9. ROBERT O. PICKARD
ENVIRONMENTAL CENTRE - ENERGY MANAGEMENT PLAN CENTRE ENVIRONNEMENTAL ROBERT O. PICKARD - PLAN DE GESTION DE L’ÉNERGIE |
That Council receive this report for information.
Recommandation du Comité
Que le Conseil prenne connaissance du
présent rapport.
Documentation
1.
Deputy
City Manager's report Public Works and Services dated
20 December 2006 (ACS2007-PWS-UTL-0001).
2. Extract of Draft Minutes, 23
January 2007.
Report
to/Rapport au :
Planning and Environment Committee
Comité de l'urbanisme et de
l'environnement
and Council / et au Conseil
20 December 2006 / le 20 décembre 2006
Submitted by/Soumis par : R.G. Hewitt,
Deputy City Manager/Directeur
municipal adjoint,
Public Works and Services/Services
et Travaux publics
Contact
Person/Personne ressource : Kenneth J. Brothers, Director/Directeur
Utility Services/Services publics
613-580-2424 x22609, ken.brothers@ottawa.ca
SUBJECT: |
ROBERT O. PICKARD ENVIRONMENTAL CENTRE - ENERGY MANAGEMENT PLAN |
|
|
OBJET : |
Centre Environnemental Robert o. pickard - PLAN DE GESTION DE
L’ÉNERGIE |
REPORT RECOMMENDATION
That Planning and Environment Committee and Council receive this report for information.
RECOMMANDATION DU
RAPPORT
Que le Comité de l'urbanisme et de
l'environnement et le Conseil municipal prennent connaissance du présent
rapport.
BACKGROUND
The purpose of this report is to communicate to Council and the public the manner that energy consumption at the Robert O. Pickard Enviromental Centre (ROPEC) is managed utilizing the digester gas cogeneration plant, the emergency diesel generators and the Supervisory Control And Data Acquisition (SCADA) system to minimize overall costs for natural gas and electricity. Over the years Process Control staff has developed a sophisticated protocol to optimize the use of available systems to minimize costs.
The ROPEC wastewater treatment plant was rebuilt and expanded with the addition of secondary treatment between 1988 and 1992. The plant was commissioned in late 1992 and came into compliance with the Ministry of the Environment Certificate of Approval discharge criteria before the end of that year. The plant was equipped with an emergency power supply consisting of three diesel generators capable of producing 4800 kW of electrical power. This system was intended to provide sufficient power to operate the main pumps, the digester gas system, SCADA and all emergency systems such as lighting and fire alarms. Digester gas, consisting of methane and carbon dioxide, produced in the anaerobic digestion process was burned in boilers to produce hot water which, in turn, was used to heat the digesters to the required 36 degrees Celsius and for building space heating. In cold weather, natural gas was used to supplement. During the summer the gas was burned in the boilers and the unneeded hot water was cooled with effluent water to get rid of the excess heat.
A cogeneration plant was undertaken to better utilize the digester gas in recognition of an inefficient use of this valuable energy source. Commissioned in 1997, the plant uses three Caterpillar 16 cylinder reciprocating engines burning digester gas to produce about 2400 kW of electricity. The heat from the engine cooling systems and exhaust (2800 kW of thermal energy) is captured through heat exchangers that are, in turn, connected to the plant's hot water heating system. Gas produced in excess of the requirements of the cogeneration engines is burned in the hot water boilers or flared if the heat is not required. Natural gas is used to supplement in cold weather as needed.
DISCUSSION
The $4.5 M investment in the cogeneration plant was returned by 2002, (net of all related financial and maintenance costs) and today saves approximately $1.565 million dollars per year in electrical and natural gas purchases.
The current Hydro rate structure defines a consumer with an average monthly peak demand less than 5,000 kW as a "General User" and those greater than 5,000 kW as a "Large User". The total electrical power demand at ROPEC is typically about 5,300 kW; however, rain events that increase flow to the plant can result in short term peaks of up to 8,400 kW. The total cost of electricity contains a number of charges based on two components: the total amount of energy consumed (kWh) and the monthly peak demand (kW) over three consecutive 5 minute periods. If ROPEC were to be classed as a Large User the City would be subject to higher peak delivery charges and fixed rate administration charges. This would amount to approximately $165,000 per year. To further complicate matters, "time of use" rates were introduced in May 2006 whereby the rate per kWh increases during higher demand periods. The higher rates are charged during the midday/evening in the summer months and in the morning and late afternoon/evening during the winter. It is critical to optimize available equipment and operating protocols to avoid the Large User designation and the higher rate periods.
Maximizing the availability of the cogeneration plant is essential to minimizing electrical and natural gas purchases. Essential maintenance work is done in low demand periods and all efforts are expended to have the engines available during high demand periods. Net of all maintenance costs, cogeneration saves approximately one million dollars in power consumption per year.
To avoid the higher peaking charges of a Large User, Process Control staff closely monitor power consumption through the SCADA system. When the purchased power approaches the 5,000 kW threshold they will peak shave by dropping electrical loads if the anticipated peak is expected to be of short duration or by starting the emergency diesel generators. This saves approximately $165,000 per year.
The use of the hot water from the cogeneration plant for building heating reduces the cost of natural gas purchases by approximately $400,000 per year.
With the introduction of "time of use" rates, ROPEC staff are modifying process operations wherever possible to take advantage of the lower rates. This work is just being undertaken and is expected to yield significant savings.
These measures contribute to the overall cost effectiveness of ROPEC which has one of the lowest unit cost of any secondary treatment plant in Canada at $129.06 per million litres treated (2005 OMBI data). It should be noted that the OMBI Water and Wastewater Expert Panel recently selected the Energy Management Plans for ROPEC and the Lemieux and Britannia water purification plants as examples of best management practices to guide other cities.
The capacity of the anaerobic digestion process is being increased by the addition of two new digesters which are currently under construction and are expected to be in operation by 2008. This increased processing capacity coupled with system growth will increase the production of digester gas. It is anticipated that the addition of a fourth cogeneration unit will be economically feasible by 2010 and funding has been identified in the Long Range Financial Plan for this purpose.
CONSULTATION
No public consultation was undertaken as this is an information report.
FINANCIAL IMPLICATIONS
The ROPEC Energy Management Plan saves the City approximately $1.565 M in electrical energy and natural gas costs per year net of operating and maintenance costs.
SUPPORTING DOCUMENTATION
None
DISPOSITION
Staff will continue to optimize the use of the cogeneration plant and emergency diesel generators to minimize energy costs.
ROBERT O. PICKARD ENVIRONMENTAL CENTRE - ENERGY
MANAGEMENT PLAN
CENTRE ENVIRONNEMENTAL ROBERT O. PICKARD - PLAN
DE GESTION DE L’ÉNERGIE
ACS2007-PWS-UTL-0001 City Wide
The Deputy City Manager,
Mr. Richard Hewitt, introduced Messrs Ken Brothers, Director, Utility Services
and David McCartney, Manager, Wastewater and Drainage Services who presented
the report to Committee by means of a PowerPoint document, held on file with
the City Clerk.
Councillor Gord Hunter
said he was happy to see some of the ideas of the former Regional Municipality
of Ottawa-Carleton coming to fruition.
He congratulated staff for their success, and he inquired about one such
idea that foresaw generating electricity from ROPEC's outflow to the Ottawa
River. Mr. McCartney advised that this
project is still scheduled for 2012, although it might be more attractive
currently, from an economics point of view.
Councillor Steve
Desroches asked about whether this could be a revenue source. Mr. McCartney responded by saying that other
facilities in Ontario have co-generation plants, although not as large as
ROPEC: it is a high maintenance plant.
He added that the heat that is generated is used for the Centre itself
and that there is no excess heat. Mr.
McCartney credited his staff for making things work as well as they do.
The Committee then
received the report, as per the following recommendation.
That Planning and Environment Committee and Council receive this report
for information.
RECEIVED