SPECTRUM: Exposing the Power Vampires in Self-Driving Cars

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Drag from rooftop sensors makes Waymo’s self-driving minivan an energy hog. Photo: Wikimedia/Dllu

By driving smarter, autonomous cars have the potential to move people around and between cities with far greater efficiency. Estimates of their energy dividends, however, have largely ignored autonomous driving’s energy inputs, such as the electricity consumed by brawny on-board computers.

 

First-of-a-kind modeling published today by University of Michigan and Ford Motor researchers shows that autonomy’s energy pricetag is substantial — high enough to turn some autonomous cars into net energy losers.

“We knew there was going to be a tradeoff in terms of the energy and greenhouse gas emissions associated with the equipment and the benefits gained from operational efficiency. I was surprised that it was so significant,” says to Greg Keoleian, senior author on the paper published today in the journal Environmental Science & Technology and director of the University of Michigan Center for Sustainable Systems.

Keoleian’s team modeled both conventional and battery-electric versions of Ford’s Focus sedan carrying sensing and computing packages that enable them to operate without human oversight under select conditions. Three subsystems were studied: small and medium-sized equipment packages akin to those carried by Tesla’s Model S and Ford’s autonomous vehicle test platform, respectively, and the far larger package on Waymo’s Pacifica minivan test bed [photo above].

For the small and medium-sized equipment packages, going autonomous required 2.8 to 4.0 percent more onboard power. This went primarily to power the computers and sensors, and secondarily to the extra 17-22 kilograms of mass the equipment contributed.

Sources of added energy consumption for Ford Fusion

Sources of added energy consumption in Ford Fusion’s autonomy system. Credit: University of Michigan

However, autonomy’s energy bill ate up only part of the overall energy reduction expected from the autonomous vehicles’ ability to drive smarter driving — such as platooning of vehicles through intersections and on highways to cut congestion in cities and aerodynamic drag on the highway. As a result the modeled Ford sedans still delivered a 6-9 percent net energy reduction over their life cycle with autonomy added, and promised a comparable reduction in greenhouse gas emissions.

EV and gas models offered comparable results. Adding equipment was less burdensome for the EVs, which provided extra power for the processors and sensors more efficiently than a gas vehicle. But autonomy delivered a slightly larger net energy reduction in the gas vehicles, whose relatively inefficient drivetrains should benefit more from smart driving.

In contrast adding the large Waymo equipment package yielded a comparatively dark picture for the modeled EVs and gasoline-fueled sedans. The larger equipment increased net energy consumption on the Ford sedans by 5 percent, thanks mostly to the aerodynamic drag induced by its rooftop sensors.

Keoleian says this modeling result likely overstates real impacts from future autonomous vehicles, which he expects will manage to streamline even substantial sensors arrays. What concerns him more is the likelihood that all of the modeled packages understate power consumption by future autonomous driving subsystems.

For instance, Keoleian says future autonomous vehicles may employ street maps of far higher resolution than those used today to ensure the safety of pedestrians, cyclists and other drivers. In fact, real-time updating of high-definition maps by autonomous cars is one of the applications pushing the development of next-generation 5G wireless data networks.

Higher-bandwidth data transmission via today’s 4G network could boost power consumption by onboard computers by one third or more according to Keoleian and his coauthors. It is premature, they write in today’s study, to judge the power consumption associated with 5G.

Another concern for Keoleian are the indirect effects of introducing autonomous vehicles. By making driving more convenient, for example, smart cars could encourage longer commutes. “There could be a rebound effect. They could induce travel, adding to congestion and fuel use,” says Keoleian.

Such indirect effects of smart cars could either slash energy consumption from driving by 60 percent, or increase it by 200 percent, according to a 2016 study by the U.S. National Renewable Energy Laboratory. Guiding the technology’s development to avoid an energy demand explosion, says Keoleian, will require a lot more study.

This post was created for Cars That Think, IEEE Spectrum’s blog about the systems making cars smarter, more entertaining, and ultimately, autonomous.

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Companies Commit to Electric Vehicles, Sending Auto Industry a Message

Peter Fairley for InsideClimate News Sept 19, 2017

A group of large corporations, including utilities and an international delivery company, launched a global campaign today to accelerate the shift to electric vehicles and away from gas- and diesel-powered transportation—which generates almost a quarter of energy-related greenhouse gas emissions worldwide and has been the fastest growing emissions source.

Since more than half of the cars on the road belong to companies, the new EV100 coalition could have a major impact. It aims to do for EVs and electric car charging infrastructure what coalitions such as the RE100 are already doing to encourage corporate purchasing of clean energy (and thus motivating development of new solar and wind power).

EV100’s goal is to send a signal to automakers that there is mass demand for electric vehicles before 2030, when current forecasts suggest global uptake will start to really ramp up.

“We want to make electric transport the normal,” said Helen Clarkson, CEO for The Climate Group, the international nonprofit spearheading the effort…

… read on at ICN

The Self-Driving Car’s Bicycle Problem

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Human error plays a role in 94% of U.S. traffic fatalities. Image: William Murphy via Flickr

Robotic cars are great at monitoring other cars, and they’re getting better at noticing pedestrians, squirrels, and birds. The main challenge, though, is posed by the lightest, quietest, swerviest vehicles on the road.

“Bicycles are probably the most difficult detection problem that autonomous vehicle systems face,” says UC Berkeley research engineer Steven Shladover.

Nuno Vasconcelos, a visual computing expert at the University of California, San Diego, says bikes pose a complex detection problem because they are relatively small, fast and heterogenous. “A car is basically a big block of stuff. A bicycle has much less mass and also there can be more variation in appearance — there are more shapes and colors and people hang stuff on them.”

That’s why the detection rate for cars has outstripped that for bicycles in recent years. Most of the improvement has come from techniques whereby systems train themselves by studying thousands of images in which known objects are labeled. One reason for this is that most of the training has concentrated on images featuring cars, with far fewer bikes. Continue reading

Censors Take On China’s Silent Spring Moment

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Jinhua skyline, 2005

Chinese censors took down a hugely popular documentary on China’s air pollution crisis this past weekend, according to reports by the Wall Street Journal and the New York Times. Under the Dome, a polished, 104-minute report by Chinese broadcast journalist Chai Jing [embedded below], had gone viral after its release last week, attracting several hundred million views in China before censors restricted domestic access to the video and squelched news coverage of it.

The film is a damning account of China’s declining air quality, the sources of its pollution, and the toothlessness of environmental agencies charged with controlling it. It’s a wide-ranging production that tries to explain the price China has paid for its industrialization and wealth generation, as well as a passionate call to action.

For me, the film’s visceral portrayal of contemporary life amidst smog—and the movie’s historic sweep—sparked flashbacks to my own discomfort breathing in Chinese air during visits in 1991, 2005, and 2006.

In 1991, my eyes burned as the aging cruise liner I’d taken over from Japan motored up the Huangpu River, past the petrochemical plants then lining the river’s eastern banks, on its way into Shanghai. But the historic city across the river was clean. Aside from a few buses, it was a city that still moved on pollution-free pedal power, its streets a flood of bicycles. And as I traveled inland for several weeks, the pollution faded further, revealing China’s natural beauty.

When I flew into Shanghai 14 years later to report on China’s rising tide of electric bicycles for IEEE Spectrum, Shanghai itself seemed still cleaner than I’d recalled. While cars and trucks were on the rise, the East-bank industry had been cleared to make way for gleaming skyscrapers.

But China was clearly changing. I visited smaller cities where smog nearly blocked out the sun. Continue reading

Renewables to Dethrone Nuclear Under French Energy Plan

After months of negotiation, the French government has unveiled a long-awaited energy plan that is remarkably true to its election promises. The legislation’s cornerstone is the one-third reduction in the role of nuclear power that President François Hollande proposed on the campaign trail in 2012.

Under the plan, nuclear’s share of the nation’s power generation is to drop from 75 percent to 50 percent by 2025, as renewable energy’s role rises from 15 percent today to 40 percent to make up the difference. That is a dramatic statement for France, which is the world’s second largest generator of nuclear energy, after the United States. France has a globally-competitive nuclear industry led by state-owned utility Electricité de France (EDF) and nuclear technology and services giant Areva. Continue reading

How Canada Should Return Obama’s Oil Pipeline Punt

Late last week President Barack Obama deferred consideration of the Keystone XL oil pipeline, designed to ship Alberta petroleum to the Gulf Coast, until after next year’s U.S. elections. Obama’s move immediately sparked vows in Canada to redirect crude exports to Asian markets less angst-ridden by the environmental impacts associated with tapping Alberta’s tough, tarry petroleum. A smarter strategy would be to reduce those impacts, starting with the black mark that brought Keystone XL to national attention: oil sands crude’s bloated carbon footprint. Continue reading

Chinese Bullet Trains’ Worrisome “Black-box” Controls

In August we brought you disquieting news that Hollysys Automation — the supplier of a control system implicated in China’s deadly bullet-train collision this summer — also provides controls for China’s nuclear reactors (which are multiplying just as fast as its high speed rail lines). The Hollysys story now looks darker after informed speculation reported in the Wall Street Journal that the company may not fully comprehend how the control systems work. Continue reading