Final answer:
Tidal flow represents a very small percentage of the Earth's total energy flow, receiving about 3 TW from tidal energy in comparison to 123,000 TW from solar energy. Tidal energy's contribution to the global energy budget is minimal, and its potential exploitation faces limitations such as environmental impacts on celestial mechanics and variations in tidal strength.
Step-by-step explanation:
The percentage of the Earth's total energy flow from tidal flow is relatively small. The Earth receives approximately 3 TW (terawatts) of power in the form of tidal energy. This is largely due to the gravitational pull of the moon, and to a lesser extent the sun, which deforms the Earth into a prolate ellipsoid. This distortion creates bulges in the ocean that move around the planet as the Earth rotates, causing tides. Compared to other sources of energy, such as solar, which inputs 123,000 TW, tidal energy is a minuscule fraction of the total energy flow to Earth. In particular, tidal energy is not much more than the total dissipation of this energy on the planet.
To put it in perspective, capturing all available tidal energy would adversely affect the natural satellite dynamics, such as the moon's orbit around Earth. Existing tidal facilities, like the Rance facility in France, operate with a capacity factor of around 24% due to the variability of tidal heights and the fact that they can only generate power for about half of the time. With respect to solar energy, only a tiny fraction of the absorbed energy is responsible for driving ocean currents and tidal flows. Overall, while tidal energy is a source of clean power, it represents only a small slice of the Earth's total energy budget.