Ranjana, the basics are a good knowledge of solar radiation (annual variability to small time scales variability), proven solar materials, a reliable storage (more than a fancy one) and accurate monitoring tools for the grid. This is really the big "technical" picture.

For the commercial feasibility, you have to consider all the initial costs, but above all the operation costs, including the maintenance of such remote grids. This last part will be essential.

The question of community/private relies on the affordability of your kWh. It can be one of these or a blend. Services this grid can bring can be an indicator.

This answer is really general. More details can be found in all the amazing reports of IEA PVPS Task 11 (http://iea-pvps.org/index.php?id=227).

Hi Ranjana, I think the major influences here would be the ability of the populace to afford the equipment. Secondly, the generated kW should add value to the purpose. In order to make the plant sustainable, you should consider cost v/s kW graph.

Assuming your location is Nepal, mini-grids are commendable for sustainability.

Ranjana, the basics are a good knowledge of solar radiation (annual variability to small time scales variability), proven solar materials, a reliable storage (more than a fancy one) and accurate monitoring tools for the grid. This is really the big "technical" picture.

For the commercial feasibility, you have to consider all the initial costs, but above all the operation costs, including the maintenance of such remote grids. This last part will be essential.

The question of community/private relies on the affordability of your kWh. It can be one of these or a blend. Services this grid can bring can be an indicator.

This answer is really general. More details can be found in all the amazing reports of IEA PVPS Task 11 (http://iea-pvps.org/index.php?id=227).

Thank you very much Arun and Aurelien. I will definitely go through the IEA report. Also, i would like to add that Solar electricity is highly feasible in Nepal with more than 300 days of sunshine. Solar home systems are really popular in rural areas. However, these are entirely used for lighting adding to the population with energy access. There needs a shift to more productive use of solar electricity and therefore minigirds might be an answer to up-scaling renewable energy and rural livelihood. I wanted to ask about the community/private model because in case of Micro-hydropower (MHP) generation in Nepal, community based model is followed. Although community mobilization is good in itself, many MHP are facing problem of efficient management. Also, rural communities are generally poor and therefore, private sector might not be interested in such areas. therefore I am wondering about different possible models to sustain such projects.

Thank you so much Rosenberg.

Dear Ms. Ranjana Budhathoki,

To gain a somewhat better appreciation of your situation, I found papers by Binay Sa Kanu from Tribhuvan University on Energy Consumption Patterns in Nepal, and one by several authors Pondyal, Bhattari, Sapkota, and Kjeldstad on the solar radiation in Nepal to be useful. The second paper shows that daily solar radiation depending on some sites can vary by a factor of 16/23/15/10 from winter/spring/summer/fall, and additionally the day to day variation can be considerable during the rainy season. This suggests that a big factor for your consideration will be to ensure any system design incorporates sufficient storage (battery) to be able to ride through at least several low radiation days, and that the system design while quite capable in sunny seasons will be tightly constrained in other seasons. A significant issue with any community based system will be the education of users as to the limitations of the system. A system operated by an individual can incorporate understanding the importance of monitoring usage and solar inflow to accommodate system limitation, but in a community setting, not all will understand that limitation, and that can put severe strain on your design. Perhaps some sort of large and easily visible battery monitor, along with input and draw graphic meters might be considered. The paper by Binay Sa Kanu might suggest that because it is typical in Nepal to use fuel wood or other biomass for heating, but kerosene for lighting, that a very necessary feature of your solar system design will be to ensure that the loads are only those "premium" uses such as high efficiency lighting, or supplies for electronic infrastructure such as communications or medical needs, as if even a few users find that electric hot plates and radiant heaters can replace the large load supplied by fuel wood, it would have the capability of rapidly overwhelming the system capability. All this makes me wonder out loud if rather than a community based system, if it there are advantages to consider instead smaller systems that individual dwellings control. Solar can be a good servant properly managed, but can be rapidly overwhelmed, leading to premature storage battery failure if some users do not understand the system limitations. I apologize if these are all issues that you are aware of, but they are the points that rapidly came to mind. Best wishes with your project. I hope this can help somewhat.

Yes, thank you very much Mr. William Palmer. I very much appreciate your conclusions. RET promotion in Nepal has a major focus on community based models that has the provision of government subsidy. But, I really think that private developer model might be more financially sustainable in the long run, provided there is sufficient anchor load and business operation from the generated electricity as you suggested. I would definitely incorporate your suggestions.

There have been many research projects on microgrids. There are even several conferences completely dedicated to the issue, for example the European PV-Hybrid and Mini-Grid Conference. But many papers on the issue also have been published at the eu pvsec. Papers before 2013 can be searched here:

5th European PV-Hybrid and Mini-Grid Conference

Correction, the papers can be searched here:

http://www.eupvsec-proceedings.com/

Thank you very much Jethro! That would be very much helpful.

Dear Ranjana

see this article on model based design of a novel Stirling solar micro-cogeneration system with performance and fuel transition analysis for rural African village locations

https://www.researchgate.net/publication/301659032_Model_based_design_of_a_novel_Stirling_solar_micro-cogeneration_system_with_performance_and_fuel_transition_analysis_for_rural_African_village_locations

Important to use your computer model to predict system performance as well as fuel transitions or energy transitions for a specific area. Our model application was extended to meet compulsory World Bank and Development Agency requirements in terms of providing energy reform and fuel transition projections in proving the suitability of newly proposed solar technologies for remote area power applications. The proposed computer model applies statistical weather data to explore the performance, feasibility and fuel transition effects for the solar micro-combined heat and power system in terms of electricity and hot-water generation as well as fuel wood replacement at various locations in Southern Africa. The results show the annual power and hot water generation capability of the system for various sites across Southern Africa, and demonstrates a significant potential in reducing fuel wood usage for villages in these areas. The technique can also be used in cost benefit studies for GHG mitigation and adaptation technologies.

Article Model based design of a novel Stirling solar micro-cogenerat...

Article Discrete cogeneration optimization with storage capacity dec...

Dear Ranjana

Just to add the importance of user consumption data and customer energy usage patterns in system design, readers  may also find this paper interesting

Scoping exercise to determine load profile archetype reference shapes for solar co-generation models in isolated off-grid rural African villages

https://www.researchgate.net/publication/306098038_Scoping_exercise_to_determine_load_profile_archetype_reference_shapes_for_solar_co-generation_models_in_isolated_off-grid_rural_African_villages

The dataset with rural energy consumption data to download excel spreadsheet is on this link

Scoping Rural Load Profile Electricity n Hot Water Energy Profile Reference Datasets and Excel Data Corpus

https://www.researchgate.net/publication/307509610_Scoping_Rural_Load_Profile_Electricity_n_Hot_Water_Energy_Profile_Reference_Datasets_and_Excel_Data_Corpus

Gerro

Article Scoping exercise to determine load profile archetype referen...

Data Scoping Rural Load Profile Electricity n Hot Water Energy Pr...

Hydro pump / turbine storage scheme could be a better solution for stabilyze eletrical grade and improved storage / power consumption. Economically speaking, its feasibility  depends on certain characteristics, of course, as for example neighborhood  site instalation. Ocean border line is a concrete case to be improved.

Hi Ranjana,

I have some experience in this area as I lived in a rural village in Nicaragua for two years and developed a community electricity system with small scale solar and wind turbines. It's very important to consider the practical aspects of the energy system. When starting out , consider the electrical devices which will provide the greatest benefit for community members. Typically the first electrical devices people will use are rechargeable flashlights and basic flip-type cell phones. These improve safety and communication. In my project we created a central community charging station, where villagers could bring a cell phone or flashlight to be charged for free. It was powered by 800 watts of PV solar panels, and 1, 500 watt wind turbine. Energy was stored in  6 x Trojen 600AH 6 volt batteries. The batteries were connected for a 12 volt system. A power inverter was used to  convert the DC electricity in the batteries to 110 AC (like a standard wall outlet). One could avoid the inverter altogether with a 12v to 5v DC to DC converter set up for charging USB devices. 

Although this was a very simple system, it was impactful and provided over 1500 charges in a two year span for the population of about 250 people. It's actually still running to this day. My paper on this topic is called "Wind Turbine for Rural electrification in Nicaragua" where you can find more details. 

In terms of financial feasibility you could investigate rural electrification advocacy groups in the region to see if there is any funding that could be secured for the project. In my case it was personally funded. Hope that helps.

Hello Ranjana, 

In Nepal (as everywhere else) the most significant factor seems to be the base load. Even with expensive batteries, most of the systems are just not sufficient during the peak demand hours at mornings and evenings.

Recently, attempts have been made to integrate both solar/wind with a fossil fuel (diesel) generator back up for those peak demand hours through hybrid systems. These models have been relatively successful. More so, if there are some sort of local enterprises involving productive end use of electricity during the day time when domestic consumption is quite low. Such enterprises are of immense importance for financial sustainability of projects.

https://www.google.co.uk/search?client=opera&q=gham+power+hybrid&sourceid=opera&ie=UTF-8&oe=UTF-8#q=renewable+hybrid+systems+nepal

Hope this helps.