Small-scale cogeneration packages, such as Mariah Energy Corporation's Heat PlusPower system, provide both heat and electricity on-site from a single unit. This system combines a Capstone microturbine that produces the electricity and a Mariah-developed heat-recovery unit (HRU) that captures the waste heat from the electrical production and converts it into usable hot-water heating. Two system sizes are commercially available: the 60/30 system, providing 60 kW of onsite heat and 30 kW of onsite electricity, and the 120/60 system that doubles the capacity.

Each system is compact and easily can fit into existing mechanical rooms, eliminating the need for separate housing facilities during refits or installations. Facilities that demand hot water throughout the year-apartment or condominium complexes, hotels, food-processing plants, recreation centers, swimming pools, and even large-scale greenhouses and other agricultural facilities-stand to benefit the most from these systems.

Mariah's combined use of the Capstone microturbine and its own HRU allows a single fuel source and system to produce both heat and electricity efficiently and reliably. The system's superior fuel efficiency and multifuel capability-ranging from natural gas, propane, and diesel to methane and ethane-provides a high degree of flexibility while allowing users to save on their operating costs. Utility savings can be up to 25%, and the payback can be accomplished within five years when a straight purchase of the system occurs.

"The 60/30 system requires a capital investment of an estimated $61,000 Canadian [$47,100 United States]. The installation charges generally run about $30,000 Canadian [$23,200 US]. The 120/60 system requires a capital investment of approximately $124,000 Canadian [$95,800 US]," states Geraldine Burn, general manager of Mariah Energy's head office. The system also can be distributed to customers through a Build-Own-Operate model, under which Mariah owns the systems and customers pay only for the heat and electricity they consume. Given system efficiencies, this often is an attractive option.

Walker Court Complex

One 60/30 unit powers a condominium complex in Calgary, AB. The Walker Court complex, which houses a Build-Own-Operate project, is home to Ian Hansen, president of GPS Central, an independent Calgary-based business specializing in GPS (global positioning system) products for recreational and marine activities. Hansen depends on the reliable production of electricity for his business. "If the city grid goes down, we don't go dark or off-line, and that's important in our business," he maintains.

The Walker Court condominium complex in Calgary houses a 60/30 Heat PlusPower Build-Own-Operate System.

The heating system at Walker Court employs radiant floor heating whose primary heat source is the 60/30 Heat PlusPower System. It also features a Raypak boiler for use as a peaking heat source. The heat utilization is metered. Domestic hot water also is available at Walker Court, thanks to the system. The heat utilization of this component of the system is monitored. As a peaking heat source, the system employs dual-fired domestic-hot-water tanks and CombiCore. The system also generates 30 kW to cover the base-load source. As a peaking power source, the system can access the grid. The Walker Court system includes electrical submetering, standalone capabilities, and load-shedding activities.

Coon Rapids YMCA

Another 60/30 system provides heat and power for a Coon Rapids, MN, YMCA. Xcel Energy, the fourth-largest electricity and natural-gas-energy company in the US, installed the system to provide electricity for the facility, which demands approximately 270 kW/yr. It also provides heat for the swimming pool, which requires hot water all year. This year-round hot-water demand guarantees that the system is used to its capacity, increasing the energy efficiency of the system while decreasing utility costs at the YMCA.

This 60/30 system brings the total number of systems purchased by Xcel Energy to 12. "This demonstration project will serve as an example of how emerging energy technologies, such as microturbine CHP [combined heat and power] systems, can help our customers save money while helping the environment," explains Anne Adrian, product developer for Xcel Energy.

Not only does the system provide a reliable source of power, but it also reduces carbon dioxide and NOx greenhouse-gas emissions when compared to traditional power generation. In 1998, when Mariah began sourcing clean-energy products, the company took an existing technology-the Capstone microturbine-and developed the HRU to fit directly on top of the microturbine. This allows the HRU to capture the escaping heat that otherwise would be wasted into the atmosphere.The placement of the HRU also allows Mariah to make the size of the system very small.

Two Capstone turbine-driven Heat PlusPower systems are the primary heating source for the pool at SAIT.

Capstone's headquarters and research, development, and manufacturing facilities are located in the Los Angeles, CA, San Fernando Valley. The company is UL-certified to the International Organization for Standardization 9001:2000 quality standards. In addition to the current 30- and 60-kW models, the company plans to introduce a 200-kW model in 2004.

Capstone shipped its first three commercially produced 30-kW microturbines in December 1998. Since then, the corporation has sold more than 2,500 units worldwide. By maintaining communications access with more than half of those units, Capstone has been able to track and document a total of 3.9 million hours (450 years) of accumulated operation to date.

Paul Liddy, president of Mariah Energy, is very satisfied with Capstone's technology: "Incorporating Capstone's turbine with Mariah's HRU technology has positioned Mariah as a North American leader in CHP. At Mariah we look forward to increasing our purchasing position with Capstone in a relationship that is mutually beneficial to both companies."

One significant benefit of the marriage of Capstone microturbines with Mariah HRU systems is that together they can replace the need for traditional, remote, electrical generation and onsite boilers or that they can work in league with these, providing the base-heat and electrical requirements. The systems can provide-and in some cases exceed-80% energy efficiency, as compared to the 37% efficiency of the most efficient coal-generated power plant in Alberta. When compared to large-scale, traditional, coal-generated power, a small-scale 60/30 system reduces carbon dioxide emissions by 244 tonnes/yr. (298 tpy). It reduces NOx emissions by up to 97%. The 120/60 system has double the emissions-reduction capabilities, reducing carbon dioxide emissions by 488 tonnes/yr. (596 tpy).

TransAlta epiCentre

One system not only is providing heat and electricity and saving money but also is presenting educational opportunities for students. "Nowhere is cogeneration so conveniently and practically demonstrated as in the basement of the Southern Alberta Institute of Technology's [SAIT] campus center," home of the TransAlta Electrical Power Industry Centre (TransAlta epicenter), says Bruce Robertson, operations and utility manager for the facilities management department at SAIT.

"This combined heat and power installation gives students a first-hand look at the economics of cogeneration, state-of-the-art rotating equipment [e.g., high-speed gas turbines with magnetic bearings], high-efficiency combustion and heat exchange, and the latest technology for grid synchronization and power-quality management. The twin turbine installation is a relevant demonstration for our electrical, power, mechanical, and instrumentation programs and is tied in directly to the epiCentre for learners," he continues.

"The two 60/30 CHP systems will reduce the greenhouse-gas emissions by 420 tonnes annually. They are an embedded generation, which connect directly to the campus electrical grid, thus eliminating the regulated transmission charges. This enables SAIT to purchase power only, without the cost of transmission, distribution, and municipal consent access fees [taxes]," Robertson explains.

"They will heat SAIT's 35-meter pool more efficiently and save money," says Ron Talbot, SAIT's dean of energy. "They are environmentally friendly, and they provide an opportunity for students to learn more about distributed power generation."

"The epiCentre is unique; [it is] a state-of-the-art training and education facility that will provide much-needed skilled workers to help the electrical-power industry remain competitive and capitalize on future growth opportunities," says Irene Lewis, president and chief executive officer of SAIT. "By educating new students and by providing best-practices training for those already in the field, the TransAlta epiCentre will create a win-win situation for the electrical-power industry, for students, for industry partners, and for SAIT."

Electrical-industry training courses in conventional and new, alternative sources of power are offered at the epiCentre through the Power Engineering Technology and Electrical Engineering Technology programs. Specialized training also can be developed for employees already working in the field. This training can be delivered on the job site, on the SAIT campus, or via distance learning.

"Graduates from these programs are entering an exciting time in the electrical-power industry," notes Mike Williams, senior vice president of human resources for TransAlta. "With the large amount of current workers in the electrical-power industry close to retiring, the development of emerging technologies, and the requirement for employees to continuously upgrade their skills, there is high demand and great opportunities in the industry for skilled workers and for training from such a center."

Construction of the epiCentre was made possible in September 2001 with a $4.5 million financial investment from TransAlta. This multimillion-dollar investment helped create a unique environment where the electrical-power industry could partner together with SAIT to concentrate on the technical training and applied research needs of the industry. Other partners in the TransAlta epiCentre include Schneider Electric Inc., General Electric Energy, SUBNET Solutions Inc., Dynatrol Systems Inc., EECOL Electric Inc., Lutron Electronics Company Inc., Benshaw Inc., and Mariah Energy.

Medicine Hat Projects

Mariah was awarded C$212,862 ($162,069 US) in funding from the Green Municipal Enabling Fund for the installation of systems in the Medicine Hat Family Leisure Centre in Alberta, allowing the company to demonstrate the benefits of its Heat PlusPower system in recreation centers at the municipal level. The Canadian government gave C$250 million ($190,345,668 US) to the Federation of Canadian Municipalities to establish and manage GMEF. In 2000, GMEF began to promote environmental projects launched by municipal governments and their partners that would diminish pollution and expand municipal services. GMEF influences larger amounts of cash for studies and demonstration projects through the use of contributions driven by municipalities and private-sector partnerships. Proposed municipal projects are evaluated for technical, environmental, and economic feasibility and innovation before they can be awarded funding.

Two 120/60 systems are installed in the Medicine Hat Family Leisure Center.

The potential for CHP in recreation centers is extensive because of the demand for heat throughout the year, which ensures that the systems reach their best efficiencies and, as a result, their best cost-savings. The Medicine Hat Family Leisure Centre houses a 50-m multipurpose pool, a leisure/wave pool, a parent/tot bubble pool, a waterslide, a steam room, a whirlpool, an ice arena, and a multipurpose recreation room. The center is a demonstration project for the company's new diverter technology where, for the first time, a diverter to handle excess heat loads is being used.

The City of Medicine Hat is the site of yet another award-winning CHP project supported by Climate Change Central (CCC) and installed in the city's Suntec Greenhouses. The system won the prestigious Project Achievement Award from the Association of Professional Engineers, Geologists, and Geophysicists of Alberta. CCC provided C$125,000 ($97,000 US) in project funding to install four 60/30 HeatPlus Power systems in the greenhouses. CCC is a private-public partnership founded to encourage and coordinate actions taken by Alberta individuals, businesses, institutions, and governments that seek to reduce greenhouse-gas emissions throughout Alberta. Other partners in this project include the National Research Council, the Alberta Research Council, Shell Canada Ltd., and the City of Medicine Hat.

Four 60/30 systems are housed in a sea container at the Suntec Greenhouses in Medicine Hat.

In all, the 60/30 systems provide 240 kW of heat and 120 kW of electricity for the greenhouse. They have reduced carbon dioxide emissions by 55% and NOx emissions by 97%, as compared to traditional coal-fired generation. The systems not only have reduced the operation's greenhouse-gas emissions, but they also have reduced the company's fuel and power costs.

"This award is a testament to the benefits of combined heat and power systems which not only are good for the environment but also [are good] for a company's bottom line," said Allan Amey, president and chief executive officer of CCC. "We are very happy to have been able to work in partnership with Mariah Energy. By working together, we have been able to develop an effective way of reducing [greenhouse-gas] emissions in Alberta."

A new addition to Mariah's systems is its Central Dispatch Control and Monitoring System that allows end users to remotely monitor their systems on-line. End users are able to log into a site on-line and check how much energy is being consumed, when energy usage is hitting peaks and lows, and monitor maintenance tasks. Additionally they are able to remotely check to see what maintenance tasks, such as changing filters, are required.

Guest author COLLEEN MADONNA FLOOD WILLIAMS writes for several business magazines.

DE - March/April 2004