Which of the following are considered alternative energy technologies?

Alternative energy technologies refer to methods of generating energy that are considered more sustainable and environmentally friendly compared to traditional fossil fuels. The correct choice includes tidal power, ocean thermal energy conversion, and hydrogen, all of which utilize renewable and abundant resources.

Tidal power harnesses the energy from the movement of tides, which is predictable and environmentally friendly. Ocean thermal energy conversion uses the temperature differences between warmer surface water and colder deep water to generate electricity, again tapping into a renewable resource that is not depleted like fossil fuels. Hydrogen, when produced through renewable sources (like electrolysis using solar or wind power), can serve as a clean fuel with water as its only by-product when used in fuel cells. Together, these technologies represent innovative ways to harness energy that mitigate the impacts of climate change and reduce dependence on fossil fuels.

In contrast, options that include natural gas or coal do not align with the definition of alternative energy technologies because they are fossil fuels, contributing to carbon emissions and climate change. Similarly, while geothermal heat and solar power are indeed alternative energy sources, the explanation emphasizes technologies that are often less common and consider their broader environmental impact and sustainability potential.