US funded tidal studies "happy with progress", but not without mix of challenges

Out of the seventeen US renewable projects which were granted funding in 2013, three of them concentrated on tidal energy progress. We look over one year on to see what has been achieved.

By Peter Taberner on Jan 5, 2015

In the autumn of 2013, the US President Barack Obama administration reaffirmed its commitment to renewable energy, allocating £16m for seventeen projects to capture energy from waves, currents and tides, as part of the “all-of-the-above” strategy to extract energy from all available sources.

The plan was to split the funding into two categories, with around $13.5m budgeted for eight projects to help energy companies build wave and tidal devices, in the expectation that the new technology developed, will reduce the cost of producing marine energy.

A further £2.4m was to be donated to environmental research, to gather data which could potentially allay fears, of what damage tidal and wave initiatives can do to their surroundings.

Testing for take-off: Advanced Controls & Next-Gen Power Take-Off Projects

The Ocean Renewable Power Company (ORPC) has received funding for two tidal designs. $1.93m for their TidGen system, and $3m for testing components for an advanced power take-off system.

The grid connected TidGen device hopes to be able to predict tidal conditions based on measurements ahead of the equipment, with the eventuality of adjusting the turbine settings to increase the performance.

For the advanced take-off system, bearings, couplings, and a subsea electrical generator will be developed.

The aim of this appliance is to act as a generator assembly that converts mechanical energy into electricity.

John Ferland, vice president of project development of ORPC, explains: “We are almost half way completed with the two-year projects. The data continues to be gathered, and the companies that we are working with are confidential over the results that we will achieve at this point.”

“The technologies that we are using include our own TidGendevice which is innovative in its own right, and has proven to be successful. Although up to this point, the data gathered thus far on this project is confidential.”

“We are happy with the progress that has been made, but it has not all been a smooth path, developing a new technology in deep fast moving water, is a very challenging experience,” he adds.

“Throughout the course of the projects, we have been in collaboration with the Department of Energy (DOE). This is competitively awarded and rigorously monitored grant funding that we have received from them.”

They now expect to apply what has been learned directly to what they call the version 2.0 of the TidGen Power System, the plan is to install this in 2016.

Close encounters of the wild kind

How tidal machines effect the behaviour of fish, and all forms of ocean wildlife has caused anxiety.

The University of Maine, through a $394,000 donation from the DOE, aims to assuage those fears by researching the interactions of fish around ORPC’s OcGen system, building on investigations which began in 2010.

The results from the study will improve the ability to distinguish between different species of fish using underwater acoustic sensors, and will also implement a model, which calculates the probability of encounters with any fish.

Universities and research think tanks have previously performed many environmental surveys around the effect of turbines. Although perhaps the most practical example, is the report produced by the environmental consultancy Royal Haskoning, at the SeaGen turbine.

The findings of the report proclaimed that there were no major impacts detected from the monitoring programmes, and that there were no changes in the abundance of either seals or porpoises detected, due to SeaGen’s presence.

Gayle B. Zydlewski, the principal investigator of the University of Maine project says: “After allocation of funding, there was a delay which lasted several months before the deployment of OcGen. During the delay, my team used previously collected data from 2011-2012, to develop analytical approaches to address the goals of separating different groups of fishes, by using two frequencies of hydro acoustics.”

Zydlewski says that the approach enabled the researchers to estimate the chance of fish encountering a marine hydrokinetic device as well as assessing how fish activity changes over long time periods in these tidally dynamic regions.

Data answering long unanswered questions

“Once the OcGen was deployed, we started collecting data around the device,” says Zydlewski . “Using the same equipment and methods used from 2011-2012, we conducted two 24-hour surveys prior to the device deployment.

“After that we conducted three 24-hour surveys around the device while it was deployed, and two more post-deployment. During those surveys we also collected fish in trawls to verify the species being detected using acoustics. Surveys were conducted with the assistance of ORPC, local fishermen, and Sea Grant Marine Extension Team.”

She says that she and the team look forward to analysing and interpreting the data collected in 2014.

“Our plans are to prepare manuscripts for all aspects of the work and seek further funding to continue assessing fish interactions with hydrokinetic devices,” she says.

The goals of the first year of funding, which included to develop approaches for new analyses and collect field data for future examination, have been achieved.

Beginning in January 2015, the second year of funding will provide the resources to analyse the data that has been collected. The project team is confident that the study will produce quality environment data, that will answer some long standing unanswered questions.