A Quick Guide to the IWCA Greenhouse Gas Emissions Calculators

Greenhouse gas (GHG) emissions inventories are critical in a winery’s path toward achieving net zero emissions. With a detailed understanding of its carbon footprint, a winery can take strategic and ambitious action.

To help wineries measure (and reduce) their emissions, IWCA has developed region-specific GHG calculators. Each is free and open to any winery to download and use. Tailored to the United States, New Zealand, and Australia (with more regions to come!), our GHG calculators:

  • were developed specifically for the wine sector, covering vineyard and business operations unique to the industry.

  • comprehensively cover all material sources of emissions in the wine value chain across Scopes 1, 2, and 3.

  • are aligned with World Resources Institute (WRI) GHG Protocols and ISO-14064 standards.

How the calculator works

Our GHG calculators are built upon three essential steps:

  1. A winery collects and fills in its own data for all direct and indirect sources of emissions. The calculator details these activities across different tabs, categorized by scope and business function.

  2. Emissions factors are applied to the winery’s source data to calculate how many GHG emissions—quantities of CO2, CH4, and N2O—are associated with each activity. Our calculators are pre-populated with regionally specific emissions factors (calculations and references are explained in the next-to-last tab of the workbook). Sit back and watch the math happen!

  3. Finally, the calculator quantifies, summarizes, and reports total GHG emissions in a standard unit of measurement. Once again, we have pre-calculated conversion formulas so that a winery’s data is output into metric tons of carbon dioxide equivalent (MT CO2e).

The summary table quickly displays a winery’s emissions breakdown across business functions and scopes. While this provides critical insights, we also require IWCA wineries to conduct a third-party audit of their completed inventories to verify and demonstrate the credibility of their inventory. This is an important requirement for membership in IWCA.

Tips for working in the calculator

The IWCA calculator is the most comprehensive GHG inventory tool in the wine industry. Because it is so detailed, we acknowledge that the tool may feel daunting for first-time users.

The calculator includes step-by-step instructions to streamline and simplify the process. Most calculations are pre-configured, and the detailed activity-by-activity tabs are reported in a summary tab to display high-level insights in a digestible format.

It’s also worth the effort: the more detailed and comprehensive the inventory, the more accurate information a winery will obtain about its climate footprint.

What if a winery is missing data for certain activities?

“You always want to use actual data first, but as a last resort, you can make estimations,” explains Josh Prigge of Sustridge Sustainability Consulting, who provided technical expertise to IWCA to develop the calculators. “Estimations are okay and will be accepted by a third-party verifier as long as you are clear about what methodology is used to make those estimations and as long as the assumptions are reasonable.” Peer-reviewed journal articles, industry averages, and other research can be sources of information to estimate emissions (but, of course, will never be as accurate or valuable as actual winery data).

From measurement to results

A GHG calculator helps a winery measure and report on emissions—but most importantly, it provides a winery with a roadmap for reducing emissions.

In the calculator’s summary tab, a winery can quickly identify its largest emissions sources to pinpoint how certain changes to vineyard and business operations could significantly reduce overall emissions. A winery can also use the calculator to model those impacts. Once a winery has completed a baseline inventory in the calculator, Josh Prigge suggests plugging in new numbers to see how these changes impact overall emissions: for example, “Try calculating the emissions impact of reducing the weight of your bottles by 20%.”

If you are a winery based in Australia, New Zealand, or the United States, our calculators are ready for you to use. If you are based in other regions, subscribe to our newsletter to be the first to know when we release new tools. We also encourage you to get in touch if you’d like to support us in developing new regional calculators or to learn more about IWCA membership!