One of the specific issues that have been analysed within STORE&GO is the expected carbon footprint of synthetic methane (SNG) from the project demo sites. Xun Liao and Victor Godina, both members of Prof. François Maréchal’s research group at the EPFL (École Polytechnique Fédérale de Lausanne), calculated the life cycle carbon footprint of SNG from the STORE&GO demo plants and compared it with the footprint of fossil gas. The calculations take into account the whole PtG process: from plant construction and operation to combustion of the product.
The study shows that the carbon footprint of SNG from PtG has high variability depending on geographical location, system configurations, electricity generation mix and CO2 sourcing. Other influencing factors are opportunities for heat integration and surplus heat valorisation, maturity and efficiency of the technology, and scale of production. For the specific case that the small-scale demo plant in Troia is powered by the regular Italian electricity mix – which includes high-carbon energy sources – the production and combustion of one cubic meter of such SNG generates CO2 emissions of 14.1 kgCO2eq/m3 (blue bar in the graph). If, however, electricity for the Troia plant comes exclusively from the nearby wind and solar installations, the carbon footprint is reduced by 85% to a low number of 2 kgCO2eq/m3 (light green bar). Future large-scale PtG plants will benefit from further optimization measures, such as economies of scale, heat valorisation, improved materials sourcing and improved efficiency of the electrolysis. With these measures, the carbon footprint of future SNG can be reduced even further to only 0.4 kgCO2eq/m3 (dark green bar). For comparison, the production and combustion of one cubic meter of fossil natural gas emits six times more greenhouse gases.
As one of the scientists involved in STORE&GO, Herib Blanco from the Center for Energy and Environmental Sciences at the University of Groningen modelled the
European energy system in the year 2050 using a tool developed at the Joint Research Centre based on cost optimization. Given the large uncertainty on how the future can unfold, an extensive sensitivity analysis was done to cover the wide range of possibilities. The objective was to identify the role PtG can play in the future and to identify the drivers and barriers for the technology. Modelling parameters included CO2 emission target, availability of carbon capture and storage, biomass potential and technology performance, among others.
21 out of the 55 low carbon scenarios show that a synthetic methane capacity within a range from 40 to 200 GW might fit in the future energy systems, which corresponds to 5% and 30% of the future overall gas demand, respectively. This means that there is a multitude of scenarios where PtG can play a crucial role. Therefore, research and development has to be continued so that the technology will be available in coming years to support the transition of the energy system to a world free of fossil carbon.
Among the model parameters that showed a strong impact on the deployment of PtG, these are the main drivers:
- Ambitious (+95%) CO2 reduction targets
- Limited availability of CO2 underground storage
- Limited biomass potential
- High process efficiency and low technology cost
- Use of liquefied methane for navigation and heavy-duty transport
- Costly, difficult or heavily delayed expansion of the electricity grid
An interview with Gijs Kreeft, Faculty of Law, University of Groningen Gijs Kreeft is a researcher within STORE&GO and staff of the Groningen Centre of Energy Law. His research focuses on legal and regulatory developments regarding Power-to-Gas, systems integration, and energy storage. One of the main objectives of the STORE&GO project is to identify legal and regulatory challenges for the deployment of power-to-gas and production of synthetic methane, both at the level of the European Union (EU) as well as at a national level for the host countries of the STORE&GO pilot plants. Studies also focus on legal measures facilitating the injection of synthetic, or substitute, natural gas (SNG) into the gas network. We asked Gijs Kreeft from the RUG University of Groningen about his work, and the challenges and possible solutions he has identified so far.
What are the challenges when it comes to licensing and regulatory regimes?
Kreeft: PtG is associated with various new concepts which are not yet (sufficiently) considered under EU and national legislation. For example, energy storage as an asset, and hydrogen and SNG as renewable energy carriers, have only recently gained attention from legislators. These new technical developments lead to various fundamental legal issues which need to be resolved. For instance, the question whether network system operators or gas storage system operators are allowed to run a PtG facility. Or whether authorisation procedures should consider PtG plants as chemicals-producing installations rather than installations that produce energy commodities. It is also necessary for legislators to define if, and under which circumstances, PtG is a gas producing activity instead of an energy or gas storage technology. Finally, due to the often fragmented and sectoral nature of energy legislation, the technical trend towards the coupling of energy sectors is not reflected in the legal framework.
Why do you think is there so much left open?
Kreeft: PtG is a relatively new technology and is still in the development phase. As is often the case: law follows innovation. Another issue is awareness. As policy-makers do not yet fully comprehend the PtG process and its potential for the transition towards a low-carbon energy system, they tend to adopt a ‘wait and see’ attitude. Consequently, PtG and SNG are not sufficiently considered in renewable energy promotion policies. We observed, for example, that electricity and heat from SNG is generally not considered as ‘renewable’. At a more structural level, policy-makers are still struggling with the question how to integrate technologies which connect energy systems through conversion. This leads to the current situation that in some cases, PtG plant operators and the actual final consumers both pay network tariffs and surcharges, leading to double taxation.
What can politics and lawmakers do to improve the framework?
Kreeft: Most important, we need a structural and fundamental shift in the political mind-set, through which we start to see the energy system not as being fragmented between electricity, gas, and heat, but instead as one single integrated system. The legal field is just starting to adapt to this new way of thinking. At the ‘issue-level’, we identified various issues. Among which are the necessity to develop harmonised rules on guarantees of origin, which take into account the need for seasonal storage, an evaluation of permit procedures, an end to double-taxation practices, and updated support schemes. Another efficient measure could be the introduction of a carbon tax, which should make renewable gases more competitive. Last but not least, R&D has to be further supported to strengthen the advantages of PtG further.