Using control systems to optimize microgrids with CHP - Thermo Systems

Page created by Fernando Matthews

Finance

English

Like
Share
Embed
Fullscreen
Slides
Download HTML
Download PDF
Abuse

←

→

Page content transcription

If your browser does not render page correctly, please read the page content below

Using control systems to optimize microgrids with CHP - Thermo Systems

Using control systems to optimize
microgrids with CHP
Proper system integration is key in today’s increasingly complex projects.

Serge Zinger, Account Executive, Thermo Systems LLC; and Jason Wittkamp, PE, Director, Thermo Systems LLC

Photo Serge Zinger.

The microgrid/CHP system at the TWA Hotel.

icrogrids are a focal point of dis- Whether a district energy system is tem (PMS). All of these will be used to

M cussion in the district energy
industry, and this trend does not
appear to be going in any other
direction but up. As the demand for
microgrids has increased, so has their
considering a traditional microgrid, one
coupled with CHP, or a hybrid microgrid, a
major area of focus should be the supervi-
sory control and data acquisition (SCADA)
automation, balance-of-plant (BOP) con-
integrate the OEM equipment and enable
the microgrid to function as one coordi-
nated system. This SCADA plant control
system should be robust, reliable and
responsive to make sure the entire
complexity. End users want to gain effi- trol system and power management sys- microgrid system works as designed.
ciencies from new technologies and
hybrid systems to optimize their micro-
grids. With the increasing complexity, it
is critical to incorporate robust, adapt-
able controls to ensure the successful
commissioning, operation and mainte-
nance of these systems. Whether the
project driver is a post-natural-disaster
recovery, the aftermath of wildfires or
an energy reliability/resiliency goal,
microgrid solutions are being discussed
and deployed.
Microgrids are sophisticated systems
that can generate electrical energy in
parallel with or independent of the local
electrical utility (main grid). Microgrids
typically consist of a prime mover (com-
bustion turbine or reciprocating engine)
that can produce power/electrical energy,
and they are often utilized with combined
heat and power technology to produce
steam or hot water. There are also hybrid
microgrid systems – consisting of addi-
tional original equipment manufacturer
Photo Serge Zinger.
(OEM) components – which are gaining
popularity. A microgrid/CHP system operator monitors hot water production at a SCADA workstation.

To illustrate the successful deploy- The PMS is typically responsible for mize the system’s efficiency and return
ment of microgrid systems, it is useful to breaker control/interlocks, load man- on investment. A BOP control system
explore three different customer types in agement (automatic load shed and/or can be installed within these facilities to
the New York, N.Y., metro area: Hudson restore) and coordination of generating coordinate and control the plant’s OEM/
Yards, a real estate megaproject; the TWA resources. The PMS controllers require BOP equipment and ensure the waste
Hotel at John F. Kennedy International fast response times to handle unex- heat is utilized effectively. The BOP will
Airport; and New York University. While pected events and to ensure the cogen- also provide control of all the miscella-
the considerations and needs driving each eration facility is kept on line through neous systems within the plant, which
of their decisions to implement a micro- upsets. In addition, the PMS provides is required to keep the electrical gen-
grid may have varied, one critical com- remote monitoring/control and long-term eration equipment operational. These
mon factor for all was the selection of historical trending using an overlaying systems typically include natural gas,
an industrial-grade SCADA solution with SCADA system. The sequence-of-events lube oil, gas detection, feedwater, cool-
a programmable automation controller- reporting for analyzing alarms and deter- ing water, plant HVAC, etc. Similar to the
based plant control system. mining trip root cause is also commonly PMS, a SCADA is overlaid on top of the
included. Utility companies require BOP to provide remote control/monitor-
MAXIMIZING POTENTIAL access into the PMS to monitor critical ing, long-term historical trending, and
Regardless of who the microgrid user microgrid information and to be able to alarm management.
is, or what the drivers are, the key to a trip generating resources offline should See figures 1 and 2 for examples
successful project is the proper integra- the need arise. of SCADA human-machine interface
tion of OEM components and the intelli- Many microgrids include cogenera- screens depicting, respectively, the CHP
gent dispatch of energy, both electric and tion or CHP equipment as the source of system process equipment and the PMS
thermal. on-site power generation. These cogen- used for management and/or coordina-
Microgrids with multiple generating eration units typically utilize natural gas- tion of electrical systems.
resources, energy storage, varying loads burning engines or combustion turbines. Effective coordination between the
and a connection to the utility company Cogeneration facilities require use of the PMS and BOP systems is essential for
require a power management system. engine’s or turbine’s waste heat to maxi- fully maximizing the cogeneration and

FIGURE 1. Screenshot of combined heat and power system overview.

Source: Thermo Systems LLC.

microgrid potential. Every site will have
a unique solution based on utility agree-
ments, electrical generating resources,
equipment capabilities and thermal load
profiles.

THREE SYSTEMS, UNIQUE SOLUTIONS
      The microgrid systems with cogen-
eration operating at the three sites in
New York – Hudson Yards, the TWA Hotel
and New York University – were each
established with different goals and driv-
ers. These included having the ability to
reliably keep the lights on and provide
heating and cooling to campus buildings,
use the microgrid as an infrastructure
enhancement to attract tenants, reduce
the site’s carbon footprint and be the
property’s sole source of power. These
customers are all achieving their goals
with microgrids that exemplify the effec-
tive use of control systems.

Hudson Yards                                        Courtesy Related Oxford.
    On Manhattan’s West Side, Hudson
Yards is New York’s newest neighborhood,         Restaurant view, the shops at Hudson Yards.

FIGURE 2. Screenshot of power management system overview.

Source: Thermo Systems LLC.

© 2020 International District Energy Association. ALL RIGHTS RESERVED.                         District Energy | Spring/Summer 2020   11

considered the largest private real estate controller, the BOP collects information son Yards CHP plant. The thermal and
development in the city since Rockefeller from the chilled- and hot water-consum- electric loads will likely never be equal.
Center. Comprising 28 acres, it will ulti- ing residents and tenants on the prop- As a result, an advanced control scheme
mately include more than 18 million sq ft erty. The BOP utilizes this information had to be developed to determine where
of commercial and residential space, along to determine where to invest the waste the output of the engines will be set.
with more than 100 shops, a collection of heat energy from the engine generator. This control scheme takes into account
restaurants, a public school, 14 acres of The waste heat can be used to generate the electric rate structure with the util-
public plazas and gardens, and more. The hot water, chilled water or both via the ity company, availability of other plant
microgrid/CHP system serving Hudson use of an absorption-type chiller. assets and criticality of the load consum-
Yards comprises four reciprocating Once the waste heat energy is prop- ers. Additionally, the control scheme pro-
engines, four directly coupled absorption erly allocated, the BOP can determine vides the ability to limit some customers’
chillers and a free-cooling system. whether it has too much or too little consumption in extreme cases. Without
Operation of the Hudson Yards micro- waste heat available. If there is excessive this control scheme and coordination,
grid system is financially driven. Depend- waste heat, the plant will be required the engines cannot run at an optimal
ing on conditions at the site, the system to reject the heat using cooling towers, output, and the Hudson Yards plant
may be either thermally or electrically which is a waste of the electrical energy would not meet the needs of its cus-
led. Regardless of which approach is created from the generators. On the tomers or could overproduce and nega-
selected, the objective is to ensure that other hand, if there is insufficient waste tively affect their efficiency and payback
the tenant/retail spaces receive the best heat, then other boiler and chiller assets period.
payback. from the facility will need to be utilized.
Once electrical demands are satis- Based on the current state, the BOP will TWA Hotel
fied, the electrical output of the engines request that the generators increase or In another case, the TWA Hotel –
may need to be increased in order to decrease output in an attempt to balance formerly the iconic Eero Saarinen-designed
produce more waste energy to satisfy the waste heat with the thermal demand. TWA Flight Center – at Kennedy Airport
the thermal demand (chilled or hot water) In a similar fashion, the PMS pro- in Queens was constructed without con-
of the site. The decision of where to set grammable automation controller is nection to the electrical grid. This was
the engine’s output is determined with monitoring the demand of the electric done to avoid the high utility prices and
input from both the BOP and PMS sys- energy customers to determine the costs for upgrading the old interconnec-
tems. Using a programmable automation appropriate electric output of the Hud- tion infrastructure that once provided

Photo Shutterstock.

The new TWA Hotel opened to guests in May 2019.

power to this 1960s-era TWA terminal
building. With the aid of the microgrid,
all the electrical and thermal energy at
the TWA Hotel is generated on-site.
The property’s microgrid includes
three reciprocating engines and an elec-
tric storage system consisting of two
batteries. The electricity and waste heat
generated by the engines is utilized to
produce the hot and chilled water for the
hotel and convention center. The electric
storage system provides the means to
allow the engines to baseload while the
battery maintains frequency and voltage.
The electric storage system also provides
a safety net to keep the lights on through
any unexpected interruptions of power
to the plant.
The coordination between this sys-
tem’s BOP and PMS is intertwined on
many levels. In this case, both systems
were combined into a single program-
mable automation controller, allowing
for one central processor to monitor
conditions and instantaneously make
operating decisions. Without the grid for
reliability and inertia, the plant’s control
system must make decisions regarding
turning on and off engines, charging or
discharging the battery, and using either Photo littleny, iStock.

gas-fired or electric chillers. Load shed-
New York University in Manhattan’s Greenwich Village.
ding of noncritical loads in the case of
an emergency is also utilized to main-
tain plant operations. Tight coordination operate at maximum capacity, and the COMBINING BOP, PMS
between the PMS and BOP enables reli- duct burners of the heat recovery steam Effectively integrating the BOP and
able, effective and efficient operation of generators modulate to match the steam PMS systems requires planning and con-
this plant. demand of the steam turbine generators, sideration upfront. The most streamlined
chiller and heat exchangers as needed. and cost-effective means is to combine
New York University NYU utilizes energy from the utility com- these systems into a single program-
In Manhattan’s Greenwich Village pany to make up the excess demands of mable automation controller, as seen in
neighborhood, New York University (NYU) the campus buildings. The plant operates the TWA Hotel example. This is an indus-
operates a microgrid with CHP equip- in this fashion 99 percent of the time. trially hardened solution with varying
ment to provide heating, cooling and However, in 2012 when Superstorm levels of redundancy applied to ensure
electricity to its classroom, office and Sandy hit, and the electrical grid of lower minimal disruptions to operations. This
dorm buildings. The CHP system includes Manhattan went dark, the plant had to approach of a single programmable auto-
two gas turbines coupled with heat change operations to an electrical island mation controller is not always practical,
recovery steam generators. The gas tur- mode. With the safety net of the grid especially for larger, more distributed
bines create electricity, and the heat gone, the control systems of the plant systems. In that case, ensuring that the
recovery steam generators produce were relied on to manage campus elec- controllers of the BOP and PMS systems
steam that feeds a steam turbine gen- trical demand, ensuring it did not exceed natively communicate with each other at
erator, a steam-driven chiller and steam- the CHP system’s capacity and endanger high speeds is imperative.
to-high-temperature-hot-water heat its operations. In the end, the plant was To ensure smooth integration, it is
exchangers. able to remain on line during the extended advisable to have a single provider of
Under normal circumstances, the grid outage, and NYU received praise for the two systems with expertise in both
plant runs per design in a relatively its vision and planning for an event such microgrid and CHP applications. Devel-
simple control scheme; the gas turbines as this. oping an upfront design specification

for the control scheme makes sure that and BOP plant control system. Early in electrical engineering from Rensselaer
the systems can be put through exten- engagement with an experienced con- Polytechnic Institute. He can be reached
sive factory testing before they are trols integration provider – one that can at serge.zinger@thermosystems.com.
deployed on-site. Due to the critical recommend the proper technology to
nature of the loads that microgrids and apply and has the expertise to deploy it
CHP systems support, on-site testing – can aid in achieving a successful out- Jason Wittkamp, PE, is a
would be disruptive or impossible. come for the project. director at Thermo Sys-
Today’s microgrid/cogeneration systems LLC, where he has
tems are evolving into complex hybrid worked for over 13 years.
systems. In addition to combustion tur- Serge Zinger currently He is an expert in the in-
bines, reciprocating engines and battery holds the position of ac- strumentation and con-
storage, these hybrid systems now count executive at Thermo trols industry; his efforts have concen-
include photovoltaic arrays, fuel cells, Systems LLC, where he has trated on utility systems and the efficient
flywheels, etc. – increasingly driven by worked for over 11 years. operation thereof. Wittkamp has exper-
the desire for more sustainable systems. He has provided high-level tise on a multitude of large projects, in-
These control systems, which make expertise on projects in the district energy cluding the New York University com-
complex electric and thermal microgrids marketplace, including microgrids, combined heat and power plant, Hudson
possible, also make it possible to inte- bined heat and power, landfill gas-to- Yards cogeneration plant and the TWA
grate renewables and waste heat, thus energy, and chilled- and hot water distri- Hotel microgrid, to name a few. A licensed
lowering carbon emissions. bution. His past work experience includes professional engineer, Wittkamp has a
As these systems grow in size and the positions of general manager of engi- Bachelor of Science degree in mechanical
complexity, so does their dependency neering at Panasonic Electric Works and engineering from Rutgers University. He
on being integrated into a robust, reli- applications engineer at Deutsch Relays. can be contacted at jason.wittkamp@
able and appropriately matched SCADA Zinger has a Bachelor of Science degree thermosystems.com.