DC Mini-grids - Revision history

Fernanda Wynter: /* Examples of DC mini-grids to date */

2021-08-30T07:30:41Z

Examples of DC mini-grids to date

Caspar Priesemann: /* Examples of DC mini-grids to date */

2018-07-23T12:42:53Z

Examples of DC mini-grids to date

Bastian Lange: /* System efficiency */

2016-12-22T07:42:31Z

System efficiency

Bastian Lange: /* Examples of DC mini-grids to date */

2016-12-22T07:35:54Z

Examples of DC mini-grids to date

Bastian Lange: /* Fault protection */

2016-12-22T07:35:01Z

Fault protection

Bastian Lange: /* Fault protection */

2016-12-22T07:32:08Z

Fault protection

Bastian Lange: /* Introduction */

2016-12-22T07:29:39Z

Introduction

Bastian Lange: /* Introduction */

2016-12-22T07:19:40Z

Introduction

Ranisha at 10:07, 13 January 2016

2016-01-13T10:07:39Z

Ranisha: Ranisha moved page DC mini-grids to DC Mini-grids without leaving a redirect

2015-12-08T09:34:53Z

Ranisha moved page DC mini-grids to DC Mini-grids without leaving a redirect

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 DC mini-grids are being implemented by:
-*[http://meshpower.co.uk/blog/ Meshpower]: Meshpower has installed 7 solar PV DC micro-grids in '''Rwanda''', providing power for lighting and mobile phone charging for up to 2-3 hours a day. They are applying the same model in '''India.'''
+*[https://www.meshpower.co.rw/ Meshpower]: Meshpower has installed 7 solar PV DC micro-grids in '''Rwanda''', providing power for lighting and mobile phone charging for up to 2-3 hours a day. They are applying the same model in '''India.'''
-*[http://meragaopower.com/ Mera Gao Power]<u>(MGP)</u>: MGP has installed DC mini-grids in around 900 villages in '''India''', providing lighting and mobile phone charging services to around 20,000 households. Installation costs averaged INR 55,000 per 30 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
+*Mera Gao Power&nbsp;<u>(MGP)</u>: MGP has installed DC mini-grids in around 900 villages in '''India''', providing lighting and mobile phone charging services to around 20,000 households. Installation costs averaged INR 55,000 per 30 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
 *[http://www.cygni.com/ Cygni]: Cygni is headquartered at Hyderabad in '''India'''. By 2018 it has implemented DC systems in 816 villages across 9 states servicing 19.000 homes.
 *[http://www.teriin.org/ The Energy and Resources Institute (TERI)]: By 2014, TERI had installed 30 DC micro-grids in Uttar Pradesh ('''India'''), providing 130 households and 1,100 business units with LED lighting (4 hours per day, 1-3 lights per HH) and mobile phone charging. Costs averaged INR 2,000,000 per 50 households connected.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
-*[http://neda.up.nic.in/ Uttar Pradesh New and Renewable Energy Development Agency (UPNEDA)]: In 2011-12, UPNEDA installed 23 DC solar PV micro-grids in Uttar Pradesh ('''India'''), covering around 4,000 families. Electricity provision is limited to 4-5 hours in the evening, with 2 LED lamps and mobile charging for households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
+*[http://upneda.org.in/ Uttar Pradesh New and Renewable Energy Development Agency (UPNEDA)]: In 2011-12, UPNEDA installed 23 DC solar PV micro-grids in Uttar Pradesh ('''India'''), covering around 4,000 families. Electricity provision is limited to 4-5 hours in the evening, with 2 LED lamps and mobile charging for households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
-*[http://www.mindanexgentech.com/power-generation/projects Minda]: Minda has installed 13 DC solar PV micro-grids in '''India '''to date, providing electricity primarily for lighting (2 LED lamps per HH). Installation costs averaged around INR 360,000 per 40 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
+*[https://in.linkedin.com/company/minda-nexgentech Minda]: Minda has installed 13 DC solar PV micro-grids in '''India '''to date, providing electricity primarily for lighting (2 LED lamps per HH). Installation costs averaged around INR 360,000 per 40 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
-*[http://solar-ic.com/solaricdev/major-innovations/nano-grid/ Solaric]: Solaric installs DC micro-grids, utilising 1.5 to 3 kWp PV systems. The company is active in '''Bangladesh, India, Nepal and Malaysia'''.
+*[https://www.facebook.com/SolaricEnergy/ Solaric]: Solaric installs DC micro-grids, utilising 1.5 to 3 kWp PV systems. The company is active in '''Bangladesh, India, Nepal and Malaysia'''.
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 *[http://meshpower.co.uk/blog/ Meshpower]: Meshpower has installed 7 solar PV DC micro-grids in '''Rwanda''', providing power for lighting and mobile phone charging for up to 2-3 hours a day. They are applying the same model in '''India.'''
 *[http://meragaopower.com/ Mera Gao Power]<u>(MGP)</u>: MGP has installed DC mini-grids in around 900 villages in '''India''', providing lighting and mobile phone charging services to around 20,000 households. Installation costs averaged INR 55,000 per 30 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
 *[http://www.teriin.org/ The Energy and Resources Institute (TERI)]: By 2014, TERI had installed 30 DC micro-grids in Uttar Pradesh ('''India'''), providing 130 households and 1,100 business units with LED lighting (4 hours per day, 1-3 lights per HH) and mobile phone charging. Costs averaged INR 2,000,000 per 50 households connected.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
 *[http://neda.up.nic.in/ Uttar Pradesh New and Renewable Energy Development Agency (UPNEDA)]: In 2011-12, UPNEDA installed 23 DC solar PV micro-grids in Uttar Pradesh ('''India'''), covering around 4,000 families. Electricity provision is limited to 4-5 hours in the evening, with 2 LED lamps and mobile charging for households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>

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 == System efficiency ==
-In providing for a more ‘natural’ solution for the growing number of native DC components in electricity generation, storage and consumption (see Introduction), DC can contribute towards reducing conversion losses and achieving higher efficiency in electrical systems.
+In providing for a more ‘natural’ solution for the growing number of native DC components in electricity generation, storage and consumption (see Introduction), DC can contribute towards reducing conversion losses and achieving a higher overall efficiency in electrical systems.
-Apart from distribution (grid length, voltage, etc.), overall system efficiency depends on power conversion stages between electricity generation and load. Efficiency losses from DC-AC conversion (via inverters) and AC-DC conversion (via rectifiers) considerable affect overall system efficiency. Occurrence of such conversion steps in a mini-grid system will depend on the type of generation used (AC or DC), whether battery storage is integrated, and what type of consumptive loads are envisioned.
+Apart from distribution (grid length, voltage, etc.), overall system efficiency depends on the occurence of power conversions between electricity generation and load. Efficiency losses from DC-AC conversion (via inverters) and AC-DC conversion (via rectifiers) can have a considerable effect on overall efficiency. Whether or not such conversion steps occur in a in a mini-grid system will depend on the type of generation used (AC or DC), whether battery storage is integrated, and what type of consumptive loads will be used.
-For their sample case of a solar PV mini-grid with battery storage, Madduri et al. (2013)<ref name="Madduri, P.A. et al. 2013. Design and Verification of Smart and Scalable DC Microgrids for Emerging Regions, available from: http://power.eecs.berkeley.edu/publications/madduri_ECCE_2013.pdf">Madduri, P.A. et al. 2013. Design and Verification of Smart and Scalable DC Microgrids for Emerging Regions, available from: http://power.eecs.berkeley.edu/publications/madduri_ECCE_2013.pdf </ref> arrive at an increase in end-to-end-efficiency for a DC system with 380 VDC transmission of between 17 and 25% for DC loads (fully DC mini-grid) and around 3% for AC loads, as compared to the usage of an AC system.
+For their sample case of a solar PV mini-grid with integrated battery storage, Madduri et al. (2013)<ref name="Madduri, P.A. et al. 2013. Design and Verification of Smart and Scalable DC Microgrids for Emerging Regions, available from: http://power.eecs.berkeley.edu/publications/madduri_ECCE_2013.pdf">Madduri, P.A. et al. 2013. Design and Verification of Smart and Scalable DC Microgrids for Emerging Regions, available from: http://power.eecs.berkeley.edu/publications/madduri_ECCE_2013.pdf </ref> arrive at an increase in end-to-end-efficiency of between 17 and 25% for a DC system with 380 VDC transmission and DC loads (fully DC mini-grid) and around 3% higher overall efficiency for the same system using AC loads, as compared to an AC system design.
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 == System / operational costs ==

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 = Examples of DC mini-grids to date =
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 *[http://meshpower.co.uk/blog/ Meshpower]: Meshpower has installed 7 solar PV DC micro-grids in '''Rwanda''', providing power for lighting and mobile phone charging for up to 2-3 hours a day. They are applying the same model in '''India.'''
-*[http://meragaopower.com/ Mera Gao Power]<u>(MGP)</u>: MGP has installed DC mini-grids in around 900 villages in '''India''', providing lighting and mobile phone charging services to around 20,000 households (Palit and Malhotra, 2014).Installation costs averaged INR 55,000 per 30 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
+*[http://meragaopower.com/ Mera Gao Power]<u>(MGP)</u>: MGP has installed DC mini-grids in around 900 villages in '''India''', providing lighting and mobile phone charging services to around 20,000 households. Installation costs averaged INR 55,000 per 30 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
-*[http://www.teriin.org/ The Energy and Resources Institute (TERI)]: By 2014, TERI had installed 30 DC micro-grids in Uttar Pradesh ('''India'''), providing 130 households and 1,100 business units with LED lighting (4 hours per day, 1-3 lights per HH) and mobile phone charging (Palit and Malhotra, 2014). Costs averaged INR 2,000,000 per 50 households connected.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
+*[http://www.teriin.org/ The Energy and Resources Institute (TERI)]: By 2014, TERI had installed 30 DC micro-grids in Uttar Pradesh ('''India'''), providing 130 households and 1,100 business units with LED lighting (4 hours per day, 1-3 lights per HH) and mobile phone charging. Costs averaged INR 2,000,000 per 50 households connected.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
 *[http://neda.up.nic.in/ Uttar Pradesh New and Renewable Energy Development Agency (UPNEDA)]: In 2011-12, UPNEDA installed 23 DC solar PV micro-grids in Uttar Pradesh ('''India'''), covering around 4,000 families. Electricity provision is limited to 4-5 hours in the evening, with 2 LED lamps and mobile charging for households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
 *[http://www.mindanexgentech.com/power-generation/projects Minda]: Minda has installed 13 DC solar PV micro-grids in '''India '''to date, providing electricity primarily for lighting (2 LED lamps per HH). Installation costs averaged around INR 360,000 per 40 households.<ref name="Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P">Palit, D. and Malhotra, S. 2014. Energizing rural India using micro grids: The case of solar DC micro-grids in Uttar Pradesh State, India, available from: http://bit.ly/1m0Z65P</ref>
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 = References =

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 As of today, protection systems for DC mini-grids must be considered less mature in terms of practical experience, standards, guidelines and implementation compared to AC systems<ref name="Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.">Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.</ref>.<br/>
-A particular concern in DC systems is the absence of natural zero crossings (points at which the voltage momentarily equals zero), rendering current interruption considerably more demanding and potentially more dangerous (occurrence of switch arcs)<ref name="Justo, J.J. et al. 2013. AC-microgrids versus DC-microgrids with distributed energy resources: A review, in: Renewable and Sustainable Energy Reviews, 24 (2013), pp. 387-405">Justo, J.J. et al. 2013. AC-microgrids versus DC-microgrids with distributed energy resources: A review, in: Renewable and Sustainable Energy Reviews, 24 (2013), pp. 387-405</ref>. This is, however, not a primary concern for low voltage DC, such as the commonly used 12 VDC or 24 VDC, as principle availability of adequately sized protection solutions does not differ markedly from standard AC systems<ref name="Groh, S. et al. 2014. The Battle of Edison and Westinghouse Revisited: Contrasting AC and DC micro-grids for rural electrification, available from: http://bit.ly/1lecL9s">Groh, S. et al. 2014. The Battle of Edison and Westinghouse Revisited: Contrasting AC and DC micro-grids for rural electrification, available from: http://bit.ly/1lecL9s</ref><ref name="Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.">Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.</ref>.
+A particular concern in DC systems is the absence of natural zero crossings (points at which the voltage momentarily equals zero), rendering current interruption considerably more demanding and potentially more dangerous (occurrence of switch arcs)<ref name="Justo, J.J. et al. 2013. AC-microgrids versus DC-microgrids with distributed energy resources: A review, in: Renewable and Sustainable Energy Reviews, 24 (2013), pp. 387-405">Justo, J.J. et al. 2013. AC-microgrids versus DC-microgrids with distributed energy resources: A review, in: Renewable and Sustainable Energy Reviews, 24 (2013), pp. 387-405</ref>. This is, however, not a primary concern for low voltage DC systems, such as the commonly used 12 VDC or 24 VDC, as the general availability of adequately sized protection solutions does not differ markedly from standard AC systems<ref name="Groh, S. et al. 2014. The Battle of Edison and Westinghouse Revisited: Contrasting AC and DC micro-grids for rural electrification, available from: http://bit.ly/1lecL9s">Groh, S. et al. 2014. The Battle of Edison and Westinghouse Revisited: Contrasting AC and DC micro-grids for rural electrification, available from: http://bit.ly/1lecL9s</ref><ref name="Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.">Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.</ref>.
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 = Introduction<br/> =
-Changing patterns in electricity generation and consumption over the past decades have brought new life to the debate on the use of Alternating Current (AC) vs. Direct Current (DC) electricity supply in distributed generation systems. Direct Current distinguishes itself from Alternating Current through the fact that electric charge flows in a constant direction.
+Changing patterns in electricity generation and consumption over the past decades have brought new life to the debate on the use of Alternating Current (AC) vs. Direct Current (DC) electricity supply in distributed generation systems. Direct Current distinguishes itself from Alternating Current through the fact that electric charge flows in a constant direction. When graphically depicted, DC output thus takes the shape of a straight line, whereas AC output shapes a wave pattern, crossing the zero output line in regular intervals.
 Direct Current is native to solar PV electricity generation, battery storage and a range of common, low-power household and commercial applications, such as LED-lighting, consumer electronics (e.g. TV, radio, mobile phones) and variable speed drives in electric motors (e.g. for fans or pumps). With an increasing reliance on these components and applications, DC systems have, in many cases, become a technically and economically viable alternative to ‘traditional’ AC systems.

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 = Introduction<br/> =
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 The decision between DC and an AC provides for a number of implications in terms of a mini-grid’s system architecture and operation. In the following, a short overview on the main differences is provided.
 == Power control and management ==
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 Due to an inherently unidirectional flow of current, a DC architecture does not require the usage of the frequency/phase control mechanisms of its AC equivalent. Hence, with only voltage to be accounted for, DC systems generally provide for a lower system complexity, reduced number of variables in systems monitoring<ref name="Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.">Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.</ref>, lower cost for control equipment components<ref name="Karabiber, A. et al. 2013. An approach for the integration of renewable distributed generation in hybrid DC/AC microgrids, in: Renewable Energy, 52 (2013), pp. 251-259.">Karabiber, A. et al. 2013. An approach for the integration of renewable distributed generation in hybrid DC/AC microgrids, in: Renewable Energy, 52 (2013), pp. 251-259.</ref> and a more modular and more easily expendable structure<ref name="Groh, S. et al. 2014. The Battle of Edison and Westinghouse Revisited: Contrasting AC and DC micro-grids for rural electrification, available from: http://bit.ly/1lecL9s">Groh, S. et al. 2014. The Battle of Edison and Westinghouse Revisited: Contrasting AC and DC micro-grids for rural electrification, available from: http://bit.ly/1lecL9s</ref>.<br/>
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 Comparative savings on capital cost are, however, at least partly offset by general price penalties on the more immature DC technology components<ref name="Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.">Planas, E. et al. 2015. AC and DC technology in microgrids: A review, in: Renewable and Sustainable Energy Reviews, 43 (2015), pp. 726-749.</ref>.
 = Applicability of DC mini-grids =
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 = Examples of DC mini-grids to date =
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 = References =
 <references />
 [[Category:PV_Mini-grid]]