Residential and commercial heating is one of many energy demands that cities around the world are trying to make more efficient. Glass skyscrapers are especially poor at trapping heat and these reflective monoliths were built during past decades of growth and expansion that cared less about energy conservation. But it's not just rethinking heating: composting, sewage recycling, car-sharing, and many other innovative ideas could reinvent city living and decrease carbon emissions at the same time. As described by a new article in Science, no city is pushing harder for the lead in this type of transformation than Vancouver.

Green Goals

Vancouver city officials have challenged themselves to become the greenest city on the planet. What are the numbers behind this declaration? The city hopes to reduce energy use and emissions from buildings by 20% by 2020 and require all new structures built after 2030 to have no emissions. This is a courageous goal, one that will need not only loads of renewable energy but also ingenious changes to how cities fundamentally operate.

Green is by no means a new color for the city just north of Seattle in Western Canada. The city officially labeled climate change as a threat in 1990 (what was your city doing back then?), and its reliance on hydropower has lowered its carbon emissions beyond any other major city in North America. Even now, city planning entices citizens to live in the central part of the city, increasing population density and pushing down required resources per capita.

But more changes are on the horizon, bringing us back to the giant skyscrapers blazing red on a thermal image. More than two-thirds of Vancouver's energy is used to heat buildings, just one indication that eco-friendly population densities and some renewable hydropower is not enough. Rethinking basic city processes and reinventing the new norm is the great hope in Vancouver. Here are just some of the ideas underway concerning energy efficiency, waste management, and traffic control in the City of Glass.

1. Getting tough on trash. How well do you separate your garbage and recycling? Do aluminum cans sometimes find their way into your paper bin? If so, warning stickers and violation fees would find their way to your doorstep if you lived in Vancouver. Garbage inspectors now patrol the streets, checking for correct waste separation. But it's about more than keeping paper and metals apart. The city found that 40% of landfill methane, mostly coming from organic waste, was escaping into the atmosphere and contributing to greenhouse gas emissions. Inspectors are now handing out green bins for citizens to toss out scraps like meat, bones, and rotten leftovers. The waste ends up in composting facilities to both reduce the amount of organics finding their way to landfills and to provide soil for regional farmers. The inspectors also hope to be more than hand-slappers. "It's our job to do face-to-face education," Jez Figol, one of many inspectors who talks to residents about how to decrease their footprint.

2. Heating from sewage. Instead of dumping sewage water, plants in Vancouver now extract the heat from the wastewater flow to reuse to heat buildings. Wastewater runs through a giant strainer (imagine your kitchen colander on steriods) to remove large particles, then passes by a heat exchanger as big as a semi truck. This exchanger pushes the heat back through pipes that run through many city buildings, providing hot water to about 6000 residences from one plant. All from sewage waste!

3. Rethinking transportation. Traffic congestion plagues almost every city and Vancouver is jumping on the bandwagon of creating bike-friendly traffic patterns and easy car rentals. Bike lanes have popped up across the city to encourage more people to pedal to work. Car-sharing has also taken off, as city officials predict that every rental car removes up to 11 private cars from being on the road. Finally, the city has incentivized mass transportation, which has put a strain on the system because of its rising popularity. All of these improvements has made traffic control one of Vancouver's biggest success stories so far, as the city as already met its goal of cutting kilometers driven per person by 20%.

The challenges of being first

Vancouver officials outlined most changes in a 2011 action plan to reduce emissions 80% by 2050. Currently, emission have been reduced by 7% in about 4-5 years due to changes like the ones listed above.

Unfortunately, not all parts of Vancouver's greenification are evolving as successfully. Most skyscrapers are still leaking heat because they are nearly impossible to renovate. "Glass curtain-wall buildings are terrible and expensive to retrofit," says Sean Pander, who manages the Vancouver green building program. The only option is to slowly tear down old buildings and build new ones with stricter codes for energy efficiency, which takes a long time. The City Council has offered small financial incentives for voluntary improvements by private businesses, but the details, like where to relocate employees temporarily, have not been fleshed out.

There are other issues looming on the horizon that could muddle Vancouver's green plans. Most of these relate to conflicts of interest between the city and provincial or national level. For example, provincial officials will soon determine whether an oil pipeline and natural gas export facility can be built close to Vancouver's port, which would make emissions skyrocket. Such a conflict illustrates the unique challenge that city officials face when greening their cities, playing proud promoter of green policies to the public while working diplomatically with the other parts of Canadian government to allow them to succeed in their mission.

And then there are the paths to sustainability that only citizens can achieve. On average, cities require a land footprint about 200 times larger than the city's actual area. Cities can enact as many innovative policies as they like, but this footprint can be significantly reduced only through individual citizen choices: what they eat, when they turn off their lights, how high they turn up their AC, and what renewable energy policies they support. Cities can do their part, and it is tremendously hopeful to hear about officials that are so passionate to take the lead in going green. Let's hope citizens can match this passion and action with their own will and innovation to help turn cities green forever. In the meantime, Vancouver continues to push the green innovation edge farther along, hoping others will follow.

References

Weiss, K.R. "Vancouver's Green Dream." Science, 352(6288), 918-921, 2016

Figure Credits

Thermal photo of Aqua Tower in Chicago courtesy of Jim D'Aloisio via Wikipedia

Imagine a future when, as dusk turns to night during a long drive, the darkening highway begins to glow in soft hues of blue and green to illuminate the path ahead. Such a possibility could become reality after the creation of light-emitting cement by Jose Carlos Rubio at the University of San Nicolas Hidalgo in Mexico. The novel material could provide lighted pathways for cars, trucks, bikes, and pedestrians without using electricity.

Countries of Concrete

Most developed countries now rely on vast networks of roads to allow for fast transportation between cities. The US highway system consists of over 160,000 miles of road that web across the country, and most of these roads require some type of lighting for nighttime drivers. In the United States alone, lighting for buildings and for public use uses 262 billion kilowatt-hours (kWh) annually, or about 19 percent of all commercial electricity consumption. China's highway network will grow to a similar size by 2030 and demand similar lighting requirements.

As the looming shadow of climate change pressures society to move toward renewable energy, finding a low-carbon and energy-efficient method to light highways could significantly reduce energy consumption. At the same time, global cement production is nearing 4 billion tons; energy-efficient highway lighting introduces a giant commercial market that would reward entrepreneurs with new and useful technology.

A Phosphorescent Highway

Nine years ago, Professor Rubio recognized the need for energy-efficient road lighting. His solution was to create cement that absorbs solar energy during the day and emits it at night. In effect, his goal was to develop a road and lighting system contained in one material. "When I started the project, I realized there was nothing similar worldwide and so I started to work on it," Rubio says. "The main issue was that cement is an opaque body that doesn't allow the pass of light to its interior."

This opaqueness problem stems from traditional methods of manufacturing cement. Normally, cement begins as dust that is mixed with water to create a substance similar to hair gel. This gel eventually hardens within the mix of materials used to create the hundreds of thousands of miles of concrete roads seen today. However, this process also creates crystal flakes in the gel that block incoming sunlight.

Professor Rubio's nine-year journey of experimenting with the cement microstructure culminated in a new material that completely eliminates these crystal flakes. Without these flakes, incoming light can penetrate into and be absorbed by the deepest parts of the concrete. At the same time, the material is phosphorescent, which means that it absorbs the solar energy and later releases it as light. During the day, the cement essentially acts as an energy storage device, soaking up all the sunlight and exciting electrons in the material. At night, these electrons eventually relax to their original state, emitting light in the process. Once night falls, the cement can provide light for 12 hours, without using any electricity.

Greener Highways

The benefits of this light-emitting concrete go beyond its electricity independence. Most synthetic phosphorescent materials are made of plastics. These materials are composed of organic substances that break down over long-term exposure to UV rays, usually within about three years. In contrast, cement is only made of sand, dust, or clay, and boasts a lifespan nearing a century.

The simple composition of cement also makes it quite environmentally friendly. Resources such as sand are readily available, and the only manufacturing waste is water steam. Perhaps unsurprisingly, a material with this many benefits has attracted global attention. "Due to this patent, others have surfaced worldwide," Rubio says. "In the UK, we received recognition from the Newton fund, given by the Royal Engineering Academy of London, which chooses global success cases in technology and entrepreneurship."

Concrete made with this cement will not be lighting up a highway near you anytime soon, though. Though the basic research has shown great promise, the next step will involve technology transfer to commercialization and large-scale manufacturing. However, with this material's numerous environmental benefits, the highways of the future could be shining beacons of technological innovation during an age in desperate need of energy solutions.

Resources

Phys.org. "Looking to light highways with light-emitting cement." Accessed May 17, 2016.

EIA. Frequently Asked Questions, accessed May 17, 2016.

Photo Credits

Photo of phosphorescent cement courtesy of curbed.com