Small Scale Generation for Electrification of Rural and Remote Areas

David Heinz
December 13, 2014

Submitted as coursework for PH240, Stanford University, Fall 2014

Introduction and Background

Fig. 1: Viability of generation schemes based on local cost in Africa. Area represents number of people who have the ability to pay for electricity from that source (triple overlap is 1.5 million). Data from Maher et al. [6]

Across the world as many as 1.5 billion people lack consistent access to electricity. [1] Many of these people live in remote or rural areas where it is often too difficult or costly to transmit power using standard extensions of the power grid. The lack of access to this vital resource has hampered economic progress and is widely considered to be a major contribution to the continued poverty in these areas. [1] Though there has been extensive penetration of some modern technologies, such as mobile telephones and smartphones, the electricity required to operate these devices remains a serious challenge.

Fortunately, there do exist some solutions to bring electricity to these areas. The more advanced and complete solutions involve the construction of a micro-grid. These systems mimic the structure of a traditional power grid with centralized and continuous generation and allow for relatively high consumption, including home appliances and even industrial usage. They also do require a considerable capital investment in the range of millions of dollars and specialized maintenance. [2]

The other class of solutions relies upon truly distributed generation and are at much smaller scale. These solutions provide only sufficient electricity for a few extremely basic necessities such as LED lighting. They are typically simple and inexpensive methods of electricity generation that require little to no expertise to set up and operate. [3] Both the micro- grid and off-grid solutions can have tremendous impact on economic development and both rely upon a combination of traditional and state-of-the-art technologies.

Off Grid Solutions

There exist a vast array of methods of generating electricity completely independently of a grid infrastructure. Here we will review some of the economically favorable and interesting methods for remote and rural areas.

Usually at low voltage and low power, these systems are safe, and do not require massive capital investment. These generation strategies, among others such as hand crank/human/animal driven generation, are beginning to provide small, but important amounts of electricity in locations such as Africa, southeast Asia and the Indian subcontinent. All of these methods provide enormous economic benefits to the end-users, compared with the lack of access to electricity or cost of battery power alone.

Micro-Grids

For larger scale power generation and distribution, the basic generation strategies, like those mentioned in the above section, must be scaled up and synchronized. The infrastructure required to do this is referred to as a micro-grid. Micro grids are typically designed to be capable of providing continuous power supporting the same levels of demand as a full scale electrical grid. Unlike off-grid generation, micro-grids can support factories and large appliances like refrigerators. In order to provide these levels of service, micro-grids are much more complex and costly than off grid generation. A typical system may cost in the range of USD $30M. [2]

In order to provide consistent power, a micro-grid must have some level of redundancy, and not rely entirely upon inconsistent generation sources like solar or wind. The basic architecture of a micro-grid is as follows: Generation source(s) (and fuel), load balancing electronics, power conditioning electronics and distribution network. The generation source often is a combination of a renewable source and diesel or gas generator, possibly with a battery bank to better match the load and capacity. The electronics required to autonomously operate micro-grids must be fast responding as there is typically less averaging due to the smaller number of generation sources and loads. [14]

Micro-grids also have the benefit that as the centralized grid expands, it can be relatively simple to merge the two grids, ultimately powering the micro-grid area completely from the main grid. Though micro-grids are a much more complete solution than off-grid generation, they are expensive, require specialized maintenance are are simply not practical in many situations.

Conclusions

In previous mass-electrification efforts, like South Africa, there have been broad and substantial economic gains achieved almost immediately. The technologies discussed above have the potential to create much of the same effect, reducing poverty in some of the most disadvantaged areas of the world. As the cost of manufacturing and physical transportation for technologies like solar and micro-hydro continues to decrease, deployment will increase. Already more and more electricity generation methods are becoming competitive at the level that could be afforded by these relatively poor areas (see Fig. 2). This may allow for greater wealth, and subsequently the ability to pay for more complete electrification. These first steps, whether they be a few watts of local generation to power lights to extend the day, or a micro-grid to run a sawmill and machine shop are absolutely essential to unlocking the human potential in rural and remote, un-electrified areas.

© David Heinz. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] "Energy Strategy Approach Paper," The World Bank Group, October 2009.

[2] K. Bullis, "How Solar-Based Microgrids Could Bring Power to Millions of the World's Poorest," Technology Review, 24 Oct 12.

[3] A. B. Sebitosi, P. Pillay, M. A. Khan, "An Analysis of Off Grid Electrical Systems in Rural Sub-Saharan Africa," Energ. Convers. Manage., 47, 1113 (2006).

[4] P. Arun, R. Banerjee, and S. Bandyopadhyay, "Optimum Sizing of Battery-Integrated Diesel Generator for Remote Electrification Through Design-Space Approach," Energy 33, 1155 (2008).

[5] B. D. Batts and A. Z. Fathoni, "A Literature Review on Fuel Stability Studies with Particular Emphasis on Diesel Oil," Energy Fuels 5, 2 (1991).

[6] S. Szabó et al., "Energy Solutions in Rural Africa: Mapping Electrification Costs of Distributed Solar and Diesel Generation Versus Grid Extension," Environ. Res. Lett. 6, 034002 (2011).

[7] P. Maher, N. P. A. Smith, and A. A. Williams, "Assessment of Pico Hydro as an Option for Off-Grid Electrification in Kenya," Renew. Energ. 28, 1357 (2003).

[8] N. S. Lewis, "Toward Cost-Effective Solar Energy Use," Science 315, 798 (2007).

[9] R.H. Crawford, "Life Cycle Energy and Greenhouse Emissions Analysis of Wind Turbines and the Effect of Size on Energy Yield," Renew. Sustain. Energ. Rev. 13, 2653 (2009).

[10] K. Shevory, "Homespun Electricity, From the Wind," New York Times, 13 Dec 07

[11] L. E. Bell, "Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems," Science 321, 1457 (2008).

[12] H. Bottner et al., "New High Density Micro Structured Thermogenerators for Stand Alone Sensor Systems," IEEE, 4569484, 3 Jun 07.

[13] J. P. Heremans "Enhancement of Thermoelectric Efficiency in PbTe by Distortion of the Electronic Density of States," Science 321, 554 (2008).

[14] F. Katiraei and M.R. Iravani, "Power Management Strategies for a Microgrid With Multiple Distributed Generation Units," IEEE Trans. Power Sys. 21, 1821 (2006).