At Cape Horn Engineering we pride ourselves on our regular benchmarking that adds confidence to our CFD simulation. The comparison of the Spiralis Energy Axial Skelter test rig was our second in the field of tidal energy, and like the first, we have matched the experimental data within a very tight tolerance.

After almost a year of continued collaboration between Cape Horn Engineering and tidal energy developer, Spiralis Energy, we are proud to present the first validation results of our CFD analysis with a 6-meter 1/4 scale test rig deployed at Poole Harbour, UK, in real-world conditions.

Our CFD programme matched the peak power production that the skelter produced on the test day in Poole Harbour. “At the rotation rate of 21 RPM the test rig produces 2.50kW, and we predicted 2.59kW. If we take into account the test rig friction the values are with 1.5% of each other, a very close match indeed. With this validation step completed we can have even more confidence in our prediction that the full size unit will break the 250kW threshold” commented Dr Rodrigo Azcueta, Managing Director at Cape Horn Engineering.

This is a very valuable first step towards our ambitious plans of deploying full-scale axial tidal energy converters that could revolutionise the renewable energy landscape. We are currently working on a 16m length by 5m diameter “Skelter” to be tested over the harsh winter conditions. Our simulations are key to understanding the loads on the structures and optimising the hydrodynamic shape of the Skelter for maximum performance.

Spiralis Energy aims to power up 11% of the national grid using its tidal energy technology. “The UK has the best tidal knowledge in the world. Our technology can deliver a renewable energy source that doesn’t harm sea life and sits within the circular economy framework,” said Chief Executive of Spiralis Energy, Guy Levene OBE Levene OBE.

“What makes Spiralis easy-to-scale is that our units have a modular design to enable them to fit into a standard shipping container for affordable transportation anywhere in the world. It’s really quite straightforward – we’re offering a simple, more affordable, more reliable and sustainable energy solution; our technology simply works.”

Spiralis is to test two of its Axial Skelter power-generating screws in the waters off Alderney in the Channel Islands. With some of the strongest tidal currents in Europe, and thanks to its unique seabed ownership, Alderney supports project development.

The CFD simulations were processed on a High-Performance Computing (HPC) cluster using the best-in-class software package Simcenter STAR-CCM+ in the latest version from Siemens Digital Industries.

Spiralis Energy – Axial Skelter

The ocean covers over 70% of the planet and is full of energy. Every day, all over the world, tides create constant motion in the ocean. Water flows back and forth from one area to another. If harnessed, this renewable energy source would meet much of the global electricity demand and move us closer to net zero.

Spiralis Energy are delivering solutions to make it happen. . Their innovative technology will capture these reliable tidal currents to generate clean, sustainable energy.

Inspired by the marine life that has thrived in the ocean far longer than we have, the Axial Skelter is shaped like a Turritella seashell – just much larger, but as resilient and durable. Rotating in the water, the Axial Skelter will harness tidal flows to generate a steady, reliable stream of energy day in, day out. It is designed to adapt to the tough, sometimes brutal ocean environment, with only one moving part and is made from fully recyclable, 3D printed segments.

Gentle on Marine Life

The Axial Skelter has a minimal impact on the marine environment with no sharp edges, no fast-moving parts, and no disturbance of the bottom habitat.

A bold goal for the future

The Axial Skelter has already proven it can harness tides for electricity. Spiral Energy are raising funds to build a larger 500kW system and test it further. By 2025, they plan to deploy an initial array in the UK, aiming to secure a 15-year National Grid contract, and start generating clean energy by 2028. Their bold goal for the future is to achieve 50 GW of ocean energy capacity by 2040.