Appropriate technology works from the bottom up; it is not an overlay to the situation; it is a genuine grassroots solution to economic needs. Third World craftspeople, farmers and other villagers invent, create, and contribute to the technological process of their area much more than outside "experts" do.

The idea of appropriate technology is that local people, struggling on a daily basis with their needs, understand those needs better than anyone and can therefore suggest or in fact, invent the technological innovations necessary to meet those needs. Not only that, local people can prioritize solutions to save precious funding and labor. Planners and those who want to help others grapple with food and energy problems are wise to include local people in the early stages of project vision. The result is consistency in the carry-through of the work by locals and continued maintenance and interest in the well-being of the project over the long haul.

While grassroots activity is vital in developing appropriate technology, a larger view is definitely called for in understanding how organizations can combine funds and human resources to develop and market technologies. Communication among international aid agencies can greatly enhance efficient use of funds for appropriate technology and a reduction of the "reinventing the wheel" syndrome.

The definition of "Appropriate Technology" changes with each situation. It's not appropriate to install solar modules in a place with very little sun, a wind generator in a place with little or no wind. What's appropriate in a large urban location is very different from what's appropriate in a remote, isolated environment. One quality that remains the same, however, is taking care of things. In each situation, the essence of AT remains appreciating, helping, caring. Planned obsolescence, throw-away products, poor quality all go against intelligent decision-making and the true spirit of appropriate technology.

In summary, local people within their communities knows better than others which are their needs and they are in a better situation to select the best solar technology, with the assistance of experts in this field.

Through community cooking by solar thermal technologies like a solar concentrating cooker can be a very effective and life style changing as well as time saving practice. 

As you have mentioned the word appropriate technology, such community benefiting applications of solar energy, be it PV or thermal would make a huge difference. some times a decentralized power generation for a community can be most efficient than a grid connected solar supply like how MNRE had dropped the idea of establishing the largest solar grid connected pv systems in ladakh due to high costs incurred in establishing transmission lines. The future relies on establishing solar hybrid technologies through out the world and India. Eg. like for a community meeting its power via solar pv, integration of wind trees, using fuel cells from human, cattle urine,, Hydrogen synthesis via water splitting with power supplied from solar. Decentralized solar PV systems for any community irrespective of the demography will be efficient. 

With a massive cut in the price of solar pv an subsidy available, it is the most appropriate technology available. Also all the hospitals have installed solar water heating systems to meet their hot water requirements evidencing the reach of the thermal technologies and people ready to adapt it.

For water based enegy, a small scale pumped hydro system can be thought about. 

Even night soil based biomethanation could be adapted.

Please have a look at this link also.

https://www.researchgate.net/publication/233257182_An_Application_of_Solar_Energy_Storage_in_the_Gas_Solar_Heated_Biogas_Plants

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