Fire powered cell phone chargers spotted near NYU in Downtown Manhattan. - The PG-1 power generator creates a temperature differential across the thermoelectric module inside the unit. Heat flows from the higher
temperature surface to the lower temperature surface creating an electrical output. When the electrical circuit is completed, electrons flow and generate electrical power. LINK: http://www.tellurex.com/products/thermoelectric-pg1.php
"How The Nokero SunRay Pro Power Solar Charger Saved My Skin & My Sanity During Hurricane Sandy"
Hand Crank Cell Phone Charger by Eton and the American Red Cross Could Be a Lifesaver
The cheapest method is to have some sort of sand filter:
News Report: BBC: 'Super sand' to help clean up dirty drinking water Contaminated water can be cleaned much more effectively using a novel, cheap material, say researchers.
Dubbed "super sand", it could become a low-cost way to purify water in the developing world.
The technology involves coating grains of sand in an oxide of a widely available material called graphite - commonly used as lead in pencils.
The team describes the work in the American Chemical Society journal Applied Materials and Interfaces.
In many countries around the world, access to clean drinking water and sanitation facilities is still limited.
The World Health Organization states that "just 60% of the population in Sub-Saharan African and 50% of the population in Oceania [islands in the tropical Pacific Ocean] use improved sources of drinking-water."
The graphite-coated sand grains might be a solution - especially as people have already used sand to purify water since ancient times.
Here is a list of water filtration devices well within the budget of ANY local community (if you put a little thought & possibly research into it).
Developing Self-Sufficient & Self-Sustaining Local Economies & Businesses (such decentralization strategies helps prevent the cascading effect of having everything fall apart because everything is connected, such as is common with power plants in any serious storm - More about decentralization here: The Dangers Of Nuclear Energy & Parallels To The Tower Of Babel)
For more ideas study my page on Natural Disaster Management