B. SCADA Benefit AnalysisCITY OF
CHANHASSE
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MEMORANDUM
TO:
FROM:
DATE:
SUB J:
Todd Gerhardt, City Manager
Paul Oehme, City Engineer/Dir. of Public Works
March 16, 2004
SCADA Upgrade Cost Benefit Analysis
EXECUTIVE SUMMARY
The Engineering Department has been evaluating the City's Supervisory Control and
Data Acquisition (SCADA) system because of current problems with the system and
to evaluate future needs. SCADA systems are designed to automate the management
of the wells, towers, lift stations, pumps and any other items in the water distribution
and sanitary sewer system. The system uses telemetry units to relay information back
to a main computer system which checks if the system is functioning properly. The
City's current system is antiquated and routinely gives false alarms.
Future additions to the City infrastructure and the current problems with the SCADA
system are mandating the system be upgraded. The City is planning to have a
sanitary lilt station and a new potable well constructed in 2004. The water treatment
plant currently being evaluated will necessitate a high level of supervisory control
critical to its operation. The current SCADA system cannot provide this level of
control nor can it be expanded to incorporate another lift station. Costs to maintain
the existing SCADA system are far exceeding the cost to replace the system. For
these reasons and others which will be elaborated further on in this memorandum,
staff is recommending that the existing SCADA system be replaced as soon as
possible.
EVALUATION OF CURRENT SCADA SYSTEM
The current SCADA system can be described as a piece meal network. As the City
took on new infrastructure that required SCADA, older systems and the main
computer were not updated to make the system efficient and reliable. Also, when
new SCADA pieces were added to the system the newer hardware was not always
fully compatible with the older hardware which has made the communication system
very complicated. The addition of several new lift stations over the past several years
have made the main computer reach its processing limit. The main computer cannot
add any additional stations to the system. While the "bandaid" approach has
benefited the City in some short term cost savings, it has ultimately made the system
very complicated, outdated and unreliable. The system operators lack confidence in
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Todd Gerhardt
March 3, 2004
Page 2
the data and alarms received. It is very common to have alarms in the system
questioned and in some cases ignored after field verification. The on call personnel is
required to check the computer within 15 minutes of being notified of an alarm and
must physically check the site within 30 minutes if the problem cannot be addressed
remotely. An example of a SCADA system problem has been experienced at the
Lotus Lake well field. The system there has never been equipped to send out alarms
for well failures. A red light on the outside of the building is the only indication of a
problem at these wells. A neighbor usually calls the emergency number if he sees the
red light flashing. The only indication the operator has a problems in the well field is
a "low reservoir level" alarm from the water tower. This places City crews on a
critical timetable during high demand periods. This type of situation can and has lead
to low water pressures in the system, which is a quality of life and a life safety issue.
City staff does not have the expertise to fix the SCADA software when problems
arise so the work is outsourced. In fact the SCADA software is proprietary, so one
vender holds the source codes to maintain the system software which has made the
maintenance of the system very expensive. In the last 4 years alone the City has
spent over $90,000 annually to keep the system operational. The expenditures
addressed the immediate needs of the system but did not look at future needs of the
network.
The SCADA system does not allow the operator to regulate the system remotely from
the main computer station. When additional water demand is needed, in most
situations, public works personnel have to physically drive out to the wells and turn
them on. This is an extremely inefficient practice for managing and regulating water
demands in the system.
Every month the Minnesota Department of Health requires the City to submit records
for fluoride and chloride usage. The Minnesota Department of Natural Resources
requires a report identifying the amount of water pumped be generated annually.
These reports are still generated by hand or on an Excel spread sheet (See attached).
If a new SCADA system were purchased, these reports would automatically be
generated with a few key strokes saving staff time and, potentially preventing
computation errors that could cost the City money.
FUTURE NEEDS
The cmTent rate of growth and the planned infrastructure has dictated the SCADA
system upgrades. The proposed water treatment plant had SCADA upgrades in mind.
However, staff feels the SCADA system should be upgraded prior to water treatment
coming on line because of the existing problems in the system and to manage the
other new units coming on line. Well No. 9 is proposed to come on line in 2004 and
should be equipped with the newer equipment and software. Several additional lift
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Todd Gerhardt
March 3, 2004
Page 3
stations are planning to come on line soon and should to be equipped with the new
equipment and software. The existing SCADA computer system is not equipped to
handle any additional lift station units. The CIP has programmed the sanitary sewer
SCADA system be upgraded over a 5-year period. The phased in approach will cost
the City more money over the long term because of annual administration and project
development costs and will make the system more difficult to manage during the
transition period.
THE CITY STAFF VISION
City staff would like to see a new SCADA system that is reliable, nonproprietary, and
expandable to accommodate any new units or systems that could potentially be
added. The system should be automated so adjustments can be done automatically, at
the master computer terminal or remotely. The system should have an effective early
warning system indicating equipment failures and allowing for rapid reaction to make
changes to prevent service disruption and/or property damage. The new system
should also be equipped so regulatory reports can be produced effortlessly saving
time and. money. The system should be able to generate pumping, energy usage, tank
levels and system networking reports both real time and historical so staff will have
the ability to evaluate the system and make adjustments as necessary. These reports
will also allow staff the ability to produce better needs projections for the Capital
Improvement Plan. System software should include source codes so in-house IS
technicians can fix normal software problems as they arise and have the ability to
write additional units into the system as they come on-line. In addition, the system
should incorporate security monitoring equipment at remote sites to alert personnel of
unauthorized entry.
VALUE JUSTIFICATION ELEMENTS
Wha! will be measured?
MEASURE i BENEFIT
Cost of maintenance Minimal cost for future maintenance.
More efficient system Reduction in energy usage.
Both regular and overtime hours for checking false
Staff time savings readings or adjusting system controls. Save staff time
with report making.
Units that come on line in the future will cost less because
in-house IS technicians, in most circumstances, will have
Future upgrade costs
the ability to reprogram the computer to handle the
upgrades.
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Todd Gerhardt
March 3, 2004
Page 4
How much is possible ?
Time Savings
,/ System operation - site visits to each remote station will be reduced by
approximately 780 hours/yr.
,/ System reporting - report generation will be reduced by approximately 230
hours/yr.
,,/ Checking false alarms in system - overtime hours are anticipated to be reduced
by approximately 130 hours/yr. This reduction does not include regular time for
checking false alarms during normal working hours.
Total estimated staff time savings amounts to approximately $47,000 per year.
System Maintenance Costs Savings
,/ Out sourcing software maintenance for SCADA averaged $90,000 annually over
the last 4 years.
Operational Cost Savings
,/ The City currently spends approximately $94,000 a year on electrical usage for
the wells and water towers. It is anticipated that with a new more efficient
SCADA system the City could save approximately 4% annual on the electrical
charges or $3,700 per year.
Other Benefits- Tangible and httangible
,/ Increased level of service to residents
,,/ More efficient network
,/ Better overall morale of staff
FUNDING
Funding for the SCADA improvements in the CIP were included in the utility rate
adjustment adopted in January 2004. Currently funding for the SCADA sanitary lift
station improvements are $80,000 over a 5 year period with a 4% inflation factor per
year, or $433,106 in today's dollars. Funding for the system with this inflationary
increase is approximately the same as the cost of bonding for replacement at this
time. Staff feels that this will not negatively affect the rate study analysis that was
recently prepared.
CIP 2004 2005 2006 2007 2008 Total
Lift Station
$80,000 $83,000 $86,528 $89,989 $93,589 $433,106
SCADA Upgrades
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Todd Gerhardt
March 3, 2004
Page 5
The SCADA upgrades for the water treatment plant should be included with the water
treatment plant CIP line item programmed in 2004.
Staff obtained one quote fi'om a vender of approximately $800,000 to replace the
entire SCADA system. This amount will be revised when each site is visited and
needed improvements are more clearly identified. With the cost savings staff is
projecting, the return on the investment would be in approximately six years. The
cost for upgrading the SCADA system should not necessitate increasing sewer and
water rates.
CONCLUSION
Staff feels upgrading the SCADA system is important because the system is
unreliable, expensive to maintain, and cannot be expanded to accommodate future
needs. SCADA operators lack confidence in the system because of regular false
alarms. The SCADA system problems have lead to low water pressures in the
system, which is a quality of life and a life safety issue. Funds for upgrading the
system have been budgeted with plans to upgrade the system over a 5 year period.
The phased in approach will cost the City more money over the long term and will
make the system more difficult to manage during the transition period. Staff is
requesting the replacement of the SCADA system as soon as possible.
G:\F, NG\SCADA\scada brncllt analysis doc
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WELL NO. MONTH YEAR
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