SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment

Power to gas (PtG) is an emerging technology that allows to overcome the issues due to the increasingly widespread use of intermittent renewable energy sources (IRES). Via water electrolysis, power surplus on the electric grid is converted into hydrogen or into synthetic natural gas (SNG) that can b...

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Main Authors: Alessandra Perna, Linda Moretti, Giorgio Ficco, Giuseppe Spazzafumo, Laura Canale, Marco Dell’Isola
Format: Article
Language:English
Published: MDPI AG 2020-11-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/10/23/8443
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author Alessandra Perna
Linda Moretti
Giorgio Ficco
Giuseppe Spazzafumo
Laura Canale
Marco Dell’Isola
author_facet Alessandra Perna
Linda Moretti
Giorgio Ficco
Giuseppe Spazzafumo
Laura Canale
Marco Dell’Isola
author_sort Alessandra Perna
collection DOAJ
description Power to gas (PtG) is an emerging technology that allows to overcome the issues due to the increasingly widespread use of intermittent renewable energy sources (IRES). Via water electrolysis, power surplus on the electric grid is converted into hydrogen or into synthetic natural gas (SNG) that can be directly injected in the natural gas network for long-term energy storage. The core units of the Power to synthetic natural gas (PtSNG) plant are the electrolyzer and the methanation reactors where the renewable electrolytic hydrogen is converted to synthetic natural gas by adding carbon dioxide. A technical issue of the PtSNG plant is the different dynamics of the electrolysis unit and the methanation unit. The use of a hydrogen storage system can help to decouple these two subsystems and to manage the methanation unit for assuring long operation time and reducing the number of shutdowns. The purpose of this paper is to evaluate the energy storage potential and the technical feasibility of the PtSNG concept to store intermittent renewable sources. Therefore, different plant sizes (1, 3, and 6 MW) have been defined and investigated by varying the ratio between the renewable electric energy sent to the plant and the total electric energy generated by the renewable energy source (RES) facility based on a 12 MW wind farm. The analysis has been carried out by developing a thermochemical and electrochemical model and a dynamic model. The first allows to predict the plant performance in steady state. The second allows to forecast the annual performance and the operation time of the plant by implementing the control strategy of the storage unit. The annual overall efficiencies are in the range of 42–44% low heating value (LHV basis). The plant load factor, i.e., the ratio between the annual chemical energy of the produced SNG and the plant capacity, results equal to 60.0%, 46.5%, and 35.4% for 1, 3, and 6 MW PtSNG sizes, respectively.
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spelling doaj.art-5d726f373cda4d41aa57875b470ed1602023-11-20T22:29:14ZengMDPI AGApplied Sciences2076-34172020-11-011023844310.3390/app10238443SNG Generation via Power to Gas Technology: Plant Design and Annual Performance AssessmentAlessandra Perna0Linda Moretti1Giorgio Ficco2Giuseppe Spazzafumo3Laura Canale4Marco Dell’Isola5Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, 03043 Cassino, ItalyDepartment of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, 03043 Cassino, ItalyDepartment of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, 03043 Cassino, ItalyDepartment of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, 03043 Cassino, ItalyDepartment of Engineering, University of Naples Parthenope, 80143 Napoli, ItalyDepartment of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, 03043 Cassino, ItalyPower to gas (PtG) is an emerging technology that allows to overcome the issues due to the increasingly widespread use of intermittent renewable energy sources (IRES). Via water electrolysis, power surplus on the electric grid is converted into hydrogen or into synthetic natural gas (SNG) that can be directly injected in the natural gas network for long-term energy storage. The core units of the Power to synthetic natural gas (PtSNG) plant are the electrolyzer and the methanation reactors where the renewable electrolytic hydrogen is converted to synthetic natural gas by adding carbon dioxide. A technical issue of the PtSNG plant is the different dynamics of the electrolysis unit and the methanation unit. The use of a hydrogen storage system can help to decouple these two subsystems and to manage the methanation unit for assuring long operation time and reducing the number of shutdowns. The purpose of this paper is to evaluate the energy storage potential and the technical feasibility of the PtSNG concept to store intermittent renewable sources. Therefore, different plant sizes (1, 3, and 6 MW) have been defined and investigated by varying the ratio between the renewable electric energy sent to the plant and the total electric energy generated by the renewable energy source (RES) facility based on a 12 MW wind farm. The analysis has been carried out by developing a thermochemical and electrochemical model and a dynamic model. The first allows to predict the plant performance in steady state. The second allows to forecast the annual performance and the operation time of the plant by implementing the control strategy of the storage unit. The annual overall efficiencies are in the range of 42–44% low heating value (LHV basis). The plant load factor, i.e., the ratio between the annual chemical energy of the produced SNG and the plant capacity, results equal to 60.0%, 46.5%, and 35.4% for 1, 3, and 6 MW PtSNG sizes, respectively.https://www.mdpi.com/2076-3417/10/23/8443intermittent renewable energy sourcesenergy storagepower to gaselectrolysismethanationsynthetic natural gas
spellingShingle Alessandra Perna
Linda Moretti
Giorgio Ficco
Giuseppe Spazzafumo
Laura Canale
Marco Dell’Isola
SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
Applied Sciences
intermittent renewable energy sources
energy storage
power to gas
electrolysis
methanation
synthetic natural gas
title SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
title_full SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
title_fullStr SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
title_full_unstemmed SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
title_short SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
title_sort sng generation via power to gas technology plant design and annual performance assessment
topic intermittent renewable energy sources
energy storage
power to gas
electrolysis
methanation
synthetic natural gas
url https://www.mdpi.com/2076-3417/10/23/8443
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