I’ve been talking about the coming of automated vehicles (AVs) for years now, even writing a whole damn book about them, and while I’ve discussed the ethics and issues behind AVs, I’m a bit embarrassed to say that there are some obvious things I’ve never really considered. One of these is the subject of a recent MIT study titled Data Centers on Wheels: Emissions From Computing Onboard Autonomous Vehicles, which came to this conclusion: AVs are potentially an environmental disaster, even if they’re all battery EVs. The reason is really pretty simple: It takes a lot of computing power to drive a car, and all that computing power takes energy. And making that energy can produce emissions. In short, nothing is free.
Here’s the abstract to the study, which gives a good sense of what MIT found. I guess that’s literally what an abstract is supposed to do, isn’t it? Anyway, here:
While much attention has been paid to data centers’ greenhouse gas emissions, less attention has been paid to autonomous vehicles’ (AVs) potential emissions. In this work, we introduce a framework to probabilistically model the emissions from computing onboard a global fleet of AVs and show that the emissions have the potential to make a nonnegligible impact on global emissions, comparable to that of all data centers today.
Holy crap, that’s an alarming reference, as much emission output as all data centers? We’ll get to that more in a bit.
Based on current trends, a widespread AV adoption scenario where approximately 95% of all vehicles are autonomous requires computer power to be less than 1.2 kW for emissions from computing on AVs to be less than emissions from all data centers in 2018 in 90% of modeled scenarios. Anticipating a future scenario with high adoption of AVs, business-as-usual decarbonization, and workloads doubling every three years, hardware efficiency must double every 1.1 years for emissions in 2050 to equal 2018 data center emissions. The rate of increase in hardware efficiency needed in many scenarios to contain emissions is faster than the current rate. We discuss several avenues of future research unique to AVs to further analyze and potentially reduce the carbon footprint of AVs.
I mean, think about it: All cars today are driven using energy-hungry computing power, it’s just that the computer in question there lives in your skull and is powered by fistfuls of Pizza Rolls and lots of caffeine. And, if we think about driving in terms of computational efficiency, human driving is incredible, because you’re just re-purposing your brain-computer to drive the car, and you’d need to keep that thing running anyway, so the computational cost is really zero. But once we move to automated driving, then we end up having to add a completely separate computational system to drive the car, and that computer is doing a hell of a lot of work, and that sort of computation takes a lot of energy.
How much energy? Well, look at this:
The study found that with a mass global takeup of autonomous vehicles, the powerful onboard computers needed to run them could generate as many greenhouse gas emissions as all the data centres in operation today.
These data centres currently produce around 0.14 gigatonnes of greenhouse gas emissions per year, equivalent to the entire output of Argentina or around 0.3 per cent of global emissions, according to the researchers.
So, if AVs really catch on in a big way, the advanced, deep neural-network-running computers that drive them could create emissions equal to all the computer data centers currently running, which produces as much greenhouse gas emissions as Argentina! Holy crap. And, that doesn’t really factor in other consequences, like how the constant demand for power from computational hardware would necessarily reduce the amount of available range from a battery in an electric automated vehicle, possibly spurring the need for larger batteries, which means more weight, which means less efficiency and greater vehicle demand energy, and so on.
Like I said, nothing is free, If you want your car to drive itself, that takes energy. To compute the amount of energy needed and emissions produced, the study used four main variables: number of AVs operating on Earth, how many hours the vehicle operates, the power of each vehicle’s computer, and the amount of emissions produced per measured unit of electricity used to power the car and its systems. The study doesn’t just point out this issue, it does also suggest some possible ways to mitigate it, mostly via the development of specialized hardware optimized for just the sorts of tasks AVs require.
It’s also worth noting that nothing is certain here by a long shot. Even the basic premise that there will be vast numbers of Level 5-ish AVs on the road is by no means guaranteed, for example, and, if there are that many AVs deployed, it’s very possible they could have positive environmental effects too, as they could lessen private car ownership and be more efficient in how trips are taken in ways not possible today. Or, they could end up driving as much or even more, even if there’s fewer cars on the road. The point is nothing is really known yet, and while the study brings up a fundamental excellent point – computation in these cars demands significant energy – how the overall deployment of widespread AVs will affect the environment really isn’t clear at all.
I personally think that AVs could be less computationally demanding if there’s more infrastructural assistance for their use, and if the focus is on Level 4 – that is, restricted to a particular operating domain – as opposed to the near-magical Level 5, which can operate anywhere, anytime. But infrastructure assistance requires has its own significant hurdles, including getting actual standards in place and buy-in from government agencies, all of which are highly energy demanding in different ways.
It really is amazing that this has been glossed over for as long as it has been; currently deployed Level 2 systems like Tesla FSD Beta may be taking a toll on range, but it doesn’t seem that a real careful test of this has been undertaken. It seems a lot of the computation happens regardless of whether the system is active or not (operating in an observational “shadow mode”) but I can’t completely confirm this.
The more AVs that get deployed into the world, the more demand for power. It’s also possible that AVs may encourage more driving, since cars could hypothetically do things like drop you off at work and return home, then return to pick you up at work later. This could ease demand for parking places, but increase driving. There’s so many unknowns here. But we do know that computation takes power, often nontrivial amounts of it. No way around that.