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Flexible natural gas: Why it makes a good backup generation source 

Strategically adding fast-ramping, flexible natural gas to SRP’s generation mix helps support our commitment to reduce carbon emissions while also keeping the power on as the Valley’s demand grows. Here’s how. 

Have you ever wondered what powers the lights and other electric appliances in your home, especially in one of the fastest-growing regions in the country? 

Coal, solar, wind, nuclear and hydroelectric sources are all commonly known methods for powering homes and businesses. According to the U.S. Energy Information Administration, however, natural gas was the largest source — about 38% — of U.S. electricity generation in 2021.  

What is natural gas? 

Natural gas, which is made up of four hydrocarbon atoms and one carbon atom, is considered to be a relatively clean fossil fuel, both “colorless and odorless in its natural state,” according to the American Gas Association. And the EIA states that it emits less CO2 than coal or petroleum generation for the same amount of power generated.  

As utilities like SRP work to reduce carbon emissions through coal plant retirements and the integration of renewable energy generation like wind and solar, natural gas is one tool that we can use to help reach our goals.  

This becomes increasingly important as the Valley experiences growth at three times the national average. In fact, SRP is forecasting 35% growth in peak electricity demand by 2030, which is the equivalent of the amount of power needed to serve nearly 600,000 average-sized Arizona homes.  

This power capacity simply does not exist in the current market, and SRP will need resources like natural gas to ensure power is available to customers at all times — especially during periods of peak demand, such as Arizona’s famously hot summers. 

How does natural gas generation support reliable power for customers? 

There are two common strategies for powering the grid with natural gas: baseload generation and flexible generation. 

Baseload generation plants, says, “are the production facilities used to meet some or all of a given region’s continuous energy demand, and produce energy at a constant rate.” Plants like the Navajo Generating Station (NGS), which SRP recently retired, are examples of this ongoing generation resource. They run nearly all year round, providing power to the grid whenever it is needed. 

Technology called flexible, quick-start natural gas offers another type of natural gas generation. Similar to a plane’s jet engine, modern gas turbine technology can ramp up to full production in less than 10 minutes, and the flexible nature of these turbines allows one or both to power up to meet demand under different system conditions.  

This technology differs from combined-cycle natural gas units, or baseload natural gas units, which run at a higher capacity factor, have a longer startup duration and run for more hours out of the year.  

Why SRP believes in flexible, quick-start natural gas 

Fast-ramping, flexible natural gas turbines are used to help SRP ensure power reliability for our customers during times of highest peak demand or during capacity-constraint situations that impact the power grid. These include extreme summer weather events, wholesale price spikes and unexpected system issues.  

They are powered on to serve peak customer demand for short durations of time and help to provide a reliability backbone. This natural gas backbone is one way to incorporate more clean generation and storage options into the grid, because the turbines provide quick-start, dependable energy that is available when renewable resources have fluctuations in output or are not producing power, and when battery systems are charging. 

The future is sustainable, affordable and reliable 

Natural gas isn’t a full-time solution for the retirement of coal plants like NGS. Instead, flexible natural gas generation using fast-ramping turbines provides reliable, affordable energy while we work to integrate more solar, battery and other renewable resources into the grid. 

To see a list and details of projects SRP is planning, siting and constructing to help meet the Valley’s energy needs, visit Grid management and improvement projects.

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