A Review of Projected Power-to-Gas Deployment Scenarios

Abstract

Technical, economic and environmental assessments of projected power-to-gas (PtG) deployment scenarios at distributed-to national-scale are reviewed, as well as their extensions to nuclear-assisted renewable hydrogen. Their collective research trends, outcomes, challenges and limitations are highlighted, leading to suggested future work areas. These studies have focused on the conversion of excess wind and solar photovoltaic electricity in European-based energy systems using low-temperature electrolysis technologies. Synthetic natural gas, either solely or with hydrogen, has been the most frequent PtG product. However, the spectrum of possible deployment scenarios has been incompletely explored to date, in terms of geographical/sectorial application environment, electricity generation technology, and PtG processes, products and their end-uses to meet a given energy system demand portfolio. Suggested areas of focus include PtG deployment scenarios: (i) incorporating concentrated solar-and/or hybrid renewable generation technologies; (ii) for energy systems facing high cooling and/or water desalination/treatment demands; (iii) employing high-temperature and/or hybrid hydrogen production processes; and (iv) involving PtG material/energy integrations with other installations/sectors. In terms of PtG deployment simulation, suggested areas include the use of dynamic and load/utilization factor-dependent performance characteristics, dynamic commodity prices, more systematic comparisons between power-to-what potential deployment options and between product end-uses, more holistic performance criteria, and formal optimizations.

An Overview of the Portuguese Energy Sector and Perspectives for Power-to-Gas Implementation

“…The CO 2 sources emitting more than 0.1 Mt/year in Portugal (data from 2007) and their geographic situation were identified by Carneiro et al [41] and are illustrated in Figure 12. Figure 12 shows that all the main point sources are located close to the natural gas network, which, in addition to proximity to wind parks, as mentioned in the previous section, surely provides promising opportunities for PtG demonstration activities in the country, since CO2 transport/storage practical difficulties and related cost uncertainties [11] might be avoided/minimized.…”

“…Both interconnections with Spain are fully reversible and a third one in Bragança/Zamora (dashed line in Figure 13) is planned and identified by the European Commission as a project of common interest [24,28]. Figure 12 shows that all the main point sources are located close to the natural gas network, which, in addition to proximity to wind parks, as mentioned in the previous section, surely provides promising opportunities for PtG demonstration activities in the country, since CO 2 transport/storage practical difficulties and related cost uncertainties [11] might be avoided/minimized.…”

“…The current challenges regarding the technologies involved in PtG processes were extensively addressed in recent publications (e.g., [2,9,11,44]), and for that reason were out of the scope of this work, although their study has been the main focus of previous authors (e.g., [45,46]) and future research activities [19]. Instead, the present work aimed to provide a picture of the recent evolution of the Portuguese energy sector, highlighting the tremendous endeavor and commitment of the country for large-scale renewable energy deployment and to raise awareness about what seems to be promising conditions for PtG deployment.…”

“…As renewable power relevance increases within the energy sector, developing a way to efficiently and economically store its surpluses in periods of low demand becomes an urgent problem to be tackled [7]. Among the systems available or under development for such a purpose (pumped hydroelectric storage, compressed air energy storage, electrochemical and flow batteries) [8], power-to-gas technologies (PtG) are receiving increased attention, particularly in Europe [9][10][11], and a storage potential of at least 500 GWh has been foreseen in Portugal [6]. One PtG option could be to 2 of 20 use the surplus electricity for H 2 O electrolysis to obtain H 2 (PtH), but its storage remains a challenge and lacks a dedicated infrastructure for its distribution [2].…”

“…In the review by Quarton and Samsatli [13], these results were updated, with Germany standing out among other countries with 45 projects, either finished, planned, operating, or under construction. The main drivers towards PtG in Germany are the existence of geographic advantages for PtG implementation, like the availability of enough suitable underground gas storage capacity and a sufficient gas network development for gas distribution [11,17], as well as the country targets to increase its power generation with origin in renewable sources from 32% (in 2015) to 50% and 80% in 2030 and 2050, respectively [18]. In Portugal, despite being a pioneering country regarding the adoption and massive diffusion of wind power parks across its territory, the first national research project in the country dedicated to the topic was launched in mid-2018 [19], dealing with the development of a cyclic sorption-reaction process for simultaneous CO 2 capture and conversion to methane to be coupled in PtG applications (cf.…”