ENMAX seeks approval for small heat and power unit in Calgary

ENMAX Generation Portfolio Inc. (EGPI) applied on Jan. 13 with the Alberta Utilities Commission for approval to install a small reciprocating natural gas-fired generator to provide combined heat and power to downtown Calgary heating and electrical loads.

EGPI is a wholly-owned subsidiary of ENMAX Energy Corp., with is a wholly-owned subsidiary of ENMAX Corp.

The Downtown District Energy Centre (DDEC) is a facility owned by ENMAX Corp. that provides district energy to downtown Calgary commercial and residential buildings. Hot water is produced in boilers at the DDEC and circulated through pipes to various heating loads in the downtown area. The DDEC was completed in 2010 and consists of 55 MWt of thermal boilers, pumps and a connection to the thermal distribution system that provides heat to up to 6 million square feet of floor space in the Downtown Calgary, East Village and Victoria Park districts.

The DDEC was initially designed to host a combined heat and power (CHP) unit, however at the time of its completion the facility was underutilized relative to its capacity and the installation of a CHP was deferred. Over the years there has been steady demand growth and an additional boiler has been added, bringing capacity to 55 MWt. The facility will be fully subscribed by 2018.

Under this project, a 3.3-MW natural gas-fueled CHP generator will replace the existing 750-kW diesel-fueled standby generator currently in service at the DDEC. The CHP unit will generate electricity both for the DDEC’s internal operation and the surplus will be exported into the distribution system for use by nearby loads. Waste heat will be recovered from the exhaust and cooling loops of the CHP and sold to the DDEC to offset its own fuel use (3.05 MWt). The overall efficiency of this CHP system will exceed 80% and could approach 85% efficiency.

On a simple-cycle basis, the electrical generation from this facility will result in less carbon that the system average carbon intensity on a per MWh basis, reducing Alberta’s carbon emissions, the application noted. On a combined basis, the waste heat recovered from this system is carbon free and will offset the emissions by reducing the natural gas burned in thermal boilers at the DDEC.

The CHP system, consisting of a high-efficiency natural gas-fueled generator and heat recovery equipment, will be located completely inside the existing DDEC structure. It will replace the existing emergency generator and connect to a similar roof stack. One synchronous generator will be installed, with a maximum size of 3.3 MWe based on physical and electrical constraints of the plant. The exact make and model have not been competitively bid at this point. 

A project contact is: Grant Weismiller, Vice President, Regulatory Applications, (403) 514-3105, gweismiller@enmax.com.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.