There is some ambiguity in the table. If it's only about electricity generation, that helps a lot.

###solar
The two types of solar could get split in different ways. "Solar panels" usually refers to photovoltaic generation of electricity from semiconductors. Solar thermal could mean the directly supply of hot water from solar thermal panels or other thermal harvesting mechanisms. OR it could refer to what's also called concentrating solar power, CSP, whereby sunlight is concentrated - either by a huge array of tracking mirros onto a central tower, or by parabolic troughs onto pipes - and that heat is then used to drive a turbine to generate electricity. PV panels are nearing maturity now; CSP is still at the grid-scale commercial prototypes. There's **low uncertainty on costs of PV**, and on the rate of decline of PV costs - it's called Swanson's Law, and works similarly to Moore's Law for computers.  The IEA have famously been rather inept on predicting how quickly deployment would occur, and how quickly costs would come down. There's **high uncertainty on the costs of CSP**.

###hydro
Hydro refers either to storage hydro, where the water is held in an upper reservoir, and released through turbines embedded in a dam or in the flow channels downstream from it, to generate electricity; or to run-of-river hydro, where electricity is generated as the water flows down a river and is channeled through a turbine. Both are well-established technologies. There's **very low uncertainty over costs of both run-of-river and storage hydro**.

###wave
Wave power is a nascent technology, and harvests the kinetic energy of the waves through pneumatics or other mechanisms. There are a few prototypes in the water. There's **very high uncertainty over costs of wave power**.

###tidal
Tidal stream is also a nascent technology, and uses the kinetic energy of the daily or twice-daily (depending on where you are in the world) to drive a turbine. There are some prototypes in the water, and there's **very high uncertainty over costs of tidal stream**.

Tidal barrages and lagoons use the height differences between high and low tides to drive water through turbines to generate electricity. **Barrages are well-established, and have medium uncertainty of costs. Tidal lagoons are a bit of a fad at the moment in some places, unproven, with high uncertainty on costs**. This also applies to tidal reefs and other variants.

Tidal is distinct in one curious way from all the others above. All the others are solar power, either directly or indirectly. Tidal comes from gravitational energy, not solar energy. (wind is also indirect solar energy. Geothermal is different again, being partly a product of nuclear reactions in the crust, and partly the reservoir of heat from the creation of the Earth)