Use renewable energy, CO2 sequestered from air, and H2O to create syn-gas that can be stored or used for heating or electricity generation.
Natural gas is the cleanest burning fossil fuel available; changes to environmental policies and public perception is prompting the gas industry to explore other positions in the energy industry. Renewable technologies are continually growing in efficiency and popularity while decreasing in cost. However, the prompt phasing out of fossil fuel infrastructure will waste millions of dollars of facilities. Instead of immediately focusing on installing new facilities, it is our belief that producing carbon-neutral renewable natural gas (RNG) and using existing infrastructure can be an integral part of the economical carbon-free solution today and in the future.
The production of RNG in this proposed project uses a reversible solid oxide fuel cell (RSOFC) researched by the Birss Group, which can be run as a fuel cell (SOFC) that uses gas to produce electricity, or as an electrolysis cell (SOEC) to use carbon dioxide, water, heat and an energy input (in this case renewable) to produce hydrogen gas and carbon monoxide.
Using methanation, the hydrogen gas and carbon monoxide can be converted to methane gas. This process is exothermic, so there is potential to use the produced heat as partial input for the RSOFC or to increase the reaction rate of methanation. (Helmeth, n.d.)
To ensure RNG production is emission free, the energy used by the RSOFC must be from a carbon-neutral or renewable source (e.g. solar or wind). The heat requirement of the fuel cell can be met by consuming some of the produced RNG. ATCO currently owns salt caverns that utilize a brine pond to cap the cavern. The pond may be used to house floating solar cells that would supply the energy input for the RSOFC. An example of floating solar by Ciel et Terre is provided below:
(Floating Solar UK, 2017)
The produced RNG may be stored using storage facilities (e.g. gas reservoirs or salt caverns) and removed to produce electricity, e.g. when the demand cannot be met by renewable energy.
What are the key outcomes and impact of your solution?
The key outcomes of our solution include:
Greening the energy grid. Since the solid oxide electrolysis cell (SOEC) uses carbon dioxide from the atmosphere, water, and energy from renewable sources, the produced RNG is carbon-neutral. As such, any carbon produced when the RNG is used (either for heating through direct combustion, or energy generation through the SOFC) is net-zero. If refined and injected into the existing natural gas system, this will provide a carbon-reduced or carbon-neutral heating alternative to consumers. During periods where renewable energy sources are not available, the green electricity produced by the SOFC can be used to reduce dependency on conventional electricity generation.
Introducing a cost-effective and widely available method to transport and store carbon-free renewable energy. Conventional renewable energy storage often has limitations. For example, hydroelectric dams are geographically dependent, and battery banks have limited storage capacity and duration. Moreover, the construction of such equipment and infrastructure may be carbon-intensive or costly. By converting renewable energy into RNG, our solution allows carbon-free energy to be transported and stored using existing infrastructure, which reduces the costs to end users.
What actions do you propose to realize your stated goals?
Our solution requires two main actions: testing and implementation.
FuelCell Energy has worked with Versa Power Systems to evaluate the RSOFC. However, large-scale RSOFC have not been produced yet (FuelCell Energy, 2013). As such, the first step would be for ATCO to partner with the Birss Group to research and develop the scale and applicability of the RSOFC technology to meet the RNG production and electrical generation goals.
Using the existing technology, ATCO would pilot a small-scale RSOFC to produce RNG that would be injected and stored in an existing salt cavern. The RNG held in a storage facility would then be withdrawn and transported to the SOFC to produce electricity. It will be imperative to identify the feasible scale of electricity production to determine whether energy should be consumed on-site use or exported to the grid. Depending on the production of electricity, the possibility of constructing a power substation and connecting to the electrical grid directly at the storage location could be explored.
Once it has been tested, our solution can be taken to and implemented in any areas that have existing natural gas facilities and storage. One of the key benefits to our solution is that no new facilities are required, so adopting the solution is limited to the installation of the RSOFC.
Implementation also requires working with the appropriate regulating bodies. Parties interested in blending RNG should identify and maintain gas quality requirements for injecting RNG into the natural gas stream.
Who will take these actions?
ATCO will reach out and work with potential partners to identify grants and resources to facilitate the research and commercialization of the RSOFC. Potential partners include (but are not limited to): University of Calgary, the Government of Alberta, the Government of Canada, the Canadian Gas Association, Sustainable Development Technology Canada, Gas Technology Institute, and Natural Resources Canada. ATCO will also partner with the Birss Group to research and pilot large-scale RSOFC.
ATCO currently has approximately 40,000km of natural gas pipelines and salt cavern storage facilities that would be ideal for piloting the process. A location would be identified to set up the RSOFC and tie-in to an existing gas distribution system. New pipelines may be required to connect the RSOFC to a salt cavern. ATCO would also arrange to have the RSOFC connected to an electrical distribution system that has a renewable energy input (for example, solar) and a consumer output.
We suggest that the implementation of our solution begin in North America. As of 2010, there are more than 400 storage sites for natural gas in the United States alone.
The diverse geography of North America allows for multiple renewable energy sources such as wind, hydro, solar, and tidal to be tested in conjunction with the RSOFC.
Once the RNG production, storage, and consumption is optimized, the solution can be implemented globally wherever sufficient natural gas facilities and/or storage is located. Even without storage, injection of carbon-free RNG into existing natural gas systems will reduce the overall carbon footprint of the fuel. Since natural gas is currently being used in North America, South America, Europe, Asia, Australia and parts of Africa, there are almost no limits to the potential geographic application of carbon-free RNG.
What do you expect are the costs associated with piloting and implementing the solution, and what is your business model?
One of the primary costs of the pilot entails the research and development of a scalable RSOFC. The first milestone of our solution is to pilot the RSOFC on a small scale. Further analysis would then be required to identify the costs associated with implementation. These costs would be dependent on site-specific factors such as location. Setting up a renewable energy source, such as a wind farm or solar farm, will have an initial capital investment. Additional costs will be incurred to install or upgrade natural gas pipelines in the area, especially to connect to storage facilities. However, once all capital investments have been made, the electricity produced may be sold back to the grid.
The RNG created by the RSOFC would fall under ATCOs regulated business. Since the consumers’ demand is not affected by the gas source, the same amount of gas would pass through the distribution infrastructure. However, the amount of gas to be contracted with a transmission company would be reduced, potentially resulting in higher net earnings for the regulated distribution business. The electricity produced would be sold back to the electrical grid, offsetting the emissions footprint of electric generation while rendering earnings.
ATCO will partner with the Birss Group to research and develop a product for piloting. A smaller-scale RSOFC would be used until a scalable unit is available. Testing and analysis of the efficiency and output of the fuel cell would be completed by 2019. The produced RNG would be injected into ATCO’s existing salt caverns. Since ATCO currently monitors the quality of natural gas, the sampling would be conducted at regular intervals starting immediately.
If the source of renewable energy is consistent, the RSOFC may spend the majority of its operation creating RNG in electrolysis mode. As such, meeting the electrical demand with the fuel cell will not be possible unless a second fuel cell or similar unit is operational. ATCO has been piloting the use of combined heat and power (CHP) units that consume natural gas to produce both electricity and heat that can be used on site (resulting in a higher overall efficiency of the fuel combustion). Using the same premise as the SOFC, the CHP unit will consume the RNG, resulting in a carbon-neutral combustion.
Birss, V. (2016). Birss Group Research: Solid Oxide Fuel/Electrolysis Cell. Retrieved from http://vbirss.wixsite.com/birssgroup/sofc-soec
U.S. Energy Information Administration (EIA) (n.d.). U.S. Lower 48 Underground Natural Gas Storage Facilities, by Type (December 31, 2010). Retrieved from https://www.eia.gov/cfapps/ngqs/images/storage_2010.png
Floating Solar UK (2017). Floating Solar Panels. Retrieved from http://www.floatingsolarpanels.co.uk/
FuelCell Energy (2013). Advanced Technologies: Solid Oxide Fuel Cells. Retrieved from http://www.fuelcellenergy.com/advanced-technologies/solid-oxide-fuel-cells/
Helmeth (n.d.). Methanation Process. Retrieved from http://www.helmeth.eu/index.php/technologies/methanation-process
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