Difference between revisions of "Mini Grids"
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= Overview<br/> = | = Overview<br/> = | ||
| − | A mini grid, also sometimes referred to as a "micro grid or isolated grid" can be defined as, a set of electricity generators and possibly energy storage systems interconnected to a distribution network that supplies electricity to a localized group of customers. This power delivery architecture can be contrasted to a single customer system such as in the case of a solar home system. Where there is no distribution network interconnecting customers it can be connected to a centralized grid systems, where electrical energy is transmitted over large distances from large central generators where local generators are generally not capable of meeting local demand.<ref name="An overview of technical aspects of Mini- Grids: https://www.eda.admin.ch/content/dam/countries/countries-content/india/en/resource_en_224456.pdf">An overview of technical aspects of Mini- Grids: https://www.eda.admin.ch/content/dam/countries/countries-content/india/en/resource_en_224456.pdf</ref><br/> | + | A mini grid, also sometimes referred to as a "micro grid or isolated grid" can be defined as, a set of electricity generators and possibly energy storage systems interconnected to a distribution network that supplies electricity to a localized group of customers. This power delivery architecture can be contrasted to a single customer system such as in the case of a [[Solar_Home_Systems_(SHS)|solar home system (SHS)]]. Where there is no distribution network interconnecting customers it can be connected to a centralized grid systems, where electrical energy is transmitted over large distances from large central generators where local generators are generally not capable of meeting local demand.<ref name="An overview of technical aspects of Mini- Grids: https://www.eda.admin.ch/content/dam/countries/countries-content/india/en/resource_en_224456.pdf">An overview of technical aspects of Mini- Grids: https://www.eda.admin.ch/content/dam/countries/countries-content/india/en/resource_en_224456.pdf</ref><br/> |
Mini-grids have a unique feature as they can operate autonomously without being connected to a centralized grid. However the mini-grid may be designed to interconnect with the central grid which means it operates under normal conditions as part of the central grid with disconnection occurring only if power quality needs to be maintained. For instance in the case of a central grid failure. Alternatively, a mini-grid may be designed to operate autonomously in a remote location with the option to connect to a central grid when grid extension occurs.<ref name="A review of mini-grid used for electrification in rural areas: http://iasir.net/AIJRSTEMpapers/AIJRSTEM13-239.pdf">A review of mini-grid used for electrification in rural areas: http://iasir.net/AIJRSTEMpapers/AIJRSTEM13-239.pdf</ref> | Mini-grids have a unique feature as they can operate autonomously without being connected to a centralized grid. However the mini-grid may be designed to interconnect with the central grid which means it operates under normal conditions as part of the central grid with disconnection occurring only if power quality needs to be maintained. For instance in the case of a central grid failure. Alternatively, a mini-grid may be designed to operate autonomously in a remote location with the option to connect to a central grid when grid extension occurs.<ref name="A review of mini-grid used for electrification in rural areas: http://iasir.net/AIJRSTEMpapers/AIJRSTEM13-239.pdf">A review of mini-grid used for electrification in rural areas: http://iasir.net/AIJRSTEMpapers/AIJRSTEM13-239.pdf</ref> | ||
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A mini-grid can be supplied by all sorts of energy resources and power plants, however most of the time a mini-grid will use low AC voltage (220-380V) with a centralized production and a storage system and will have an installed capacity of between and 5 and 300kW even though bigger systems exist.<ref name="Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdf">Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdf</ref> | A mini-grid can be supplied by all sorts of energy resources and power plants, however most of the time a mini-grid will use low AC voltage (220-380V) with a centralized production and a storage system and will have an installed capacity of between and 5 and 300kW even though bigger systems exist.<ref name="Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdf">Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdf</ref> | ||
| − | Implementation of mini-grids have proved to have a positive social impact by fostering and improving the local governance structure through the involvement of the community in the decision making process linked with the energy system. There are hundreds of diesel-based isolated grids worldwide which lend themselves to be retrofitted with renewable energy technologies. Sharing limited resources and power among users in a mini-grid requires rules and a tariff structure that ensures sustainability in the operation. In general, mini-grids involve intense preparation to ensure the systems operation and maintenance will be sustainable.<ref name="Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdf | + | Implementation of mini-grids have proved to have a positive social impact by fostering and improving the local governance structure through the involvement of the community in the decision making process linked with the energy system. There are hundreds of diesel-based isolated grids worldwide which lend themselves to be retrofitted with renewable energy technologies. Sharing limited resources and power among users in a mini-grid requires rules and a tariff structure that ensures sustainability in the operation. In general, mini-grids involve intense preparation to ensure the systems operation and maintenance will be sustainable.<ref name="Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdf The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf">Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdffckLR The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdffckLR</ref><br/> |
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| + | = Opportunities<br/> = | ||
| + | <u>There are a lot of opportunities that have been observed with mini-grid systems:</u><br/> | ||
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| + | *They can be used to increase the reliability of electricity supply. Due to their small scale in nature and enhanced local level ownership of physical infrastructure or management, power theft which is a commonly associated with centralized on grid systems can be reduced.<ref name="The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf">The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf</ref><br/> | ||
| + | *Reliability of supply is generally greater from hybrid mini-grid systems as compared to a single technology. This not only lowers the net costs over the lifetime of a project, but also ensures availability of power when one system is not working.<ref name="The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf">The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf</ref> | ||
| + | *There is environmental improvement from the use of mini-grids. This is in terms of efficiency and reduction in carbon emissions. Hybrid mini-grid systems, for example, often incorporate a 75-99% renewable supply.<ref name="The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf">The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf</ref> | ||
| + | *Economic assessments indicate that of the renewable technologies available, biogas, geothermal, wind and micro-hydro systems costing US¢6-15/kWh are the potential least-cost generation options for mini-grids in developing countries, this however assumes that sufficient renewable energy resources are available. Biogas digesters and biomass gasifiers are particularly promising from this economic perspective; this is because of their high capacity factor and availability in size range matched to mini-grid load. Geothermal on the other hand also appears economically viable for countries that have geothermal resources although it is limited to larger grid connected systems.<ref name="Technical and economical assessment of off-grid, mini grid and grid electrification technologies: https://openknowledge.worldbank.org/bitstream/handle/10986/17911/430990ESM0REVISED01public1.txt?sequence=2">Technical and economical assessment of off-grid, mini grid and grid electrification technologies: https://openknowledge.worldbank.org/bitstream/handle/10986/17911/430990ESM0REVISED01public1.txt?sequence=2</ref> | ||
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= Further Information<br/> = | = Further Information<br/> = | ||
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Revision as of 18:20, 15 December 2014
Overview
A mini grid, also sometimes referred to as a "micro grid or isolated grid" can be defined as, a set of electricity generators and possibly energy storage systems interconnected to a distribution network that supplies electricity to a localized group of customers. This power delivery architecture can be contrasted to a single customer system such as in the case of a solar home system (SHS). Where there is no distribution network interconnecting customers it can be connected to a centralized grid systems, where electrical energy is transmitted over large distances from large central generators where local generators are generally not capable of meeting local demand.[1]
Mini-grids have a unique feature as they can operate autonomously without being connected to a centralized grid. However the mini-grid may be designed to interconnect with the central grid which means it operates under normal conditions as part of the central grid with disconnection occurring only if power quality needs to be maintained. For instance in the case of a central grid failure. Alternatively, a mini-grid may be designed to operate autonomously in a remote location with the option to connect to a central grid when grid extension occurs.[2]
A mini-grid can be supplied by all sorts of energy resources and power plants, however most of the time a mini-grid will use low AC voltage (220-380V) with a centralized production and a storage system and will have an installed capacity of between and 5 and 300kW even though bigger systems exist.[3]
Implementation of mini-grids have proved to have a positive social impact by fostering and improving the local governance structure through the involvement of the community in the decision making process linked with the energy system. There are hundreds of diesel-based isolated grids worldwide which lend themselves to be retrofitted with renewable energy technologies. Sharing limited resources and power among users in a mini-grid requires rules and a tariff structure that ensures sustainability in the operation. In general, mini-grids involve intense preparation to ensure the systems operation and maintenance will be sustainable.[4]
Opportunities
There are a lot of opportunities that have been observed with mini-grid systems:
- They can be used to increase the reliability of electricity supply. Due to their small scale in nature and enhanced local level ownership of physical infrastructure or management, power theft which is a commonly associated with centralized on grid systems can be reduced.[5]
- Reliability of supply is generally greater from hybrid mini-grid systems as compared to a single technology. This not only lowers the net costs over the lifetime of a project, but also ensures availability of power when one system is not working.[5]
- There is environmental improvement from the use of mini-grids. This is in terms of efficiency and reduction in carbon emissions. Hybrid mini-grid systems, for example, often incorporate a 75-99% renewable supply.[5]
- Economic assessments indicate that of the renewable technologies available, biogas, geothermal, wind and micro-hydro systems costing US¢6-15/kWh are the potential least-cost generation options for mini-grids in developing countries, this however assumes that sufficient renewable energy resources are available. Biogas digesters and biomass gasifiers are particularly promising from this economic perspective; this is because of their high capacity factor and availability in size range matched to mini-grid load. Geothermal on the other hand also appears economically viable for countries that have geothermal resources although it is limited to larger grid connected systems.[6]
Further Information
References
- ↑ An overview of technical aspects of Mini- Grids: https://www.eda.admin.ch/content/dam/countries/countries-content/india/en/resource_en_224456.pdf
- ↑ A review of mini-grid used for electrification in rural areas: http://iasir.net/AIJRSTEMpapers/AIJRSTEM13-239.pdf
- ↑ Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdf
- ↑ Rural electrification with renewable energy: http://www.ruralelec.org/fileadmin/DATA/Documents/06_Publications/ARE_TECHNOLOGICAL_PUBLICATION.pdffckLR The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdffckLR
- ↑ 5.0 5.1 5.2 The history of mini-grid development in developing countries: http://www.gvepinternational.org/sites/default/files/policy_briefing_-_mini-grid_final.pdf
- ↑ Technical and economical assessment of off-grid, mini grid and grid electrification technologies: https://openknowledge.worldbank.org/bitstream/handle/10986/17911/430990ESM0REVISED01public1.txt?sequence=2
