This document summarizes Luca Madiai's presentation on geothermal energy potential in Tuscany, Italy and Hungary. It discusses the history of geothermal energy use from ancient Roman times to its modern applications. Geothermal energy is renewable, unlimited, and produces no air pollution or CO2 emissions. The document describes geothermal resources and technologies in Tuscany, Hungary, and three of Madiai's projects analyzing a geothermal heat pump system, a dry steam power plant in Larderello, and a proposed small binary cycle power plant in Hungary.

1. Geothermalenergy Short Presentation on Geothermal Energy Potential in the twoEuropeanregions: Tuscany and Hungary Luca Madiai Università degli Studi di Firenze Dipartimento di Filologia Moderna – Area Ugro-finnica Dipartimento di Energetica – “Sergio Stecco” EötvösLorándGeofizikaiIntézet – Budapest Budapest, Maggio 2010

2. Geothermalenergy Introduction Basis History Geothermalresources Utilizationtechnologies Projects

3. Introduction Geothermalenergyis: Renewable Unlimited Constant Produces no air pollution Doesnotemit CO2 Isrelatively cheap toextract

4. Geothermalenergybasis 99% of the volume of the Earth is warmer than 1000°C, and only 0.1% has lower temperature than 100°C Geothermal gradient: towards the interior of the Earth the temperature rises Earth geothermal gradient has an average value of 3°C/100 m (in Hungary it reaches 5-6°C/100 m)

5. History At the beginning thermal waters were used mainly for medical, household and recreational purposes. In Roman times geothermal watersweredistributeddirectlyto the buildingstroughpipe systems. Some Roman hot springs were also used for eye and skin treatment. In Pompei houses could be heated by geothermal hot water. Thermalbath in Pompei Roman thermalbath (Naples)

6. history In 19th century, the development of technology has allowed the discovery and exploration of underground water resources. Tuscany geothermal steam was first used as source of boron and ammonium compounds. The heat production had only secondary importance. The electricity production began in 1904 thanks to the work of Prince PieroGinori Conti. Then in 1913 the first plant in Larderello had been installed with 250 kW capacity. Today the complex of Larderello has a power of more than 600 MW and development programs expected to increase the power to 880 MW. From 1960 more than 200.000 apartments have been being heated by geothermal water in France. In Hungary from the seventies geothermal hot water has been being used primary to heat greenhouses.

7. History VilmosZsigmondy (miningengineer) expetedtofindthermal water in Városliget (Budapest – Pest side) The drilling work wasvery risky, expensive and full of difficulties. At the time no one believed it was possible tofindthermal water in Pest. In 1878 Zsigmondycompleted the well (970 m – oneof the deepest in the World). The drillingwassuccessful Thatwell can produce 1200 m3of 73.8 °C thermal water everyday Thankstohis work and thiswell the world famousSzéchenyi Bathwasbuilt in 1913 VilmosZsigmondy (1821-1888) –Mining engineer

8. Geotermikus Energia Magyarországon In Hungary the average geothermal gradient ranges between 5-7 °C/100 m, while the world's average value is 3°C/100 m At depth of 1000 m the temperature can reach or even exceed 60 °C. Currently, geothermal energy usage is only 0.28 % of total energy demand of the country. In Hungary there is no electricity production from geothermal resources, while the largest producers - the USA and the Philippines - produce from 2 to 2000 MW

9. Geothermalenergy in tuscany In Tuscany there are two main areas of geothermal exploitation: Larderello (632 MW – dry steam). Pressure: 4-7 MPa and temperature: 300-350°C Monte Amiata (79 MW –water dominated)

10. Geothermalenergyusage Today, geothermal energy is used in several areas: In agriculture: heating of greenhouses Direct district heating Thermal baths Heating and cooling with geothermal heat pumps Power generation I havebeenworking on 3 differentprojects: Geothermalheatpumpsystems Dry steampowerplant Binarycyclepowerplant

11. Geothermalheatpumpsystems Geothermalheatpump (GHP) consists in a inverse cyclethatuses the groundas low temperature source (insteadofexternal air) The groundhasanaverage temperature ofaround 10°C, and itdoesnotvarysignificantlywith the seasons With GHP systemsitispossibletoheat(max 50°C fluid) and coolbuildingsonlyusing the ground and electricity There are two kind of GHP: open loop and closed loop (in this case antifreeze must be used)

12. Electricity production with dry steam Dry steamisextractedfrom a production well Dry steamdirectlyexpands in turbine and a generatorproduceselectricalenergy The turbine outlet steamhastobecooled in a water condenser or in a coolingtower The cooledfluid can bere-injectedinto the ground

13. Electricity production with hot water The geothermal water heats up a secondaryfluid in the heatexchanger Geothermal water temperature can be in the rangeof80-150°C The secondaryfluidexpands in turbine like in a normalrankinecycle (ORC) The secondaryfluidhas a lowerboling temperature than water Secondaryfluid can beeither a refrigerant or hydrocarbon

14. Project 1 : Geothermalheatpump A simulation model has been created in order to study the long term transient behavior of the system The model includes a building, a storage tank, a heat pump, and a borehole heat exchanger The model can simulate weather conditions and can be used to compare different configurations and external parameters The model was built with TRNSYS software

15. Project 2: Dry steampowerplant A dry steampowerplantforLarderellohasbeenstudied A complete energy and exergy analysisof the system hasbeenperformedusing EES software The system works in steady state and severalsimplificationswereapplied Constantexternalconditionshasbeenassumed (averageambient temperature and humidity)

16. Project 3: binarycyclepowerplant A smallbinarycycleplantforHungaryhasbeenproposed and studiedusing EES software The resultshavebeencomparedwith the resultsof some similarstudies Severalconfigurations are possible and fewofthemhavebeenconsidered

17. Thanksforyourattention ! Further information can be found in my thesis Luca Madiai luca.madiai@gmail.com