Energy associated with ocean currents can be captured, just like wind currents can with wind turbines. Ocean turbines can be fixed to the seabed, or float nearer the surface with moorings attached to the seafloor. No one technology has yet emerged as a clear winner, but this Japanese turbine, which has been in development and testing for many years is clearly still in the race. After successful recent trials, the company is set to scale up to a 2 megawatt unit. https://www.sciencealert.com/japan-s-dropping-a-kaiju-sized-turbine-into-the-ocean-to-fish-for-limitless-energy
Steam turbines have to date been the most traditional way to covert heat into electricity. Steam turbines are able to convert between 35-60% of the heat into electricity. However, scientists have kept investigating alternative ways to turn heat into electricity. Thermophotovoltaic cells (TPV) were initially promising, but only ever achieved efficiency rates of 20-32%. By increasing both the temperature of the heat emitter & the absorption properties of the TVC (visible, ultraviolet & infrared) engineers at MIT have achieved efficiency rates of 40%, with a clear idea of how to reach 50%.
Israel lacks roughly 12,000 acres to meet its 30 percent share of renewable energy goal by 2030.But what if land wasn’t a limiting factor for solar energy? What if we could harness the unused surfaces of our lakes and various types of water reservoirs instead? This is the concept behind floating photovoltaics (FPV), otherwise referred to as floating solar––PV modules mounted on buoyant platforms that float on sunlit bodies of water where surface conditions are calm. Xfloat’s system has buoyancy tanks arranged in a grid of connected vessels that control the rotation of the PV tracking tables in unison. https://nocamels.com/2022/05/xfloat-mekorot-solar-panels-energy-floating/