TANKS 4.09 was a commonly used model for estimating tank emissions, but is no longer supported by the EPA. Excel workbooks have been developed to address the shortfalls in TANKS 4.09, but rely heavily on macros to estimate emissions. The macros make it very difficult for users to troubleshoot when unexpected results are produced. Our client asked JBE to create tool that made it easier for them to perform quality assurance and troubleshoot tank emissions calculations so that they could be confident in their permit limits and emissions compliance.

Approach:
JBE developed a fully transparent Excel tool so the user can easily follow the calculation process from column top to column bottom. There are instructions that guide the user in troubleshooting results that have errors, zeroes, or just look “off”. Side-by-side inputs and outputs allow the user to:

(1) easily trace back to see where an input was missed or entered incorrectly,
(2) fix the error, and then,
(3) look at the results again to ensure they are
correct – all on the same workbook tab.

Impact:
An easy-to-follow process reduces time to input data and helps the client identify errors easily. This reduces the risks associated with incorrect calculations such as:

(1) indicating exceedances when they aren’t real, and
(2) under-forecasting potential to emit resulting in permit limits that are too low, for example.