeline uses linepack (gas stored in the pipeline) and local storage.

Are these methods sufficient to keep the power on in times of extreme weather?

To answer this question, encoord and The National Renewable Energy Laboratory (NREL) ran scenarios with encoord’s software SAInt to analyze a real-world coupled gas and electricity network during a period of stress and low flexibility of gas supply.

The Key Scenario: A severe cold front with low wind

• A weather front moves in with a significant decrease in temperature, lasting for several days.

• The wind drops to low levels, significantly impacting generation.

• The lower temperatures lead to higher gas demand for heating (residential and commercial).

• Electricity demand also increases due to low temperatures.

The real-world scenario was mitigated by the gas network operator. The increased generation requirements from the gas-fired power plants compelled the gas network operator to reduce gas deliveries to other parties to ensure deliveries to both the gas-fired power plants and a local distribution company (LDC), which delivers gas to other customers.  For this scenario, NREL and encoord explored what might have occurred if the gas network operator had been unable to exercise the flexibility with interconnected pipeline deliveries to supply the gas-fired generators.

The Findings

• Without the flexibility of gas supply, curtailment of gas generation occurred.

• More expensive generation sources were required to handle the generation demand.

• There was a high probability for load shedding to keep up with the demand in important areas, or worst case, prolonged power outages.

Recommendations: How can we ensure the lights and heat stay on?

There are ways to ensure that all customers receive power in times of extreme events, including:

• Improve forecasting of coupled gas and electric demand under extreme weather conditions.

• Change gas nominations (requested allocations) to a shorter time scale (i.e., hourly or subhourly instead of day ahead or intra-day)

• Coordinated investment and operation of gas storage.

• Coordinated power system investments (i.e. energy storage, transmission) to reduce the need for rapid changes in natural gas offtakes.

• Modeling and planning around the coupling points of the gas and electric systems.

Want to learn more about how SAInt can help with gas security? Contact Us