Wastewater to Hydrogen - Enabling A Green Hydrogen Economy
Green hydrogen (H2) production has been labelled too expensive by many in the industry and blame the costs of electrolysers and electrons for pricing H2 out of the energy market. With the majority of projects focusing on the application of H2 for a specific purpose (export, grid support or mobility), we are a long way from the proposed export targets of 'H2 under $2'.
A different way to approach the commercial feasibility of H2 is to apply the 'sector coupling' theory. This theory is based on coupling mature industries and sectors, with innovative models for early market adoption. To apply this theory, you must ask the question, 'what other industries or sectors could benefit from co-locating H2 production on or near their facilities'.
One of the answers to this question is Wastewater Treatment Plants (WWTP). These facilities have access to water, are energy intensive, have risk, safety and governance protocols in place and are managed by governments and/or utility companies that are well practiced in managing all of the required engineering processes. In fact, most governments or utility companies own and/or operate several WWTPs, allowing for scaled production and integration across multiple facilities.
The production of H2 at WWTPs is a relatively easy process that utilises electrolysis. Combining treated water from the WWTP with renewable energy in an Electrolyser produces H2 and also high purity oxygen (O2). In fact, electrolysis produces on average eight times more O2 than H2. The utilisation of O2 is the key to understanding the benefits of 'sector coupling' through the co-location of H2 production at WWTPs.
Almost 100% of current projects utilising electrolysis vent the resultant oxygen into the atmosphere. Commercialising this 'waste' product will allow for an increase in the value chain of electrolysis and a reduction in the cost of producing hydrogen. In fact, some of the initial projects scoped by The Hydrogen Collective have become waste H2 projects with a focus on the benefits provided by electrolytic O2.
WWTPs utilise many different processes to treat wastewater and almost every facility is different. The integration of high purity O2 can provide benefits such as:
Increasing throughput (the rate of flow within the facility)
Reduction in energy consumption
Increasing the process capacity of the facility
A higher quality of treated water
Reduced bio-solids at the end of the process
This method is best used in facilities that rely on aeration processes to treat the wastewater. It is important to note that every WWTP is different and that these opportunities are not a silver bullet solution. There must be rigorous analysis and testing to ensure the feasibility, construct-ability and operational readiness of these integrations.
The Hydrogen Collective's first project to achieve a Financial Investment Decision and progress to construction is Goondiwindi Hydrogen. This project has been established on the basis of the benefits that O2 can provide to a WWTP. Goondiwindi Regional Council needed to increase the capacity of their local WWTP costing up to $20million. The utilisation of electrolytic oxygen will enable Council to reduce, delay or negate the majority of this cost, saving local ratepayers millions of dollars.
The Hydrogen Collective has been engaged by multiple operators to analyse the feasibility of integrating H2 and O2 production at WWTPs. The results to date have been encouraging and have identified potentially significant capital expense savings, operational efficiencies, environmental impacts and local economic growth through developing local H2 supply chains.
With over 1250 WWTPs across Australia, there is a significant opportunity to utilise wastewater networks to develop a Green H2 economy. Utilising sector coupling methodology can also provide commercial, operational, economic and environmental impacts for an industry sector that is both energy intensive and requires significant capital to maintain and upgrade.