Energy Management System for Users (view PDF)
Solution for Energy Cost Reduction
The VisualMesa Energy Management System (VM-EMS) is an online solution
that facilitates cost-effective operation of an industrial site's utility
system, including production and use of steam, fuel, power, and water and consideration
of emissions. It facilitates the management and operation of those systems, by
reducing cost by solving daily operating inefficiencies, and providing all the
necessary information for targeted monitoring and optimization of site-wide
operations from a single interface. The following examples show how VM-EMS improves
daily management of a site's utility system operations and maintenance:
The VisualMesa Energy Management System offers two products to model, monitor, and optimize of energy systems:
- VisualMesa Energy Real-Time Optimizer (ERTO)
- VisualMesa Energy Monitor (EM)
VisualMesa Energy Management System products have been successfully implemented in various types of energy systems including steam, fuel, electricity, hydrogen, emissions, water and district cooling. The products are built on the same VisualMesa Energy Management System core functions that were in continuous development for over 30 years. The products share the same user interface providing the user a uniform platform to work with. VisualMesa Energy Management System products are easy to use and maintain as the site changes over time.
- Utility Operators will be able to:
- Deliver optimized
production and consumption of steam, fuel, power, and water, while, in
parallel, tracking emissions at individual equipment, unit, and site-wide
levels to ensure regulatory compliance.
and solve problems quickly through user interface alerting and automatically
updated recommendations for improving operation.
- Engineers will be able to:
changes to the utility system operations and reduce the operating cost.
- Evaluate the
cost and benefit of new or modified equipment or utility supply and purchase
contracts to justify capital investment.
- Evaluate the
effects of a plant shutdown in terms of cost, reliability, and emissions, in
order to plan for optimized operation of the utility system in advance.
- To detect,
track and determine the cause of imbalances in the utility system.
- Maintenance personnel will be able to:
- Identify failing
meters in need of replacement or calibration
- Reduce time
spent seeking the source of imbalances in the utility system.
VM-EMS solution provides increased value in the following seven
- Real Time
and Imbalance Detection
Performance Indicators (KPIs)
Case Studies - "What If?" Analysis
VisualMesa Energy Monitor (EM) provides a single interface (and integrates with third party dashboards) for monitoring
steam, electric power, fuel and water systems, as well as emissions from an
equipment to site-wide level. By displaying real time data, the user can
understand the current operation and is immediately made aware of problems and
potential improvements. The following example shows how a typical process unit
is displayed inside EM:
The operator receives detailed information by
clicking on a piece of equipment, meter, or header on the model interface in
order to display desired trends and operational data.
In addition, EM alerts the user to
measurements that have changed significantly during a particular time period,
so, an operator or engineer can quickly identify and diagnose the cause of any real-time
change. For example, a boiler house operator can understand the reason of an increase
in the steam demand at any moment, contact staff responsible for operations in
the area where change has occurred, and adjust to more efficient boiler operation
through targets which are automatically updated in the Em operator interface.
The following figure shows the "Big Changes" report in the EM
operator interface. The particular view shown indicates all measured steam values
that have changed more than 5 klb/h within the last 3 hours:
2. Real Time Optimization
VisualMesa Energy Real-Time Optimizer (ERTO) is based on a rigorous model with built-in
mathematics and optimization routines designed to recommend lowest cost
real-time utility system operation which meets required process plant utility demand
and critical constraints. The energy cost which the online, real-time
optimization minimizes is defined as follows:
Total Energy Cost = Fuel Cost + Power Cost + Other Cost
"Other Cost" may include demineralized water
costs, such as oxygen scavenger and other chemicals, CO2 emission
cost, and any other incremental costs which should be taken into account to
ensure accuracy of the optimization. The results of the optimization can be
implemented through operator directives or through closed-loop control with
operator directives for manual changes, such as pump drive swaps.
Typical operator directives resulting from
real-time optimization include changes to steam production (biasing of boilers
or generators) and changes to manual set points on steam turbines required in
order to provide steam to different pressure levels most cost-effectively. Such
directives to operators also include optimization of fuel, such as natural gas,
process off gas, and fuel gas, based upon availability, cost and emissions
constraints for each, and in light of the electric power purchase cost and
price for power exported to the grid, as applicable.
The following picture shows an example of the
operator directives that ERTO automatically updates, indicating the changes
required for operators to achieve lowest cost real-time operation:
The operators can review specific changes directed
by ERTO in the user interface in order to better understand how their specific
changes will impact the utility system as a whole. The operator can see the final
result of the optimization directives by selecting the "Optimization View" in
the ERTO menu in the user interface.
The "Delta View" allows the user to see the specific
changes in the utility system that will occur as a consequence of
implementation of the optimization directives. In the "Delta View", ERTO
highlights with those streams that will change as a result of the optimization directives
being followed, so the user can see and follow the specific optimization results
The figure above shows the recommended change
in boiler production ratio or "bias" as a result of the optimizer reducing total
boiler load, which most often occurs as consequence of other changes, such as steam
turbine and electric motor trade outs or "swaps." In this example, ERTO has
directed the operators to reduce Boiler-1 and 2 by 48.8 and 45.2 klb/h,
3. Accounting and Imbalance Detection
ERTO performs a rigorous balance of all the energy
producers and consumers, calculating the imbalances using real-time data. The
imbalances are graphically represented in blocks called "balloons," which are
added anywhere metering allows a mass balance to be calculated. Balloons
graphically indicate where mass balances are large or small based upon size and
color, and imbalances are typically saved to the historian with every automatic
run of the model. ERTO's capability to more precisely monitor where metering
error is large or is changing over time is the first step toward proactive
energy loss minimization.
Using the ERTO graphical capabilities, the
users can quickly discern size of the imbalance in each header. The following figure
indicates the imbalance calculated by ERTO in the fuel system for both the natural
gas and the refinery gas headers in the balloons on the right side of the
diagram. The balloon is indicating that the refinery gas imbalance is significant
and may require investigation, based upon its larger size and change in
By clicking on any balloon, the EM mass balance report is
displayed, indicating the specific measurements contributing to the balance, as
well as the total balance error, on a mass and percentage basis. This provides
an easy way to track and correct or replace failing measurements in the system,
which reduces loss and increases production capacity. The figure below shows the
mass balance report for a 150 psig header, for example.
Tracking the history of the balloon mass balances assists the
energy management team, including operations, engineering, and meter
technicians, in ongoing analysis and improvement site-wide utility metering. The
following figure shows the steam balance trending capability ERTO also provides
which demonstrates each local mass balance's impact on the site-wide imbalance
This figure above shows the reduction in the 30F402.PV
flow measurement in the lower chart correlates to a reduction of the overall imbalance,
but no correlation exists between the 10F211 measurement and the overall
imbalance in the upper chart. So, ERTO highlights the specific meter requiring calibration
or verification, which is 30F402.PV in this case.
In the figure above, the 60F417.PV flow
measurement in the lower chart shows a strong correlation to the overall
imbalance, whereas the measurement in the upper chart, 70F417.PV, shows no correlation
to the imbalance. Therefore, ERTO indicates calibration or verification of the
60F417.PV is recommended in this case.
ERTO mass balance trending capability improves
accuracy of instrumentation and measurement, which directly contributes to more
timely identification and elimination of actual losses.
ERTO provides the ability to understand the
incremental cost of utilities providing heat and horsepower to a plant or unit,
as shown in the example below. This "Process Plant Cost" block calculates the amount
of energy consumed or generated per unit plant feed or per unit production.
ERTO can calculate the lost opportunity or Energy Cost Gap, which is the difference
between the cost of current utility operation and the lower cost that would be
provided if operators were to implement the current directives for optimum
operation calculated by ERTO
All the energy streams imported to or
exported from the process units are included in the "Process Plant Cost" block,
including accounting for their costs. So, if a process unit has a consumption
of 55.5 klb/h of 600 psig steam, as in the example below, ERTO calculates the
actual real-time cost of the steam, $324.68/hour in this case. With the cost
of all streams into and out of the process plant, the "PPC-ALKY" in the case
below, ERTO also provides the incremental cost of utilities for the process
plant as a whole, as well.
Such exposure of real-time incremental cost on
both the stream and plant level provides new and powerful information for
system operators, engineers, and management to leverage in decision-making.
Such information would not otherwise be available without ERTO.
4. Key Performance Indicators (KPIs)
The online execution of EM can be used to calculate important
Key Performance Indicators or "KPIs" related to energy. Typical KPIs calculated
by the EM model and saved to history include the following:
- Steam header imbalance
- Incremental cost of steam for each header
- Energy consumption per unit load or feed
- Difference between theoretical and actual equipment performance
5. KPI Operator Alerts
VM-EMS provides the basis for em's generation of
useful real-time KPI's and KPI Operator Alerts. Operators are routinely
alerted to large changes in real-time utility system operation, such as steam
balances and equipment shutdowns. In the same way than EM can alert the
operator of big changes, EM provides additional alerts when certain KPIs are
outside defined range. Such alerts are activated either if the real-time value is
outside the defined range or if the deviation of the current value from the
mean is outside a defined range for a given time frame.
In either case, the operator is immediately
directed to the KPI for which any real-time alert is given by EM. The
following figure shows an alert caused by the real-time efficiency of the first
stage of a compressor violating the defined low limit alarm. The calculated
value of 61.55% has fallen below the Low Limit defined as 63%.
6. Engineering Case Studies - "What If?" Analysis
Based on the same model used for
optimization in ERTO, Engineering
Case Studies can be executed for such important functions as planning for
shutdowns and turnarounds, determining cost and benefit of capital investment,
and seasonal operation planning. The following examples illustrate such use:
- Planning for an upcoming equipment shutdown by simulating the expected
operation in a case study to determine the most economic, reliable and
environmentally safe operation of the site-wide utilities under the new
- Evaluating the cost and benefit for replacing a turbine driven
pump with an electric motor.
- Evaluating the benefit for adding a steam turbine generator
against the capital investment.
- Evaluation of a steam, power or fuel supply contract under
negotiation, given expected seasonal operation of the utilities.
Improved investment and planning provided by ERTO's Case
Study capability can easily double the value ERTO provides through optimization
ERTO calculates real-time equipment performance,
such as boiler and turbine efficiencies, including the benefit provided and
time required for cost recovery if maintenance were to be performed.
VisualMesa Energy Management System provides
multiple unique capabilities to industrial utility system operators, engineers,
and maintenance personnel not available from any other technology solution
available. Savings from real-time monitoring and optimization alone routinely
provide ample return on investment to justify investment in the VisualMesa Energy Management System.
New and powerful information provided and the
time saved through more structured approach to utility operation on the basis
of VM-EMS's rigorous thermodynamic model increases operational reliability and
can help ensure achievement of environmental targets.