Advances in Gensets: Powering Diverse Configurations

Credit: MTU Onsite Energy
MTU Onsite Energy installed four 2,250 kW generator sets at Nemours Children’s Hospital in Orlando, FL.

“People are becoming more dependent on power,” notes Curt Gibson, P.E., power solutions manager for Generac Industrial Products. “We always just assume it’s going to be here…” until it’s not. And that’s where gensets play a crucial role.

Advances and technologies that improve performance ensure gensets are more reliable than ever before. Today, gensets run on diesel and natural gas. Tier 4 technology ensures cleaner air quality. They can run in parallel. Improved control systems are bringing “smart” technology to gensets. And systems are less noisy due to noise attenuation improvements.

Weather events, climate change, and power security are among the driving factors underscoring the increased demand for gensets, industry experts say.

Generator sales are taking off, notes Gibson, adding that his company has doubled in size over the past five years. Industrial applications are a “hugely growing market,” he adds.

Loren Carlson, North American sales manager for Herc Rentals’ ProSolutions group, points out that there’s a growing demand for temporary power, given the unpredictable nature of the climate. Herc Rentals is providing solutions.

Contingency plans should be in place for unplanned events, he adds. Facility owners and operators should know what their ability is to tap into temporary power, and what their core need is going to be so they aren’t going through the process of figuring out what the proper solution is in the moment, he adds.

It’s important to create a contingency plan in partnership with a local dealer, notes Carlson. “We look at that with them and scope it out,” he says, adding that the same process can apply to a planned event, but there is more time to work through it. “It’s the same approach in trying to understand what things come up over the course of the year that they have to account for, and help them figure out the most efficient and cost-effective way to get it done.

“It helps us when we can get in there and present them with a plan in the event of an emergency because then we’ve got possession of it as well, and it helps us get them back up and running quicker.”

Mission critical facilities’ plans should not only address the power, but what the power is running, such as HVAC air compressors, says Chuck Miller, vice president of operations for Herc Rentals, adding that he’s seeing plans for temporary or supplemental solutions that are more inclusive of all critical systems.

“That entails more integrative solutions; install for all of those things at once or in packages that make sense,” says Miller. “You bring in the power and the HVAC systems to take care of whatever the critical business need is, as opposed to having one source of supply for the power and another for the air conditioning and another for the compressors.”

Considering the entire demand “sets you up to operate more efficiently, run more smoothly, and have fewer problems,” adds Carlson.

Credit: Doosan Doosan’s G50 Mobile Generator. The G25, G50, and G70 models are the first mobile generators equipped with Doosan-built engines. The high-performance engines deliver increased fuel economy, unrivaled motor starting capability, and reliable operation in extreme conditions.

Credit: Doosan
Doosan’s G50 Mobile Generator. The G25, G50, and G70 models are the first mobile generators equipped
with Doosan-built engines. The high-performance engines deliver increased fuel economy, unrivaled motor starting capability, and reliable operation in extreme conditions.

“Contingency planning, even at a basic level, is really important. Space requirements, where you plug in, and the re-fueling are important,” notes Miller. “You can’t plan for every contingency, so you need a solution and know who to call to parachute in and help out with the total solution in the moment when something does happen.”

Centinela Hospital Medical Center in Inglewood, CA, is a case in point for how modern gensets are bringing more reliability and mitigating other issues such as noise and air quality to end-users.

The 369-bed hospital—recently named one of the top 15 healthcare systems nationwide—began an extensive upgrade program in 2012 that included the replacement of its standby power system.

The project’s specifications were demanding. The hospital was located near an apartment complex, so noise abatement was one concern. Another concern was that the system had to meet California’s environmental and seismic regulations. MTU Onsite Energy distributor Valley Power Systems recommended a solution that exceeded the requirements.

Credit: MTU Onsite Energy MTU Onsite Energy installed four 2,250 kW generator sets at Nemours Children’s Hospital in Orlando, FL.

Credit: MTU Onsite Energy
MTU Onsite Energy installed four 2,250 kW generator sets at Nemours Children’s Hospital in Orlando, FL.

Centinela Hospital was outfitted with two MTU Onsite Energy 1,000 kW diesel generators, each powered by an MTU 16V 2000 engine. They are designed for a 24-hour average load factor of 85%
—15% over the ISO standard—and as such enabled Valley Power Systems to reduce the number of generator sets needed to support the hospital’s power needs, while increasing capacity, fuel efficiency, and durability. In doing so, they will be able to accommodate the facility’s future growth.

Inglewood’s sound ordinance requires generator sets to meet 45 decibels of sound (dBA) within 50 feet of the nearest property line. With a typical generator set emitting up to 105 dBA, Valley Power Systems aimed for a system at 40 dBA.

The generator sets are contained in a rigid structure, enabling the units to run with minimal vibration. An enclosure from ACS Manufacturing helped Centinela reduce noise levels to the sound of a whisper.

Another challenge the hospital had to face was the city’s sound curfew, which is lifted every morning at six am. The noise of the hospital’s original generator sets required Centinela to balance a six am generator set startup time with its surgery schedule to avoid interrupting the flow of electricity to the hospital’s critical equipment. Now, the hospital can switch the units on before beginning daily activities and procedures.

To meet seismic codes, all electrical and mechanical equipment supplied to California hospitals must withstand a three-axis earthquake simulation called the “shaker table test,” which violently shakes full-size generator sets to simulate the movements of a real-world earthquake in laboratory conditions to ensure the equipment is functional, with all essential components intact, following a seismic event in order to protect patients’ lives.

Air quality is another consideration. The South Coast Air Quality Management District requires that the concentration of a diesel engine’s particulate matter emissions not exceed 450 milligrams per cubic meter.

To satisfy this requirement, a diesel particulate filter—the combination of a filter and a muffler—was installed on the Rule 1470-compliant MTU 16V 2000 engine. An electronically controlled, common-rail fuel injection system that enables the combustion process to be optimized to achieve low pollutant levels and lower fuel consumption.

The installation of a new underground diesel tank with several leakage backups, tests, and sensors is designed to ensure the tank can’t leak into the water table.

Factors for facility owners and operators to consider when choosing a genset start with local codes, says Gibson.

“Do you need one, or just want to have one?” points out Gibson.

Some facilities need them due to regulatory requirements. For instance, the National Fire Protection Association’s Article 708 of Standard 70 requires backup power for critical operations such as a gas station or emergency operations.

“If you just want to have one, you would end up probably going with a natural gas unit because of the emissions and the simplicity of maintenance,” says Gibson. “Those are the key pieces for business owners.”

Business continuity insurance is another consideration. “Most businesses can get a deduction on their insurance policy if they have a generator there,” adds Gibson.

In making the choice between a site-installed or mobile genset, Gibson points out that there is normally a one-year allowable time to have a mobile unit onsite, a mandate normally driven by emissions requirements. Mobile units normally meet Tier 4 compliance, he adds.

But if a hospital construction project, for example, is going to exceed a year, it will need a stationery unit, says Gibson. Major factors to consider in stationary applications are particulate filters and NOx reduction.

The market offers many options for both permanently installed and mobile units.

MTU Onsite Energy offers power solutions tailored for sites requiring 20 kW to 3250 kW out of one unit, as well as solutions for the integration of multiple units. Units are typically site installed. Trailer-mounted units are available via MTU Onsite Energy’s distribution network.

Generac offers generators from 800 W to 2 MW. The company has 52 choices in business standby power, from natural gas units up to 500 kW and 2 MW for diesel units. Generac offers 47 choices of permanently installed residential backup power generation units up to 50 kW to back up an entire home or just its essential components. The generators run on existing natural gas or an LP fuel supply.

The company offers 28 choices of mobile generators used for home backup, recreation, construction, and job sites. Mobile power is available up to 2 MW, and units in the 20 to 400 kW range are often towed by contractors for job sites, notes Gibson.

When portable power is all that is needed, options abound. Doosan Portable Power recently rolled out three newly designed models to its mobile generator lineup. The G25, G50, and G70 mobile generators incorporate numerous innovations based on end-user input and are designed to improve operator experience.

The newly packaged Tier 4 final-compliant generators are designed for improved fuel efficiency, extended run times, and low sound levels.

They are the first mobile generators equipped with Doosan-built engines: the D18, D24, and D34 respectively. The engines are designed for high-performance, increased fuel economy, optimal motor starting capability, and reliable operation in extreme conditions.

The D18 and D24 engines are designed with a nearly maintenance-free diesel oxidation catalyst (DOC) after-treatment system. The D34 engine consists of DOC with selective catalytic reduction (SCR) after-treatment.

The Doosan powertrain allows the company’s dealer network to provide end-to-end service and full warranty support for umbrella maintenance and repair services, says Todd Howe, global generator product manager for Doosan Portable Power.

The G50 mobile generator’s introduction marks a size increase in the company’s portable power generator product line. The G50 (51 kVA) replaces the G40 (35 kVA) generator in response to end-user demand for higher kVA output.

Another new feature of the generators is increased onboard fuel capacity for runtimes in excess of 24 hours at any load factor. An optional 48-hour runtime solution is available on the G25 and G70 models.

The newly packaged generators are also quieter than previous models—the G25 features low sound levels at 63 dBA.

The multipurpose generator models are popular rental items, especially for general construction and event applications, where extended runtime without refueling and low sound levels are required, Howe points out.

The generators also feature enhanced controls designed for easy operation. The new Doosan engine controller includes a backlit LCD screen for easier viewing of common parameters. Analog gauges allow at-a-glance monitoring. Fault codes display in simple text designed for faster diagnostics and troubleshooting. The new controls are also designed to allow integration of a variety of telematics packages for remote monitoring capability.

A dual-frequency feature allows an operator to select 50 Hz or 60 Hz, dependent upon the application, and a multi-voltage selection switch.

Doosan Portable Power generators are designed to withstand rugged transport and job site needs. They are built on heavy-duty skid bases and feature a 14-gauge galvannealed steel enclosure and rugged running gear for towing.

Additionally, Doosan Portable Power has introduced an Intelligent Load Management System (ILMS) as an option for the G70 and larger generator models in its product lineup.

The internally packaged ILMS is designed to improve machine performance and decrease potential downtime associated with Tier 4-compliant mobile generators when applied in light load or cyclic applications. It also is designed to reduce fuel costs compared with other methods of adding supplemental load.

According to Doosan, diesel generators with Tier 4-interim engine systems, operating below 30% of rated capacity or in extremely cold environments, often cannot produce the required internal heat to effectively complete diesel particulate filter (DPF) regeneration, an after-treatment process that consumes particles and impurities in the exhaust stream in order to meet emission standards.

Tier 4-Final engine systems equipped with SCR after-treatment technology require elevated exhaust temperatures for periodic conditioning of the SCR system to maintain efficiency and performance.

The Doosan Portable Power ILMS is designed to create supplemental heat within the exhaust system to aid in the passive regeneration process required for reliable generator performance without limiting the generator capacity by adding a sizable load.

In contrast to methods that employ conventional load banks to elevate exhaust temperatures, the ILMS adds a relatively small amount of load and applies the heat generated by the ILMS directly to the after-treatment system, to enable it to more efficiently achieve the temperature threshold needed to ensure proper after-treatment performance.

Doosan Portable Power plans to make the ILMS option available on new Tier 4-Final models of the G70, G125, G150, G190, G240, and G325 mobile generators, as well as select Tier 4-interim models.

Herc Rentals, which spun off from the rental car business’ Hertz Global Holdings in July 2016, offers units with 1,000 watts to 2 MW of portable power.

The company services the construction, industrial, and service industries with an inventory that provides solutions for the smallest needs, such as a home office, to multi-residential properties, and industrial projects.

Regarding when it’s best to rent and when it’s best to purchase a genset, Miller notes that over time, national and individual rental companies have improved their products and service offerings to a degree that end-users—including those with critical applications—can source from them what they need to have onsite for redundancy and get it within hours or days, depending on the nature of the problem.

“They don’t have to have as extensive redundancy or triple redundancies in case their backup unit goes down,” he says. “They don’t have to have a backup for the backup. The backup gets deployed on a planned or unplanned basis. It alleviates the need for a business to buy a number of systems.”

One factor to consider when renting systems is “where you’re going to tap in, what is the accessibility, how long you’re going to be running, and what your consumption needs are going to be? It’s important to have a fuel supplier and source in advance,” says Carlson, pointing out those are key factors in an unplanned event.

While there may not be many advancements taking place in the area of prime movers and alternators, there are significant changes taking place in fuel sources and emissions issues, such as after-treatment and timing.

“In high-level trends, we see much more natural gas than we had seen in the past. During Superstorm Sandy and Hurricane Katrina, we saw that natural gas stayed available whereas diesel wasn’t quite available,” notes Gibson, adding that his company fielded calls from end-users regarding failed generators that hadn’t been tested in more than a year and the diesel went bad.

“Natural gas is maintenance-free and has become a stronger alternative,” he says. “It’s getting more and more acceptance—natural gas is being acknowledged in New York City now as a life-safety source.”

In terms of emissions, “people don’t want those old-fashioned diesels puking out fumes and hydrocarbons,” notes Gibson. “Natural gas is on the plus side there. Everybody is leaning towards natural gas, yet it’s making the whole system less reliable.”

Gibson points out that because natural gas is a real-time fuel source, it makes the infrastructure “more brittle” by its use.

“When the pipe goes down like in southern California, where there was a large ruptured storage vessel and it blew out all of the natural gas, they were worried about not having power for southern California because all of the power plants are natural gas,” he says.

Brian Ponstein, regional sales engineer at MTU Onsite Energy, notes that exhaust gas after-treatment is another key technology required to keep up with the changing federal and local regulations.

In other genset advances, “we’re seeing a lot with controls—more wireless, real-time annunciation,” says Gibson. “There are more communications being added into the control systems.”

Reliability is a prime factor in choosing a genset, Gibson points out.

“When we look at performance, we see what would make it more reliable,” he says. “In controls, upgrades are more important than anything else.”

Generac is expected to introduce a new controller designed with “vast improvements in control technology between communications and logic,” says Gibson.

Integrated controls in Doosan’s ILMS enable the generator to instantaneously respond to fluctuating load demands to ensure the total rated output of the generator is always available.

The system requires no operator control or monitoring and is automatically compatible with any voltage output produced by the generator to meet a variety of needs without special setup or switching required.

Controls and system integration are factors significant to the improvement of MTU Onsite Energy’s performance, notes Ponstein.

Recent advances have occurred in system controls and capabilities. MTU Onsite Energy has designed a solution that can start and parallel 15 units in less than 14 seconds, notes Ponstein. Going forward, look for advances in system controls to integrate different forms of power, such as solar, utility, wind, diesel generator sets, and gas generator sets.

“The controls to make these systems work together sounds easy upfront, however, each power source has unique requirements that need to be addressed to keep the electronic performance support system reliable,” says Ponstein.

“I also see the lock-in strategy that many manufacturers use with their system controls to become rivaled,” he adds, saying today’s end-users seek “plug-and-play” backup systems to avoid being locked into one supplier or where the cost to change suppliers isn’t high. That minimizes the risk on the purchasing side as well as the engineering side.

One of the latest advances in genset technology is the ability to parallel multiple units, notes Carlson.

“We’re able to do it in conjunction with Tier 4 engines,” he adds. “Proper loading is critical to performance on the job, so the ability to parallel generators is much easier now with this technology.”

Before the newer generation of portable power moved into Tier 4 environmental emission standards, “the old way to solve the problem was less concerned with proper load sizing of the generator, with higher tolerances to work with and less consequences for inefficiency. The new Tier 4 engines are more efficient combustion-wise, and clean burning, but have lower tolerances for under-loading, making properly-sized turnkey solutions more critical,” says Carlson.

Running units in parallel enables end-users to bring more power online “so you don’t have to be producing power all of the time that’s not being consumed,” he points out. “As demand for power increases, if you have three or four generators paralleled, one can be run to satisfy normal demand but when there’s peak demand, other generators would pop into place, start producing power, and then they would fall off as the demand decreased. It also creates redundant power, so if there was a problem with one generator, it would pick up the slack so you would never be without power.”

Generac units have paralleling capability.

“Instead of a large, single, two-megawatt unit, you can buy a less expensive pair of smaller, one-megawatt units and be able to get them to work together,” points out Gibson, adding that paralleling is available on most of the company’s units.

Generac also offers a “spec writer,” enabling engineers and others to answer a list of questions and the software will write a spec for job bids, says Gibson. BE_bug_web

Comments

Leave a Reply

Enter Your Log In Credentials
×