Transcript Free Electricity - Recycled Energy Development

FREE ELECTRICITY
Making the most of a CHP System Design
Presented to the World Energy Engineering Congress
Atlanta, GA
November 12, 2003
Sean Casten
Chief Executive Officer
161 Industrial Blvd.
Turners Falls, MA 01376
www.turbosteam.com
Creating Value from Steam Pressure
The economics of all power generators are based on a few very
simple calculations:
• What is my fuel cost?
• What is my electricity value?
• How much spread do I need to cover O&M, capital recovery &
profit?
• When one considers real-world, location-specific fuel and
electric rates, it becomes apparent that even with a very modest
3 c/kWh spark spread, the market for power-only generation is
nearly non-existent (see next)
– This forces DG designers to add ancillary value to their system
designs.
30 – 40% efficient generation isn’t enough!
So how do you make the economics of DG work?
1. Only target states with attractive spark-spreads
–
No surprise that most DG installers market heavily into CA, NY, MA, NJ
2. Chase higher value power
–
“Premium power” market is real, but limited
3. Chase lower-cost fuel
–
Wood-waste, coal, landfill gas all present more favorable economics – but
are much harder than gas to site or permit
4. Chase efficiency
–
CHP systems recover “free heat” to realize added value, bump efficiency
up.
However, while CHP is typically understood to take a “powerfirst” approach to generate free heat…
Electricity
Fuel
Free Heat
Heat
Recovery
Device
Power
Generator
Waste Heat
Without Heat Recovery
Cost of Power
Generation
With Heat Recovery
Fuel Cost
…there are many opportunities to take an inverse, “heat-first”
approach to generate free electricity.
Useful Heat
Fuel
Free Electricity
Power
Recovery
Device
Heat
Generator
Waste Heat
Without Power Recovery
Cost of Heat
Generation
With Power Recovery
Electric Cost
Properly designing “heat-first” CHP is a near-exact inversion
of “power-first” approaches.
•
“Power-first” design: prime mover + heat recovery
 Recovered thermal energy displaces boiler fuel, reducing the
delivered cost of electricity.
 Focus is electricity with steam as a byproduct
 Usually designed to maximize power output, then recover as much
heat as is economically feasible.
•
“Heat first” designs: steam boiler + power recovery
 Recovered electricity displaces purchased electricity, reducing the
cost of steam.
 Focus is on thermal with electricity as a byproduct
 Usually designed to maximize thermal output, then recover as
much electricity as is economically feasible.
One flavor of “heat first CHP”: typical steam plant design
High pressure steam process load
Medium pressure steam process load
Boiler
Header
H.P. steam
Feed water
Fuel
Pressure
Reducing
Valve (PRV)
PRV
Low pressure steam process load
Turbine-generators deliver the same pressure drop as a PRV –
but produce useful electricity in the process.
Low Pressure steam out
High Pressure steam in
Electricity
Note that this generator is sized to the thermal rather than
electric load (thus “heat-first”)
Turbosteam has installed 164 systems worldwide following this
approach.
Non-U.S.
>10,000 kW
5001 – 10000 kW
1001 – 5000 kW
501 – 1000 kW
1 – 500 kW
• 17 countries
• 63 installations
• 35,900 kW
“All-In Cost of Generated Heat”
A closer look at heat-first economics.
Cost of delivered thermal energy before power recovery
Cost of delivered boiler fuel
Cost of delivered
thermal energy
after power
recovery
Retail Electricity Rate
Note 1: At all electricity rates, the cost of
steam is reduced
Note 2: In many cases, the cost of steam
is reduced to less than the cost of fuel for
steam generation!
Where note 2 applies, plants develop substantial downstream flexibility, since
steam-driven equipment – e.g., dryers, chillers, etc. – becomes more cost-effective
than direct-fueled alternatives.
The opportunity for heat-first CHP is entirely a function of a
given facility’s thermal load.
•
Recover electric power from existing pressure reduction
stations
 Sized to downstream thermal load
 Maximize value by increasing thermal loads or pressure drop
•
Create pressure reduction opportunities in existing steam
networks
 Increase boiler pressures – design and/or operating
 Reduce steam utilization pressure (often possible due to existing
safety factors)
•
Convert mismatches in thermal generation and
consumption into electricity
 Condense steam generated in waste-disposal boilers (sawdust
boilers, thermal oxidizers, etc.)
 Recover steam energy from existing vents
Sample installation: Brattleboro Kiln Dry (Vermont)
•
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Largest custom-lumber dryer in New England
Startup: 1989
Sawdust-fired boiler converts millwaste into
steam which is used to heat on-site lumber
kilns
PRV replacement
Turbosteam system generates 380 kW,
reduces steam costs by $1.75/Mlb, reduces
CO2 emissions by 570 tons/year
35% Project ROA
Sample installation: Morning Star Packing Company
(California)
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•
•
•
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Tomato processor – produces 40% of tomato paste used in U.S.
during 3 month operating season
Startup: 1995 (2 systems), 1999 (3rd system)
High pressure boilers produce steam for tomato cookers
PRV replacement + boiler pressure increase
Turbosteam systems generate 3,000 kW, reduces steam costs by
$2.50/Mlb, reduces CO2 emissions by 2,700 tons/year.
Plant completely insulated from CA power crisis in 2000
>60% Project ROA
Implications
Power-first CHP
Cheap steam boiler
Heat-first CHP
Cheap power generator
No need for fuel train, exhaust
treatment, etc.
No need for fuel train, exhaust
treatment, cooling tower, etc.
$300 – 1000/kW installed
Operating Costs
Free heat
(very minor O&M)
Free Electricity
(very minor O&M)
Environmental
Zero-emission heat
Zero-emission Electricity
Capital Costs
Bottom Line
Environmental performance of a solar panel
Capital costs of a reciprocating engine
Maintenance costs less than a gas turbine
So what is heat-first CHP?
The only distributed generation technology that is
proven to be economically and environmentally
beneficial on every corner of the globe.