The 34 th Congress of Euroheat & Power

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1 Varese Risorse An intelligent way to increase cogeneration and energy savings Fabio Fidanza Director Varese Risorse S.p.a.

2 INTRODUCTION 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 shareholders are Milano and Brescia municipalities

3 INTRODUCTION Plant The CHP plant was erected in the last 80s and has been set at work in The gas turbine has been in operation for more than 70,000 operating hours, generating more than 150 GWh of electricity, obtaining more than 38,000 tep of energy savings, 350 tons NOx, 170,000 tons CO2 Network The DH network is extended for more than 20 km in the south east part of the town distributing hot water to 125 civil, tertiary buildings, hospitals and businesses at a temperature of 90 C cooling down to C. More than 20,000 equivalent inhabitants are reached by the service for a total volume of about 2,000,000 m3.

4 INTRODUCTION DH Network

5 PLANT CONFIGURATION 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

6 PLANT CONFIGURATION CHP SIMPLIFIED FUNCTIONAL SCHEME AXIAL COMPRESSOR, BARRING ENGINE AND COMBUSTION CHAMBER GAS TURBINE HEAT RECOVERY BOILER + POSTCOMBUSTOR The burned gas expands In the combustion chamber the air is mixed with the natural gas coming from the reduction station and happens the combustion GENERATOR (Power Unit) 11,5 + 4 MWt Hot water (90 C) to the district heating network The air from the outside is compressed and sent to the combustion chamber 5 MWe Electricity to the national grid

7 AUXILIARY BOILERS They operate in order to cover the heat peak demands from the end users or in case of gas turbine malfunction as spare heat generation equipment Dual Fuel (Natural gas or diesel) Hot water TOTAL POWER 37 MWt

8 HOT STORAGE WATER TANKS Total volume = 430 m 3 During the night the tanks are filled with hot water which is used to cover the heat demand in the early morning

9 OTHER TANKS Softened water storage tank Volume 215 m3 Fire water storage tank Volume 125 m3 Diesel storage tank Volume 50 m3

10 SCR PLANT During the year 2008 a SCR system was installed in order to respect the new regional emission limits; in the picture you can see the flue gas discharge channel, integrated with the catalytic reactor and the three blue urea storage tanks.

11 OPERATION The CHP plant now is operating only in correspondence of what is defined by the Italian law as the thermal season (from October to April). The plant is managed maintaining obviously the priority on cogeneration using auxiliary boiler and the two hot water storage tanks to satisfy the peak heat 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 sold at the best possible economic condition in the electricity market thanks to the service of a trading company integrated in the A2A group.

12 New trigeneration plant In the early 2005 Varese Risorse, after having provided a feasibility study then approved by the general manager of the city hospital, signed a multi-annual agreement for the supply of: Hot water for heating and sanitary usage; MP steam for sterilization and technological usage ; Cold water for air conditioning. The project should be completely integrated with city DH network and should serve mainly the new hospital that was opened in 2007 together with the old buildings in the hospital area. Nowadays new trigeneration plant construction is in progress.

13 PROVISIONAL ASSET Now the new hospital is already connected with DH network in a provisional asset by means of: 2 plate heat exchangers (total heat power 10 MWt) 2 plate heat exchangers for sanitary water (total heat power 4 MWt)

14 PROVISIONAL ASSET For summer conditioning hospital need Varese Risorse set in operation a temporary modular plant: 4 compression chillers with 4 cooling towers (total chilling power 6 MWf)

15 NEW 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 trigeneration plant electric consumptions able to recover from the exhaust gases 565 kwt for hot water production and 445 kwt for steam generation Four absorption chillers (2 single stage using DH hot water and two double stage using 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

16 NEW ASSET New plant under construction

17 NEW ASSET THERMAL PLANT Main equipment 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) COGENERATION PLANT Natural gas engine (GE Jenbacher) : electric power: 1065 kw thermic power: 1010 kw

18 NEW ASSET Water to / from district heating 1) Water supply T = 90 C 2) Water return T = 67 C 2 plate heat exchangers Hot water circuit in the hospital 1) Water supply T = 85 C 2) Water return T = 63 C 2 plate heat exchangers Sanitary water circuit 1) Water supply T = 60 C 2) Municipal network T = 15 C

19 NEW ASSET Heating demand Plate heat exchangers District heating network Sanitary water demand Plate heat exchangers Integration/back up exchanger Cooling demand Hot water absorption chillers Steam absorption chillers Steam boilers Technological steam demand Electric energy demand Natural gas engine

20 NEW ASSET Steam boilers Steam boilers satisfy the below reported duties: Demand 1) Back up and peak heating by means of one shell and tube heat exchanger 2) New hospital technological steam 3) Old hospital technological steam 4) Back up and peak cooling through two absorption chillers Equipment 3 steam boilers 12 tons/h each During normal conditions a boiler is completely of reserve because the actual maximum need is 20 tons/h.

21 NEW ASSET Natural gas engine Electric power 1065 kw Cogenerated thermic power for hot water production 565 kw Cogenerated thermic power for steam generation 445 kw

22 NEW ASSET 2 Hot water absorption chillers Thermal cooling plant Total chilling power 5 MW 2 Steam absorption chillers 6 Cooling tower cells 4 Cooling tower cells Total chilling power 4,8 MW Total cooling power 12,6 MW Total cooling power 8,4 MW

23 NEW ASSET Winter operation Hospital heat demand will be covered for 88% by DH, while the remainder will be divided almost 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.

24 NEW ASSET Summer operation The two absorption chillers fed with DH hot water will cover 80% of cooling demand and allow to operate the GE Nuovo Pignone PGT5 also in the summer months using the heat distributed by the DH network.(now the GE turbogas is instead not in operation due to the 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 absorption double effect chillers fed with MP steam (generated by CHP engine and steam boilers) will be put in operation for the remaining 20% and peak cooling demand or as spare equipment with respect to single effect ones.

25 NEW ASSET Economics Total 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%

26 NEW ASSET Primary energy savings Conventional plant Estimated primary energy consumption: TEP / Year Our plant Estimated primary energy consumption: 8900 TEP / Year Primary energy savings 2200 TEP / Year 20 % savings

27 NEW ASSET Avoided emissions Conventional plant emissions Estimated emissions from our new plant CO 51 tons/year CO 22 tons/year NO X 65 tons/year NO X 33 tons/year SO 2 72 tons/year SO 2 3 tons/year CO tons/year CO tons/year Estimated emission savings CO 29 tons/year -56 % SO 2 69 tons/year -95 % NO X 32 tons/year -50 % CO tons/year -20 %

28 PERSPECTIVE Future Challenges Carry out a new trigeneration initiative in the city matching it with the new on-going urban 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 renewable energy resources (waste, biomass) in order to get lower PRFs

29 Science becomes dangerous only when it imagines that it has reached its goal G.B. Shaw Thank you for your kind attention!