How PJM Prepares for Summer & Winter PJM works with its member companies to assure that the system is positioned to run reliably no matter what the weather brings. Winter and summer are the peak seasons for energy use. Temperatures are more moderate and demand isn’t as high in the months between winter and summer when maintenance outages are typically scheduled. There are some differences to consider for each season. Both summer and winter operations rely on using a diverse fuel mix for generation. However, in the winter, consumers rely on natural gas for their heating, and some electricity generators rely on natural gas to run their plants. Gas-electric coordination becomes more critical in the winter. Seasonal Differences Select the icons to see ways these differences are addressed. Summer Hot summers drive air conditioning use. Usually, summer has the highest peak usage of electricity for the year. Prolonged heat waves can lead to increased power load on transmission lines and wear on facilities. Wind generation is not as strong as in winter. Typically more demand response resources are available. Winter Cold weather causes high demand for natural gas because of the need for residential heating systems and fueling power plants. Delivery of gas from pipelines can sometimes be affected by severe weather conditions. Electricity from wind generation is higher than in other seasons. Cold temperatures can impair the start-up of plants that aren’t already running. Ice and snow can cause problems on distribution lines. Consumers can participate in demand response programs by agreeing to curtail AC use. Capacity Performance assures all units that committed to be available are available and meet stringent requirements. The system is monitored closely and conservative steps are taken behind the scene to avoid emergency issues. New PJM market rules make it easier for seasonal capacity resources to aggregate with resources stronger in the opposite season. PJM members have economic demand response programs such as air conditioner cycling programs to reduce load during peak energy use times if needed by PJM. Generators must complete a fuel survey to assess firm fuel supply. Generators must assure PJM they have firm fuel contracts and must complete a fuel survey. New PJM market rules make it easier for seasonal capacity resources to aggregate with resources stronger in the opposite season. PJM surveys generation units to assure they have completed a start-up exercise pre-season. Communication between distribution companies and PJM enables monitoring of potential impacts to the grid.