Deer Island Treatment Plant “Heat FirstHeat First-Power ... 2010/Dan OBrien_NBP Webcast_CHP... · Deer Island Treatment Plant “Heat FirstHeat First-Power SecondPower Second”

Massachusetts Water Resources Authority

Deer Island Treatment Plant“Heat First-Power Second” CHPHeat First-Power Second CHP

Daniel O’Brien, PEDeputy Director OperationsDeputy Director, Operations

NBP WebcastSeptember 22, 2010

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Presentation Outline

• MWRA Background • Overview of Deer Island• Energy Use Profile

S lf G ti & E S i I iti ti• Self-Generation & Energy Savings Initiatives• Current CHP Scheme• Future CHP Modifications• Future CHP Modifications• Questions

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MWRA Background

• Independent Public Authority – created in 1985

• Wholesale Provider of Water and Sewer Services

• Service Population – 2.2 million (42% of State)

• 61 Communities receive some form of service• 61 Communities receive some form of service

• Centralized wastewater treatment at Deer Island

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D I l d T t t• Deer Island Treatment Plant

• 2nd Largest Wastewater gTreatment Plant in the United States

• Built on 150 Acres• Built on 150 Acres

• Treatment Capacity:– Maximum

• 1.27 Billion Gal/Day

– Avg. Daily Flow365 Million

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• 365 Million Gal/Day

MWRA – Leading by Example

• As a leading environmental agency, MWRA has been striving to meet the goals established in Governor Patrick’s Executive Order 484 (April 2007)g ( p )

• Goals include:• Overall Reduction of Energy Consumptiongy p• Increase Renewable On-site Energy Production (30% by 2020)• Purchase of Renewable Energy

• Original 1988 design already had similar goals

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Self-Generated Renewable Energy

• MWRA self-generated over 40% of it’s energy demand in FY10 from D I l d R bl E tDeer Island Renewable Energy assets

– Digester gas heat supply

– Digester gas STG electricityDigester gas STG electricity

– Hydro electricity

– Wind

– Solar

• Deer Island Renewable Energy assets generated over 16% (35M• Deer Island Renewable Energy assets generated over 16% (35M kWh/yr) of MWRA’s total electricity demand (215M kWh/yr) in FY10

– Or 22% of Deer Island total electricity demand (164M kWh/yr)

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Self-Generation & Energy Savings Initiatives

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Deer Island Electricity

ELECTRICITY USAGE BY PROCESS AREA

Pumping – 30%

Secondary – 30%

Residuals 14%Residuals – 14%

Primary – 12%

Thermal – 8%

S pport Facilities 6%

99

Support Facilities – 6%


Overview of DI Facilities

• Deer Island – 365 mgd (avg); 1270 mgd (peak)• Pure Oxygen Secondary Plant• Primary:Secondary Sludge Ratio – 65:35• Thickening Gravity Thickeners & Centrifuges• Thickening – Gravity Thickeners & Centrifuges• Egg-shaped Digesters – 12 units at 3 mg each• Detention 15-21 days; VS Destruction 65% (avg)Detention 15 21 days; VS Destruction 65% (avg)• Gas Utilization – 98-99%; Production – 185,000 scfh• Sludge Production – 105 dry tons per day

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Deer Island – Aerial View

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Deer Island – Site-Specific Factors

Site-Specific Factors Impacting Decisions

• Remote Site – Limited Access• Constrained Site – Little Open Space• Power Plant Complex – Tight Interior Layout

N S l f N t l G (P bli O iti )• No Supply of Natural Gas (Public Opposition)• Sale of power to grid prohibited by supplier contract• Air Emissions Permit• Air Emissions Permit• Noise Restrictions

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Residuals Complex – Egg-Shaped Digesters

DIGESTER GAS

Current Utilization 98-99%Thermal ValueThermal Value• 5 MG ($10-15M/yr)

El t i it P d tiElectricity Production• 28M kWh/yr ($2.8M/yr)

MA RPS - Renewable Energy Certificates• > $500k/yr

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y

Digester Gas Utilization – 2003-2010

Digas Beneficially Utilized at the Deer Island Thermal Power Plant

90%

100%

50%

60%

70%

80%

lized

20%

30%

40%

50%

% U

til

0%

10%

Jul-03 Nov-04 Mar-06 Aug-07 Dec-08 May-10

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Digester Gas Utilization – 2008-2010

Digas Beneficially Utilized at theDigas Beneficially Utilized at the Deer Island Thermal Power Plant

90%

100%

60%

70%

80%

ized

20%

30%

40%

50%

% U

tili

0%

10%

Jul-08 Oct-08 Jan-09 Apr-09 Aug-09 Nov-09 Feb-10 Jun-10

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CHP – Original Design Concept

Original Design Concept• Dedicated power cable to local supplier – base power• On-site availability of digas to fire dual-fuel boilers• High-pressure boilers to meet thermal load• STG to generate electricity• CTGs (Pratt Whitney) to provide backup power• CTGs (Pratt-Whitney) to provide backup power• STG sized to provide add’l power if needed

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Boilers – Existing Installation

• Installed - 1998• Model - Zurn (2)• Rated Capacity – 150,000 #/HR each

A O t t 70 000#/HR• Average Output – 70,000#/HR

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STG – Existing Installation

• Installed - 1998• Model - Demag Deval• Rated Capacity – 18 MW• Average Output – 3.2 MW

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BP STG – New Installation

• Installed – 2011(planned)• Model - Siemens• Rated Capacity – 1.2 MW• Expected Output – .5 MW• Cost $2 2M• Cost - $2.2M

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STG Production – 2003-2010

STG Production at the Deer Island Thermal Power Plant

4 50

5.00 6,000

3.00

3.50

4.00

4.50

atio

n, M

W

4,000

5,000

Gas U

tiliz

1.00

1.50

2.00

2.50

STG

Gen

era

1,000

2,000

3,000

zed, KSC

FH

0.00

0.50

Jul-03 Nov-04 Mar-06 Aug-07 Dec-08 May-100

,

Steam Generator Output Gas Used at Thermal Power Plant*

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STG Production – 2008-2010

STG Production at the Deer Island Thermal Power Plant

4.00

4.50 250

2.50

3.00

3.50

00

atio

n, M

W

150

200

Gas U

tiliz

1.00

1.50

2.00

STG

Gen

era

50

100

zed, KSC

FH

0.00

0.50

Jul-08 Oct-08 Jan-09 Apr-09 Aug-09 Nov-09 Feb-10 Jun-100

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Steam Generator Output Gas Used at Thermal Power Plant*

Existing CHP Issues

• Actual conditions differed from design projections• Sludge (and therefore digas) production much less• Both power and thermal demand less• Treatment Plant full build-out was reduced• STG full output requires lots of supplemental fuel• STG full output requires lots of supplemental fuel• Some ancillary support equipment undersized

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BP STG – Planned Modifications (winter mode)

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BP STG – Planned Modifications (summer mode)

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Dump & Vacuum Condenser – Existing & Future

• Original Installation – 1998 (tube bundle replaced 2004)• Model - Katema Heat Transfer

• New Installation – 2011• Model – TBD• Cost - $2.8M

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Expected Benefits of Modifications

• Overall STG Output Increased• Expected Increase – 5.4M KWH/YR (20%)

$• Estimated Annual Savings - $540,000• Boiler efficiency increased (hotter feedwater)• Less wasted steam• Less wasted steam• More flexibility for seasonal heat load swings• Payback Period – 6-8 yearsPayback Period 6 8 years

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Self-Generation – Current & Future (Annual)

• Deer Island – Total Power Demand – 166M kWh• Purchased Power – 127M kWh (76%)

• Existing STG – 28 5M kWhExisting STG 28.5M kWh• Future BP STG – 5.4M kWh

E i ti CTG 5 2M kWh• Existing CTG – 5.2M kWh• Existing Hydro – 6.0M kWh

• Existing Wind & Solar – 2.3M kWh• Future Wind & Solar – 3.5M kWh

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Thank You

Contact Information - Daniel O’Brien, [email protected]

617-660-7680(Questions will be taken once all presentations have

been completed)

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Documents

Deer Island Treatment Plant “Heat FirstHeat First-Power ... 2010/Dan OBrien_NBP Webcast_CHP... · Deer Island Treatment Plant “Heat FirstHeat First-Power SecondPower Second”