What Is the DDDC Factor?

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.

DDDC Factor Calculation Bill Example from Gas South

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.

For more information, visit Gas South’s Frequently Asked Questions or AGL’s Guide to Atlanta Gas Light Charges.

20 thoughts on “What Is the DDDC Factor?”

  1. I have charges for a customer service fee, an AGL Pass Through Charge, and Taxes each month although I don’t have any gas consumption for the majority of the year in the summer months 0 CCFs.

    Is there some way to avoid these fees when I’m not consuming any product? I’ve looked into this before and I think there was a re-connect charge that amounted to more than just paying the fees and taxes?

    1. Bill, thanks for the comment! There is a way that you can avoid paying the customer service fee, AGL Pass Through charges, and taxes throughout the warmer months. We call our customers that chose this option Seasonal Customers. You can turn your gas off in the spring and turn it back on in the fall, but there is a reconnect fee associated with the process. Depending on your account, you may find savings by going seasonal. We’ve sent an email to the address listed here and we’d love to take a look at your account for you to help you determine if this is the right option for you. Please reply to the email with your account number and we will call you to figure out how we can help. Thanks for reading Bill!

  2. So…if I happen to be on vacation next winter, during the coldest month, and use very little gas, my DDDC Factor will be lower for an entire year?

    1. Chesley,

      Thanks for reading and commenting with your question. You definitely have the right idea about how your natural gas use will affect your DDDC Factor. However, you never know when the coldest period of the year will be. For instance, this past March was unusually cold. Your DDDC Factor calculation also includes some additional factors that are not dependent on your individual natural gas use, but the entire Atlanta Gas Light system as a whole. We also hope, that for your sake, your DDDC Factor doesn’t determine when you take vacations :). If you have any further questions, feel free to email us at social.media@gas-south.com. Thanks again, Chesley!

  3. I just reviewed my September bill and the Interstate Pipeline Charges increased from .973 DDDC to 16.209 DDDC! Yikes! Then the AGL pass through charge changed from $36.54 to $199.38. I used less gas last month and am paying $235 more. Is this correct? Can I have a representative explain this to me?

    Thank you in advance for your assistance.

    1. Hi Jason, thanks for reading our blog! We are more than happy to look into your account, verify that everything is correct and talk through the charges with you. Please send me an email at social.media@gas-south.com with your name, phone number and account number. We will call you as soon as possible. Thank you.

  4. Why do I not have a DDDC rate on my bill? It just has a AGL #. Thanks!!

    1. Jeff, we can definitely look into this for you. Please email me at social.media@gas-south.com with your account number and a contact number. We will look into it and give you a call. Thank you.

  5. Thai, we have been getting a lot of spam comments lately and we apologize for that! We are working towards adding an anti-spam application to the comments section to fix this issue. Unfortunately, we do not have a way to remove you from receiving notifications. Hopefully the application will cut down on the notifications you receive. Thanks for following us.

  6. What is the reason for ever month DDDC factor is different in gas bill. Thank’s for your time.

  7. My AGLC Base Charges are 56.88
    GNG Customer Service Charge is 4.99
    Gas Charge is 11.31
    Sales Tax is 4.45

    My Questions are

    1 – Why is my AGLC so High?
    2 – Why should I pay Sales Taxes on Service Charges. My Gas Usage was just 11.31.

    I am on Fixed income, I do not turn my Furnace on any more. My only Gas use is Stove and Hot Water Heater. My Water Bill is 8.00 per month, so I’m not using a lot of Hot Water.

    Given the Run around from my Gas Company.

    Please Help.

    1. Buford, thank you for your comment. I’ll be sending you an email to the address listed with your comment to try to help. Thank you!

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  9. Hello,

    If my account is new, I never used gas, and the price of my DDDC is realy high. How gas South calculate this? I need to know because I think my DDDC is wrong. Thank you.

    1. Thank you for your comment. I’ll be sending you an email to the address listed with your comment to try to help.

      1. Antonio – My colleague tried to call the phone number on your account to answer your question, but he has not been able to get a hold of you. If you still have questions regarding the price of your DDDC please let me know. Thank you!

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