Renewable energy allows electricity generation with lower environmental and resource impact than generation from fossil fuels. However, the manufacture, use and ultimate disposal of the equipment used to capture renewable energy has an environmental impact. This impact should be minimised. Most tidal turbine blades are currently manufactured from glass or carbon fibre reinforced polymers. Such blades cannot be recycled at the end of their life, and are disposed of in landfill or by incineration. As the tidal energy industry grows, the volume of non-recyclable waste is a potential problem. Here we consider the environmental impact of ten combinations of material and disposal method for tidal stream turbine blades, including recyclable options. Our findings suggest that:
• Glass fibre blades have greenhouse gas emissions of around 15,500 kgCO2e for the scope considered, and a significant environmental impact in all impact categories.
• Steel blades are heavy and have greater material and manufacturing greenhouse gas emissions than glass f ibre blades, but these are partly offset by recycling.
• Carbon fibre blades have the greatest impact of the cases considered in greenhouse gas, human toxicity, and marine toxicity. The impact is particularly large when disposed of in landfill.
• Composite materials using flax fibre and recyclable resin may have lower impact (26% lower greenhouse gas emissions than glass fibre), provided they are treated correctly after use. These materials may also offer the potential for lower cost blades in future.