The utilisation of natural gas is very important within the European energy system. Intensive activities concerning the substitution of natural gas with synthetic natural gas, respectively biomethane are currently ongoing based on the objectives in the contexts of climate protection and diversification of supply sources. Therefore, a number of concepts are available. Here, the production of biomethane via thermo-chemical conversion of solid biofuels - Bio-SNG - is a favourable addition to the provision of biomethane from bio-chemical conversion routes (biogas). Technologies for the feed-in, the distribution as well as the utilisation of biomethane are market- ready and applied commercially.
The biogas production technology based on anaerobic digestion, wet fermentation of biomass residues (and wastes) as well as from energy crops (e.g. maize silage) is mature. The conversion of biomass into Bio-SNG is not that far developed yet. Currently, biomass gasification based on steam for the production of heat and electricity is successfully demonstrated and market-ready. The European project 'Demonstration of the production and utilisation of synthetic natural gas' started in May 2006 against the background of the required subsequent methanation that was implemented in a pilot stage with a few kW thermal capacity.
The objective of the 'Bio-SNG' project was to demonstrate the SNG production from woody biomass in the 1 MW-range using steam gasification, advanced gas cleaning, methanation and gas upgrading as a part of an innovative 8 MW biomass CHP gasification plant and to integrate this Bio-SNG into the existing energy infrastructure (i.e. fuel station for vehicles). To meet the specifications required for the gas utilisation in vehicles or the gas-feeding into an existing natural gas grid, the produced SNG has to be upgraded.
Cars were refuelled with this upgraded renewable gaseous fuel. These cars currently operate for the purpose of demonstrating the application of Bio-SNG within the transportation sector.
The project assessed the overall provision chain of SNG starting with the biomass supply and ending with the utilisation of biomethane, including (i) technical (e.g. overall efficiencies), (ii) economic (e.g. cost efficiency) and (iii) environmental aspects (e.g. overall primary energy demand, GHG emissions).
Furthermore, effects of the commercial implementation of Bio-SNG into the energy system were examined and can be directly compared with other options (e.g. FT, DME) in order to provide transportation fuel from biomass. Additionally, it is a goal of the project to optimise the entire process chains from the wood up to the running car with the overall goal to develop a market-ready technology. Therefore, the technological readiness of the methanation of syngas and the utilisation of the produced biomethane within the transportation sector should be demonstrated. Finally, the chances and limitations of the Bio-SNG technology within the current and future European energy system should be assessed.
To meet the specifications required for gas-utilisation in vehicles or gas-feeding into an existing natural gas grid the SNG that is produced was upgraded. Cars were operated with this upgraded renewable gaseous fuel to demonstrate the powerful application within the transportation sector. This overall system of SNG production and use options was assessed comprehensively according to:
- economical, and
- environmental aspects, as well as possible contributions within the European energy system.
The effects of the commercial implementation of SNG into the energy system were examined and compared with other options to produce transportation fuel from biomass. The possibility of heat and power production from solid biofuels were also be taken into account within this overall assessment, for example by taking into consideration economic advantages beyond the pure fuel production for transport issues.
The project work was divided into ten Work Packages:
- WP 1 – Coordination
- WP 2 – Biomass provision
- WP 3 – Detailed engineering
- WP 4 – Construction and commissioning
- WP 5 – Gasification and gas cleaning
- WP 6 – Methanation and gas upgrading
- WP 7 – Demonstration and monitoring
- WP 8 – Demonstration and SNG in vehicles
- WP 9 – Technical, economic and environmental analysis
- WP 10 – Process simulation
Results presented per WP:
- WP 1 - Coordination activities: Communication with EC; Financial management and project administration; Management between work packages and sub-contractors;
- WP 2 - Biomass provision: Biomass potential and provision concepts in the region of Güssing;
- WP 3 - Detailed engineering: The detailed engineering was performed for the methanation plant;
- WP 4 - Construction and commissioning: The delivery, construction and commissioning of the Bio-SNG plant is carried out and cold start of the plant took place;
- WP 5 - Research on gasification and gas cleaning: Optimisation of the allothermal steam biomass gasification and producer gas cleaning;
- WP 6 - Research on methanation process and gas upgrading: Design of the methanation process and optimisation of the catalyst;
- WP 9 Technical, economic and environmental analysis: Technical analysis of the entire biomethane provision chain carried out;
- WP 7 and 8 - Demonstration activities: Organisation of conferences and seminars; Pilot and Demonstration plant in Güssing; project web site launched;
- WP 10 - Process simulation: A number of conversion plant sizes and modifications simulated.
Overall process chain
It has been demonstrated, that the entire process chain (wood to Bio-SNG) is feasible and fulfils the expectations in terms of efficiency. Such technology can be applied in the energy industry for the production of sustainable fuel as a replacement of fossil fuel. The interested potential user of such technology is the energy sector, particularly the natural gas industry (distributors). Since the EU decided to replace fossil fuels partially, this technology can fill part of the gap. The technology is not yet fully mature, but a first small industrial scale project will allow the technology to achieve maturity. Such a project is being planned. The project was started upon a granted base patent which has been extended. Patent rights have not yet been granted.
In order to run the catalyst of the process, the synthesis gas needs to be purified from sulphur to a very large extent. A process stage has been developed in order to remove sulphur containing tars to an extent not yet known using biogenic solvents which can be regenerated. Such a process cannot