ENCYCLOPAEDIA OF HYDROCARBONS ISTITUTO DELLA ENCICLOPEDIA ITALIANA FONDATA DA GIOVANNI TRECCANI
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CHAIRMAN Roberto Poli CHIEF EXECUTIVE OFFICER Paolo Scaroni DIRECTORS Alberto Clô, Renzo Costi, Dario Fruscio, Marco Pinto, Marco Reboa, Mario Resca, Pierluigi Scibetta
ISTITUTO DELLA ENCICLOPEDIA ITALIANA PRESIDENT Francesco Paolo Casavola BOARD OF DIRECTORS VICE PRESIDENT Cesare Geronzi Gian Mario Anselmi, Roberto Artoni, Pierluigi Ciocca, Marcello De Cecco, Giuseppe de Vergottini, Giovanni Fiori, Ademaro Lanzara, Federico Pepe, Giovanni Puglisi, Guido Rossi, Giuseppe Vacca MANAGING DIRECTOR Francesco Tatò SCIENTIFIC COUNCIL Carlo Azeglio Ciampi, Francesco Cossiga, Oscar Luigi Scalfaro, Giovanni Conso, Rita Levi-Montalcini; Mario Agrimi, Adriano Alippi, Girolamo Arnaldi, Baccio Baccetti, Giuseppe Franco Bassani, Mario Beccari, Giuseppe Bedeschi, Giampio Bracchi, Pietro Calissano, Luciano Canfora, Mario Caravale, Sergio Carrà, Enrico Castelnuovo, Francesco Clementi, Piero Coda, Benedetta Craveri, Francesco D Agostino, Giuseppe Dalla Torre, Nino Dazzi, Antonio Fazio, Domenico Fisichella, Giuseppe Galasso, Paolo Galluzzi, Emma Giammattei, Antonio Giuliano, Gherardo Gnoli, Augusto Graziani, Tullio Gregory, Maurizio Iaccarino, Carlo Jean, Fiorella Kostoris Padoa Schioppa, Luigi Labruna, Lucio Lanfranchi, Carlo Maria Ossola, Giorgio Parisi, Sandro Petruccioli, Giovanni Pugliese Carratelli, Gian Tommaso Scarascia Mugnozza, Pietro Scoppola, Salvatore Settis, Francesco Sicilia, Fulvio Tessitore, Edoardo Vesentini, Vera Zamagni, Ortensio Zecchino BOARD OF AUDITORS Gianfranco Graziadei, Chairman; Mario Perrone, Saverio Signori Luciano Pagliaro, Delegate of the State Auditor s Department
ENCYCLOPAEDIA OF HYDROCARBONS PROJECT DIRECTORS Mario Beccari, Ugo Romano SCIENTIFIC CO-ORDINATING COMMITTEE Pier Federico Barnaba, Piero Bernardini, Giovanni Brighenti, Sergio Carrà, Alberto Clô, Carlo Giavarini, Renzo Mazzei, Ferruccio Trifirò EDITORIAL DEPARTMENT Chief Editor: Carlo Amadei Technical-Scientific Area. Supervisors: Fabio Sebastiani; Maria Teresa Amoroso. Chemistry: Andrea Ciccioli, Alessandro Di Menno Di Bucchianico, Antonio Di Meo - Physics: Maria Grazia Ianniello - Engineering: Lucilla Monteleone, Roberto Steindler - Biological, Geological and Natural Sciences: Francesca Beolchini, Simona Martullo, Francesca Ricci, Paola Vinesi Legal, Economics and Historical-Geographical Area. Supervisors: Giandomenico Patrizi; Pino Bongiorno. Law: Fabio Di Fonzo, Fabiana Di Porto, Bianca Maria Raganelli - Economics: Chiara d Auria, Giuseppe Smargiassi - Geography: Arianna Ballabene - History: Silvia Dionisi Italian language edition. Supervisor: Enrico Piccioni. Cristiana Baldazzi, Ilenia Romana Cassetta, Fabio Catino, Claudio Censori, Marina Chiarioni, Katia Furìa, Patrizia Greganti, Tomáš Kubíček (illustrations), Michela Mastroddi, Enza Milanesi, Stefano Petrocchi, Tiziana Provvidera, Laura Volpe English language edition. Co-ordination: Cosima Campagnolo. Donald Blair Bartlett, Janice Calf, Anne Colbeck, Johanna Erhardt, Helenka Dodge Kinnan, Patrick O Keeffe, Mary Anne Tafuri. Consultant: Peter Joseph Glendening. Translators: Andrea Baldi, Fabrizio Balsamo, Richard Bates, Massimo Benedetti, Anthony Martin Cafazzo, Fabio Catino, Paolo Del Giudice, Paul Michael Garwood, Peter Joseph Glendening, H.J. Michael Harris, Erika Louisa Milburn, Gian Mario Moggio, Stefano Salpietro, Maria Serena Scariolo, Ruth Patricia Williams Secretaries: Pasqualina Leone, Tiziana Pieretti
ART DEPARTMENT Art Director: Gerardo Casale Graphics: Giuseppe De Gregori Illustration sourcing: Daniele Piselli; Claudio Cigognetti; Anna Maria Ciai, Bernardo Ruzicka, Angelo Zanni Drawings: Marina Paradisi; Giuseppina Elia, Marco Evangelista, Massimo Montelli, Anna Olivieri, Paola Salvatori (cartography) Graphics and layout: Giuseppe De Gregori (control) Quality control: Anna Rita De Nardis Secretaries: Aurora Corvesi, Carla Proietti Checchi LIBRARY Gabriella Miggiano; Elsa Adducci, Marina Battaglini, Massimo Menna, Giuliana Scudder Secretary: Gabriella Michetti PUBLISHING DEPARTMENT Publishing administration: Luisa Fusé; Cecilia Rucci, Mirella Aiello Planning: Luisa Cinquina; Alessia Pagnano, Tiziana Picconi Quality control: Rosalba Lanza; Simonetta Paoluzzi Industrial production: Maria Devrushian; Loreta Lucchetti Secretary: Eliana Naddeo PUBLISHING DIRECTOR Massimo Bray
ENCYCLOPAEDIA OF HYDROCARBONS volume iii NEW DEVELOPMENTS: ENERGY, TRANSPORT, SUSTAINABILITY SCIENTIFIC CO-ORDINATION Ugo Romano
INDEX OF VOLUME III NEW DEVELOPMENTS: ENERGY, TRANSPORT, SUSTAINABILITY 1 FROM PRIMARY SOURCES TO THE MARKET Dante Casati, Raffaella Turatto 1.1 EVOLVING TECHNOLOGIES AND POSSIBLE SCENARIOS 3 1.1.1 Scenarios and strategic decisions 3 1.1.2 Scenarios and reference markets 3 1.1.3 Factors for change and technological innovation 4 1.1.4 The macroeconomic scenario 5 1.1.5 Energy scenario 5 1.1.6 Technological scenario 6 1.1.7 The development scenario for the issue of environment and sustainability 15 2 HYDROCARBONS FROM NON-CONVENTIONAL AND ALTERNATIVE FOSSIL RESOURCES Maurice B. Dusseault 2.1 OIL FROM NON-CONVENTIONAL SOURCES 21 2.1.1 Non-conventional fossil fuels 21 2.1.2 Pressure-driven viscous oil technologies 25 2.1.3 Gravity drainage technologies 32 2.1.4 In situ combustion option 39 2.1.5 Technology mixing and sequencing 41 2.1.6 Reservoir screening criteria 44 2.1.7 Oil shales and mineable oil sands 45 2.1.8 Upgrading and transportation 48 2.1.9 Environmental impact 50 2.1.10 Predictions 52 Charles M. Boyer, Joseph H. Frantz, Creties D. Jenkins 2.2 NON-CONVENTIONAL GAS 57 2.2.1 Introduction 57 2.2.2 Reservoir fundamentals 60 XV
2.2.3 Drilling, completion, and production 72 2.2.4 Resources and reserves 74 2.2.5 Technology and future trends 75 2.2.6 Project summaries and comparisons of applied technologies 77 2.2.7 International potential for coalbed methane and shale gas 79 2.2.8 Conclusions 80 Gian Paolo Borghi 2.3 GAS HYDRATES 85 2.3.1 Introduction 85 2.3.2 The structure of hydrates 85 2.3.3 Hydrates as a problem in the oil industry 91 2.3.4 Hydrates as a future energy resource 98 2.3.5 Research and development activities in the gas hydrates sector 107 Alberto Delbianco 2.4 HYDROCARBONS FROM THE DIRECT LIQUEFACTION OF SOLID FUELS 113 2.4.1 Introduction 113 2.4.2 Liquefaction technology 120 2.4.3 New-generation processes 126 2.4.4 Properties of coal liquids 128 2.4.5 Further developments of the technology 129 2.4.6 Integration with hydrogen production technologies 133 2.4.7 Process economics and development potential of the technology 134 Alberto Delbianco, Romolo Montanari 2.5 EMERGING TECHNOLOGIES FOR THE CONVERSION OF RESIDUES 137 2.5.1 Introduction 137 2.5.2 Properties and chemical characteristics of non-conventional oils 139 2.5.3 Chemistry of the conversion and upgrading processes 143 2.5.4 Carbon rejection technologies 147 2.5.5 Hydrogen addition technologies: hydrocracking 151 2.5.6 Technologies for the exploitation of oil shale 156 2.5.7 Main development projects 158 Giuseppe Bellussi, Roberto Zennaro 2.6 HYDROCARBONS FROM NATURAL GAS 161 2.6.1 Introduction 161 2.6.2 Gas to Liquids process by means of the Fischer-Tropsch reaction 163 2.6.3 Products 179 3 NEW UPSTREAM TECHNOLOGIES Ali Daneshy 3.1 UPSTREAM TECHNOLOGIES. NOVEL WELL AND PRODUCTION ARCHITECTURE 185 3.1.1 Introduction 185 3.1.2 Horizontal drilling 186 3.1.3 Multilateral wells 190 XVI
3.1.4 Downhole flow regulators 196 3.1.5 Novel well architectures 198 3.1.6 Flow optimization 205 3.2 ENHANCED OIL RECOVERY 209 Emilio Causin 3.2.1 Processes 209 Steven L. Bryant 3.2.2 Recovery factor optimization 214 Thomas Lockhart, Francesco Crescenzi 3.3 SOUR OIL AND GAS MANAGEMENT 237 3.3.1 Introduction 237 3.3.2 Origin of H 2 S in oil and gas accumulations 238 3.3.3 H 2 S removal in small volume plants 241 3.3.4 High volume sour gas treatment processes 243 3.3.5 Sour gas re-injection 256 3.3.6 Sulphur storage and disposal 260 3.3.7 The sulphur market and new uses 264 Francesca de Ferra 3.4 BIOTECHNOLOGIES APPLIED TO OIL AND GAS EXPLORATION, PRODUCTION AND CONVERSION 271 3.4.1 Microbiology associated with hydrocarbons 271 3.4.2 Reactions 274 3.4.3 Applications 281 3.4.4 Biological activation of methane 292 4 ENERGY CARRIERS Mario Marchionna 4.1 FROM SOURCES TO MARKET: ENERGY CARRIERS 301 4.1.1 Introduction 301 4.1.2 Life cycle of the energy carrier 301 4.1.3 Conventional energy carriers 304 4.1.4 Innovative energy carriers 308 4.1.5 Conclusions 315 Marco Nicola Carcassi 4.2 THE HYDROGEN ECONOMY 319 4.2.1 Introduction 319 4.2.2 Characteristics of hydrogen 321 4.2.3 Production, transportation and storage of hydrogen 323 4.2.4 Advantages and disadvantages of hydrogen as an energy vector 325 4.2.5 Research and development programmes 329 4.2.6 Conclusions 333 XVII
John R. Benemann, Paola Pedroni 4.3 BIOLOGICAL PRODUCTION OF H 2 : MECHANISMS AND PROCESSES 337 4.3.1 Introduction 337 4.3.2 Biological catalysts for H 2 production 339 4.3.3 Bioreactors for H 2 production 341 4.3.4 Photobiological H 2 production processes 344 4.3.5 Dark fermentations 350 4.3.6 Biohydrogen applications and potential 355 Ernesto Scafè 4.4 TRANSPORT AND STORAGE OF HYDROGEN 361 4.4.1 Introduction 361 4.4.2 Traditional transport and storage 361 4.4.3 Innovative transport and storage 364 5 POWER GENERATION FROM FOSSIL RESOURCES Ennio Macchi, Giovanni Lozza, Stefano Consonni 5.1 LARGE-SCALE ELECTRICAL GENERATION SYSTEMS 377 5.1.1 Introduction 377 5.1.2 Steam electric power stations 384 5.1.3 Gas turbines 397 5.1.4 Combined cycles 404 5.1.5 Gasification and combined cycles (IGCC) 413 Ennio Macchi, Giovanni Lozza 5.2 INDUSTRIAL COGENERATION 421 5.2.1 Introduction 421 5.2.2 Plants with external combustion prime movers 425 5.2.3 Plants with internal combustion prime movers 428 Ennio Macchi, Stefano Campanari 5.3 DISTRIBUTED GENERATION 435 5.3.1 Introduction 435 5.3.2 Microgeneration technologies 438 5.3.3 Trigeneration 457 Ivano Miracca, Mario Molinari 5.4 POWER GENERATION WITH CARBON DIOXIDE SEGREGATION 461 5.4.1 Introduction 461 5.4.2 Technological development 466 5.4.3 Future prospects 472 Francesco Pittalis, Vincenzo Antonucci 5.5 FUEL CELLS FOR STATIONARY GENERATION 475 5.5.1 Historical outlines 475 5.5.2 Introduction 477 XVIII
5.5.3 Fuels 482 5.5.4 Low temperature fuel cells 485 5.5.5 Medium and high temperature fuel cells 491 Maurizio Cumo 5.6 ADVANCED NUCLEAR SYSTEMS 499 5.6.1 Introduction 499 5.6.2 The six fourth-generation nuclear systems 501 5.6.3 High-temperature reactors 505 5.6.4 Reduction in the radiotoxicity of waste 508 5.6.5 The III + generation reactors 510 Giovanni Battista Zorzoli 5.7 TRANSMISSION, DISTRIBUTION AND STORAGE OF ELECTRIC ENERGY 515 5.7.1 Introduction 515 5.7.2 Storage of electric energy 515 5.7.3 The first steps 517 5.7.4 Types of transmission networks and connected problems 518 5.7.5 The North American network 520 5.7.6 The European networks 522 5.7.7 Problems posed by deregulation 524 5.7.8 Examination of a typical case of blackout 525 5.7.9 Distribution networks 527 6 POWER GENERATION FROM RENEWABLE RESOURCES 6.1 SOLAR ENERGY CONVERSION 531 Mauro Vignolini 6.1.1 Concentration systems 531 Francesca Ferrazza 6.1.2 Photovoltaic technology 547 Jacques Ruer 6.2 WIND POWER GENERATION 561 6.2.1 The wind resource 561 6.2.2 Theory of wind turbines 563 6.2.3 Wind turbine regulation systems 564 6.2.4 Turbine equipment 566 6.2.5 Typical characteristics of modern large turbines 570 6.2.6 Other types of wind turbines 570 6.2.7 Development of onshore wind energy 571 6.2.8 Development of offshore wind energy 571 Wavegen 6.3 WAVE AND TIDAL POWER GENERATION 575 6.3.1 Introduction 575 6.3.2 Historical perspective 579 XIX
6.3.3 Current status 582 6.3.4 Estimation of wave energy resource and device performance 586 6.3.5 Environmental impact of wave and tidal devices 590 6.3.6 Global prospects for the energy industry 591 Mario Fanelli, Piero Manetti, Mary Hana Dickson, Leonardo Zan 6.4 GEOTHERMAL ENERGY 595 6.4.1 Introduction 595 6.4.2 Nature of geothermal resources 597 6.4.3 Geothermal exploration 603 6.4.4 Utilization of geothermal resources 604 6.4.5 Environmental impact 609 Vito Pignatelli, Andrea Robertiello 6.5 BIOMASS FOR RENEWABLE ENERGY 611 6.5.1 Introduction 611 6.5.2 The role of biomass in the energy spectrum 613 6.5.3 Fuels from biomass 615 6.5.4 Technologies for the use of biomass energy 621 6.5.5 Conclusions 628 7 ENERGY SYSTEMS ANALYSIS Alberto Tintinelli 7.1 LIFE CYCLE ASSESSMENT AND ENERGY SYSTEMS 633 7.1.1 Introduction 633 7.1.2 Life cycle assessment method 634 7.1.3 Applications of life cycle assessment in the field of energy systems 641 Teresa L. Hill, David H. Marks, Jefferson W. Tester 7.2 PATHWAYS TO A SUSTAINABLE ENERGY FUTURE 651 7.2.1 Introduction 651 7.2.2 The future of fossil energy 652 7.2.3 Alternatives to fossil 655 7.2.4 Energy systems 664 7.2.5 Choosing options for a sustainable energy future 666 7.2.6 Conclusions 668 8 TRANSPORT Alessandro Piccone, Giorgio Cornetti 8.1 RECIPROCATING INTERNAL COMBUSTION ENGINES 673 8.1.1 Introduction 673 8.1.2 Architecture 677 8.1.3 Combustion, emissions and control system 684 8.1.4 Evolution 695 XX
Jacopo D Andria 8.2 HYBRID DRIVE SYSTEMS 699 8.2.1 Introduction 699 8.2.2 Current environmental problems and potential solutions 700 8.2.3 Hybrid-electric vehicles: historical outline and current situation 703 8.2.4 Features of the hybrid systems in use 704 8.2.5 Strengths and weaknesses of hybrid-electric vehicles 8.2.6 Possible developments in components for hybrid-electric vehicles 8.2.7 The future of the market for hybrid-electric vehicles Fulvio Giavazzi, Patrizia Buttini, Carlo Perego 8.3 POLLUTING EMISSIONS CAUSED BY TRANSPORT 717 8.3.1 Pollutants emitted by motor vehicles 717 8.3.2 Low-emission fuels 729 Riccardo Maione, Luigi D Elia 8.4 LUBRICATION AND LUBRICANTS 751 8.4.1 Introduction 751 8.4.2 Functions and performance of lubricants for heavy-duty vehicles 757 8.4.3 Main components of lubricants for heavy-duty vehicles 764 8.4.4 Lubricants for industry 768 9 SUSTAINABILITY Andrea Robertiello, Alberto Tintinelli 9.1 THE OIL INDUSTRY TOWARDS ZERO IMPACT 775 9.1.1 Introduction 775 9.1.2 Oil cycle: upstream 776 9.1.3 Oil cycle: downstream 787 9.1.4 Natural gas cycle 793 9.1.5 Operating instruments available for eliminating environmental impact 795 George J. Stosur 9.2 SUSTAINABLE DEVELOPMENT IN THE OIL AND GAS INDUSTRY 801 9.2.1 Defining sustainable development 801 9.2.2 The need for sustainable development 802 9.2.3 The precautionary principle 803 9.2.4 Industrial activities related to sustainable development 803 9.2.5 Greenhouse gases and global warming 807 9.2.6 Biodiversity and loss of habitat 808 9.2.7 The role of technology and research and development 808 9.2.8 Regulatory processes at corporate, country and global level 809 Paul Freund 9.3 CO 2 CAPTURE AND STORAGE FROM FOSSIL FUELS 811 9.3.1 Introduction 811 9.3.2 Sources of CO 2 812 XXI
9.3.3 Methods of capturing CO 2 814 9.3.4 Transportation of CO 2 818 9.3.5 Storage of CO 2 819 9.3.6 Costs and benefits 824 9.3.7 Environmental impact, risks, legal aspects and public acceptance 829 9.3.8 Monitoring, verification and commercial/regulatory requirements 832 9.3.9 Conclusions 834 John R. Benemann, Paola Pedroni 9.4 BIOFIXATION OF FOSSIL CO 2 BY MICROALGAE FOR GREENHOUSE GAS ABATEMENT 837 9.4.1 Introduction 837 9.4.2 Photosynthesis, microalgae productivity and GHG abatement 839 9.4.3 Microalgae cultivation systems and CO 2 capture 843 9.4.4 Microalgae harvesting and conversion to fuels 847 9.4.5 Microalgae multipurpose processes for GHG abatement 851 9.4.6 Economics and R&D issues 855 9.4.7 GHG abatement potential with microalgae processes 857 Abigail Entwistle, Timothy Reed, Paola Pedroni 9.5 BIODIVERSITY AND THE OIL AND GAS SECTOR 863 9.5.1 Introduction 863 9.5.2 Biodiversity and the oil and gas sector 866 9.5.3 Operationalizing biodiversity awareness in the oil and gas sector 870 Ugo Romano, Franco Rivetti 9.6 CHEMICAL INDUSTRY AND SUSTAINABLE DEVELOPMENT 879 9.6.1 Sustainability 879 9.6.2 Sustainability in the chemical industry 881 9.6.3 Innovation areas for sustainable chemistry 887 9.6.4 Looking ahead 907 10 ENVIRONMENTAL TECHNOLOGIES Ivo Allegrini 10.1 ATMOSPHERIC CHEMISTRY 915 10.1.1 Introduction 915 10.1.2 Atmospheric chemistry in the gas phase 916 10.1.3 Atmospheric chemistry in the aqueous phase 925 10.1.4 Depletion of stratospheric ozone 931 Ivo Allegrini, Patrizia Buttini 10.2 EMISSION AND CONTROL OF GREENHOUSE GASES 937 10.2.1 Introduction 937 10.2.2 Sources of greenhouse gas emissions 945 10.2.3 Techniques for measuring greenhouse gases in ambient air 948 10.2.4 Techniques for measuring greenhouse gases in emissions 949 10.2.5 Strategies to control greenhouse gases 950 XXII
Giovanni Grillo, Paola Pedroni 10.3 POLLUTION PROCESSES IN SOIL AND WATER, MONITORING AND RISK ANALYSIS 955 10.3.1 Introduction 955 10.3.2 Migration and transformation of hydrocarbons in the environment 955 10.3.3 Environmental characteristics of the principal groups of pollutants 959 10.3.4 Characterization and monitoring of pollution at a site 960 10.3.5 Modelling the movement of pollutants 964 10.3.6 Evaluation of the pollution at a site: risk assessment 966 XXIII
NOTES UNITS OF MEASUREMENT The units of measurement generally adopted are those of the Système International (SI), with corresponding multiples and submultiples. Only in particular contexts, typically connected with the petroleum industry, certain non- SI units of current use have been maintained. Main units of measurement adopted ampere A angstrom Å atomic mass unit u bar bar barrel bbl becquerel Bq British thermal unit Btu calorie cal candela cd coulomb C darcy D day d decibel db degree Celsius C degree Fahrenheit F degree (sexagesimal) electron volt ev farad F foot ' (ft) gram g gray Gy hectare ha henry H hertz Hz horse-power hp hour h inch '' (in) joule J kelvin K kilogram kg kilowatt-hour kwh litre l lumen lm lux lx metre m square metre m 2 cubic metre m 3 minute (angle) minute (time) min mole mol newton N nit nt ohm Ω parts per million ppm pascal Pa poise P pound lb pounds per square inch psi radian rad second (angle) second (time) s siemens S sievert Sv standard cubic foot scf or SCF or sft 3 steradian sr stock tank barrel stb stokes St tesla T tonne t tonnes of oil equivalent toe volt V watt W weber Wb yard yd year yr TERMINOLOGY AND SPELLING In the sectors of petroleum engineering and chemistry, of the petrochemical industry and of the earth sciences, specific terms, acronyms and expressions are frequently used. The criterion adopted in this work is based on their frequency of use, i.e. given two possible terms, the more common one has been used. British spelling, according to the most authoritative reference works, has been adopted. XXV
CHEMICAL NOMENCLATURE In the nomenclature of simple compounds, the rules of IUPAC (International Union of Pure and Applied Chemistry) have been adopted as far as possible, traditional names being limited to the cases admitted by IUPAC. When there are two or more names admitted, the commonest one is adopted. Two principal exceptions to the above rule have been applied in this work: For organic compounds used in the petrochemical industry, the name adopted is that listed in: Wells G.M. (1999) Handbook of petrochemicals and processes, Aldershot, Ashgate; Brookfield (VT), Gower. The British English spelling of sulphur and sulphur containing compounds is adopted. TRANSLITERATIONS In writing names belonging to other languages with an alphabet other than the Latin alphabet, the Romanization Tables compiled by the Library of Congress of Washington have been applied, introducing however certain modifications intended to reduce to a minimum the number of diacritical marks, and in particular in the case of Arabic and Persian adopting a number of transliterations by now accepted in local and international usage. Opposite page: The Val d Agri deposits, along with those in the Sauro Valley, make up the largest energy resource ever discovered in Italy. In the picture a drill in the drilling stage. In the subsequent production stage the drill is no longer in sight: the wellhead is lodged in an underground space, substantially reducing its visual effect while guaranteeing utmost safety. Technological advances in the energy industry allow the possibility to minimize the environmental impact and respect biodiversity. XXVI