The making of a green city

“Going green” throughout history

At few millennia ago, Italy’s forests lay nearly bare –stripped down to the bones for the extravagant heating and building needs of some 60 million Romans at the height of the empire. Desperate for fresh supplies, the Romans looked up for a more frugal answer: the sun.

They began by building south-facing homes with roofs angled to complement the sun’s seasonal height in the sky, so that the rooms could be naturally heated in winter and kept cool in summer. They crafted bathhouses with southern walls of glazed glass or translucent mica stone to trap in the heat, keeping a steady 100 degrees F water temperature even after sundown. Sometimes it worked a bit too well. The philosopher Seneca once wrote, “It seems to me that nowadays there is no difference between ‘the bath is on fire’ and ‘the bath is warm.’”

Around the same time, ancient Persian cultures were creating wind catchers called badgirs to move the stifling desert air around mosques and other large buildings with zero energy input. They used the badgirs to ventilate and, at times, to refrigerate. Meanwhile, windmill-powered water pumps ground harvested grain –much like the water wheels that propelled the flour mill industry in Minneapolis years ago.  

Ancient Persian badgir or “wind catcher,” used for ventilating and cooling desert buildings. Photo by roadconnoisseur

Fast-forward to the modern era, where post-WWII America enjoyed its own timeline of impressive building feats. Architects began a race to the top, each one plotting a higher steel skyscraper than the last. These buildings used enormous amounts of energy as a matter of course. Like the early Romans, American builders were not yet in want of material, and they spared no amenities. In fact, fossil fuels were so cheap that one could scarcely imagine a future in which their exorbitant use could pose a financial burden. It took the oil crisis of the 1970s to draw national attention to the political price and risk of petroleum products.

By 1992, the US had fully launched into the “green building” era. Clinton offered the White House as early model –allowing staff to experiment with new methods of energy efficiency and waste reduction until they were saving $300,000 in operation costs annually (three times Clinton’s personal salary).

Today, Minneapolis hopes to become the model city for a more sustainable future –and it is on track with its annual benchmarking program, which keeps track of the city’s largest buildings’ energy use. In 2014, building energy use was responsible for nearly half of all greenhouse gas emissions in Minneapolis. Because energy use is also the largest controllable operating cost in buildings, the benchmarking program hopes to draw attention to opportunities for new energy savings.

Tracking energy in buildings around the city

The City of Minneapolis began rolling out its benchmarking program four years ago, back in 2013. It started first with public buildings, and then moved in subsequent years to include private buildings of 50,000 square feet or more –a total of 417 buildings by 2015. At the core of Minneapolis’ benchmarking initiative is the federally created ENERGY STAR program, which you may already be familiar with if you have purchased new energy-efficient appliances, windows, or light bulbs in recent years. Each qualifying appliance is branded with a noticeable blue sticker bearing the star of its namesake.  

Many believe ENERGY STAR benchmarking to be the best means of measuring a building’s sustainability because it treats energy usage as the defining factor. Properties earning ENERGY STAR certification consistently consume about 35-40% less energy than their non-ENERGY STAR counterparts.

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An ENERGY STAR certification placard is awarded to qualifying buildings. 

Scores are calculated on a 100 point scale (with 75 and above qualifying for ENERGY STAR status) based on factors like size, location, number of occupants, and machines in use. The resulting number points to where a building ranks relative to other buildings around the country that share the same use –e.g. hospitals compared to hospitals, offices to offices, etc. Not all buildings are eligible for an ENERGY STAR score. To qualify, a building must not be too short, too tall, have too few people or too many, etc.

The City of Minneapolis collects each participating building’s ENERGY STAR data and makes it available to the public, along with analysis of trends in energy use and improvements.

A learning curve pays off

To benchmark buildings, the City needs data. A lot of it. Unlike the VOC project that I wrote about last week, which involved so many enthusiastic citizen volunteers that some had to be turned down, this project involved a different set of challenges. A local ordinance makes submitting benchmarking data mandatory, with a fine imposed upon those who meet the qualifications for reporting but fail to do so. As with anything required, the City faced a mixed response. Some were enthusiastic to participate, while others needed more convincing.

And it was not always a question of attitude, but sometimes of available time and expertise. In the program’s pilot year, team members discovered that many participants entered utility measurements only partly (perhaps in a hurry), or incorrectly. Participants ranged from the very tech-savvy to those who struggled with the online reporting platform, which is not entirely intuitive. Some did not catch things like the wrong units of measurement, entering numbers that were multiple factors of ten off. The following year, the City council added specifications to the ordinance requirements so that quality of data was enforced along with quantity.

As the program enters its fourth year, it is clear that participants are paying more attention to the details of the benchmarking process and what it represents, and they are learning as they go. They are reporting much more accurately on the first try, though there is free help available from the City in the event of confusion. Slowly but surely, buildings are keeping tabs on their energy use in a way they have never done before.

And there have been some major reveals in the process.

For example: this past year, the City of Minneapolis discovered that the Whittier Clinic on Nicollet –which had been awarded an impressive LEED Silver certification for its original building plan –scored an abysmally low 17 on the ENERGY STAR scale by their data. In other words, Whittier was performing at the 17th percentile of similarly used clinic buildings nationwide. Upon further examination of the facility’s monthly energy use sources, building owners discovered that their in-ground ice melting system was running 24 hours a day, every day for the whole year. That immense annual energy loss in an otherwise sustainable building has since been rectified thanks to the tip-off of energy-use benchmarking.

Historic buildings can shine anew

In a city with more than a handful of beautiful, historic properties, one piece of good news revealed by the benchmarking analysis is that there appears to be no real relationship between a building’s age and how well it performs on energy tests. Buildings constructed in the 1890s, 1930s, and 1990s all earned ENERGY STAR certifying scores. Likewise, some structures built in the 1970s performed on the same poor level as counterparts from the turn of the twentieth century.

Consider the historic Ford Centre in the North Loop downtown, with its towering ten stories in red brick. At the top is a now-defunct water tower bearing the Ford name.

The historic Ford Centre in the downtown North Loop neighborhood was renovated in 2011, and is now ENERGY STAR certified. Photo by Michael Hicks

The Ford Centre was built in 1913 by none other than father of the automobile Henry Ford, just 10 years after he had opened his first motor plant in Detroit. He wanted to bring the Model T to the heart of Minnesota, declaring in his company newsletter that, “There is something about the hardy life of the farmers, most of them descendents of the Vikings, that led them to appreciate peculiarly the clean-cut strength of the Ford.”

It was the first vertical factory designed for Ford’s automobiles, and quite possibly the tallest ever built. Each car began its journey on the top floor, moving down one floor at a time on a freight elevator until the finished product could be wheeled out of the building’s east side at ground level. At the factory’s peak, it employed about 600 workers turning out close to 300 cars a day.

The original construction required 108,000 sacks of cement, 3.6 million pounds of steel, and 2000 fifty foot Norway pines. Arguably its most defining feature to this day is the floor-to-ceiling window facade overlooking the city –300 multi-paned industrial steel windows replaced with new, energy-efficient panes a few years ago. In 2011, the Minnesota Pollution Control Agency also remediated the lingering pollution of its factory past so that it could be converted into office space. In 2013, the first year of the City’s benchmarking program, the Ford Centre had an ENERGY STAR score of 79 –enough for official building certification. In 2014, it bumped up to 88. Then, in 2015, 91.

Other historic buildings with ENERGY STAR certification dot the city, the Midtown Exchange, Butler Square, and the Colwell Building among them.

Simple changes add up

Improving a building’s energy efficiency doesn’t necessarily require the kind of major remodel that Ford Centre had, with complex pollution remediation and a complete window replacement. Very simple changes can be made by every kind of building owner, and benchmarking can reveal how those changes can make an environmental impact and save a great deal of money.

The low-hanging fruit, so to speak, of energy improvement is in the lighting. Many buildings still operate with incandescent, fluorescent, or halogen bulbs that are extremely inefficient by today’s standards. LEDs also last up to 20 years, cutting down on the need for regular maintenance. Their cost has dropped quickly in recent years, making them an easy choice for owners looking to green their building.

Local parking garage before and after LED light replacement. Photos from Retrofit Companies.

Because a lighting switch is so easy to accomplish, it may not seem like it will have a huge payoff. But it does. A parking ramp downtown recently replaced all their lighting with new LEDs. The transition cut down on their energy use by a staggering 75% and saved over $14,000 in the course of one year. In terms of CO2 savings, it also meant the annual equivalent of keeping more than 20 cars off the road, or nearly 40 tons of waste out of the landfill.

Sometimes, an LED switch-out has interesting secondary effects. For example, when Shriners Hospital for Children switched the bulbs in their elevators, they discovered that they didn’t have to air condition their elevators any longer. Think back for a moment to the EasyBake ovens of your childhood, baking brownies with a light bulb. Incandescent bulbs turn a whopping 70% of the energy given to them into heat (wasted energy, unless you are channeling it into child-sized brownies). The temperature in Shriners’ elevators dropped noticeably without the heat of inefficient bulbs.

By the same principle, the Mall of America has gone its entire history without a heating system. The space is kept warm by open skylights (like the Roman baths), running machines, thousands of moving bodies, and its sheer, unprecedented size. Now that the Mall is considering how and when to switch to LEDs on the grounds, they will have to reexamine whether the current (lack of) heating system will still be sufficient.

And no matter what kind of lighting is in place, making sure things are off when no one is around is another very achievable way to cut down on energy. The Days Hotel, another benchmarked building, was surprised by their relatively high ENERGY STAR score. But they policy for cost-saving was very strict: when a guest had gone, and housekeeping entered a room to clean, they were to ensure that everything was turned off. In this way, even building owners who may not have the means to change the circumstances of their building can work with what they already have to promote changes that are simple, but effective.

Green is growing

At this moment, the City of Minneapolis encourages buildings to “move beyond benchmarking.” That is, it hopes to motivate owners into noting their current ENERGY STAR score and actively working to improve it.

The team recognizes two main motivating factors for owners: cost efficiency and marketability. Of course, cutting down on energy use saves money. But innovation in sustainability is also increasingly becoming a means for buildings to stand out beside their peers in the area. Prospective tenants are beginning to ask specifically how buildings perform when deciding where to spend their rent money.

Part of the incentive for the annual publication of benchmarking data, and for sending cleanly designed energy score-cards to building owners explaining the results of their reports, is old-fashioned peer pressure. Owners often feel more motivated to improve their building when they discover that similar buildings around the city are vastly outdoing them in conservation measures.

To fully encourage the next step for building owners newly galvanized by their benchmarking results, the City has expanded the incentives it offers. For example, it now provides grants to private commercial properties hoping to improve their energy footprint. And for those scoring above a 75 on the ENERGY STAR scale in their benchmarking results, the City offers to subsidize $500 of the $800 needed to formally certify a building. In this case, a building engineer will come to inspect the property and then award a placard for display, a point of pride and increased marketability for an owner hoping to showcase his or her building’s ENERGY STAR status.

Minneapolis currently has 40 ENERGY STAR certified buildings, more than many other major cities. The City hopes to continue its benchmarking study for several more years at least. To see the results of the past year’s report, or to look up the data for individual buildings, visit the City’s project page.


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