Arguably there could be perhaps two ways to reduce or eliminate poverty: One is to make everybody or every nation rich; though it is not possible politically and logistically, it would still not solve the problem of poverty due to the limited global resources and their geographical distribution and constraints.
Critical to achieving sustainability and eradicating poverty is to have sustainable energy and water supplies that have little or no geographical or climatic condition constraints.
Additionally they have negative impact on the environment, which has resulted in the challenge of Climate Change.
Renewable energy sources, on the other hand, whether solar, wind, tidal, hydropower, etc., though have less negative impacts on the environment; they are not free from geographical and climatic constraints regardless of their development status.
The most populated parts of the world suffer from water shortages.
Tapping into seawater was considered as an option solution for freshwater supply, but as mentioned before desalination is energy intensive technology and has high installation cost, which limits its use to wealthy and oil rich countries.
The world needs water and food as well among other key requirements. Hence having secure, adequate, sustainable and low cost energy source provides sustainable and affordable water.
For example, in the case of energy, scientists and engineers for a long time, probably since the beginning of the Industrial Revolution, have associated energy transformation and power production to fuel consumption; e.g. burning wood, coal, oil and gas including the nuclear reaction.
Given that accessible, affordable, secure and low cost energy is central to achieving sustainable development, energy therefore must have the highest global priority.