Ask the Expert: How Does Hot Weather Strain the Energy Grid?

As South Carolina faces another extremely warm summer, Central Electric Power Cooperative is working tirelessly to ensure our member cooperatives continue to receive the energy they need at affordable rates. To better understand exactly what Central is doing behind the scenes, we interviewed our Power Supply Portfolio Manager, Steven Harrington, to dive into how the hot weather impacts our electric power grid and what we’re doing to support the state’s needs.

1. Why is the grid more strained during the summer months?

When we experience multiple days with temperatures in the 90s to 100s, our air conditioners are working overtime and run more frequently, increasing peak demand on the grid. Peak demand causes our power plants to run at maximum capacity throughout the day to ensure there is enough power to meet demand. We typically have enough planning reserves to meet excessive demand, but it is possible for the grid to become too strained, leading to potential unplanned outages.

2. Explain ‘peak demand’ and why it matters.

Peak demand refers to the highest level of electricity use during a given hour each day. It typically occurs between 3 to 6 p.m. in summer and 6 to 9 a.m. in winter. Utilities must accurately forecast peak demand to ensure enough power is available. If supply falls short, temporary outages may be necessary to maintain grid stability.

3. What role does Central play in increasing grid reliability?

Central plays a huge role in increasing grid reliability and has implemented several programs for members to help better manage our loads and reduce peak demand. Examples of these programs include Beat the Peak, smart thermostats, water heater controls, voltage controls, and controls to bring large industrial members temporarily offline during peak demand. These programs save members money and help support the grid during critical times in the summer and winter.

4. How has population growth impacted the grid in the past several years?

South Carolina’s population and economic growth are putting more stress on the grid. Industrial expansion, residential development, and interest from large data centers all contribute to higher demand and thus a need for more generation. Central works closely with power suppliers to ensure current and future energy needs are met, without disrupting service to existing members.

5. What are utilities doing to strengthen the grid and prepare for summer surges?

Utilities continue to plan and prepare to either build or purchase additional power resources to meet current and future demand. We also work closely with our power suppliers to ensure members receive reliable, affordable energy for years to come. 

The programs like Beat the Peak and the smart thermostats make a huge difference, so Central also works closely with member cooperatives to provide these educational resources for their members. Some members are also implementing time-of-use rates to incentivize members to reduce energy usage during peak hours during the day, which has been very successful in lowering energy use during peaks and the grid strain.

6. Are renewable energy sources, like solar, playing a role in relieving some of the pressure?

Yes, solar helps relieve some of the pressure on natural gas and coal plants, especially during the summer months. With the peak demand happening between 3 p.m. and 6 p.m., the sun is still out and can help generate energy to support the grid. However, solar doesn’t fully cover all generation needs since the sun is not always out. We are also investing in battery energy storage systems that store energy during low-demand periods, which can be deployed during peak hours.

7. What can households do to help lessen the strain on the grid in South Carolina?

Households can sign up for peak alerts and participate in programs from their utility providers. If they are cooperative members, there are several programs in which they can participate that help the cooperative reduce peak demand.. Ultimately, the more households working together to reduce demand during peak periods, the greater impact we will see on the grid.

8. Are there any long-term strategies being discussed to help boost grid reliability in South Carolina?

The largest impact will be the South Carolina Energy Security Act (H.3309) the South Carolina General Assembly passed earlier this year. This bill enables more in-state power generation, streamlines regulations, and prioritizes long-term grid reliability. It’s a strong example of state leaders responding to energy needs. 

To ensure we continue meeting future grid demands and provide affordable, reliable energy, we will need to continue collaborating between utilities and lawmakers. Strategic partnerships and smart investments in our state’s energy ensure a brighter, safer future for South Carolina.