The duck curve is a graph that illustrates the changing demand for electricity during a typical day, with a sharp increase in the morning as people wake up and begin their daily routines, a peak in the late afternoon as everyone arrives home and turns on lights and appliances, and a decrease in the evening as people go to bed. The curve gets its name from the shape of the graph, which resembles the profile of a duck.

The duck curve has become increasingly relevant as more renewable energy sources, such as solar and wind power, are integrated into the electrical grid. These sources generate power during the day when the sun is shining and the wind is blowing, but not at night or when conditions are not favorable. This can lead to an oversupply of electricity during the middle of the day, when demand is low, and a shortage of electricity in the evening, when demand is high.

To address this problem, utilities are exploring ways to store excess energy during the middle of the day and release it in the evening when demand increases. This can be done through the use of batteries, pumped hydroelectric storage, or other energy storage technologies. Additionally, utilities are also looking at ways to shift some of the electricity demand from the evening to the middle of the day, for example by encouraging people to use electric vehicles for transportation and charge them during the day when solar and wind power are abundant.

In summary, the duck curve illustrates the challenges that utilities face in balancing electricity supply and demand as more renewable energy sources are integrated into the grid. The use of energy storage and demand management strategies can help to mitigate these challenges and ensure a stable and reliable electricity supply.

The concept of peak, off-peak and mid-peak rates is used by utility companies as a way to manage and balance energy demand. These rate structures are implemented to encourage energy consumption during periods of lower demand, and discourage consumption during periods of higher demand. This can help to keep energy prices more stable and reduce the strain on the power grid during peak usage periods.

Peak hours are the times when energy demand is at its highest, and the cost of electricity is the most expensive. This is usually during the daytime and early evening on weekdays, when people are at home and businesses are operating. As an example, peak hours in New York City might be from 8am to 10pm on weekdays. These peak hours are typically set by the utility company and may vary depending on the region.

Off-peak hours are the times when energy demand is at its lowest, and the cost of electricity is the cheapest. This is usually at night, when people are asleep and businesses are closed. As an example, off-peak hours in New York City might be from 8pm to 8am on weekdays and all day on weekends. The off-peak rates are set to encourage people to use appliances and other energy-consuming devices during these hours to reduce the strain on the power grid during peak hours. This also helps to ensure that the energy supply is sufficient to meet peak demand.

Mid-peak hours are the times when energy demand is moderate, and the cost of electricity is higher than off-peak but lower than peak hours. These hours are usually in the early morning and late evening, and the rates are designed to encourage people to use appliances and other energy-consuming devices during these hours instead of peak hours. As an example, mid-peak hours in New York City might be from 10am to 4pm on weekdays.

To sum up, peak, off-peak, and mid-peak rates are designed to balance energy demand and costs by providing incentives for energy consumption during off-peak and mid-peak hours when demand is lower and costs are lower, while discouraging energy consumption during peak hours when demand is highest and costs are highest. This helps to keep energy prices more stable and reduce the strain on the power grid during peak usage periods. Additionally, by using energy at off-peak hours, the chances for blackouts and brownouts are reduced.