Office buildings are increasingly incorporating energy-efficient technologies in response to the rising costs of maintaining comfort levels in the workspace.
Perhaps nowhere is the relationship between buildings and energy efficiency more evident than in New York City, NY. Seventy-five percent of New York City’s carbon emissions stem from energy used in buildings. By 2030, existing buildings will comprise 85% of all real estate. One of the goals of PlaNYC—an effort by Mayor Michael Bloomberg to prepare the city for one million more residents through strengthening its economy, enhancing quality of life, and dealing with climate change—is to reduce annual citywide greenhouse gas emissions by 4.5 million metric tons of carbon dioxide equivalence (CO2e) by 2030.
One office building moving forward with that effort is at 1350 Avenue of the Americas in Manhattan, NY. The 35-story office building uses 12 Capstone C65 High Pressure Dual Mode ICHP units that create an individual power plant generating 780 kW of electricity and heat onsite. The system meets about 35% of the building’s day-to-day electricity needs. Additionally, the Capstone microturbines provide thermal energy that carry up to 80% of the building’s heating load during colder months.
OfficePower’s backup facilities offer up to the ability of the size of the plant to provide backup in grid outage. Joel Wilson, CEO of OfficePower, points out that the Avenue of the Americas installation allows OfficePower to run the plant in parallel with the grid and in grid outage. During a grid event on the Consolidated Edison system, the microturbines reconfigure to provide backup power to designated protected loads.
In the office space real estate market, the newest amenity that’s rapidly becoming a necessity is a building’s ability to deliver power, says Wilson.
“Energy is the raw material for production of financial services, legal, accounting, and other similar enterprises,” he points out.
OfficePower, a Connecticut-based company, builds small-scale combined cooling and heating power plants in, on, or around multi-tenant office buildings. OfficePower owns and operates the power plant in a long-term arrangement with the building owner and sells the entire electrical load to the building, with everything produced consumed onsite. Under terms of the agreement, OfficePower ensures a building’s total power costs do not exceed the cost of remaining completely tied to the grid.
“We are addressing either problems or needs, or whatever the perception for the building owner is,” says Wilson. “They’re getting a benefit to the building without having to make a capital investment.”
“Installing Capstone microturbines is a way for building owners to differentiate their buildings in the marketplace so they can attract higher-level tenants and increase the value of their building at the same time,” says Wilson. “Because of their outstanding efficiency, reliability, almost complete lack of vibration, and super-green emission levels, Capstones are the right power generator for virtually all urban buildings.”
The system was commissioned in 2006 with 12 Capstone C60 High Pressure Dual Mode ICHP units fueled by natural gas, which in 2008 were upgraded to C65 High Pressure Dual Mode ICHP units. The system is located on the 16th floor setback roof of the building. A Capstone Heat Recovery Module is installed on the top of each microturbine, capturing exhaust heat energy normally unused and sent into the atmosphere.
“Our economic business model aside, this also is about what we’re bringing to the market by relieving the grid of some of its problems and how that, in turn, benefits the environment,” says Wilson.
“If we’re twice as efficient as the grid, then we cut in half the CO2 footprint of buildings on the grid. We partnered with Capstone because they share our vision of an energy option that not only serves building owners, but also is environmentally responsible.”
Wilson says if one considers a multi-tenant office building as a manufacturing facility where what it manufactures is the output of the service industry, such as accounting, legal, and finance, their “feedstock” is electricity and thermal.
“You have to have a good working space in order to produce your product,” he says. “You have to have air conditioning, heat, and electricity in a balanced way for productivity. If you were sitting in a closed window office space in Florida where the temperature is 95 degrees [Fahrenheit] and 90% humidity and you didn’t have balanced air conditioning, how productive would you be doing your job?”
There are many challenges to address when building power plants for office buildings in an urban area like New York, Wilson says.
The density of the power footprint is one issue.
Energy-efficient onsite power is an increasingly attractive amenity for building residents.
|Multi-fuel conversion adds options for onsite power system operators.
“That’s when using equipment like Capstone becomes very important for us, because it allows us to provide more flexibility in our layout,” says Wilson. “You also need to address the needs, concerns, or wants of the building departments, because obviously the building departments in these cities have to issue permits or do other things to allow you to start your plant up, and the idea of building a power plant on a building in an urban area is fairly new to the building departments.”
Wilson says his company spent a lot of time with New York City’s building department to help develop codes for these types of plants.
“When you look at the building codes in New York City, they reflect very much some of the things we were able to pioneer as far as how these are designed,” says Wilson.
Now that the Avenue of the Americas plant is in its sixth year of operation, Wilson has been able to determine the system offers 99.8% dispatch reliability.
“Capstone has done a very good job for us,” he says. “We are not only pleased with their product and innovation, but we’re also very pleased with their ability to understand their customers’ needs.”
Maintenance on the system has been “fairly effortless,” notes Wilson.
“All manufacturers give you maintenance projections, cycles, and expectations,” he says. “In our experience, Capstone’s input on that has been very conservative. We have not experienced the level of maintenance that they predicted.”
Wilson says his company has been oriented to the infrastructure for multi-tenant office buildings.
“When the utilities started to deregulate, we started to look at what impact this may or may not have on real estate, particularly in multi-tenant office buildings,” he says. “Our plan from our views, research, and discussion with building owners has been not just what their perceptions were—not only for current needs, but looking to future power needs and what was going to be happening with the utilities’ aging infrastructure.”
Wilson says his company has been able to address the key hurdles people face in designing and deploying smaller-scale CHP plants.
“You can never quite anticipate where your hurdles are going to be,” he says. “It’s all a question of having the right team together that doesn’t crumble under hurdles, but looks at them and figures out how to address them.”
Some may speak of building departments as hurdles, Wilson says.
“Building departments fulfill a very important role, and they have a job to do,” he says. “You can either look at them as an insurmountable hurdle, or you can work with them and solve what they need to do. As long as you address issues in a collaborative way, then things start to develop properly.
“Being entrepreneurs, we’re always impatient and want everything done yesterday,” he explains. “The lessons learned are really a reinforcement of having the right team that knows how to address things as they go along when you’re in a business that is not only a new business for you, but a new business for the marketplace.”
Wilson says his business has grown incrementally, and when the capital markets come back he looks for it to grow exponentially.
“It’s not a question of a lack of demand for our product in the marketplace—as a matter of fact, it’s just the opposite,” he says. “Nobody has an easy time financing their businesses these days. There’s a shortage of capital.
“It’s difficult sometimes for more institutional types of investors to understand businesses that cross different disciplines,” adds Wilson. “Our business involves both energy and real estate. That’s difficult in a market where there’s not a lot of push for people to do any investing anyway. Most organizations have a real estate expert and an energy expert, but they don’t have a real estate and energy expert.”
Making the Business Case
One of the key challenges for office buildings in setting up onsite power systems is getting financial approval, points out Aniruddha Natekar, marketing manager for Cummins Power Generation. Cummins manufactures compression-ignited generator sets, spark-ignited generator sets, and automatic transfer switches.
“The way gensets are specified is you’ve got NFPA 110 Level 1—the legally required standby systems—and most of the other systems follow Level 2, so it’s not legally required, but you have to make a business case for it,” he says. “Once you get to the level of qualifying the need for the power generation system, it’s finding the right resources to figuring out what exactly do you need.”
Serviceability of the gensets also is critical in an office setting, Natekar points out. If a system doesn’t start up when it needs to in order to keep office operations running smoothly, it’s important that trained technicians be able to give prompt support, he adds.
The system only is as good as the preventative maintenance given it.
Monitoring systems are integral in maintaining efficiency.
Each component contributes smooth, efficient equipment operation.
“Some people are actually scared of maintenance of a generator,” says Natekar. “It’s an engine which historically runs between 25 to 30 hours a year, so it’s really not much. The maintenance is limited to checking the oil and the filters at a frequency depending on the model you get.” Cummins offers an optional preventative maintenance contract.
Deriving energy efficiencies through the use of gensets can be a difficult proposition, “because you’re still burning fuel,” says Natekar. “If you go for a diesel system because of the location you’re in, it’s probably not the greenest in terms of energy management. Coal-fired could be a more suitable option. Getting it from a natural gas engine would actually be better.”
To that end, how the components of a genset fit with each other act to minimize emissions, Natekar says.
“When we design a genset, we don’t pick an engine and design everything around it,” he says. “We start our technical profile with a genset that has to deliver X amount of power. All of the components are made to go with each other so they can deliver that amount of power. We are not wasting any energy. We don’t have an oversized engine.”
Accounting for future growth is important when choosing a genset system, Natekar points out.
“Typically office users will look at what they need right now. They’ll look at their budget and say they need 100 kilowatts, which is perfect. But when you grow your business, at a later point it’s not sufficient.
“When you’re designing a facility—a completely different facility or an addition to the existing facility—how are you pre-wiring the system to have a backup power system? Those two factors will basically save a lot of money in the long run from a planning perspective.”
In choosing a generator, an office building owner or operator should consider the experience the manufacturer has in pairing one generator to another for the right power in the system, Natekar points out.
“Do they have a broad range of generators that will go from a lower to a higher kilowatt? Breadth of experience in systems, networking, and switchgear that will help them grow their business is something that can give them a lot of confidence. They can do this now to increase their business to 50% and can always have one system and add another system.”
The Space Problem
The main challenge office buildings face is that with office space being “very expensive”, standby systems to address power outages are taking up premium space, says Curtiss Hahn, general manager of the Americas for Kawasaki Gas Turbines. Kawasaki’s GPS Standby Units—a dual-fuel system—offers a footprint of about one-eighth of a diesel, says Hahn.
“The sheer size, weight, and the number of maintenance cycles on a diesel is quite high,” says Hahn. “When a building maintenance manager sets up his maintenance, it takes quite a bit of time compared to our GPS standby turbines.”
Also, the noise level on diesel systems tend to be very high and can be heard throughout an office building, Hahn notes. The standard attenuating closures only output 85 decibels ampere (dBA) at one meter.
“It’s a high frequency, so it’s easy to attenuate that noise,” says Hahn. “A diesel’s low frequency is very hard to block.”
Diesel requires water cooling with a system of piping and radiator fans, Hahn says.
“Turbines are air-cooled, so the cooling system is not required, and it increases the reliability because there are fewer moving parts to break down,” he adds.
Another benefit of the dual-fuel system is it doesn’t require as much testing as a diesel system, Hahn says.
“I’ve worked on several building locations and they have to start the diesel every week or two weeks to make sure that it works, and they run it for some time,” he says. “A typical maintenance run is about 10 hours for a diesel.
“For turbine, it’s two hours over the course of a year. You only have to run it a few minutes to make sure that it starts. You virtually never change the oil, because the number of hours required on a standby system is typically low.”
In contrast, diesel systems require frequent oil and filter changes, Hahn adds.
“You also have the issue of used oil, and filters have to be disposed of properly as hazardous material,” he says.
Weight is another benefit.
“The gas turbine is much lighter and can be mounted on a roof, which is typically an unused area in a building,” says Hahn. “You can’t do that with diesels, because they’re very heavy, plus a building needs to be designed to handle that type of load frequency.”
Emissions are cleaner as well, he adds.
The fuel supply is another consideration. “Gas turbines can burn natural gas or diesel, and they can burn both, whereas with reciprocating engines, you can either buy a diesel or gas, but you can’t buy duel fuel,” says Hahn.
Frequency response—how fast a turbine reacts to changes in a load—is another benefit, Hahn says.
Modulating fuel intake is key for onsite power systems.
|Photo: FLS Energy
More and more building owners are adding solar to their onsite power portfolio.
“If you have a load drop-off or have to add a load while you’re running a standby, the frequency will be maintained,” he says. “The reason that’s important is that a lot of equipment is frequency sensitive. You have less of a chance of popping your low-frequency breaker. If you go below it, you can destroy equipment, so you have a protective relay that opens in the case a frequency drops too low.”
Emissions output is a critical environmental consideration, Hahn says, adding that the gas turbine produces lower emissions that a typical diesel system. A typical gas turbine runs about 120 parts per million (ppm) Nitrous Oxide (NOx) and 15 ppm carbon monoxide (CO) versus a typical diesel’s 700 ppm NOx and 500 ppm CO. Some buildings run baseload turbines as constant power as well as a standby system, allowing the operation to run a cogeneration system, Hahn notes.
“Those come in dry low emissions—you do not have to inject water or steam into the turbine to get the low emissions,” he says. “You simply burn the fuel under very lean conditions to keep the NOx emissions down.”
There’s a misconception about turbines that they are high tech and require special technicians and engineers to operate and maintain them, Hahn says.
“The instrumentation, sensors, and the monitor—anything that goes on that turbine is essentially the same thing that goes on any other industrial equipment,” he says. “Any good technician or mechanic can work on the turbine system,” he adds. “It’s actually easier because of the low amount of moving parts.”
Hahn believes that while turbines cost more at the onset than diesel, in the long run, the costs even out.
“When you put it in a building, the real estate costs have to be included—the fact that you have to build special walls around the turbine and diesel tank,” he says. “It’s not required of GPS if you use natural gas.”
Attenuating walls require barriers, he adds.
“All of these costs add up, including the cost of real estate if you’re putting it on the ground, rather than on the roof or the on the top section of a parking garage,” says Hahn.
Although the lifetime costs may be the same, Hahn says the reliability on the GPS standby units is high, with 98 to 99.98% reliability. That’s especially critical in installations such as data centers, he adds.
“They cannot afford to be down, even for a few minutes,” he says. “They put our systems in, because they understand that although they have a backup battery system, it’s only good for a short time. If you put a turbine in behind that, you’re guaranteed 100% on your up time on your computer system.”
The Cogeneration Option
Among the many products Enercon Engineering manufactures is cogeneration packaging and multi-fuel systems, such as the Enercon Engineering Multi-Fuel System, a new system the company recently employed.
“It’s taking a diesel engine that normally operates on 100% diesel fuel, and we gasify it anywhere from 50 to 80% gasification, depending on the type of fuel and the load in question,” says Charles Gears, the Multi-Fuel Product Manager and Senior Application Engineer for Enercon Engineering.
Multi-fuel conversion converts a diesel-fueled engine to accept the introduction of significant amounts of various gaseous fuels such as natural gas, compressed natural gas (CNG), liquefied natural gas (LNG), propane, and biogas into the inlet combustion airstream of the diesel engine. In multi-fuel systems, natural gas is metered into the air stream by a gas/air blender installed before the engine turbocharger. Enercon Engineering’s control system continuously modulates the gas over the entire load range—given any required engine load and speed—while protecting the engine. Enercon’s NoKnock knock detector/controller enables engine operation at the most efficient gas-to-diesel ratio.
It is suited for all genset engines and engine drive packages, 1,200 to 1,800 revolutions per minute (rpm). Other benefits include no negative impact on genset transient response or load pickup, no reduction of engine power or efficiency, a smooth transition between diesel and multi-fuel operation at any time, and no modifications to internal engine components are required, according to Enercon Engineering.
Some office buildings are located in areas of the country where local power reliability is poor, and they must use standby auxiliary power frequently, Gears says.
There is a lower cost benefit in running the engines as a prime power or for peak shaving, “because you’re not going to be using the diesel fuel to run the engines for a long period of time, which is a more expensive fuel,” notes Enercon Engineering spokesperson Eric Kells.
Maintenance on the system is minimal, Gears says. “They have to look at the sensors, and the system tells them the health of it,” he says. “It’s basically computer-operated, and if the sensor fails, it shuts the system off and tells them that a sensor has failed.”
Gears talks of one end user that uses a genset and a standby power unit.
“When they get to peak demand periods in the summer because utility rates go extremely high for anybody using above the normal demand, they would normally kick on their generator sets to shave that peak and keep their normal electrical pricing from their utility in its normal range,” he says.
“They’re allowed to shave their peak to get it down to normal demand, but if they get it too low, they pay another demand charge, so they’ve figured out they can use the largest of two engines and get an overall benefit,” he adds.
Solar power is increasingly becoming an energy efficiency option in office buildings. FLS Energy specializes in commercial, industrial, and utility-scale solar energy systems that provide hot water and electricity to clients as a hedge against rising energy costs and a clean source of energy. The commercial office building is a market that is just now being tapped, says Joanna Baker, company spokesperson.
“It’s an open roof space market,” she says. “Every building has a wide open roof space. For those owners who have a highly favorable type of roof, then it has great potential and is definitely something that can be considered.
“Office builders are users of electricity and we can help them with photovoltaic systems,” says Baker. “We also provide solar hot water systems. In an office building setting, the only types of hot water usage typically are sinks in the bathrooms and maybe a cafeteria, but it’s not high volume use—it would be the electricity usage.”
In North Carolina, where the company is based, FLS Energy provides systems that it owns, paying the building owner a roof lease for letting the company use the roof to sell the energy back to the utility.
“For building owners that want to invest in their own solar energy project, we work with them to develop a project that would meet their energy needs, whether that be a net metered system, or a system where the energy is sold back to the grid,” says Baker.
Baker says solar use is slow to catch on in urban settings.
“Maybe this building is surrounded by tall buildings and there are some urban shading issues,” she says. “There could be other measures that the building owner is considering first, such as new types of windows or making sure their tenants are using new types of light bulbs or other kind of energy-saving measures.”
A lack of education also is hindering greater solar use, Baker says.
“New building owners for commercial buildings may not know they can use their wide-open roof space to generate income,” she says. “In these types of settings, the developer owns the system, and they pay the roof owner a lease payment.”
Solar can be used in conjunction with other approaches to provide optimal onsite power generation options, Baker points out.
In choosing to employ solar at an office building, end users need to consider their location: what’s around the building in terms of trees and shading, the age of the building, the age of the roof, whether the structure can support the panels.
If solar can be installed, “it’s definitely a sustainability measure that can be passed on to the tenants,” says Baker. “The tenants in that building are able to say to their customers and to people who invest in them that they are in a building that is dedicated to renewable energy. It’s also something the landlord can say to his tenants as well—that this is important to us and this is important to me as a member of my community.”
There also more points in the Leadership in Energy and Environmental Design system for onsite energy generation, Baker points out.
Carol Brzozowski writes on the topics of technology and industry.