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Measuring the carbon footprint of creatives and ad formats

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Terminology: Placements, Ad Formats, Creatives, and Assets

A placement is an empty spot on a particular media property where an ad could be inserted. An “ad hole” if you will! Examples - a rectangle on a web page; the interstitial between levels of a game, the airtime before a podcast starts, a wall at an airport. In an embedded placement (web page, social news feed) the ad sits inside content that the user controls. In an ad-primary placement the creative IS the content and controls duration.

A media asset is an image, video, audio, or text that the advertiser wants to deliver to the consumer. An ad format is code, metadata, or other non-media assets that, in combination with one or more media assets, facilitate the delivery of the advertisement to the consumer.

A creative is one or more media assets combined with an ad format. For instance, a CTV creative would typically be a 15-second or 30-second video (the media asset) wrapped in VAST/VPAID (the ad format) and deployed in a commercial break (the placement).

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Methodology

The lifecycle of a creative starts with its production. Depending on the channel and format, creative production can be very lightweight (typing a couple of lines of text into a search tool) or have a significant carbon footprint (an on-location shoot with a full crew). Currently, this project does not include modeling creative production or transcoding of creative assets, but we are considering these for future development.

The use phase of a creative has three areas of impact:

  • The consumer device uses energy to deliver/render the creative
  • Energy is used to transfer the creative from a server to the device
  • Various vendors participate in the delivery and reporting of the creative.

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Consumer Device Emissions

To determine consumer device emissions we need to know whether the ad controls the user experience or is embedded into the user experience.

  • For an embedded placement - for instance, a banner ad on a web site, or a sponsored post in a social news feed - the energy use should be proportionate to the percentage of the consumer device used by the creative and the average time that the placement is in view.
  • For a ad-primary placement (standard TV/radio commercial, etc) the energy used by the consumer device during the display of the creative is determined by multiplying the duration of the creative by the energy use of the consumer device.

The time the ad is on the device multiplied by the percentage of the screen/device used by the creative is device coverage-seconds. The embodied emissions for the delivery of the creative are (device coverage-seconds) x (embodied emissions per second) and the usage emissions are (device coverage-seconds) x (energy per second). See consumer device methodology for details on the per-device calculations.

For instance, a 30 second video ad played on a television will use 0.73 Wh of energy and an allocation of 0.63 gCO2e from the production of the television. A split-screen ad using half the screen would use half the energy and production emissions.

Format notes:

  • We consider out-of-home media to have no consumer device emissions because a consumer device is not required to view the creative
  • For dynamic display environments like a website where a banner may use only a fraction of the screen and be viewable for a variable duration, the ideal measurement would use placement size / screen size x time in view.

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Data Transfer Emissions

For CTV, where the creative is typically inserted into the video stream, we use a slightly modified version of the the Carbon Trust “Power Model” to calculate emissions as described in the data transfer methodology. This uses the duration, network type, and device type to calculate the marginal impact of the creative on network infrastructure.

For all other channels, we use the conventional model based on the payload of a creative (the number of bytes transferred to display the ad). We calculate the energy used per GB from the data transfer methodology based on the network type.

An ad format consists of:

  • Static assets: anything that is not an video, including images, players, metadata, HTML, and Javascript.
  • Video assets: any video asset used to display the creative. Video assets are characterized by duration (the total length of the video) and bitrate (480P, 720P, or 1080P).

Some video players will stream video content, buffering a few seconds ahead of the user’s position. We model streaming players using min(placement average view time + buffer, duration) x min(default bitrate. For instance, a 15s creative delivered through a streaming player that buffers 2s into a placement with 6s of average view time would be the equivalent of an 8s non-streaming creative.

The total data transfer from a creative can be calculated as static assets + video assets.

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Vendor Emissions

For each vendor that participates in delivering and tracking the creative, we need to calculate the emissions per creative delivery request. This is part of the ad tech vendor methodology.