New projects in the province of for Geothermal systems

An overview of the experiences acquired in the study and exploitation of DEEP and SHALLOW geothermal combined with indirect uses

Paolo Tarantino Fabio Carlo Molinari Thecnical Director Geologo COGEME SpA Freelance Geologist The is one of the 12 provinces of region. It is constituted by 206 municipalities and it has a catchment area of 1.265.000 people.

Lake Iseo

Lake Garda

Brescia

Cogeme SpA is one of the first Italian holding totally owned by the municipality; it operates in the local public utilities It was born in 1970, it belongs to 71 municipalities of Brescia and Bergamo. The companies of the group manage the water, energy, environmental and technology services for a catchment area of about 400.000 people. What kind of geothermal source is These are some of the questions which see present in the territory? the COGEME group committed, over the last years, to the research of the “richness If present, is the employ of the resource of the territory” which can be employed as sustainable and replicable in the sources and which could territory? supply the “energy-intensive” users of existing buildings.

Deep Shallow geothermal energy at medium and high enthalpy. Deep geothermal energy Deep geothermal energy at low enthalpy. Temperature >90°C at low enthalpy. at low enthalpy. Indirect use of the energy. dominant water and steam for Direct use of the energy. Indirect use of the energy. supply the electric energy production temperature between 60 and 90°C temp. between 20 and 60°C Temperature < 20°C

COGEME holds a geothermal permit called “” to research and study geothermal fluids. Rodengo Saiano

Erbusco Cazzago Paderno The aim of the license is the characterization of Franciacorta the geothermal reservoirs at low enthalpy( <90°C) which are present in the subsoil of the “Franciacorta”. The geological formations, where these potential reservoirs are located, have a mainly carbonatic or silicoclastic origin.

CURRENTLY USED DATABASE ENI wells log profile

Temperature Water wells profile The data of the well profiles allow a first geological and hydro-geological assessment of the geothermal reservoirs

Electric log (SP – Resistivity) total porosity

Example of the well data (ENI- AGIP)

Formation pressure from Elecric log drilling mud density temperature

geothermal reservoir The first phase of mining characterization allowed the identification Possible mining targets «Castegnato» of the eastern sector of the research permit as one of the most geothermal power plant promising sectors for a geothermal potential. Cogeme SpA decided the acquisition of two seismic reflection profiles in the municipality of “Castegnato”.

Municipality of CASTEGNATO

Seismic Profile B-B’

Second Target: Ghiaie e sabbie continentali BASE Quaternario District heating power plant First Target :Sabbie/ghiaie plioceniche The interpretation of the seismic profiles associated with BASE Pliocene the interpretation of the well data, allows the identification of two possible targets for the exploration well within a depth of 500-600 m:

First target «G1»: pliocenic sands and gravel Seismic Profile A-A’ Second target «G2»: quaternary gravel and sands NEATPUMP The High Temperature Ammonia Heat Pump Emerson Climate Technologies Preliminary design of the exploratory well EXPLOITATION OF THE GEOTHERMAL POTENTIAL RESERVOIRS FOR THE CASTEGNATO DISTRICT HEATING NETWORK

Second target : The indirect use is combined with the employ of a heat «G2 reservoir» G2 pump in order to rise the secondary circuit temperature temp.: 20°C of the process by a prearranged SET value. Withdrawal temperature 18°…20 °C The machine efficiency (COP) will vary according to the Return temperature 13°…15 °C withdrawal temperature. Flow rate 25-30 l/s Max withdrawal thermal power ~ 0,6 MWt Estimated wells depth ~ 200 m

COP COP 4…4,5 4,5…5 G1

Withdrawal temperature 28°…30 °C Return temperature 13°…15 °C Flow rate 15-18 l/s Indicative thermal power ~ 1,0 MWt Estimated wells depth ~ 500-600 m

performance NEATPUMP Emerson Climate Technologies First target : «G1 reservoir» temp.:28…30 °C If the feasibility study of use of geothermal reservoir give a positive result we will proceed with the drilling of exploration well and the characterization of geothermal resources Municipality of CASTEGNATO

…a project of Deep geothermal energy at low enthalpy. Indirect use of the energy. temp. between 20 and 60°C next construction

NEXT COMBINATION WITH AN URBAN DISTRICT HEATING SYSTEM

Example of a urban district heating system operating with production and distribution LOW TEMPERATURE, developed for the integration with renewable energy sources CASTEGNATO MUNICIPAL DISTRICT HEATING EXPLANATORY SCHEME thermal plant combined with a future low enthalpy geothermal plant

DISTRICT HEATING NETWORK

min/max flow temp. 62/95 °C min/max return temp. 50/60 °C

Emergency boilers and Electric Energy co-generation integration with winter peaks facilities with a total recovery of thermal energy

CURRENT CO-GENERATION PLANT FOR THE FUTURE GEOTHERMAL INTEGRATION GEOTHERMAL PLANT

Electric Energy Electric Energy for the plant self- Geothermal plant consumption consumption

Thermal supply residual E. E. from network transferred to the natural gas National electricity BENEFITS

 PRESERVATION of the resource through the re-injection of the thermically exploited fluid;  COMBINATION with any use of ambient conditioning;  POSSIBILITY to replicate the initiative on the territory;  POSSIBILITY OF THE ENERGY REVAMPING of the existing building heritage;  POSSIBILITY of a located and dislocated use;  MODEST INITIAL INVESTIMENT and partially recoverable through the attainable energy saving ;  AUTHORIZATION PROCEDURES and construction times < 12 months;  POSSIBILITY of combination with other renewable sources;  POSSIBILITY of combination with other “poor” alternative energy sources otherwise lost in the environment;  ENVIRONMENTAL IMPACT EQUAL TO ZERO;

Shallow geothermal energy at low enthalpy. To be considered in the ASSESSMENT OF THE Indirect use of the energy. INVESTIMENT Heat pump supply Temperature < 20°C  INDIRECT USE with the use of HEAT PUMPS;

 CONNECTION with the national electricity grid;

Example of municipality zonation with main interval depth of the 1°hydrostratigraphic units (phreatic and semi-confined aquifer) 1°hydrostratigraphic units (15-60 m depth) from 15 to 50 m < 15 m

2° hydrostratigraphic units (70- 150 m depth)

Exemple of hydrostratigraphic units

The analysis of the hydro-geological cartography of the territory, together with the analysis of the results of the well drillings for an industrial and potable use, has led to the identification of the main hydrostratigraphic acquifer units that allows a first identification of the depth of the main hydrothermal resource present in the first 50-100 meters depth

The documental verification of the tests of the well pumping previously drilled, has confirmed the importance of the aquifer capacity in our area. This huge hydraulic capacity generates constant temperatures variable between min 13 °C in winter and max 18°C in summer. 12

The centralised and decentralised exploitation of the geothermal shallow source the context

. An area which includes the basin of the river Olio, consisting in the higher and lower part of the Sebino, The Franciacorta and the Po Valley Plain and which stretches to the borders with the province of Cremona; . 71 associated municipalities with an average population density of around 5.000 inhabitants; . An area marked by important streams and shallow aquifers; . Public buildings situated mainly inside old town centres, usually subjected to environmental, historical and architectonical constrains; . Areas subjected to a strict acoustic zoning; the demand:

. Revamp and adapt end-of-life heat generation plants of public buildings; . Reduce the current cost of the energy bill; . Facilitate the use of renewable and alternative energy sources;

the aim of the project:

. Re-use the existing plant spaces; . Exploit the particularities of the area; . Create a simple, extensible system which can be replicable in the area; . Identify an economical solution which can be repaied, also partially, through the reduction of the energy bill; use water as a renewable energy re source; draw the renewable resource and store it in smart Withdrawal tanks; and storage transfer the renewable resource from the storage to the use area; revamp existing thermal plants by “indoor” heat pumps at low or medium temperatures; use high temperature heat pumps to supply “difficult” heating plants;

The COLD District heating Distribution . The water loop is supplied mainly by drawn from network underground; . It develops through a buried propylene network; . The pipes are laid without any insulation in order to facilitate the thermal exchange with the soil before the re-injection in the aquifer through an injection well; . The water cycle is altered only by the change of the temperature when the resource is returned to the environment (around 7°C); . Use of “poor” and commercial material as well as ease in the use, End user in the maintenance and management; OPERATION PRINCIPLE

. Distribution of the geothermal fluid in a centralised mode; . Each user draws the right amount of water strictly necessary to the heat pump operation; . Once the geothermal Energy is extracted, the drawn water is returned to the buried storage; . Pumping in wells only works if the thermal conditions of the buried storage change; . The surplus water is returned to the original aquifer through a injection well with a maximum ∆T of 4°-7°C;

FREE THERMAL Heat pump SOURCE 4÷6 kWh thermal groudwater ( COP >4 ) 11…15°C 3 ÷ 5 kWh

The COLD DISTRICT HEATING – further uses

The presence of a used water network allows the possible supply of the

following additional and measurable services, and which are present 1 kWh 1 throughout the network: network

electric from . IRRIGATION of public green areas . Non-Potable domestic uses (washing machine, water closets, etc.) The Cold district heating:

 Combines, in a single plant, the heating and cooling production;  Preserves the management autonomy of the supplied buildings and the individual production of the heating, sanitary hot water and air conditioning;  Eliminates the distribution energy losses typical of a conventional district heating network, losses due to the network thermal dispersion;  Reduce drastically the local CO2 emissions for the urban heating;  Is not invasive in the case of the revamping of the existing thermal power plants;  Has an environmental and landscaping impact equal to zero; the Cold district heating represents an unusual case of hydraulic “smart grid” because :

 It is an open distribution network serving private and public users, extendable and/or repeatable in the area;

 it is a bijective energy network the network can supply NEUTRAL geothermal energy drawn from the used water ; the network can receive an antagonist energy from the heat pump in order to balance the circuit energetically (in the case of users operating in eating and cooling mode);  it is a mixed network the user, connected with the network, can draw the used water also for uses which are different from the energy ones, such as irrigation and non potable users;

Groundwater Supply from source supply municipal treatment plant

range temperatura range 15…30°C temperatura 11…18°C Supply from industrial waste non- reusable energetically

range temperatura 13…15°C

The Cold District Heating allows the combination with alternative energy resources non- usable differently because of their low temperature Among the alternative resources The use of an ALTERNATIVE or waste resource can there are the sewage reduce the use of the geothermal renewable resource for facilities of the small maintainance operations of the plants generating the municipalities which are located alternative resource. Far from the large urban centres. The depurated water deriving from a plant of a small A typical resource of energy not reusable is represented by the municipality typical of the province of Brescia, cooling circuits of the Steel, Food and Moulding Industry generally possesses a chemestry and a temperature compatible supplied by the refrigeration groups or by the evaporation towers. with the operation principle of the Cold District Heating. THE CHOICE OF THE HEAT PUMP WATER-WATER • The Choice of the “COMMERCIAL” heat pumps, characterized by a detailed technical consultancy in the area; • The Choice of the H.P. typology according to the maximum temperature of the user to be supplied; • The Identification of the climatic curve of the plant supply in order to determine of the average medium seasonal COP value. According to the outside temperatures of the place (minimum monthly averages), it is possible to determine the resulting “climatic” flow temperature to the heating bodies; • The Choice, with equal maximum temperature reached by the H.P., of the typology of the machine able to reach the highest average seasonal COP; while the production performance (COP), used in the energy and economic balance, will be determined by the average weighted flow temperature;

An example of choice for an existing building

For the existing buildings supplied by radiators, the HEAT PUMP is able to totally 90,0 °C replace a conventional thermal generator; for example: 85,0 °C 80,0 °C

- Office use building of the years 1950; 75,0 °C - Radiators heating plant; 70,0 °C - max temp 65°C, with outside temp. -7°C; 65,0 °C 60,0 °C

55,0 °C

50,0 °C

45,0 °C

40,0 °C

35,0 °C

Temperaturadi mandata [°C] 30,0 °C

25,0 °C

20,0 °C

15,0 °C

10,0 °C In this example, the average average 25,0 °C 20,0 °C 15,0 °C 10,0 °C 5,0 °C 0,0 °C -5,0 °C -10,0 °C -15,0 °C seasonal temperature of the radiator temperatura esterna [°C] supply is equal to 50°C. Here, it is possible to use a simple It will be the value to which the commercial heat pump (R134) with an average seasonal COP has to be average Seasonal COP equal to 4,1. determined . HEAT PUMP

simple cycle R407 o R410 RADIATOR ° max temp. 55…65 C; ______Max temp. 70°C simple cycle Work variable temp. from 40 to 60°C Average seasonal temp. 50°C R134a: max temp. 65…70°C; ______double cycle R410 / R134a max temp. 75…80°C;

FANCOIL

Max temp. 60°C The use of the Heat Pump in the revamping Work variable temp. from 40 to 50°C Average seasonal temp. 45°C of the existing building

. the H.P. can avoid the total revamping of the internal plant; . the H.P. can allow the re-use of the existing pipes; . the H.P. can allow the re-use of the heating terminal equipment; . the H.P. has to generate hot water with variable RADIATING SURFACE temperature according to the outside temperature; Max temp. 45°C . with the H.P. it is necessary to make a chimical Work variable temp. from 30 to 40°C washing of the existing heating plant to preserve Average seasonal temp. 35°C the integrity of the condenser; . the H.P. has to be protected with the cartridge filters of almost 100 mm with a wide filtering surface;

Municipality of

Shallow geothermal energy at low enthalpy. Indirect use of the energy. The results of a Heat pump supply Temperature < 20°C

PILOT STUDY

COGEME has applied the basic concerts of the Cold District Heating to some constructions where the geothermal energy represents the renewable resource combined with single buildings.

The aim of these “pilot” applications is to test the behaviour of the disconnection thermostatic storage of the source circuit, evaluating the energy and plants benefits through a constant monitoring and recording of each variable of the process.

We would refer to the example of Berlingo, a “virtuous” municipality located in the lower plain of the Brescia province. This municipality commissioned to Cogeme the construction of the geothermal power plant serving the heating end cooling plant of the new building of the Secondary School. PILOT PLANT STRUCTURE MONITORING OF THE

Withdrawal well at a depth of 50 m; THERMAL SEASON 2013-2014

Withdrawal pump of 15,6 m3/h with ON/OFF fixed flow CONSTANT RECORDING OF: rate; Source circuit water flow rates, primary and secondary; Geothermal storage with thermostatic control; “typical user” electrical consumption; Variable flow distribution network; Distribution circuits electrical consumption; Atmospheric output of storage overflow; Photovoltaic production; Return well at a depth of 50 m; Source and storage circuits temperatures; Typical user with geothermal power plant of 90 kWh; Power plant circuits temperatures; “typical user” ambient temperatures; Photovoltaic plant of 19 kWep;

PLC ENERGY BALANCE OF FIRST PRINCIPLE Simplified scheme

CONSUMPTION WITH THERMAL PLANTS SUPPLIED BY SERVED BUILDINGS Useful thermal requirement 47.868 kWht HEAT PUMP + Heating only THERMAL NEED at the top of the plant 47.868 kWht E.E. per heat pumps 9.030 kWhe E.E. per power plant electric pumps 401 kWhe E.E per plantwide electric pumps 690 kWhe Photovoltaics E.E. production - 8.764 kWhe National electricity grid residual E.E 2.874 kWhe

Cold district heating network

Electric energy for thermal Plant used as a sample 9.030 + 401 + 690 kWhe

Photovoltaics electic energy 8.764 kWhe Electric energy supply E.Energy for well Residual electic and water loop energy 1.517 kWhe 2.874 kWhe

E.E. production with national thermoelectric power plant

standardised performance 46% equivalent energy E.E. produced for introduced the national 6.249 kWh electricity grid

Total losses 3.374 kWh The solar contribution of the soil

Natural heating of the It is possible to appreciate the solar tanks by the soil in a contribution, even if modest, on the covering typical January day soil of the distribution and storage system. (outside temperature *C max 7.8…min -3.2 )

Landfill area of the geothermal tanks Ground cover max 70 cm

Theorethical quantification of the solar contribution

Theoretically speaking , the difference between the real groundwater consumption compared to the calculated, highlights, in the energy diagnosis and with equal climatic conditions, a reduction by 4,6% of the resource extracted from the subsoil. The laying of the connection pipes between the outlet shaft and the geothermal tanks

View from above of the storage system during the hydraulic testing of the pipes

A detail of the connection between the A moment of return network the return well and the construction geothermal tanks

Municipality of

Shallow geothermal energy at low enthalpy. Indirect use of the energy. Heat pump supply ° …a project in progress Temperature < 20 C

THE PROJECT TARGET

Energy revamping of the thermal generation for the sports centre The arrangements for the future energy revamping of the thermal plants of the primary and secondary school Supply to the nursery school The use of renewable sources compatible with the environmental constraint imposed by the Superintendency of Fine Arts;

Sport centre

Primary and secondary school

Nursery school Particularities of the context The shores of lake Iseo are protected by a Law safeguarding the landscapes and urban context. This Law prohibits the use of thermal or photovoltaic solar panels as well as the building of technical volumes which could alter the landscape. Three-dimensional

Sport centre geothermal representation of power plant supply the distribution SPORT CENTRE network of the users to be OUTLET SHAFT supplied and of Cold district heating buried punping the outlet and inlet station shafts

Thermostated geothermal tank PRIMARY and SECONDARY SCHOOL

INLET SHAFT

Groundwater discharge network Primary and secondary school geotermal power Nursery school geothermal plant supply NURSERY SCHOOL Cold district heating network

MAIN INFORMATION ON THE NEW PLANT

. Outlet shaft: 50 meters deep, Ø 225/400 mm; . Static and dynamic level depth Profondità : -6 / -7 m . Withdrawal well of 40 m3/h with a on/off fixed Flow; . Geothermal storage of 25 m3/h with thermostated control; . Return atmospheric circuit , from the storage overfill to the inlet shaft; . Inlet shaft: 40 m deep, Ø 200/350 mm; . Buried filtering station, measurement of the groundwater and cold district heating pumping, with a rescue system against flooding and condensation; . Cold District Heating network of 40 m3/h, with a variable flow and a constant pressure; . Three connected geothermal power plants with a total peak thermal power equal to 300 kWt; . one building with cast-iron radiators built in 1960; . one building with radiators + high temperature floor radiating built in 1975; . one building with low temperature floor radiating built in 2014; . The measurement of groundwater entering into the geothermal power plants with consumption remoting; . Evaporator direct supply without the uses of the separation sacrificial exchanger; . PLC of cold district heating network management with remote tele-control; . Recording of each variable of the process; the sport centre The sport centre geothermal power plant

OUTLET shaft

District heating buried pumping station

RESPECT OF THE LANDSCAPING PROTECTION

The absence of the technical spaces, typical of previously built contexts, has been solved with the use of a plant with a visual impact equal to zero. The vision of the covers and inspection hatches will be mitigated by the uses of specific flowerbeds with flowering shrubs. the sport centre

Sport centre former Dismantling phase of thermal power plant the existing chimneys emptied of all the existing facility Drilling activity of the outlet shaft

Building phase of the the building site containment structure of the cold district heating 7 August 2014 buried pumping station Thank you for your attention…see you to the next project

COGEME SPA - Via XXV Aprile, 18 - 25038 Rovato (BS) www.cogeme.net

geothermal Energy serving public buildings