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Project Description
Coastal areas are home to a significant portion of the world's population, including many large cities. Climate change-induced disasters pose a substantial threat to coastal communities globally. Hybrid solutions, integrating hard engineering structures with Natural-based Solutions (NbS), have been proposed for coastal protection and adaptation. However, the maintenance costs of these structures could become prohibitively high under future climate change scenarios, requiring frequent upgrades and repairs. This project aims to explore the feasibility of innovatively combining NbS with more adaptable solutions to enhance coastal resilience against climate change.
So far, the research has included:
Enhancing Coastal Resilience and Regeneration by Combining Ocean Energy Extraction and Nature-Based Solutions (In preparation)
1. Enhancing Coastal Resilience and Regeneration by Combining Ocean Energy Extraction and Nature-Based Solutions (In preparation)
Introduction
Climate change-induced disasters, such as sea-level rise, increased climate variability, and more frequent and intense floods and storms, pose a substantial threat to coastal communities globally. It is estimated that both the magnitude and frequency of these events will continue to increase. This underscores the urgent need for effective coastal defense strategies to keep pace with accelerated climate change.
Traditional approaches to coastal defense primarily rely on hard engineering measures such as breakwaters, dikes, dams, groins, and levees. However, the maintenance costs of these structures can be extremely high under future climate change scenarios, given the need for continuous upgrades and repairs.
Coastal defense options that incorporate natural components, known as "Nature-based solutions" (NbS), have garnered attention as more sustainable and cost-effective measures compared to conventional hard engineering. However, NbS can be less effective in high-energy environments and during extreme events, which may lead to a reliance on traditional hard engineering approaches for coastal defense. While hybrid solutions, which combine hard engineering structures and NbS (e.g., breakwaters in front of saltmarshes or mangroves), have been proposed for coastal protection and adaptation1, a critical question remains: Why are we not reducing the energy by extracting the portion of energy that necessitates the use of hard engineering structures alongside NbS? This approach could potentially mitigate the need for extensive hard infrastructure and enhance the effectiveness of NbS. Not only would this approach improve coastal resilience, but it could also make wave energy devices more economically viable by addressing other challenges in coastal areas. Additionally, it would reduce adaptation costs under future climate change scenarios by minimizing the need for continuous upgrades. This makes the adaptation strategy highly regenerative, as it involves simply deploying more energy devices or adjusting their locations and combinations.
How should we deploy renewable energy devices for optimal coastal protection?
Despite oceans covering 70% of the Earth’s surface and wave energy being abundant day and night, regardless of weather conditions, there are currently no commercial wave farms due to their expense and technical complexity. However, efforts to make wave energy more commercially viable have never ceased. The latest attempt is by Carnegie Wave Energy of North Fremantle, which aims to be operational by June. Additionally, companies are testing various designs to capture energy from tides and waves (see ‘Water works’)2.
In this scenario, our primary focus should be on developing the most efficient energy conversion devices to harness energy from coastal threats in the upcoming years. It is essential to determine the maximum energy that can be extracted without compromising the effectiveness of natural coastal defenses.
Once the energy difference between input and allowable energy is established, optimization of these devices requires consideration of various parameters. This includes the types of devices, their quantity, optimal configurations, locations, and management strategies. Moreover, anticipating climate change conditions is crucial for maximizing energy absorption, along with the potential for adaptation.
What are the most effective vegetation/planting strategies for coastal resilience?
Optimum NbS approaches to coastal defense and ,adaptation depend on local, context-specific factors.However, due to the interaction between these NbS approaches and our wave energy or other devices, as well as their future climate change adaptation, these interactions should be considered in our planning.
However, robust local comparisons of the performance of different NbS for coastal defense and climate change adaptation (and their interaction factors) are particularly needed. Such comparative knowledge can inform decision-making on how to deploy renewable energy devices. These comparisons can include topics such as the energy limits that these NbS can withstand, their positive effects on biodiversity, and their contributions to sustainable physical geography.
For example, recently researcher compared the performances NbS for coastal defense across different functions of risk reduction, climate change mitigation, and cost-effectiveness by using Meta-analysis which is a statistical technique that combines the results of multiple scientific studies to derive a more comprehensive understanding of a particular research question or topic. By aggregating data from various independent studies, meta-analysis aims to identify patterns, discrepancies, and overall effects that may not be apparent in individual studies3.
Credit: Claire Welsh
How to make plans adaptable and protect NbS against the impacts of climate change?
The integration of renewable energy devices and NbS into coastal resiliency enhances adaptation to climate change, making it feasible to address a wide range of changes we may face. Naturally, as we use renewable energy devices, the demand for absorbing more energy from the environment increases due to climate change. By adding more devices, we can absorb more energy, thus preventing the energy limit of the solution used in the area from being exceeded. This advantage is not present in current methods, despite being vital and significantly reducing the costs of adapting to climate change.
An interesting point is that devices powered by wave energy are mostly portable, allowing them to be moved to other environments if the need in the original environment decreases. This flexibility enables us to address increased demand in other areas affected by climate change, helping to mitigate uncertainties in our climate change predictions.
Moreover, this high update capability gives us the freedom to periodically adapt to climate changes, allowing us to take advantage of higher-performance and cheaper devices that will be developed in the future. An example of this is Zhong Lin Wang's proposal for a radically different way to harvest renewable energy from the ocean using floating nets of nanogenerators (see ‘Blue-energy dream’)4. Power is generated based on the speed at which the nanogenerator moves with the waves, regardless of direction. Multiple devices can be linked with conducting cables to generate more power, making this a promising candidate for integrating with combined wave energy devices and NbS.
Credit: Claire Welsh
1. Sutton-Grier, A. E., Wowk, K. & Bamford, H. Future of our coasts: The potential for natural and hybrid infrastructure to enhance the resilience of our coastal communities, economies and ecosystems. Environ Sci Policy 51, 137–148 (2015).
2. Tollefson, J. Power from the oceans: Blue energy. Nature 508, 302–304 (2014).
3. Huynh, L. T. M. et al. Meta-analysis indicates better climate adaptation and mitigation performance of hybrid engineering-natural coastal defence measures. Nat Commun 15, (2024).
4. Wang, Z. L. Catch wave power in floating nets. Nature 542, 159–160 (2017).
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