Throughout the 2000s, the emerging wave and tidal stream energy industries operated as a unit. Together they embarked on the journey across the "valley of death" towards commercial maturity, facing shared challenges - such as grid connection, permitting and securing R&D support.
These are heady times for tidal energy, says Matthew Reed, engineering director at Marine Current Turbines (MCT). "It's all kicking off now," he said in an interview at RenewableUK's Wave & Tidal 2013 event in mid-March. "There's a sense of excitement."
As global energy demand continues to increase, renewables are clearly becoming a much more important part of the energy mix. Of the various renewable energy options, marine energy (wave and tidal) is particularly interesting as it is relatively new but offers significant opportunities for growth. Vast resources are being spent to design and build marine energy systems that are scalable and provide energy at a reasonable cost, and significant testing is now underway.
Growing global interest in harvesting the sea's vast generation potential is now focused on the UK, where a series of initiatives such as the new Marine Energy Parks are aimed at maintaining the country's technological lead.
If you're overlooking an estuary, you'd never guess that vast amounts of energy are flowing into the sea. But what if you place a thin and strong membrane between the fresh and brackish water? Then it might be possible to tap so much energy that tens of thousands of households could be provided with electricity. At least, that is the goal of Dutch and Norwegian researchers, as they seek to make osmotic power commercially viable.
Aquamarine Power Oyster, Aquamarine's wave energy device is designed to capture energy from near-shore waves. The system consists of a simple oscillating wave surge 'paddle' fitted with double acting pistons, deployed in depths of 8–16 metres. Each passing wave activates the pump which delivers high pressure water via a sub-sea pipeline to the shore. Onshore, the high-pressure water generates power using conventional Pelton wheel-type hydroelectric generators.
As any engineer will tell you, developing the engineering concepts for a novel energy production device is an iterative process. For ocean energy, this process is further complicated as any device destined to generate electricity from the marine environment must be sufficiently robust to survive the extremely harsh conditions, all the while maintaining complex operations at sea.
Like many of the current crop of ‘cutting edge’ renewable energy technologies, the concept of extracting energy from waves and tides is not a new one. Indeed, it is well over 100 years since the first tidal wheel was built and the 240 MW La Rance tidal barrage project in Brittany, France, has been operating for well over 40 years. What has changed over the intervening years is the level of urgency with which such projects are now being addressed and the technical achievements by some manufacturers which are making tidal and wave energy a reality.