Technology is power
This month's panel discusses on-site power, with regard to power generation, new designs, and renewable technologies.
CSE: How are facility administrators focusing on issues of on-site power generation and distributed generation?
THOMAS FLICKINGER : Obviously, financial incentives play a large part in most of their decisions. If funding is readily available, then distributed power (microturbines, fuel cells, photovoltaics, and wind turbines) can be considered. If facility administrators have to rely solely on the distributed power system economic payback (sans rebates), then alternate power sources become less viable and certainly more of a challenge. For more information regarding available rebates for a given state, go to www.dsireusa.org . This is a noncommercial database, which appears to be routinely updated with the latest state and federal initiatives.
MICHAEL KUPPINGER : The drivers for facility administrators going to on-site power generation, often referred to as “distributed power,” are specific trends and factors, the priority of which is as follows: 1. Reliability and availability of power for mission-critical operations, like a data center, call center, or healthcare facility; 2. Federal or other regulations like the SEC requirements for on-site emergency power;3. Sustainable design and LEED goals, such as the ability to use “heat recovery” systems or meet other energy goals; and 4. Sufficient power in remote areas where electricity demands can not be otherwise met. The return on investment (ROI) for the initial capital cost of on-site generation is very difficult to achieve and usually takes several of the stated factors. For example, a 24/7 data center requires a generator. The client desires a USGBC LEED rating and obtains LEED points for “on-site generation,” and the heat generated by the system is recovered and used to pre-heat a large boiler. In this case, the client meets technical and reliability demands, corporate goals, and might see a five- year ROI.
CSE: What are the most promising technologies and strategies for on-site primary power generation?
KUPPINGER : Technologies like fuel cells, wind turbines, and photovoltaics are becoming more popular for small kilowatt loads and achieving longer term ROIs. The ability to scale up the systems to service even a small office building usually is not feasible, as the systems require large spaces and become complex. Natural gas and diesel generators are the vast majority of larger on-site generation projects that get built. One new technology is the use of bio-fuel for generators that move this age-old design toward a more sustainable solution.
KEN LOVORN : While solar, photovoltaic cells have some clear advantages from the environmentalists’ perspective, there is a conflict between the cleaning of the environment due to the increased use of these cells and the increase in pollution created by the greater production of solar cells. The rare earth elements required for the operation of photovoltaic cells are some of the most toxic elements in the world, and containing these pollutants is a major concern.
Wind turbines have a lot of potential but, again, the environmentalists who are in favor of reducing pollution by using wind-generated electricity in place of burning hydrocarbons have a major conflict with the environmentalists who believe that wind turbines kill too much wildlife.
For those of you who have seen how fast the wind turbine blades turn, it appears that the only birds and bats that are killed by the turbine blades are those eliminated by Charles Darwin’s ”survival of the fittest.” Any bird or bat that flies so slow as to be killed by the slow revolution of the wind turbine blades undoubtedly would be killed by any one of a plethora of other dangers like flying into a tree or mountainside.
The most promising alternative fuel has to be methane recovered from waste decomposition. Technologies using recovered methane from a waste stream have been in use for at least 50 years in sewage treatment plants, and the same technologies could be used in the recovery of other flared fuel sources with little modification.
FLICKINGER : The two promising technologies are wind and fuel cells. Though wind turbines have been in use for a while, efficiencies in propeller design have lowered the minimum wind speed necessary for power production. The lower maintained wind speed requirement increases the number of new sites available for wind applications. If a locale’s wind map indicates adequate/continuous wind, then wind turbines in the 50- to 400-kW range can prove economically practical.
Further, in a few states, it would appear that with financial incentives, phosphoric acid fuel cells can be economically viable. Manufacturers have recently increased fuel cell stack capacities from 200 to 400 kW, while maintaining essentially the same physical dimensions. Additionally, by incorporating tri-gen applications, their overall thermal efficiency approaches 92%. Though fuel cells are not completely sustainable, their carbon footprint is significantly less than traditional distributed power sources due to their efficiencies and recombinant process of their combustion byproducts, with the main byproduct being water.
CSE: Describe some recent on-site power designs you are familiar with, and how the design team used innovative approaches.
LOVORN : A local, solid waste management firm had several capped landfill sites that were producing decomposition methane that was being flared. The firm received a grant from the Federal Energy Regulatory Commission (FERC) to install a small, waste gas engine generator to recover the flared methane and use the generated electricity in operating their site facilities, which included offices, lechate treatment, truck maintenance garages, and other ancillary buildings. It was the firm’s intent to sell the excess electricity back to the local utility at the avoided-cost rate based on the FERC regulations for on-site power generation.
FLICKINGER : We have been involved in the installation of microturbines (60-kW range), which are used in base loading applications and arranged in a co-gen configuration for providing domestic hot water and building heat. The thermal efficiency approaches 60% versus the normal grid, which is about 32%, thus resulting in a significant reduction in the carbon footprint.
CSE: How do renewable energy solutions figure into the on-site power strategies?
W. SCOTT COLLINS: Renewable energies typically serve as a supplement or a substitute to utility power. Today’s renewable technologies tend to be expensive and do not promise reliable power at all times. Although renewable energy is a great method to reduce crude dependency you typically find larger consumers of power cannot viably sustain its use for all of their power requirements. Customers with critical loads must continue to invest in on-site standby power solutions to assure full-time operations. FLICKINGER : The opportunities for using on-site generation present themselves frequently, and with adequate rebates and other incentives, they can be realized. Durrant’s new headquarters building incorporates a photo-voltaic system adequate to serve our data center during the day. Our building is presently registered with LEED and we are seeking a Platinum accreditation for the facility. The photovoltaic installation would not be economically practical had it not been for the financial grants provided by the state.
CSE: What are some of the obstacles and challenges for the engineer in specifying on-site power and switching systems?
LOVORN : Some of the challenges that were encountered in the landfill project that I mentioned were: local contractors’ unfamiliarity with technology of this sophistication; refusal of the local utility to comply with FERC regulations on purchasing electricity from the facility; and coordination of the protective relaying required to permit the local utility to be available during on-site generation outages and yet not jeopardize the reliability of the utility system or the on-site generation system.
FLICKINGER : There may have been significant issues a number of years ago; however, we have not had difficulties interfacing with utilities primarily due to the use of microprocessor-based multifunction relays. There are several manufacturers whose relays incorporate most of the common ANSI/IEEE relay types in a single integrated package.
COLLINS: The modular design of a power system is a heavy consideration is today’s changing load environment. Data centers to medical centers to shopping centers are included in the increasing spectrum of constantly changing demands for additional power. Many designers prefer to build as modular of a system as possible without breaking the bank often finding clients retrospectively commenting, “If we would’ve chosen this design….I wouldn’t be in this predicament”. Choices in distribution equipment, UPS and on-site standby power target modularity for various reasons. Although distribution and UPS systems can be reasonably set up for modularity the standby power system is often a struggle with tough decisions for how much power should be planned for. The solutions are maturing in the standby power industry with many modular selections that allow additional power to be scaled economically to match the customer’s load demand. This completes the puzzle for the modular power system granting flexibility throughout its design.
KUPPINGER : I touched on it above and can expand, but basically the systems require valuable space that does not obtain monthly rent, and the capital cost of these systems causes ROIs that far exceed what typical class “A” or “B” developers will invest in or tenants will pay for.
CSE: How are current codes, standards, and environmental impact issues affecting the implementation of on-site power strategies?
FLICKINGER : One would presume with the enactment of EPACT 2005, where net metering was mandated, there would have been a proliferation of alternative energy sources. However, this not the case; the complexity and definition of “net metering” as regulated by individual state and public utility boards is a challenge.
EPA has enacted more stringent air quality standards for diesel generators. As the generators are required to be Tier 4 by 2011, there will be fewer economically viable opportunities for this type of generator, particularly for “base loaded” applications.
KUPPINGER : There was a code change in Illinois and a past client, UBS, was required to provide an air-sampling system and increase the level of diesel fuel monitoring and alarm.
COLLINS: Governmental power requirements via codes combined with reduced EPA engine emissions are leading to mandatory on-site power at a price many U.S customers thought were in the distant future. Purchasers of standby power place heavy emphasis on the initial capital to purchase equipment often overlooking the long-term operating costs. With rising prices of fuel it pays to look at all of your engine technology options. Engines allowing the use of multiple fuels can empower clients with the right to choose between primary use of natural gas or diesel. A bi-fuel type engine grants this flexibility.
CSE: How is the current utility environment affecting the implementation of on-site power systems?
COLLINS: Many utility companies are well aware of the state of the power grid in the form of availability and cleanliness. Today’s power customers harbor sensitive loads that simply cannot accept a loss of power or a power signal that’s distorted without going through a reboot process that costs time, money and, in worst cases, client loss. Uninterruptable power supplies and/or standby power generation units are typically endorsed by many utilities with some offering lease programs that supply the equipment to assure reliable power at all times. Diversification of power sources greatly increases when redundant on-site power designs are chosen. Integrated paralleling systems are the best choice. Today’s selections are modular and can be readily implemented just as economically as one large unit typically with significantly reduced lead times. KUPPINGER: Utility companies have traditionally not allowed the direct connection of on-site generation equipment to their electrical grid. On-site generation typically is not connected to the grid and requires a short “outage.” The primary reason the utility did not allow direct connection or “closed transition” of on-site generation into the grid is that problems on the customer equipment could cause an outage to the entire area. We have seen this happen on the East Coast a few years back, when the operations of a single utility plant caused the surrounding grid to become unstable and ultimately fail. The IEEE has developed improved standards, and pressure from multiple areas has forced utility companies to be more accommodating. Closed transition requires sophisticated switch gear, power breakers, and relay systems that were expensive and caused risk concerns.
Thomas F. Flickinger PE, CSI
Principal, VP—Director of Electrical EngineeringDurrantMadison, Wis.
Michael Kuppinger, PE
Senior Vice President—Mission Critical Facilities and Technology
Environmental Systems Design Inc.
Ken Lovorn, PE
President, Chief Engineer
W. Scott Collins
Product Manager, Industrial
Generac Power Systems
Ask the experts: renewable energy power
Every month, Consulting-Specifying Engineer editors ask a distinguished panel of experts for information about how to best solve your problems, challenges, and new engineering issues at
“Out here in northern California, the next level of state rebates is just for fuel cell or wind generation. Solar is no longer to receive the level of state subsidy used for the last two years. Are renewable energy sources going to be cost-effective, with dwindling state support and few federal tax credits available? What technique should plant managers, and users of large chunks of power, use to minimize their peak demands of electrical (or other) power?” —John Turner, Electrical Engineer, CD Engineers, Fairfield, Calif.
THOMAS FLICKINGER : The reader’s observations are interesting. Intel is building new manufacturing plants that will use silicon-based technology, which can convert usable light to electricity at an efficiency of 9% to 12%. IBM is using thin film cell technology, which combines copper, indium, gallium, and selenide to yield about 15% electricity from the incident sunlight. Both of these technologies are poised for substantial growth in the immediate future, primarily due to current fuel prices.
The second part of the reader’s question is significantly more complicated. The first place to start is to determine the facility’s overall load factor. A load factor of 65% or greater is good. For commercial spaces and schools, which typically have poor load factors (less than 40%), the most immediate solution is daylight harvesting. Not only does this reduce the electrical lighting load but also the HVAC requirements for cooling the associated space. One can also enlist the help of consultants to do an energy audit of the facility. One strategy for limiting peak demand might include the rescheduling of energy-intensive manufacturing processes to stagger production schedules and nonpeak periods. There is no simple way to economically minimize on-peak demand short of simply turning things off.