The DDDC Factor is a calculation done by Atlanta Gas Light Company (AGL) that indicates how much natural gas deliverability is reserved (or ‘dedicated’) for your home or business if Atlanta were to reach an average daily temperature of 10oF (a ‘design day’), making it unique to each home or business. You’ll see the DDDC Factor, or Dedicated Design Day Capacity, on your bill because it is used to calculate a customer’s AGL Pass-Through Charges.
How is the DDDC Factor Calculated?
The DDDC covers the cost of operating the system on the coldest day of the year, and it recalculated every year. AGL is responsible for having enough pipe and storage capacity to meet every customer’s need during extreme cold weather conditions. For most residential customers and small businesses, natural gas is used for heat. And when it’s cold outside, you’ll want enough natural gas to keep your home or business warm. Therefore, your DDDC Factor is calculated using past usage history, the number of gas appliances and additional factors that determine the location’s demand on the system.
If you are a new customer and Atlanta Gas Light does not have 12 months of consumption history, then the DDDC is calculated based on the gas equipment used, the footage and type of structure.
Why did my DDDC change?
AGL recalculates and updates the DDDC at your location annually, so each September you will see an updated DDDC on your bill. During this yearly calculation, AGL reviews the past gas consumption and usage pattern at your home or business. The most important influence on your DDDC calculation is how much gas was used last year during the coldest period of the year compared to your typical summer usage (if any). A calculation is done to determine how sensitive your consumption is to cold weather and then used to set your DDDC indicating how much capacity should be reserved for your home or business. Because your DDDC affects the AGL Pass-Through Charges, you may see a change in the amount of your bills year to year if your DDDC is adjusted.
Remember, your DDDC Factor is tied to your location as opposed to you. So, if you move, your DDDC will be changed to the DDDC of your new location and then will be reset, as usual, in September.