Creating Value from Steam Pressure

1
THE REVOLUTION HAS NOT BEEN TELEVISED A Case
Study in Cost-effective, Environmentally-Advantage
ous Kilowatt-scale CCHP at Middlebury College
Sean Casten Chief Executive Officer 161
Industrial Blvd. Turners Falls, MA
01376 www.turbosteam.com
Creating Value from Steam Pressure
Mike Moser Manager, Central Heating
Plant Middlebury College Middlebury, VT
05753 www.middlebury.edu
Sher Peterson Manager, Absorption Product
Marketing 3600 Pammel Creek Road La Crosse, WI
54601 www.trane.com
2
Technology development cycles for disruptive
technologies perceived path vs. observed path.
High
Techno-Economic Viability
Low
Low
High
Market Demand for / Awareness of Technology
3
Technology development cycles for disruptive
technologies perception vs. reality.
DARPAnet ? Internet
GPS
High
CCGT

• Expected New DG / CHP Technologies
• Fuel cells
• Microturbines
• Etc.

Technology Viability
Low
Low
High
Market Demand for / Awareness of Technology
4
Technology development cycles for disruptive
technologies perception vs. reality.
Any power generation technology
High

• Expected New DG / CHP Technologies
• Fuel cells
• Microturbines
• Etc.

Technology Viability
Low
Low
High
Market Demand for / Awareness of Technology
A prediction growth in DG/CHP markets will arise
in the place that the world least expects it.
5
So why is DG / CHP / CCHP disruptive?
Central Power Plants
End Use
Transmission Distribution
Fuel In
Electricity
Electricity
Heat Purchase
Heat Losses
Heat Losses
6
So why is DG / CHP / CCHP disruptive?
Central Power Plants
End Use
Transmission Distribution
Cooling _at_ 3 10 c/ton-hour
2 3 c/kWh
4 10 c/kWh
Heat / Fuel _at_ 3 7/MMBtu
7
So why is DG / CHP / CCHP disruptive?
Central Power Plants
End Use
Transmission Distribution
Expecting benefits from deregulation
Business models treat consumer-owned generators
as competitive threat
Increasing Demand for Reliability
Increased Outages
Increasing Demand for Power Quality
Diminishing Returns in Power Quality Investments
are Inherent in System Design
Growing Concern for CO2
No significant reduction in CO2 emissions per kWh
delivered in 40 years
8
THE FALLACY We cant capitalize on these
opportunities until we

• Knock down all the regulatory barriers
• Develop the technology to the point that it can
  do what it needs to do (OM, fuel flexibility,
  etc.)
• Get production volumes operating experience up
  to the point that the economics work.

But what about that prediction? These
assumptions presume that we know where to look!
9
THE REALITY Shouldnt we be able to go back to
the future?
10
THE REALITY Yes, you can.
116 year-old Technology
Central Power Plant, ca. 2001
11
Case Study Middlebury College

• 2000 student liberal arts college located in
  Middlebury VT.
• District steam system heats 1.6 million square
  feet spread over 350 acre campus (36 buildings on
  system)
• Big winter heating load (60,000 lbs/hour at peak)
• Big summer cooling load for (1,200 tons at peak)
• Campus steam load delivered by 4 6 oil boilers,
  2 _at_ 125 psig, 2 _at_ 250 psig
• Boiler fuel prices range from 60 75
  cents/gallon (6 oil)
• Equivalent to 5 - 6.25/Mlb steam
• Delivery pressure 22 psig
• College uses 20 million kWh/year, at an average
  price of 8.5 cents/kWh
• March 1, 2000 Started up a 912 kW Turbosteam
  backpressure steam turbine generator
• Supplemented 2 existing turbine-generators (850
  kW) have been generating power with
  backpressure turbine-generators since 1980.

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Typical steam system design
High pressure steam process load
Medium pressure steam process load
Boiler
Header
H.P. steam
Feed water
PRV
Fuel
Low pressure steam process load
PRV
PRV Pressure Reducing Valve
13
A backpressure turbine delivers the same pressure
drop as a PRV -- but produces useful electricity
in the process.
Low Pressure steam out
High Pressure steam in
Electricity out
14
Middlebury Design
Thermal Load
H.P. steam
Thermal Load
Boiler
kWh
Header
L.P. steam
Feed water
TG Set (X3)
Fuel
Thermal Load
15
This design generates power at the efficiency of
Middleburys boiler or higher!
Thermodynamics
1st Law Balance
PRV Efficiency
This is almost 3X the efficiency of the grid!
16
In actual data, it is virtually impossible to
detect this slight increase in fuel consumption
TG Set 2 Installed
TG Set 3 Installed
17
Economic considerations
Middlebury College / Turbosteam Backpressure
Turbine-Generator
Compare Modern Combined Cycle Gas Turbine
912 kW generator reduces 250 psig steam down to
22 psig campus distribution pressure
Description
Current state-of-the-art central power plant.
Commonly sized at 500 MW (500,000 kW)
195,000 Equipment 75,000 Installation Cost
270,000 Total Cost (296/kW)
Installed Capital Cost
Typically 500/kW
60 75 cents/gallon boiler fuel oil 1000/year
average OM cost All-in cost 1.8 2.3
cents/kWh
Marginal Cost of Power Generation
50 55 efficiency Typically 2 3/MMBtu gas
cost Typically 0.5 1 cent/kWh OM All-in cost
2.4 3 cents/kWh
On-site CHP is more cost-effective than the
state-of-the-art central power plant!
18
Additional synergies from absorption chilling
Thermal Load (heating)
H.P. steam
Thermal Load (heating)
Boiler
kWh
Header
L.P. steam
Feed water
TG Set
Fuel
Thermal Load (cooling)
19
Additional synergies from absorption chilling

• In 1992, a Trane single stage absorption chiller
  was installed in arts center, using the low
  pressure exhaust steam from the turbine-generator
  to provide cooling
• Rated at 465 tons, currently operating at 375
  tons
• Fully installed capex 132,000
• In 2001 two Trane single stage absorption
  chillers were added to provide cooling for the
  colleges new Science Center, using the exhaust
  steam from the Turbosteam backpressure steam
  turbine-generator
• 2 X 520 tons
• Fully installed capex 357,000
• Net result Almost doubles TG set capacity factor

20
The addition of the absorbers has almost doubled
the annual value created by the
turbine-generator.
Annualized C.F. 53
Annualized C.F. 34
21
The TG set capacity factor increase brought about
by the absorber installation has saved the
college 852,000 to date.
852,000 chiller-derived savings on 489,000
chiller capex
Savings increase estimated based on comparison of
each years capacity factor to 1992 baseline, all
at current electric rates. Chilling is assumed
to be a campus necessity, and its cost of
production is therefore not included in this
calculation.
22
In addition to saving money, the system reduces
CO2 emissions currently by 1,600 tons/year.
CO2 Impacts based on regional grid-intensity
factors as provided by the Oregon Climate Trust.
Impacts do not include boiler emissions not
associated with power generation. Cooling is
thus treated as a necessary source of energy,
with associated emissions ignored.
23
Net Results

• Middlebury College has installed a 1.8 MW cogen
  plant to produce
• 100 of the colleges heating load
• Over 80 of the colleges cooling load
• 13 of the colleges electric load in 2001
• The turbine-generator thus installed delivered
  better overall economics than the current state
  of the art in central power plants at just
  1/500th of the size.
• Simple payback lt2 years
• The installation of absorption chillers increased
  annual savings, sufficient to completely recover
  all chiller capital costs.
• Estimated 852,000 savings over 8 years on
  489,000 capex
• This financially motivated installation is
  currently reducing CO2 emissions by 1,600
  tons/year
• This value is expected to increase with continued
  campus expansion
• Similar reductions have occurred for criteria
  pollutants (NOx, SOx, etc.)

24
So where else can you find opportunities?
Steam flow rate
Inlet pressure
Pressure drop
Price of electricity
Capacity factor
In short, on almost any college campus.
25
The revolution has arrived.
Onsite, environmentally-beneficial CCHP in sub-MW
sizes is available, proven and cost effective.
As a steam plant owner/operator, you do not need
to wait for DG / CCHP you just have to know
where to look.