COGENERATION / ENERGY

1.0     GENERAL

        Aldworth Engineering Inc. (AEI) is an independent mechanical-electrical consulting firm specializing in cogeneration, district energy , biogas power, 'waste-to-energy' (incineration), and environmental protection. Since an initial cogeneration project in Sarnia in 1962, our staff has developed extensive experience both in 'non-utility generation' and 'load-displacement' cogeneration projects. In fact, AEI is second to none in experience on smaller cogeneration projects from coast to coast in Canada.

        Our power plant designs incorporate all major prime-mover and exhaust gas boiler classifications.  Clients range from municipal/governmental to industrial/institutional groups, and include utilities, 'full-service' developers, turnkey-contractors, and power equipment suppliers. Services provided by the firm cover feasibility studies, facility design (preliminary through final), and construction supervision together with facility commissioning and operations assistance.  We have provided cost-conscious selections for pre-owned equipment where project economics dictated.  The following are representative areas, in which our staff has participated, and each area is set out in detail on the ensuing pages.


1.2     REPRESENTATIVE PROJECTS

1.2.1   COGENERATION (nat. gas)

        This project involved a 4.0 MW gas-turbine generator and a heat recovery steam generator located in an old coal bunker section of the Central Heating Plant. It was a high profile project for Canada's renowned NRC which is prestigious in scientific and engineering fields on a world-wide basis.  Our consulting firm was part of a winning team headed up by E.S. Fox Ltd., Niagara Falls (turnkey-contractor), and the work was won competitively from three other pre-qualified teams.   AEI North York and MCI, Markham were joint-venture engineering firms on this project.

        The special features of this project included:

 

 

        AEI provided overview monitoring and engineering input on the expansion of this waste-wood fuelled steam plant in the heart of industrial Ajax for the Bank of Montreal and Kermecho Co. Ltd, Brampton. The work involved the addition of additional wood-fired furnaces, upgrading of wood feeding and ash handling, centralization of plant central systems, and general upgrading of auxiliary systems.

 

 Photo of a 650 kW, 600 V steam turbine genset on 'load-displacement' service at Energy Plus 2000, Ajax;  the genset control panel at right-rear featuring advanced digital governing and controls; also the utility interfacing panel is evident on the right-centre.

 

        AEI performed an engineering study and design for Tecogen Inc. Waltham, MA, of a 3200 kW cogeneration plant for this large hospital complex in the heart of downtown Toronto. The power plant included four 800 kW ebulliently-cooled gas-engine gensets with exhaust gas boilers which were to provide 125 psig base-load steam to the hospital complex (or 200 psig excess steam to nearby Toronto District Heating System) after being compressed by special steam compressors from 15 to 125 psig normally. The electric power produced was to be consumed internally via load-displacement, thus alleviating the need for a costly additional electric power supply feeder to meet the hospital's growing power demand. A new 1500 RT two-stage absorption chiller was included in the project. This was to be fed, for improved steam demand in summer, with 125 psig steam produced by the cogeneration units. Additional cooling tower capacity as to be provided or rejecting heat from the new absorption chiller.

        Subsequently, an alternative scheme was investigated in-depth involving a single 3,500 kW gas-turbine generator with a heat recovery steam generator producing 200 psig steam. This approach, without expensive steam compressors, has been under consideration by the hospital and Toronto District Heating Corporation.

 

 

        This initial cogeneration project in Ontario involved a feasibility study and the final design for a 450 kW cogeneration installation. The prime-mover was a turbocharged, natural gas, engine-ebulliently cooled.  Heat recovered from the engine's jacket water plus exhaust gas streams generated low pressure steam (13 psig) for use as the greenhouses' base thermal load. A synchronous generator operated in parallel with Ontario Hydro rural supply, and provided the plant with both base electrical load and uninterrupted emergency supply. Recovering heat from the separate lube-oil/intercooler loop and radiation from the engine yielded an installation with a "combined-heat-power" (CHP) efficiency well above 80%.

 

 

        Detailed engineering by AEI for Atlas-Polar Co., East York, on a 250 kW cogeneration facility associated with an olympic size swimming pool complex.  The synchronous generator operated in parallel with the local utility. This project featured a weatherproof acoustic enclosure located outside the building, plus the transmission of operating variables by telephone line to a remote PLC at Atlas Polar's remote office for operations monitoring.

 


 1.2.2  BIOGAS POWER

AEI staff has had a long-standing involvement in biogas power from landfill gas, digester gas, and manure gas; and offers a broad background of experience in this area.  The firm has carried out feasibility studies and final designs in both the gas utilization area (power generation) and the landfill area (gas well extraction and collection); and is knowledgeable in economic analysis and facility operations.  We have participated extensively with Toronto Works in landfill gas projects at Keele Valley (35 MW steam), Brock W (25 MW steam), Beare Rd (5 MW recip), Thackery (1.6 MW recip).


Landfill Gas (LFG) Power

        Our firm carried out the total design of a 5.6 MW non-utility generation (NUG) plant for E.S. Fox, Niagara Falls - a major Canadian developer in the biogas power / cogeneration field. The project involved seven LFG reciprocating engine- generator sets, exporting electrical energy to Scarborough PUC and Ontario Hydro. The design included a 4160 volt switchgear lineup and a 27.6 kV switchyard nearby, together with related protection and control for both generation and distribution systems.

        A feature of the design was the gas cleanup train comprising inlet raw gas knockout tank, water scrubber, extractor-blower, pre-cooler, main cooler, condensate separator, reheater, and coalescing filter. This process train, in conjunction with an electric chiller, functioned to remove corrosive contaminated condensate from the landfill gas fuel supply to the engines.

        Noise control features included dual-mufflers, concrete roof and block (STC=50), acoustic silencers for all wall perforations, and radiator noise containment by acoustic barrier walls.

        The firm also designed a cost-effective landfill gas extraction and collection system,  with 50 new vertical gas wells spread over the entire 66 hectare site, containing 9.6 million tonnes of refuse, to maximize gas collection efficiency.  In addition, we initially provided detailed LFG appraisal service on two gas test wells drilled for this purpose, and monitored the drilling of gas wells from the landfill surface.

A panoramic view looking westerly of Beare Rd. landfill showing the LFG power plant, access road, and sprawling metropohs of Scarborough Ont in the backround.  Note the gas well in the foreground.

 

SUMMARY OF BEARE RD. PROJECT

Existing Landfill
· Toronto Beare Rd. Landfill, Scarborough, Ont.
· 9.6 million tonnes; 66 hA, up to 60 m deep
· active period:  1967 to 1983

New Facility
· 5.6 MW landfill gas power plant (c/w related gas field)
· reciprocating engine type
· capital cost $7.25 million, ¸ 5.6 MW gross = $1300 /kW
· start-up:  Jan. '96

Project Basics
· scope:  gas field & power plant
· full-service contract - design, construct, own & operate
· revenue:  from electrical energy sales to Ontario Hydro via Scarborough PUC distribution system
· royalty to City of Toronto; engineering & operating assistance from Toronto Works

Key Participants

        Landfill Owner                          Metro Toronto
        Developer                               E.S. Fox. Ltd., Niagara Falls
        Economic/financial analysis       J. Pritchard, Fergus
        Financing                                 Barklays Bank, Toronto
        Legal                                       Fraser & Beatty, Toronto
        Engineering                             Aldworth Engineering Inc., North York

 

 

This photograph shows the drilling rig utilized to drill the gas production (test) wells at Site "A" and "B".

 

 

A view of 6 (of  7) LFG engine gensets, each 810 kW, set in place before the installation of pre-cast concrete roof slabs.

 

A view the new power plant at Beare Rd. Landfill (in background) showing 7 exhaust stacks and 6 acoustic exhaust hoods.

 

 

A view of electric radiators for cooling of engine jacket water; located within the acoustic barrier walls behind the main-building.

 

A view of landfill gas clean up room, showing "Knockout Tank" in background, gas scrubber in middle, gas extraction blower in foreground, and gas chiller package to the right (not visible).

 

1.2.3  Digester Gas Power

        AEI participated on this project with Pacific Power Consultants (Sandwell / Stone & Webster) as the gas engine specialist firm.  Four original 650 kW dual-fuel engine gensets, installed in 1960, were replaced by five new 810 kW spark-ignition gas engine gensets in 1998 featuring the latest in digital controls.  This plant was arranged to generate in parallel with BC Hydro on a 'load-displacement' basis, and 'stand-alone' during power outage.

An 810 kW gas engine genset being reached for installation at GVRD Iona Island WPCP, Vancouver BC

 

        The firm carried out a pre-design study for the Ontario Clean Water Agency for digester gas cogeneration facilities at Clarkson & Lakeview WPCP's, each involving an 810 kW gas engine genset.  The simple payback at Clarkson was 3.9 years, and at Lakeview 6.6 years.

 

1.3     Energy

General

     AEI has had broad experience in the 'energy' sector including:


Representative Projects:

          Emergency Power Generation