Harnessing just 2% of the energy potential from tidal and offshore solar sources could make a significant dent in global CO2 emissions, new research has found.
Researchers at the Universities of Strathclyde and Maine examined more than 660 assessments of offshore renewable energy (ORE) potential in more than 3000 locations worldwide. They found that tidal and solar consistently had more energy to offer than other sources such as wind and wave but were the subject of far less research and, consequently, remained largely untapped.
Offshore solar energy, in particular, was found to be more reliable and less variable than other sources, making it ideal for energy mixes. Despite their lower theoretical potential, wind and wave energy accounted for three-quarters of the assessments examined by the researchers.
Small percentage
The study concluded that even a small percentage of tidal and offshore energy could make a notable contribution to CO2 reduction and to meeting the United Nations’ Sustainable Development Goals (SDGs) on Climate Action and Affordable and Clean Energy.
Assuming global emissions are equivalent to 2019 levels, an additional 2% of combined tidal and solar resources would remove 0.299 gigatons per year. At this rate, net neutral would be reached in 68 years.
The research standardised the energy estimates into the single unit of kilowatts per square metre (kW/m²). It is believed to be the first study to give a comprehensive assessment of global offshore renewable energy sources. It has been published in the journal Renewable and Sustainable Energy Reviews.
Significant opportunities
James Spalding, a PhD student in Strathclyde’s Department of Civil and Environmental Engineering and lead researcher in the project, said: “This is the first time such a broad and interdisciplinary comparison has been possible. By standardising data across resource types and locations, we have identified significant opportunities for clean energy that have so far been overlooked.
“Our research highlights the value of assessing where the greatest resource potential exists, rather than limiting development to what is currently most technologically mature.
ORE potential is estimated to be up to double the global electricity demand. It has also been shown to improve access to clean energy for many nations which have smaller GDP and are dependent on fossil fuel imports for electricity supply.
Projections indicate that the energy sector must reach at least 60% of global energy generated by renewables by 2030, and 80% by 2050, if net-neutral CO2 emissions are to be achieved. However, the global energy supply in 2019 included only 23% renewable energy, with less than 1% coming from ORE sources. More than half of the ocean energy capacity came from projects located in Europe and was produced by offshore wind, tidal current, and wave energy converters.
The researchers assessed data for the study in six global regions, which they defined as: eastern North Atlantic; Mediterranean; eastern North Pacific; coastal Asia; eastern North Atlantic, and southern hemisphere. Six ORE sources were assessed: offshore wind; wave; offshore solar; ocean currents; tidal range and ocean thermal energy conversion (OTEC).