Self-powered wireless sensing platform for monitoring marine life based on harvesting hydrokinetic energy of water currents

This work presents fully underwater triboelectric nanogenerators (UTENGs) to harvest hydrokinetic energy of water currents towards self-powered marine life sensors and IoT applications.

Assessments of Available Riverine Hydrokinetic Energy: A Review

Methods of estimating riverine hydrokinetic (HK) power for localized and regional studies are reviewed, evaluated, and compared. It was found that localized HK studies were not entirely consistent, with the most common discrepancies being discharge variability characterization, uncertainty analysis, and the amount of data used to derive the results. The issues associated with localized assessments were amplified for regional assessments. Regional HK assessments were less common, the methods were less consistent across studies, and the amount and type of data available varied widely across regions. New techniques and technologies, developed in Canada and globally, were evaluated for their usefulness to improve regional HK assessments. Emphasis was put on satellite remote sensing methods to estimate discharge and channel dimensions, as well as regionalized curve fitting to estimate channel roughness. The review of new techniques suggests that accuracy of the results is dependent on the amount and quality of the data available.

Numerical Study and Theoretical Comparison of Outlet Hole Geometry for a Gravitational Vortex Turbine

The gravitational water vortex turbine is an alternative to renewable energies, it transforms the hydrokinetic energy of the rivers into electric energy and it does not require a reservoir. According to studies carried out, the hydraulic efficiency can increase or decrease according to the turbine geometrical configuration. This paper presents a numerical (CFD) and analytical comparison between conical and cylindrical designs for the outlet. The results show a higher performance for conical geometry than the cylindrical tank. The fluid behavior in CFD and analytical studies presents a tangential velocity increase near to air core and outlet hole (similar behavior). The maximum theoretical power generated was 167 W and 150 W for conical and cylindrical design respectively. The differences between geometries of the outlet holes using CFD and analytical models were 11 and 7%, respectively. However, the closest results to the CFD model had different values of 31 and 29% for conical and cylindrical design, respectively. The furthest result regarding the CFD study was 55%. The principal difference is due to tank geometry, the change in discharge zone, as well as the ratio of diameter tank and outlet hole can increase or decrease the tangential velocity and make a stronger and more stable vortex formation. The theoretical power generated is a good parameter to select the height to place the rotor.

Assessing Hydrokinetic Energy in the Mexican Caribbean: A Case Study in the Cozumel Channel

This paper presents a techno-economic assessment of hydrokinetic energy of Cozumel Island, where ocean currents have been detected, but tourist activities are paramount. The main objective of this research is to identify devices that have been used to harvest hydrokinetic power elsewhere and perform an economic analysis as to their implementation in the Mexican Caribbean. First, the energy potential of the area was evaluated using simulated data available through the HYCOM consortium. Then, for four pre-commercial and commercial turbines, technical and economic analyses of their deployments were performed. Socio-environmental constraints were reviewed and discussed. Three optimal sites were identified, with an average annual hydrokinetic energy density of 3–6 MWh/m2-year. These sites meet the socio-environmental requirements for marine kinetic energy harvesting. Of the turbines considered in the analysis, the best energy price/cost ratio is that of SeaGen device, with a maximum theoretical energy extraction of 1319 MWh/year with a Capacity Factor of 12.5% and a Levelised Cost of Energy (LCOE) of 1148 USD/MWh. Using this device, but assuming a site-specific design that achieves at least 25% of Capacity Factor, 20-year useful life, and a discount rate of 0.125, the LCOE would be 685.6 USD/MWh. The approach presented here can be applied for techno-economic analyses of marine turbines in other regions.