Small Island Developing States (SIDS) rely heavily on non-renewable energy sources. With the energy transition taking place, how can these rather vulnerable island states participate in it too? Researchers of the University of Twente provide a new process design for sustainable energy generation that outcompetes fossil fuels for Small Island Developing States (SIDS) using green ammonia.
Building resilience in our energy system is a fundamental challenge as we shift away from a fossil-based economy, especially under changing and uncertain climate conditions. The situation is exacerbated in extremely vulnerable regions, such as Small Island Developing States (SIDS). The United Nations classifies 38 islands in the Caribbean, the Pacific, the Atlantic, the Indian Ocean and the South China Sea as SIDS that face unique social, economic, and environmental vulnerabilities.
Here, generating electricity relies heavily on non-renewable feedstocks (e.g. coal-, diesel-, and natural gas-fired power plants). In addition, the limited fossil-based resources and restricted economies of scale increase production costs and CO2-footprint of energy in SIDS. For these reasons, it is not surprising that electricity costs in SIDS, such as Curaçao, are among the highest in the world. More recently, the onset of the COVID-19 crisis exposed this fundamental vulnerability in many Caribbean Island states and island territories.
This vulnerability is not new, but the explosive growth of the tourism industry has made this a growing issue. Building true resilience in the Caribbean Island states and more broadly in SIDS can only come from the systematic development of robust and sustainable supply chains. While all these islands have drafted national plans to achieve the United Nations Sustainable Development Goals (UN-SDG) and are part of the SIDS Accelerated Modalities of Action (SAMOA) pathway, the large investments and complex technologies required for transforming the islands into self-sustained regions greatly hinder the implementation pace. Clearly, cost-effective and down-scalable technologies that can empower SIDS are needed for the sustainable production of energy, as outlined in the UN-SDG and SAMOA plans.
Water electrolysis powered by renewable electricity will be key to unleashing the true potential of renewable energies as it allows seasonal energy storage, which in combination with batteries, for daily operation, can allow 24/7 on-demand electricity generation. Unfortunately, hydrogen storage and transportation are costly and complex. Luckily, storing hydrogen in the form of ammonia can solve these issues as it is cheap, scalable, and safe to store, transport, and use.
Ammonia (NH3) is considered the only carbon-free hydrogen storage material that allows low-cost and long-term energy storage and transportability of hydrogen. The problem with the current Haber-Bosch (HB) ammonia synthesis process is its poor down-scalability (i.e. relative cost increases as scales decrease). For this reason, new small-scale power-to-ammonia-to-power (P2A2P) concepts must be developed to enable the energy transition in SIDS.
To tackle this challenge, MSc student Victor Sagel developed in collaboration with PhD student Ir. Kevin H. R. Rouwenhorst a new process that combines wind-generated electricity with batteries for short term operation and small-scale Absorption Enhanced Haber Bosch (AEHB) for seasonal energy storage in Curaçao. A similar concept was previously introduced by Ir. Kevin H. R. Rouwenhorst for the municipality of Haaksbergen, under the guidance of Dr. Ir. A. G. J. Van der Ham, Prof. Dr. S. R. A. Kersten, and Prof. Dr. Ir. G. Mul within the Sustainable Process Technology group.
Building upon these results the concept was expanded to on-demand electricity for the islanded community of Curaçao over the entire year (see Fig. 1). In the months with excess wind electricity generation (Fig. 1a) the energy is stored in the form of ammonia, which is then consumed during the months with deficient renewable energy production (Fig. 1b). To stabilize the P2A2P process for daily fluctuations, short term energy storage is also in place (<1 day). For this task, conventional batteries are suitable. Battery storage is a better option for small, short term storage as the round trip efficiency of batteries (ca. 85%) is significantly higher than that of chemical storage in the form of hydrogen gas or ammonia (25–40%).
Dr. J. A Faria (Jimmy), the senior author of the research and Tenure-track assistant professor in the Catalytic Processes and Materials group, explains: “The wind in Curaçao is formidable for renewables. Unfortunately, generation and demand are out of phase as the months with the highest demand for electricity are those with the lowest wind speeds and poorest consistency. That is why green ammonia is a key ingredient in the energy transition on this island.”
Fig. 1. Operation modes of islanded green ammonia powered system.
Countries like Japan, Germany, The Netherlands, and the UK have already drafted clear plans to use “green” ammonia as zero-carbon fuel and hydrogen carrier in the next ten years. These new projects will expand the annual production of ammonia beyond the current 183 million tons per year, which are primarily employed in the production of fertilizers. Extrapolating this to SIDS with large potential for renewables (wind and solar) could transform these islands from energy importers to self-sustained or even net energy exporters. Further research on piloting these concepts in SIDS is essential to demonstrate their practical value.