Solar energy is great while the sun is shining. But not so useful once night falls. Most people think batteries are the answer, but Stanford University researchers have been working on another option. TEG's (Thermo-electric generator) are energy conversion devices. Basically, by using the temperature differential between one side of the panel and the air, more electricity can be generated ( both during the day and at night). Even better TEG's are reliable, safe, affordable and available right now.https://twitter.com/i/status/1543377040996548614
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%.