The 34th Congress of Euroheat & Power

The 34th Congress ofEuroheat & Power

Varese Risorse – An intelligent way to increasecogeneration and energy savings

Fabio FidanzaDirectorVarese Risorse S.p.a.

25-26 Maggio 2009 Hilton Molino Stucky, Venice


Varese Risorse is the company which manages the district heating of the city of Varese.The company was founded in 1987 by the Municipality together with a private partner;starting from January 2009 Varese Risorse is part of the A2A group which main shareholdersare Milano and Brescia municipalities

INTRODUCTION



The CHP plant was erected in the last 80s and has been set at work in 1992.The gas turbine has been in operation for more than 70,000 operating hours, generatingmore than 150 GWh of electricity , obtaining more than 38,000 tep of energy savings , 350tons NOx, 170,000 tons CO2

Hilton Molino Stucky, Venice25-26 Maggio 2009

INTRODUCTION

The DH network is extended for more than 20 km in the south east part of the towndistributing hot water to 125 civil, tertiary buildings, hospitals and businesses at atemperature of 90°C cooling down to 60-65°C . More than 20,000 equivalent inhabitantsare reached by the service for a total volume of about 2,000,000 m3.

Plant

Network



INTRODUCTION

DH Network


The plant , located in Varese, mainly consists of:• Gas turbine (PGT5 Nuovo Pignone) ISO performance 5 MWe• Heat recovery boiler 11 MWt• Post combustor 4 MWt• SCR reactor• 5 auxiliary boiler 37 MWt• 2 hot water storage tanks (430 m3)• Pumping station (8 pumps for a maximum flowrate of 1800 m3/h)

All pumps are provided with VFD

PLANT CONFIGURATION


PLANT CONFIGURATION


AXIAL COMPRESSOR, BARRING ENGINEAND COMBUSTION CHAMBER

The air from the outside iscompressed and sent to thecombustion chamber

In the combustion chamberthe air is mixed with thenatural gas coming from thereduction station andhappens the combustion

HEAT RECOVERY BOILER +POSTCOMBUSTORGAS TURBINE

GENERATOR(Power Unit)

The burned gasexpands

Electricity to thenational grid

Hot water(90°C) to the

district heatingnetwork

CHP SIMPLIFIED FUNCTIONAL SCHEME


5 MWe

11,5 + 4 MWt

PLANT CONFIGURATION



They operate in order to cover the heat peak demands from the end users or in caseof gas turbine malfunction as spare heat generation equipment

AUXILIARY BOILERS

TOTAL POWER37 MWt

Dual Fuel (Natural gasor diesel) Hot water



HOT STORAGE WATER TANKS

During the night the tanks are filled with hot water whichis used to cover the heat demand in the earlymorning

Total volume = 430 m3



SoftenedwaterstoragetankVolume215 m3

Fire waterstorage tankVolume125 m3

DieselstoragetankVolume50 m3

OTHER TANKS



During the year 2008 a SCR system wasinstalled in order to respect the new regionalemission limits; in the picture you can see theflue gas discharge channel, integrated withthe catalytic reactor and the three blue ureastorage tanks.

SCR PLANT


The CHP plant now is operating only in correspondence of what is defined bythe Italian law as the “thermal season” (from October to April).The plant is managed maintaining obviously the priority on cogenerationusing auxiliary boiler and the two hot water storage tanks to satisfy the peakheat demand as determined by the DH network.The plant control system is tuned on the “gas turbine following” mode.So the electric power generated is a by-product with respect to heat.The electric power is supplied to the national grid at a voltage level of 132 kV and is soldat the best possible economic condition in the electricity market thanks to the serviceof a trading company integrated in the A2A group.


OPERATION


In the early 2005 Varese Risorse, after havingprovided a feasibility study then approved bythe general manager of the city hospital,signed a multi-annual agreement for thesupply of:

•Hot water for heating and sanitary usage;•MP steam for sterilization and technologicalusage ;

•Cold water for air conditioning.


The project should be completely integrated with city DH network and should serve mainlythe new hospital that was opened in 2007 together with the old buildings in the hospitalarea. Nowadays new trigeneration plant construction is in progress.

New trigeneration plant


2 plate heat exchangers (total heat power 10 MWt)2 plate heat exchangers for sanitary water (total heat power 4 MWt)


Now the new hospital is already connected with DH network in a provisional asset by meansof:

PROVISIONAL ASSET



For summer conditioning hospital need Varese Risorse set in operation a temporarymodular plant:

4 compression chillers with 4 cooling towers (total chilling power 6 MWf)

PROVISIONAL ASSET



The new trigeneration plant mainly consists of:

•Three dual fuel MP steam boiler (12 tons per hour each one at 11 barg)•One natural gas engine (GE Jenbacher 1,065 KWe) sized for trigenerationplant electric consumptions able to recover from the exhaust gases 565 kWt forhot water production and 445 kWt for steam generation

•Four absorption chillers (2 single stage using DH hot water and two double stageusing MP steam) for a total chilling power of 9.8 MWf

•Ten cooling tower cells for a total dissipated power of 21 MW•One shell & tube heat exchanger (total power 10 MWt)•Pumps for hot water, cold water and cooling towers•Natural gas reduction station•Diesel storage and pumps•MT electric substation•Demi water plant

NEW ASSET



NEW ASSET

New plant under construction



THERMALPLANT

• 3 boilers for steam generation (Bono)• 2 plate heat exchangers (Alfa Laval)• 2 plate heat exchangers for sanitary

water (Alfa Laval)

THERMAL COOLING PLANT• 4 absorption chillers (Johnson Controls)•10 cooling tower cells (Scam)

COGENERATIONPLANT

Natural gas engine (GE Jenbacher) :• electric power: 1065 kW• thermic power: 1010 kW

NEW ASSETMain equipment



Hot water circuit in the hospital 1) Water supply T = 85 °C2) Water return T = 63 °C

Water to / from district heating 1) Water supply T = 90 °C2) Water return T = 67 °C

Sanitary water circuit 1) Water supply T = 60 °C2) Municipal network T = 15 °C

2 plate heat exchangers

2 plate heat exchangers

NEW ASSET



District heating network

Hot water absorption chillers

Steam boilersSteam absorption chillers

Plate heat exchangers

Plate heat exchangers

Heating demand

Sanitary waterdemand

Natural gas engineElectric energy

demand

Cooling demand

Technological steamdemand

Integration/back up exchanger

NEW ASSET



Steam boilers satisfy the below reported duties:

Demand1) Back up and peak heating by means of one shell and

tube heat exchanger2) New hospital technological steam3) Old hospital technological steam4) Back up and peak cooling through two absorption

chillers

Equipment3 steam boilers 12 tons/h each

During normal conditions a boiler is completely of reserve because the actual maximum need is 20tons/h.

NEW ASSET

Steam boilers



NEW ASSET

Natural gas engine

Electric power

Cogenerated thermic power forhot water production

1065 kW

565 kW

Cogenerated thermic power forsteam generation 445 kW



NEW ASSET

Thermal cooling plant2 Hot water absorption chillers

2 Steam absorption chillers

Total chilling power

Total chilling power

6 Cooling tower cellsTotal cooling power

4 Cooling tower cellsTotal cooling power

5 MW

4,8 MW

12,6 MW

8,4 MW



NEW ASSET

Winter operation

Hospital heat demand will be covered for 88% by DH, while the remainder will be dividedalmost equally between CHP engine and steam boilers.

The plant electricity demand will be fully covered by the CHP engine.

The modest chilling demand will be met by one of the two double effect chillers.



NEW ASSET

Summer operationThe two absorption chillers fed with DH hot water will cover 80% of cooling demand andallow to operate the GE Nuovo Pignone PGT5 also in the summer months using the heatdistributed by the DH network.(Now the GE turbogas is instead not in operation due tothe small heat request coming from users simply satisfied by means of auxiliary boilers).

These equipment will satisfy with priority the base cooling load while the two absorptiondouble effect chillers fed with MP steam (generated by CHP engine and steam boilers) willbe put in operation for the remaining 20% and peak cooling demand or as spareequipment with respect to single effect ones.



NEW ASSET EconomicsTotal Investment

11 millions euro

Simple payback period (Worst case)

10 years

Net present value (Worst case)

4 millions euro

Internal rate of return (Worst case)

10%



Primary energy savingsNEW ASSET

Estimated primary energy consumption: 11100 TEP / YearConventional plant

Our plantEstimated primary energy consumption: 8900 TEP / Year

Primary energy savings

2200 TEP / Year 20 % savings



NEW ASSET Avoided emissionsConventional plant emissions

CO

NOX

SO2

51 tons/year

65 tons/year

72 tons/year

Estimated emissions from our new plant

CO 22 tons/year

NOX 33 tons/year

SO2 3 tons/year

CO2 CO235220 tons/year 28240 tons/year

Estimated emission savings

CO 29 tons/year

NOX 32 tons/year

-56 %

-50 %

SO2 -95 %69 tons/year

CO2 6980 tons/year -20 %



Future ChallengesPERSPECTIVE

• Carry out a new trigeneration initiative in the city matching it with the new on-goingurban development plan

• Realize a new district cooling network for Insubria university campus

• Replace the present CHP fossil fuel by making the most of locally based renewableenergy resources (waste, biomass) in order to get lower PRFs



“Science becomes dangerous only when it imagines that it has reached its goal”G.B. Shaw

Thank you for your kind attention!

[email protected]

The 34th Congress of Euroheat & Power

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