PROJECT EASY GREEN

When it comes to building efficiency, there’s lots of talk about networked lighting, upgraded HVAC, green roofs and other improvements to cut energy use and save money.

But many of the most aggressive retrofits or new green construction projects don’t address one energy user that sits in every large building: elevators.

There are plenty of reasons why elevators don’t get any respect in the world of green. Most only account for about five percent to eight percent of a building’s total energy use. In many cases, elevators have been in place for decades and undertaking a full replacement is expensive and inconvenient. What's more, performing heavy maintenance (forget about retrofits) does nothing to garner the good will of inconvenienced tenants. 

“Elevator energy has largely just been ignored,” said Jim Bos, an elevator technology expert and consultant.

But it doesn’t have to be that way, Bos argued recently at the ConEd Energy Efficiency Summit in New York City. The Big Apple is home to approximately 58,000 elevators. The average lifespan of an elevator is about 25 years before it gets any significant upgrades or improvements.

For anyone who has spent any time in an old hotel or pre-war building, it's patently clear that there are many elevators that are living solely off their charm, far beyond the time when an upgrade was due. In an average case, however, making the right component changes can cut elevator use up to half or even more — saving up to about five percent of a building’s total energy use.

Most of the energy that goes into elevators can be split into three categories: lighting, hoisting and standby. Even without switching out an entire system, there are improvements that can be made in each area.

Lighting is not the energy hog in most elevators, but replacing lights in elevators with CFLs or LEDs can easily cut power use.

The next category is where the heavy lifting really comes in. Hoisting is just that: the mechanism used to hoist the elevator up. There are two types of hoisting: hydraulic and traction. Hydraulic lifts are expensive to maintain and use much more energy than a traction system; therefore Bos said that they’re essentially on their way out. Fully switching out these systems is probably the most bang for the buck when it comes to replacing whole systems.

The other, more common elevator is a traction elevator, which rides on a steel rope with a counterweight on the other end. It takes energy to make it go up, but it also generates energy on the way down. In the past, capturing that downward power, known as regeneration, was inefficient, but the process has gotten much better in recent years, said Bos.

For some buildings, just retrofitting the right motor to capture that energy could offer a lot of savings. Shopping by energy efficiency takes some effort, however, as there are currently no required energy specifications for elevators. Elevators themselves also don’t contribute to USGBC LEED points, so there is a lack of incentive in the green building world to make the improvements.

The third area of energy use is standby. At the Omaha Public Power District, the utility made a retrofit to its elevator system and cut standby use by more than 75 percent.

Another place for improvement is destination dispatching. Although this type of system can seem insanely annoying the first time you encounter it (it involves punching in the floor number you’re going to when standing outside the elevator bank; once you get inside the car, there are no buttons to choose your floor), they are far more efficient in delivering people in the most efficient pattern.

Another more subtle issue is that occupancy changes might require rethinking how the elevator layout is utilized. Elevator banks are designed into a building, but no matter how occupancy shifts over the decades, the banks are still all being used. In some cases, placing some banks in standby mode for all or some of the day could be a big energy saver. “No one ever asks if you need them all,” said Bos. In fact, usually owners and occupants are clamoring for more.

Like all other energy efficiency retrofits, the solutions for saving elevator energy varies greatly from building to building.  A good baseline to measure usage patterns and energy consumption is an important place to start. Add in a skilled consultant, and improvements can be found for nearly every elevator system. “The equipment exists,” said Bos. "Small component changes can have big results.”

Like our youth-obsessed culture, the Dexter Horton building in downtown Seattle has something of a complex about getting old. To keep up with younger whippersnappers, the managers of the historic building have been benchmarking and rating its energy performance for several years to help stay competitive. Starting this month, all other commercial buildings over 10,000 square feet in Seattle will have to follow suit.

Seattle is just one of a handful of large U.S. cities and states to enact energy efficiency benchmarking legislation in large buildings, and many of the programs go into effect this year. The efforts are far behind those of the European Union, which has required all 27 member states to certify and disclose energy usage in large commercial buildings for nearly a decade.

The different styles of benchmarking — which vary between locales — will allow cities to gather better data on a sector that usually consumes the bulk of overall energy. New York City estimates 75 percent of the city’s carbon emissions stem from energy used in buildings — and today’s buildings will still make up 85 percent of the real estate in 2030.

“In a couple of years, the markets will have time to respond to these policy initiatives, and cities having access to this information — it is a game changer,” said Andrew Burr, Director of the Building Energy Rating Program for Institute for Market Transformation (IMT), a non-profit that works to promote energy efficiency and green building.

Of the five cities that have active legislation, only New York City, San Francisco and Washington, D.C. will require buildings to disclose the information on a public website. San Francisco and Seattle require the information to be given to buyers, lessees or lenders. In Austin, the information only has to be disclosed to buyers.

Bringing the information into the point of sale not only allows for transparency, but is also the first step in monetizing efficiency and increasing the value of retrofits. “With existing buildings, people are becoming more aware that it’s still something of a black hole for actually saving energy,” said Burr.

It’s not that retrofits can’t save money, but with commercial buildings, there is often a gap between the stakeholders — tenants use the electricity but owners pay for the upgrades. The result is that building managers don’t always look at energy as an opportunity and there is often a question of who will pay the high upfront costs of retrofits.

(At a panel on May 25, Greentech Media, Solar One and New York City Accelerator for a Clean and Renewable Economy (NYC ACRE) at Polytechnic Institute of New York University will look at value of a negawatt — and what that word even means to different stakeholders — both in New York City and beyond. To register, visit Clean Energy Connections.)

Burr argues that, ideally, there are far more stakeholders that could use this information, and therefore having a public website and transaction-based disclosure is the most valuable solution. With public disclosures, everyone from reporters, investors, public organizations and bankers can access the information.

Once the public databases are filled — in the case of New York City, it will have information for nearly 2.5 billion sq. feet of space — it can be used to target low-performing buildings. In San Francisco and New York City, there are requirements for audits along with the benchmarking. That will help open the market for lighting and HVAC upgrades. When the legislation is done right, Burr says that creates jobs while costing the city very little. “Rating and disclosure are really market mechanisms, like miles per gallon,” he said, “that’s a pretty inexpensive policy.”

Nine other states are currently putting together laws that would require energy rating and disclosure; however, only Massachusetts is debating the creation of a public website, according to IMT. Although tracking the information is a step in the right direction, if it never gets into the market, it could be a missed opportunity. “The onus is on the building owners,” said Burr, “and the policy will be as effective as the market makes it.”