Can algae harvest energy from the sun

Yes it can. They have chloroplast, just like almost all other plants, and that allows them to get energy from the sun to go through photosynthesis, which helps the water get oxygen which allows the fish to live.

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy