Abstract
Harnessing wave energy from the world’s oceans provides an enormous chance to fulfil substantial parts of the energy transition’s demand for electricity from renewable sources. The technology that makes this possible is wave energy converters (WECs) - offshore structures that can convert the energy in waves into electricity. Although the energy conversion of this precommercial technology is not directly linked to greenhouse gas emissions like in other conventional power plants, environmental sustainability over the whole life cycle of the device needs to be ensured for a sustainable large-scale application. To assess this, in recent decades some Life Cycle Assessment (LCA) studies have been carried out on different WECs. However, there is still a gap in terms of number, quality, coverage of more sustainable design alternatives as well as impact assessment beyond greenhouse gas (GHG) emissions. Therefore, in this study a specific type of WEC – the point absorber – is assessed for its environmental sustainability by means of LCA. A parameterized cradle-to-grave LCA model of a single representative point absorber is implemented to assess the environmental impacts of a WEC, the influence of different hull materials, hotspots in impacts of WEC components as well as variations induced by different deployment locations. A GHG-intensity of 300-325gCO2eq./kWh with periphery and 52-77gCO2eq./kWh without periphery is found for a WEC deployed in the Dutch North Sea depending on the hull material. Using an alternative fibre reinforced concrete material for the hull can reduce impacts across all impact categories between 10% and 78%. Next to the structural materials in the WEC the electrical cable and vessel operations, especially for maintenance, were found to contribute significantly. This study showed that impacts of electricity from WECs have to decrease to reach the level of other renewable electricity generation technologies but revealed possible levers to achieve such a reduction.