Laclede Gas Building - Midwest Clean Energy Application Center

In Partnership with
the US DOE
Laclede Gas Tower
Laclede Gas Building
4.3 MW CHP Application
Quick Facts
Location:
Saint Louis, Missouri
Energy Plant Equipment:
Four 800 kW Waukesha engines
Two 550 kW Waukesha engines
One York absorption chiller rated
at 1050 tons of refrigeration
CHP System Operation:
Totally independent of the electric
distribution grid (islanding mode)
Generating Capacity:
4.3 MW
Thermal Capacity:
25,200 lbs/hr low pressure steam
Equipment Cost:
Facility built in 1969. Original
cost estimates not available.
Annual Energy Savings:
$14,000
Simple Payback:
Facility built in 1969. Simple
payback estimates not available
Project Profile
Project Overview
The Laclede Gas Building Cooling Heating and
Power Plant was constructed in 1969 together
with the Laclede Gas Building, a 31-floor office
building located downtown Saint Louis. The
building is owned by Stirling Properties, which
also owns and operates the power plant.
The plant serves the heating, hot water, electric,
and cooling loads of the 500,000 square feet
building. The plant operates in the stand-alone
mode, which means it is not interconnected to the
local electricity provider, Ameren UE. The
power plant is fueled by natural gas, which is
purchased from CenterPoint Energy Gas
Marketing and distributed to the building by
Laclede Gas Company.
Compared to the cost of purchasing the
equivalent amount of electricity and natural gas
from the local utility companies, the CHP plant at
Laclede Gas Building shows net yearly savings
of approximately $14,000. These savings are
predominantly incurred during the summer
months, when the steam recovered from the
engines is used to provide cooling via an
absorption chiller, thus displacing electric load
from the mechanical chiller systems.
The CHP plant has a remarkable reliability
record. There has not been an unplanned outage
of the system since 1980. One reason for this
reliability record is a rigorous preventative
maintenance schedule to service the engines. A
second reason for this reliability record is the
plant design, where six engines provide inherent
redundancy; peak-loads can generally be served
with four or five engines and off-peak loads with
three engines.
The CHP plant recovers close to 650,000 therms
of energy annually. This results in a total
efficiency of approximately 68%.

Major Energy Plant Components
Roof
C ooling T ow ers
31st Floor
1 - 1050 Ton Absorption Chiller
2 - 350 Ton Engine Chillers
2 - 200 hp boilers
H eat exchangers, pumps, and fans
3rd Floor
4 - 800kW , 1200 rpm engine generators
2 - 550 kW , 900 rpm engine generators
4 - 4700 lb/h heat recovery boilers
2 - 3200 lb/h heat recovery boilers
Control room and Spare parts
Additional Steam Host
The CHP system has the capability
to produce excess steam during the
winter months, beyond what is
currently utilized for building
heating purposes. An analysis
shows that further savings of
approximately $85,000 could be
achieved from the CHP system if
an additional steam host was
served in the winter.
Lessons Learned
The CHP plant has a remarkable reliability record with no major outage during the last
20 years. This shows that a standalone CHP system can provide long-term, reliable
power with positive economics.
The positive economics of this particular facility could be improved further if excess
steam available during the winter months could be sold to an additional steam host. A
new parking garage and retail space is currently in construction adjacent to the Laclede
Gas Building. Stirling Properties is evaluating the financial potential to serve the energy
needs of this new structure from the CHP plant. This arrangement would provide a
good hedge against any natural gas price increases in the future.
Waukesha Engines at Laclede Gas Building
Savings ($)
Laclede Gas Building
40,000
30,000
20,000
10,000
0
-10,000
Additional Steam Host
-20,000
Jul Sep Nov Jan Mar May
Month
Current Savings Additional Steam Host
For further information contact
Midwest CHP Application Center
851 S. Morgan Street
Chicago, IL 60607-7054
Phone: (312) 413-3835
Fax: (312) 996-5620
www.CHPCenterMW.org
The Laclede
Power Plant was
constructed in
1969 as a total
energy system,
operating totally
independent of the
electric grid.
The power
plant serves
all of the
building’s
heating, hot water,
cooling, and
electric
requirements.
The story to be
told here is
that this
system has a
remarkable
reliability
record with no
major outages of
the energy
system in over
20 years.