All three, solar energy, wind power and tidal power are renewable sources of energy.

1. Tidal Power: Tidal power is considered inexhaustible within a human time frame. It has great potential for future power and electricity generation because of the total amount of energy contained in this system of energy depending upon orbital mechanisms of the solar system.

Tidal power is reliably predictable compared to wind and solar power. But, it has a high capital cost, low running cost. As a result, a tidal power scheme may not produce returns for years and investors are, thus, reluctant to participate in such projects. Governments may be able to finance tidal power, but many are unwilling to do so also due to the time lag before investment return and the high irreversible commitment.
A tidal power scheme is a long-term source of electricity. More importantly, as the fossil fuel resource is likely to be exhausted in future, tidal power is one of the best alternative source of energy.

2. Solar Power: Solar power has become of increasing interest in developed countries, because of the environmental costs and limited supply of other power sources such as fossil fuels. Solar power is relatively pollution free, although the impact of environmental pollution during manufacture and construction should not be neglected. Solar power can be viewed as a local resource where it is abundant as in tropical countries.

However, it is only practical in certain areas with a favourable climate and latitude. It is not available at night or when there is a dense cloud over. This makes it unreliable.

3. Wind power: Wind's long-term technical potential is believed to be 5 times current global energy consumption or 40 times the current electricity demand. A moderate proportion of wind generation can be connected without the need for a storage. The cost of maintenance and storage is comparatively lower compared to any other source of energy renewable or non-renewable. Power output from wind varies though it can be predicted with a fair degree of confidence many hours ahead.

The trees might have to be cleared, a practice against the convention of conservation of resources. The birds killed by wind turbines could also cause a concern.