Is the climate cost of digital billboards too high to justify?

Earlier this month, Greenpeace tweeted a vandalized Clear Channel six-panel, which read: “This ad uses the same electricity as three average households. Global heating machine.” It was posted as a video of parkouring teens turning off overnight street signage did the rounds on social, while Europe hit all-time high temperatures. The Drum investigates...

Is the writing on the wall?

Are OOH units “global heating machines”? The answer is complicated. The device you’re reading this article on is technically a global heating machine. Everything uses energy – the question is whether the sector’s use of energy is irresponsible.

One 2010 study claimed a 48-sheet digital billboard (6.096m x 3.048m) consumes about 30 times more energy than the average American household in a year.

2019 research from Adblock Bristol showed that a much smaller but double-sided digital freestanding unit from Clear Channel used more electricity than four homes each year. Meanwhile, a large JC Decaux billboard was found to consume the equivalent of 36 homes “if it was running for a full year at maximum output.” These are thirsty machines.

This year, a freedom of information request from The Guardian found that 86 digital out-of-home (DOOH) boards in Manchester city center each use an average of 11,501kWh of electricity every year. That’s roughly 345 households’ worth. But these units deliver £2.4m a year in rent, plus 2.8% of the revenue from each ad. That’s well in excess of £6,956 per ‘household.’

In cities all over Europe, tens of thousands of these units consume several homes’ worth of energy each year... so is it worth it?

Outdoor industry responds

Media owners have been cleaning up their act as they transition from analog to digital real estate. Their involvement in urban architecture is dependent on the public’s permission, therefore it must demonstrate utility and be receptive to their needs.

Tim Lumb, insight and effectiveness director at Outsmart, the trade body representing UK OOH, issues a defense saying media owners have been seriously reducing their carbon impact, prioritizing energy-efficient suppliers and supply chains, buying renewable energy and offsetting carbon. Anything from adopting non-fossil fuel fleets to ditching plastic coffee cups is on the table.

Richard Kirk, chief strategy officer at media agency Zenith, believes OOH is bearing the brunt of a wider anti-ad sentiment because it is “highly visible and very physically tangible,” but adds that the sector has a “much better sustainability story to tell” than other channels.

Agencies are now calculating their carbon footprint across the entire media ecosystem in a bid to offset their impacts. They know consumer sentiment is turning hostile toward the biggest polluters, but right now the tools lack sophistication.

Research from Cavai estimates that the average online ad impression emits the same amount of carbon dioxide (CO2) into the atmosphere as driving an electric car between 0.4 to 9.65m, watching a 40 inch $K OLED TV between 1.5 to 35 seconds, or having a LED light bulb on between 30 and 700 seconds.

The energy consumption of a single impression is between 0.14Wh and 1.93Wh. Meanwhile, Ovo estimates the average annual UK household electricity consumption sits at 3,760,000Wh per year, the equivalent of a mere 26,857,142 ad impressions. This sounds like a lot, but a study from Good-Loop estimates that programmatic tech handles 2,000 times more bids than the New York Stock Exchange on any given day – 8tn transactions all in the name of targeted advertising. That’s a lot of online impressions. Furthermore, advertising likely added an extra 28% to the annual carbon footprint of every single person in the UK in 2019. So the OOH sector might be the tiniest tip of the melting iceberg of advertising’s damaging impact.

So with the wider context laid out, as Lumb points out, OOH doesn’t “just” deliver advertising but serves as a public and community message board too. On billboards, advertisers formed coherent pandemic advice before the government, encouraged the public to clap for the NHS and – increasingly – issue weather warnings during periods of high heat. You’ll also see them try to rejuvenate the high street, with local businesses often embracing the tech now it’s more accessible and affordable than it was in static formats.

When considering the energy expenditure of OOH, it’s worth remembering that it, like TV, is a broadcast media – it serves one ad to many people at once (unlike ads on your mobile or computer, which are targeted and rendered on each individual device at a greater energy cost). Clear Channel reckons the UK hosts 30,000 DOOH panels – a small share of some 100m video screens in the UK.

Adds Lumb: “On a ‘carbon-impact-per-ad-served’ basis OOH is an incredibly low-impact advertising medium because every OOH ad is seen by thousands of people.” He laments that it is the public screens that “pressure/artist groups focus on.”

As an extreme example, London’s Piccadilly Lights reaches more than 56 million people a year. The energy costs will be extremely high, but how many individual screens would advertisers would have to render ads on to reach all those people individually?

Nicole Lonsdale, chief client officer at Kinetic Worldwide, thinks that OOH is very public and attracts scrutiny that other channels (particularly online display and social) don’t. “The energy required to deliver millions of messages to millions of manufactured devices is way beyond.”

The industry is implementing programmatic buying so advertisers can bid for inventory with localized campaigns in almost real-time (which is much more energy intensive). Clear Channel boasts some 11,000 screens that can now be bought programmatically, capable of delivering more than 1bn monthly impressions.

But Lonsdale believes that concerns about the increasing sophistication of the bartering are “probably a red herring.”

“The amount actually delivered via a DSP is still very small as a percentage of total spend.” But she thinks the increased efficiency of targeting will mean advertisers have to send fewer ads (which saves energy), a thought shared by Kirk.

She adds: “If it is increasingly automated, it probably reduces the impact from all of the busy people in offices or at home using energy in the planning and buying.”

Meanwhile, the industry also has an answer for people nostalgic for the paste and paper placements that were bought in weekly increments. The physical production and distribution of advertising had a cost.

Kirk adds: “Because of ESG legislation a lot of the infrastructure being built has to be net zero or even net positive. You used to need heavy-duty paper, there was a lot of energy involved in production inks, a lot of nasty chemical ink, and then the transport and distribution to each site.”

One study claims that a 14×48m digital billboard with LED bulbs uses only twice as much power as a static billboard, and adds that LED lights use about 75% less energy than incandescent bulbs (although you need way more of them). Other studies have digital using as much as 13 times more energy.

Comparatively, a digital site will always use more energy than a static one – but if correctly implemented, media owners could meet advertiser demand with fewer sites.

Is there a public good?

Martin Page, Clear Channel’s environment and sustainability manager, reminds The Drum that the business is a public infrastructure operator AND a media owner.

A third of Clear Channel’s UK infrastructure is bus shelters. The industry, from its very roots, is about building utilities that people will use or gather around and monetizing them with ads. The humble bus stop is installed and maintained by the ad it houses.

On a Clear Channel blog posted in 2018, Page expressed the business’s efforts to reduce landfill waste and increase lighting efficiency. But he admitted: “Bringing our electricity usage down as far as possible will have a massive impact.”

Since 2017, it has only purchased renewable energy (although there is conflict over what actually constitutes ‘renewable energy’ and fears that sources are being double counted). Nonetheless, the business has reduced its carbon footprint by 65% since that year, and by 89% since 2008. Also on the horizon are more efficient LED lighting and solar panels, as well as fleets of electric vehicles, pollinator-friendly infrastructure ‘living roofs’ and CO2 scrubbers to improve air quality.

Research from rival JCDecaux states that the use of LEDs can increase furniture energy efficiency by up to 70%. Meanwhile, Page boasts that its next-gen digital six-sheet screens “are 50% more energy efficient than the current generation.” Efficiency is good for OOH providers – especially with the current prices of energy.

Do clients care?

Laura Wade, vice-president head of sustainability at media buying agency Essence, says energy consumption and carbon footprint come up “frequently” because the agency and its clients (often) have net zero ambitions.

“It should be taken into consideration that 50% of ad revenue goes to local councils, and in many instances OOH companies are key partners in helping decarbonize cities – investing in street furniture and regeneration projects. So while Greenpeace, Brandalism and Adblock Bristol are pushing citizens to consider and challenge the societal value of advertising, it’s not as simple as just looking at the negative impact of a channel; we must consider the contribution as a whole to society.”

Meanwhile, Oliver Deane, co-founder at sustainable ad partner The GoodNet, previously a senior outdoor advertising exec at Global, believes DOOH is compatible with sustainability. He points out that any money going into public transport takes cars off the road, for example.

“If they are run in an environmentally conscious way and commercially contributing toward communities and public transport, then yes, a sustainable OOH industry can embrace digital screens.”

Deane adds: “The immediate opportunity is to measure and mitigate your carbon footprint through gold standard offsets while identifying both short- and mid-term ways to reduce your footprint.” He concludes that media owners need to do a better job in communicating how they fund vital public services – they could do this with spare inventory.”

It’s worth remembering that Greenpeace itself, a Cannes Lions winner and OOH advertiser, recognizes the importance of the medium in changing hearts and minds – and we’re going to be needing a lot of that. Maybe it’s time campaigners start making OOH work for them. Then again, maybe acts of brandalism are their way of getting the canvas working.