This is indeed a very interesting question. Although I do not have any actualized element on grid extension's costs, I found this 2000's ESMAP report specifically looking at this issue. Please see table below.
If numbers may be outdated, this report provides with some interesting insights on the factors affecting such cost: Reducing the Cost of Grid Extension For Rural Electrification, ESMAP, 2000.
I also remember that Mr. Balthasar Kimbie from the Alliance for Rural Electrification had mentioned some numbers during our last event in London and may therefore be able to help us with actualized data?
The figures I mentioned, where pretty basic and from our report:
(I hope the link works, otherwise go to ruralelec.org and to the publication page).
It is not the most recent publication that we have. There is more on the ARE website.
Did you come to some kind of conclusion on whet the costs of grid extensions are? I fear that there are quite a number of variables involved. But compared to the costs of mini grids it is always amazingly expensive.
Van: Yann Loic Tanvez email@example.com
Verzonden: donderdag 23 mei 2013 16:46
Aan: Balthasar Klimbie
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Grid extension cost
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Yes - we have been playing with a lot of variables recently and have now started to converge on some numbers for grid extension costs and the cost of the delivered power for villages (with dependencies on distance from the grid, number of people in the village, average consumption etc.) I'll be happy to share the report with the group once we are done with it.
A rural electrification project entails far more than material costs plus installation labor of a hypothetical kilometer of line.
- Site surveying
- Pegging (staking the route)
- Bush clearing
- Commissioning (livening) of transformers and other equipment
- As built drawings
Hills and curves can require medium or heavy angle structures that are far more expensive than a simple inline (tangent) pole. A heavy angle pole can be more than double the cost of an inline pole. In addition, there are costs associated with sustaining the forces exerted on angle structures. (guy/stay wires, strut poles, or larger self-sustaining poles)
A project that entails hundreds (or thousands) of kilometers has an entire infrastructure needs to be accounted for as well. Management, field supervision, warehouses with material handling equipment, pole and material delivery, tools, transportation, etc. If the material is not locally, you can have additional expenses associated with customs, import duties, port clearing, as well has container costs.
Single phase construction offers substantial savings over a three phase line. There is often resistance to using single phase due to the belief that every village will have a corn grinder with a 3-phase motor. Many projects skip smaller villages along the route because they are deemed too small to qualify for the installation of a 3-phase transformer. We've found these small villages can be economically served with a single-phase transformer on a regular line pole. They may not be able to operate large motors, but at least the homes have electricity for their basic needs. "No Village Left In the Dark"
There are a couple of slightly more up-to-date papers from Nouni et al. which show data on grid extension costs, specifically in the Indian context.
I hope this helps
Also look at this report which looked at new business models for off -grid electrification and has analysis of grid vs off grid in specific areas in two Indian states. http://online.wsj.com/public/resources/documents/WorldBankreport0215.pdf
Also see- Nouni M. R., et al. “Providing electricity access to remote areas in India: An approach towards identifying potential areas for decentralized electricity supply