As the world transitions to a low-carbon economy, Small Island Developing States (SIDS) face unique challenges in adopting renewable energy solutions. Often located in remote, tropical regions, these islands are particularly vulnerable to the impacts of climate change, such as rising sea levels and extreme weather events. At the same time, they are heavily reliant on imported fossil fuels for their energy needs, resulting in high electricity costs and increased susceptibility to global energy price fluctuations. This combination of challenges has created a pressing need for SIDS to develop sustainable energy solutions that are both reliable and affordable. One such technology that holds immense potential for SIDS is Ocean Thermal Energy Conversion (OTEC).
OTEC is a renewable energy technology that leverages the temperature difference between warm surface seawater and cold deep seawater to generate electricity. The technology can provide a continuous source of baseload power, unlike intermittent renewable energy sources like solar and wind. During the Virtual Island Summit 2024, organised by Island Innovation, a session sponsored by PLOTEC brought together industry experts and stakeholders to discuss the opportunities and challenges of implementing this technology in SIDS.Â
The Potential of OTEC for SIDS
OTEC has the potential to transform the energy landscape of SIDS by offering a stable, continuous, and renewable energy source. According to the speakers at the VIS 2024 session, one of the key advantages of OTEC is its ability to provide baseload power. Unlike solar and wind energy, which are dependent on weather conditions, OTEC can generate electricity 24/7, making it a more reliable option for islands that are prone to extreme weather events.
OTEC is a particularly attractive solution for islands where land scarcity is a major challenge. Solar and wind farms require large areas of land, which can be difficult to allocate on small islands where space is limited. In contrast, OTEC plants can be located offshore, preserving valuable land for other uses.
Additionally, OTEC offers several co-benefits. For example, the cold deep seawater used in the OTEC process can also be utilised for air conditioning and desalination, providing islands with freshwater and cooling solutions in addition to electricity. These additional applications of OTEC technology could help address some of the other pressing challenges faced by SIDS, such as water scarcity and the high cost of cooling systems.
Challenges to Implementing OTEC in SIDS
While OTEC holds great promise for SIDS, several significant challenges must be overcome before it can be widely adopted. One of the most pressing issues is the high upfront cost of developing OTEC plants. As noted by several speakers during the session, OTEC projects require significant capital investment, which can be a major barrier for small island nations with limited financial resources. High investment costs are exacerbated by the relatively nascent stage of OTEC technology, which has yet to be proven on a large scale.
Sam Johnston, lead engineer at Global OTEC Resources, provided technical insight into the complexities of building OTEC plants. He explained the differences between the open cycle and closed cycle OTEC systems, with the latter being more viable for SIDS. The closed cycle system uses warm surface seawater to boil a working fluid, typically ammonia, which then drives a turbine to generate electricity. The working fluid is then condensed back into a liquid using cold deep seawater. Johnston pointed out that while open cycle OTEC has the potential to release absorbed CO2 into the atmosphere, closed cycle OTEC offers a more environmentally friendly alternative. However, the engineering challenges involved in constructing these systems, particularly in remote and storm-prone locations, add to the complexity and cost.
In addition to financial and technical challenges, SIDS also face regulatory hurdles and limited access to finance. Charlin Bodley, Associate Director at the Bezos Earth Fund, emphasised the importance of developing innovative business models to make OTEC economically viable for SIDS. She called for partnerships between the private sector, governments, and international organisations to create financing mechanisms that can reduce the financial risks associated with OTEC projects.
The PLOTEC Project: A Proof of Concept
The PLOTEC project is an exciting and innovative European-funded initiative aiming to demonstrate novel designs and materials for OTEC platforms capable of withstanding the harsh realities of tropical oceans.
A key challenge is designing an OTEC system that includes a long riser pipe reaching sea depths, which must endure significant tension and environmental stressors. The project’s ultimate goal is to design, model, and install a demonstration of a novel cylindrical OTEC platform in Canary Islands. The design is focused on maintaining durability against tropical ocean conditions, all while adhering to an economically viable cost model. A key target is to achieve efficiency gains that reduce the Levelised Cost of Energy (LCOE) below the market rate for diesel, making OTEC a competitive alternative.
PLOTEC merges technical advancements in marine engineering, material science, and computational modeling, leading to lower capital expenditures (CAPEX) for offshore OTEC. These innovations are also transferable to other renewable energy projects and marine engineering applications.
Building a Robust Ecosystem for OTEC
Throughout the session, several speakers emphasised the importance of building a robust ecosystem to support the development and deployment of OTEC technology. This ecosystem would need to include not only technical and financial support but also partnerships with local institutions, governments, and communities.
Paula Bastos, Economic and Environmental Impacts Researcher at WAVEC, highlighted the importance of integrating OTEC with other sectors of the economy, such as tourism and fisheries. She suggested that spin-off business models, such as those that connect the green and blue economies, could help make OTEC projects more economically viable. For example, OTEC plants could be used to power desalination facilities that provide freshwater for island communities, or to support aquaculture projects that boost local food production.
Another critical component of the OTEC ecosystem is environmental sustainability. It is critical to consider the environmental impacts of OTEC projects, particularly in relation to marine biodiversity. Speakers emphasised the importance of developing environmental monitoring plans to address potential conflicts with other marine industries, such as fisheries and tourism.Â
The Role of Philanthropy and International Support
Given the high upfront costs and financial risks associated with OTEC, philanthropic organisations and international donors have a crucial role to play in supporting the development of this technology in SIDS. Charlin Bodley shared her experience working with the Bezos Earth Fund and discussed the role of philanthropy in funding OTEC projects.
She pointed out that while OTEC is still a relatively new technology, it has the potential to attract significant investment if it can demonstrate success at a small scale. The PLOTEC project, for example, could serve as a proof of concept that encourages further investment in OTEC. Charlin also emphasised the importance of aligning OTEC projects with broader goals related to climate resilience and sustainable development, as this can make them more attractive to philanthropic donors and international organisations.
The Future of OTEC in SIDS
This session provided a comprehensive overview of the opportunities and challenges associated with this promising technology. OTEC has the potential to provide SIDS with a reliable, continuous source of renewable energy that can reduce their dependence on imported fossil fuels and enhance their resilience to climate change. However, significant challenges remain, particularly regarding high upfront costs, technical complexity, and regulatory hurdles.
The PLOTEC project represents an important step forward in demonstrating the feasibility of OTEC for SIDS, and if successful, it could serve as a model for other islands looking to adopt this technology. Moving forward, it will be essential to build a robust ecosystem that includes technical support, innovative financing models, and environmental safeguards to ensure that OTEC can be successfully implemented in SIDS.
As the world continues to grapple with the impacts of climate change, the developing renewable energy solutions like OTEC will be critical to ensuring a sustainable and resilient future for island communities. The discussions at the Virtual Island Summit 2024 highlighted the immense potential of OTEC and offered valuable insights into how this technology can be harnessed to meet the unique energy needs of SIDS. With sustained innovation, collaboration, and international support, OTEC could become a cornerstone in the energy transition for islands worldwide.
