By Eric Bibeau
As an aspiring renewable energy researcher, I chose to approach Manitoba Hydro in 2004, initially, to fund hydrokinetic scaled-turbine laboratory tests to be performed in a controlled university setting. Manitoba Hydro agreed, but also requested that actual turbines be tested in rivers. How hydrokinetic turbines perform in cold weather, their maintenance schedule, life-cycle costs, and how to access this equipment on a fast flowing river, are some of the many questions Manitoba Hydro had, which could be answered by testing hydrokinetic turbines in rivers.
As a result, the University of Manitoba created the Canadian Hydrokinetic Turbine Testing Center (CHTTC) on the Winnipeg River, initially located at the 78-MW Pointe du Bois hydroelectric plant, and now located at the 165-MW Seven Sisters generating station, Manitoba since 2012. Funding contributions over the last 12 years in excess of 5 million Canadian were obtained mainly from: Natural Resources Canada Eco-II funding program; Canadian Western Economic Diversification; Natural Sciences and Engineering Research Council of Canada; Manitoba Hydro; and device developers Clean Current, New Energy Corporation and Mavi Innovations Inc.
CHTTC works with turbine manufacturers, developers and universities, focusing on MHK life-cycle solutions for remote and grid-integrated systems, offering a commercial setting that includes:
• Canadian regulatory approval;
• Equipment for manned and unmanned deployment and retrieval of turbines;
• Location to test the effects of cold weather;
• Availability of state-of-the-art systems and techniques to safely measure flow velocities and turbulence around turbines;
• Required infrastructure to test new power converters; and
• Ability to investigate the impact of the environment on turbines.
This article describes the framework and status of research CHTTC conducts that contributes towards the commercialization of riverine hydropower.
The frontier of hydrokinetic power
Our sun evaporates earth’s water using 2,100 times more energy than the energy we consume. This vaporizing process fuels a vibrant hydropower industry that makes renewable electricity. Hydropower converts about 0.001% of the sun’s energy that went into making vapor by harnessing the water potential energy made available through rain.
One hydropower frontier derived from this evaporation process yet to be conquered is to convert hydrokinetic energy from river currents using a turbine, not unlike those used in the wind power industry. There are significant challenges inherent to the commercialization of river currents. Hydrokinetic water-to-wire costs are relatively high as the marine industry has to address remaining technological gaps and accumulate more experience to reduce system costs.
River hydrokinetic power will soon offer a replacement for diesel generation that will power isolated communities in North America in a more cost effective fashion. This has the potential to improve local economies and avoid scientifically proven health risks associated with soil contaminated by diesel fuel. However, the marine industry must first lower the water-to-wire levelized cost of electricity (LCOE) for hydrokinetic energy before it will serve as a reliable alternative to diesel fuel in remote communities.
Over time, the cost of renewable energy technologies like solar photovoltaic and wind energy has fallen considerably due to continued technological development and government financial incentives.
It is expected that hydrokinetic energy will attract similar incentives due to its predictability to address base loads with renewable energy, and the abundant river and tidal resources in many countries that are locally accessible for most communities.
Natural Resources Canada has identified more than 340 GW of river hydrokinetic potential, exceeding Canada’s current total nameplate electrical generating capacity by more than three times. This means that hydrokinetic river technologies could provide communities economic opportunities using their renewable energy resources.
Compared to fossil fuels, recent energy investments are now 2 to 1 in favor of renewable technologies. As the cost of all renewable energy technologies decreases, it becomes important to understand how each technology can contribute to the energy planning process. Comprehensive resource maps and cost-reduction curve projections contribute to this planning.
CHTTC
CHTTC helps address the pre-commercialization needs identified in the Canadian Marine Renewable Energy Technology Roadmap issued by Natural Resources Canada (www.marinerenewables.ca/ technology-roadmap). By employing the CHTTC concept of shared infrastructure, the marine industry can reduce its LCOE more efficiently, and at the same time help to address climate change.
At CHTTC, a variety of means exist for developers of marine hydrokinetic turbine technologies to increase their technological readiness level (TRL). TRL is based on a scale from 1 to 9, with 9 being the most mature technology. The use of TRLs enables consistent, uniform discussions of technical maturity across different types of technology. CHTTC allows developers to test their hydrokinetic turbine systems water-to-wire to increase their TRL. We assist companies like New Energy, Mavi Innovations Inc., Jupiter Hydro and Gem Holdings to develop hydrokinetic marine turbine technologies that increase their technological readiness level from 3 to 9 at reduced cost. Moreover, CHTTC provides additional cost savings to marine stakeholders by providing a framework for the industry to develop standards, protocols and safety procedures.
Other research centers in North America working to further marine energy include the Fundy Ocean Research Center for Energy in Canada, West Coast Wave Initiative in Canada, and Alaska Hydrokinetic Energy Research Center in the U.S.
The center addresses key areas of hydrokinetic technology development:
• Validate the operation and performance of hydrokinetic turbines;
• Field test hydrokinetic turbine integration with electrical grids;
• Reduce installation, deployment, and retrieval costs;
• Develop safety protocols;
• Develop techniques for subsea cable management;
• Field test new anchors and turbine deployment methods;
• Investigate the effects of scouring on turbine components; and
• Test system reliability and availability.
Ongoing research at CHTTC includes:
• Investigate numerically and experimentally how hydrokinetic turbine economics can be more favorable based upon the placement of turbines in a farm arrangement;
• Develop turbulent flow and hydrokinetic characterization techniques;
• Perform error analysis of acoustic flow measurement devices;
• Develop an effective kiting turbine;
• Fabricate a low-cost Gambian anchor;
• Investigate a low-cost marine cable installation;
• Provide data and inputs to the SMC/IEC TC114 international standards for marine energy conversion systems;
• Study the effects of macro-turbulent structures on operating hydrokinetic turbines; and
• Develop a long-term and low-cost flow measurement device to predict turbine capacity factors.
CHTTC provides a unique opportunity to understand the operational effects of hydrokinetic devices on the environment to help inform regulatory decisions. For example, 80 fish have been tagged with 30 receivers and placed in the Winnipeg River. This effort was led by Dr. Steven Cooke, of Carlton University, and assisted by and the Department of Fisheries, to study the impact of river turbines on walleye and sturgeon.
Moreover, it is uncertain how much of the hydrokinetic potential can be extracted and methodologies are needed to find ideal sites near remote communities. To that end, CHTTC has developed a methodology to apply satellite images acquired in the winter season to identify river stretches that are free of ice. Through measurement of river flows using an acoustic Doppler velocimeter, data supports the center’s hypotheses that such areas are indicative of high flow velocities. Thus, these areas offer potential for producing electricity using hydrokinetic turbines.
Safety for the MHK industry
Safety is a major concern when working on rivers that have velocities varying mostly between 2 and 3 m/s. CHTTC is presently implementing a safety program that establishes a framework for industry-wide safe work procedures, safety risk analysis, safety equipment requirements and non-conforming issues available in one software program accessible from any location. As our research team is expanding its operations to the Canadian west coast with Mavi Innovations and developing collaborations in South America and Normandy, France, there is a need to have safety apply uniformly, maintaining compliance with national, state/province and local labor laws.
In addition, some research projects are focused on investigating new approaches to simplify how to install and operate hydrokinetic turbines to reduce safety risks. Emphasis is on decreasing operator requirements by eliminating more difficult on-water procedures, simplifying operator training and workplace safety procedures, and considerably reducing on-water safety risks (i.e., some turbines are installed without on-water procedures while the turbine is being deployed).
It is important for the hydrokinetic industry to develop and implement a marine energy safety culture so safe on-water procedures are improved, simplified and enforced to ensure the safety of personnel that are operating these systems in rivers and remote areas.
LCOE
CHTTC has tested turbine improvements aimed at reducing the LCOE. With examples that include elimination of the gearbox, and reduced power electronics costs, many new cost reduction designs are tested at CHTTC. Moreover, tests are conducted using local equipment, typical of those available in more remote locations. For example, New Energy turbines tested at CHTTC are now being installed in remote villages in Asia, providing power to villages that have previously seen limited access to electricity. New Energy can transport its 5-kW turbine system to remote villages using yaks.
We are pleased to be commencing work with New Energy on the first Canadian commercial system, which will be installed at the Sagkeeng First Nation community. Located on the Winnipeg River, the community will be operating a 25-kW hydrokinetic turbine. Our team is contributing to the project by performing flow resource mapping and long-term turbine monitoring. Developing low-cost and reliable remote monitoring of commercial turbines is important to the industry. Here we focus on installing rugged instruments that can transmit operational parameters of the turbine and perform some pre-filtering of the data to generate alarms.
In addition, CHTTC began working with Mavi Innovation to test a remote tidal installation in Blind Inlet on Vancouver Island. This project is aimed at displacing diesel generation, testing a smart-grid tidal turbine system coupled with solar energy.
The frontier of renewable energy
When looking at the total energy from our sun, it provides us with more than 9,000 times the energy we consume, yet 84% of today’s energy is extracted below the ground surface.
Achieving affordable LCOE using a portfolio of base load and intermittent renewables technologies is well within our grasp. With atmospheric CO2 levels of 500 ppm presently lurching around the corner, the present generation needs to derive its energy from recent sunlight, made available to all in diverse forms that integrate together somewhat like a puzzle during the planning process.
The Canadian Hydrokinetic Turbine Testing Center (CHTTC), based at the University of Manitoba, conducts marine hydrokinetic turbine testing at no direct cost to companies, the results of which are furthering commercial marine energy applications.
Eric Bibeau, Ph.D., is program leader for the Canadian Hydrokinetic Turbine Testing Center research team. New Energy turbines, similar to the 5-kW model pictured above, are being installed in remote villages in Asia, where there is limited access to electricity.
— Reprinted with permission from HYDRO REVIEW, July 2016 www.hydroworld.com.