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News

GSES India to present at Intersolar 2014

Dwipen Boruah, Managing Director of GSES India, will be presenting at Intersolar 2014 in the Bombay Exhibition Centre, Mumbai, India on Thursday 20 November 2014. His presentation, 'Quality Framework to Ensure Manpower', will be held in Hall 6, Auditorium 1, from 3:40pm to 4:00pm (see the program here).

Intersolar India is India’s largest exhibition and conference for the solar industry and, as a leading industry platform, focuses on the areas of photovoltaics, PV production technologies, energy storage and solar thermal technologies.

See Dwipen's biography on the Intersolar website here, & read more about the conference here.

Renewable Energy and Alternate Fuels

GSES India is proud to be associated with the Delhi Technological University (DTU) faculty development program on Renewable Energy and Alternate Fuels (REAF-2014), which will be held from June 16th to June 20th, 2014.

The program will cover:

  • Renewable Power Sources and their Technologies 
  • Alternative Fuels for Transportation 
  • Energy Efficiency, auditing and conservation 
  • Solid and Liquid Waste Management 
  • Wind and Small Hydro Energy Systems 
  • Solar Air Heating Systems and their Applications in Drying of Agricultural and Industrial products. 
  • Solar water heating systems and their domestic and Industrial applications. 
  • Concentrated Solar Thermal for steam generation and their applications for cooking and Power Generation. 
  • Solar Refrigeration and Air-conditioning 
  • Solar furnace 
  • Solar Photovoltaic, Balance of systems, Energy Storage, Battery sizing, off grid and on grid PV applications. 
  • Overview of Solar Design Simulation Software for PV & Thermal 
For more information, please see the brochure linked below:

http://www.dce.edu/web/Sections/Specials/Programmes/FDP/FDP_on_RE_Brochure.pdf

Event: Solar Tech India Conference 2014

GSES India is delighted to be speaking at the Solar Tech India Conference 2014, which will be held in New Delhi, India, 22–23 July 2014.

Dwipen Boruah, Managing Director of GSES India, will give a presentation on Best practices for design and installations during Session V: Best EPC and O&M practices and novel solutions for solar energy industry in India (16:30–17:30) on the first day of the conference (Monday 22 July).

For more information, and to register for the conference, please visit the event website below:

http://www.greenworldconferences.com/produkt_104_solartech_india_2014.htm

SolarTech India 2014
22–23 July 2014

The Leela Ambience Gurgaon Hotel & Residences
Ambience Island, NH8
Gurgaon 122 002
Delhi - N.C.R, India

Metering 101: Understanding metering for rooftop PV systems

Amidst all the action around grid connected rooftop PV systems, it is important to understand the type of metering and how that would impact your generation based incentives. This article aims to provide some clarity on the topic.

The type of meter that will be installed with a grid-connected PV system will depend on the purchasing agreement with the electricity distributor. Two types of widely used metering arrangements are net metering and gross metering:

1. Net Metering

In net metering arrangement, the meter is allowed to operate in both directions. The electricity produced by the PV system (Sg) either provides power directly to the loads or is exported to the grid making the meter rotate backwards, reducing the actual number of units consumed as counted by the meter (Figure 1.1). 

When information is required on both the export and import electricity, a dual metering system is used. In this arrangement two mechanical meters can be installed with i-dents that only allow them to operate (or rotate) in one direction only (Figure 1.2). In this arrangement, the export meter will record the amount of electricity generated by the PV system that is exported to the grid during the day, while the import meter will record the exact amount of electricity that is consumed from the grid. By setting the export price of generated electricity at appropriate levels, users can be incentivized to increase self-consumption.

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Figure 1.1

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Figure 1.2

2. Gross Metering

This type of metering measures the generation and import of your electricity separately. By metering the total number of solar units of generated and total number of units consumed, this method allows the utility to charge the customers separately for import, generation and net consumption and if required, even at different rates. This is imposed by having two separate meters or using dual metering (dual-element electronic import and export meter; Figure 2). However, in this type of configuration, all of the energy generated is exported to the grid and user has no incentive to increase self-consumption.

 alt

Figure 2

 

Learn about more such topics, best practices and international standards in GSES ‘Grid Connected PV Systems Design’ online course or read more in GSES ‘Grid Connected PV Systems Design and Installation’ Handbook. Visit www.gses.in/training or www.gses.in/publications for details.

Buy now using your credit or debit card on the GSES online shop (www.gses.in/shop).

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Copyright GSES India Sustainable Energy Pvt. Ltd 2013

Understanding Earthing

Recent updates in the PV array installation standards and best practices have led to questions about the types of earthing and bonding in photovoltaic systems. This article aims to clarify what is meant then terms like earthing and bonding are used, and to briefly explain why each of these methods is needed.

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Earthing possibilities/Types of Earthing?

The following options for earthing or bonding of parts of a PV array exist: 

  1. Functional earthing of conductive non-current carrying parts. 
  2. Equipotential bonding to avoid uneven potentials across the installation.
  3. Earthing for lightening protection.
  4. Functional earthing of one current carrying pole (conductor) of the PV array.

When is Functional Earthing implemented?

Functional earthing whether as per part (a) or (d) is required when the DC voltage of the PV system is above the Decisive Voltage Classification (DVC) - A category i.e.? 60V, as per IEC 62548.

Why functional earthing is implemented?

Some modules require functional earthing (as part (d) above) so that they operate correctly (performance) or so that they do not corrode internally. Thin film modules generally need to be negatively earthed, to prevent ‘bar-graph’ corrosion inside the module. Back-contact modules (i.e. Sunpower) need to be positively earthed to achieve their rated efficiency (See figure). 

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Functional earthing (as per part (a) above) and equipotential bonding are implemented to allow for better detection of leakage paths to Earth and to prevent electric shock.

What is Equipotential Bonding?

In the case of PV arrays, there are two forms of equipotential bonding:

  • Main equipotential bonding: It is the connection of exposed conductive parts to the main earthing terminal.
  • Supplementary equipotential bonding: It is the connection of exposed conductive parts to exposed conductive parts and/or extraneous conductive parts with a purpose of keeping the voltage in exposed conductive arts sufficiently low.

This conductor is then connected back to the earth in the MEN system, and must be a minimum of 6mm2 (as per IEC 62548).

Why do you need Equipotential Bonding?

When a PV array is connected to a PCE (especially transformerless), high frequency switching occurs within the inverter and can cause a small AC-like fluctuation in the array cables. The array cables are effectively capacitively coupled to the module frames, and over time this induces a voltage on the module frames and hence chances of electrical shock. To eliminate this voltage any array connected to a PCE needs to have equipotential bonding on all array frames and mounting rails.

What configurations are NOT recommended?

It is not recommended to connect a functionally earthed array (as per part (d)) to a transformerless (non-isolated) inverter. The configuration is not recommended due to the high probability that the inverter will introduce direct current into the AC electricity grid.

 

Learn about more such topics, best practices and international standards in GSES ‘Grid Connected PV Systems Design’ online course or read more in GSES ‘Grid Connected PV Systems Design and Installation’ Handbook. Visit www.gses.in/training or www.gses.in/publications for details.

Buy now using your credit or debit card on the GSES online shop (www.gses.in/shop).

Follow us on Facebook, Twitter and LinkedIn for more such updates.

Copyright GSES India Sustainable Energy Pvt. Ltd 2013

DC Circuit Breakers vs AC Circuit Breakers

 

Source: Ali@gwc.org.uk (wikipedia)

 

1. Actuator lever – used to manually trip and reset the circuit breaker
2. Actuator mechanism – forces the contacts together or apart
3. Contacts – Allow current when touching and break the current when moved apart
4. Terminals
5. Bimetallic strip
6. Calibration screw – allows the manufacturer to precisely adjust the trip current of the device after assembly
7. Solenoid
8. Arc divider / extinguisher

Source: http://en.wikipedia.org/wiki/Circuit_breaker

Always wondered why DC circuit breakers are/should be used with solar PV systems when AC circuit breakers are less expensive and more readily available?!

Here’s why:

In AC circuits (regular household circuits), the voltage source changes the polarity of its output regularly. In India, this happens 100 times per second. By contrast, in DC circuits, the current flow is unidirectional due to the fixed polarity of the voltage source. This leads to undisrupted, longer and sustainable arcs in DC circuits (the reason why arc welding machines use DC current and not AC current). See DC arcs in action here:

Source: RISE

While breaking a DC circuit, it is easy to form such arcs, and if they are not extinguished in time they lead to device overheating and ultimately to fire. AC circuit breakers are not equipped well enough to deal with such arcs, whereas DC circuit breakers have special arc chutes to capture arcs and extinguish them safely, hence they are highly recommended. See what happens when AC circuit breakers are used in DC circuits or when safety devices are under-rated:

Source: RISE

Learn about more such best practices in the GSES online course Grid Connected PV System Design, or read more in GSES' Grid Connected PV Systems: Design and Installation Handbook. Visit www.gses.in/training or www.gses.in/publications for details.

Follow us on FacebookTwitter and LinkedIn for more such updates.

GSES India goes to Paris

GSES India recently participated in the 2013 European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC) in Paris, France. Hailed as one of the biggest solar PV events in the world, EU PVSEC 2013 gathered expertise from both industry and academia to provide a long list of plenary sessions, oral presentations and poster displays, accompanied by industry-organised parallel events and workshops.

EUPVSEC Posters

EUPVSEC posters

Integrating storage with PV systems received lots of attention from the industry as a means to solve the rising voltage fluctuations issue by increasing self-consumption. Training and education also formed a significant part of the 5-day conference, with talks from representatives of the Install+RES Project and the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA).

On the modules side, the issue of Potential Induced Degradation (PID) dominated the discussion. Although, as widely believed, PID is exacerbated by factors like high voltage, heat and humidity, precise causes and scientific explanation of the phenomenon still largely remain an enigma. Leading component manufacturers and academicians presented their views and suggested solutions to this problem.

With the increasing flow of PV-related materials and equipment from more than 200 manufacturers across different regions of the world, the development of international standards was seen as an important issue to facilitate trade and further reduce costs. In one of the talks, members of IEC Technical Committee 82 detailed their efforts to bring standardization to the global PV industry. The committee has so far developed over 60 technical standards addressing risks along the value chain.

With the cost of solar at rock-bottom prices, innovation, change and education will be key to keeping costs down and the industry sustainable. GSES India’s training and publication services help keep your business abreast with the latest industry standards and best practices, to enable you to be competitive in this growing and rapidly changing industry.

 

Multi-Mega-Scale PV Systems

Large-scale PV system 

Image from Gujarat Power Commission Ltd.

Multi-Mega-scale photovoltaic (PV) projects have been in news for a while but are they really the way to go? We analysed the pros and cons of such centralised solar electricity-generation systems to get some insight.

Pros

  1. Technology forerunner: The largest solar project commissioned in the world so far is the Agua Caliente Solar Project in the USA, 26 MWp larger than the Charanka Park, Patan district PV power plant. Developing a project over 500 MW project would not only establish the nation as a technology leader but also prove its seriousness towards the fight for climate change. 
  2. A step closer to energy sufficiency: India is a power-deficit nation, with a generation deficit of 10–12% of its peak demand. Large-scale solar projects would help in bridging that gap quickly and in reducing the nation’s CO2 emissions per MWh.
  3. Cost–benefit: Large-scale projects would benefit from economies of scale and hence potentially lead to lower bidding price. Other factors, such as lower overhead costs per MWh, would further lead to lower cost of generation.
  4. Ease of implementation: Distributed solar and rooftop schemes have been effective in many parts of the developed world but at the same time have proved to be expensive and unsafe if not controlled or regulated properly. Also, in a country like India, where grid stability is still an issue, it would be difficult to reap full benefits of such schemes. Therefore, the centralised multi-Mega-scale projects would be more beneficial and easier to implement.

Cons

  1. Lack of experience: With the current largest plant in the world being a 250 MWp plant, designing, installing and commissioning projects larger than 500 MW would pose new problems requiring innovative solutions.
  2. Lack of local expertise: Projects of such scale would require several hundred technicians and engineers to be working onsite at any given time. Although this would create job opportunities for the local workforce, training the workforce onsite in the local dialect would be a major issue.
  3. Grid stability issues: An important factor that directly affects the performance ratio of PV plants, the lack of a stable and robust grid capable of handling large fluctuations would be one of the biggest issues when implementing such projects.
  4. Safety: Raising the capacity bars would require generation at higher voltages and transmission of higher current. Such high-current, high-voltage DC supply might render the plant unsafe.
  5. Transmission losses: It makes sense to install these multi-Mega-scale projects in areas of high irradiance and, because of their size, the systems would require large open areas for installation; therefore, the projects would generally be located far from demand centres. This would mean higher transmission losses and lower overall energy efficiency.
  6. Technology is critical: Selection of appropriate technology suited to the location and the local climate would be of utmost importance. Lack of prior experience in such projects would mean devising new techniques to categorise technology based on local requirements.
  7. Boom–bust cycle trend: It is important to maintain certainty in the market for sustainable industry growth. Large-sized projects often lead to on–off cycles in the market, making the market unsustainable.
  8. Village remoteness: In India, there are a large number of remote villages and towns without access to the electricity grid. Large-scale centralised generation systems bring no light to villages in darkness.

 

With a widening energy deficit, rising oil and gas import burdens and global pressure to act on climate change, the country needs innovative solutions and quick reforms in its electricity industry. Large-scale PV plants, if successful would not only support India’s burgeoning manufacturing industry but also establish the nation as a world leader. However, large-scale systems form just a part of a three-pronged solution, with small-scale distributed systems and standalone off-grid hybrid systems forming the other two. Equal emphasis has to be laid on all three to meet the energy demands of this fast-growing nation.

We would love to hear back your comments and opinions. Write to us at info@gses.in with ‘GSES September newsletter’ as the subject.

 

Solar Training at ANERT

This month GSES India conducted two days of comprehensive training in the Inspection and Evaluation of Solar PV systems for engineers and officers of the Agency for Non-conventional Energy and Rural Technology (ANERT). 


ANERT is the Nodal Agency for the Ministry of New and Renewable Energy (MNRE). It is located in the southern state of Kerala, which is implementing an ambitious project of 10,000 solar rooftop systems. This course was the first of its kind in India - its aim was to build the skills of Engineers at ANERT to inspect, evaluate and monitor Solar PV Systems.

The course combined the GSES experience in the Asia Pacific region and included both classroom and hands on identification of issues. 28 ANERT engineers and officers from different districts and field offices attended. They are responsible for the inspection and evaluation of PV systems.


GSES India has designed and distributed an inspection manual for a step by step PV system inspection and evaluation. Training in system inspection, monitoring and evaluation is critical to ensure India's solar installations continue to improve in quality and last the lifetime they are intended.



Latest REEEP News

Here is the latest news for the Renewable Energy & Energy Efficiency Partnership (REEEP). You can also subscribe to their news yourself to keep abreast of what's happening in renewables and energy efficiency around the globe.

REEEP News, May 2012.

IEA-PVPS and European Hybrid Conference

 On the 23rd of April, Geoff Stapleton attended an IEA-PVPS strategies meeting in Stockholm, Sweden. Other Australians in attendance were Muriel Watt, Chair of APVA, and Greg Watt, Australia's expert on Task 1. Geoff has represented Australia on Task 9 for over 10 years. Current tasks of IEA-PVPS include:

  • Task 1: Exchange and dissemination of information on photovoltaic power systems
  • Task 8: Very large scale photovoltaic power generation systems in remote areas
  • Task 9: Deploying PV services for regional development
  • Task 11: PV hybrid systems within mini-grids
  • Task 12: PV environmental health and safety
  • Task 13: Performance and reliability of photovoltaic systems
  • Task 14: High penetration of PV systems in electricity grids
The purpose of the workshop was to develop the strategy for IEA-PVPS tasks and activities relating to the period of 2013 - 2018. Through the collaboration of member countries, IEA-PVPS has developed useful technical and non-technical information. Historically it has aimed at identifying issues in the deployment of PV, working at developing solutions through collaboration and then documenting the outcomes in freely available reports.

Discussions included; what are the upcoming issues for the PV industry that PVPS could be involved with, and how to more widely disseminate the information that is developed by PVPS. The strategy would day would then be used by the executive committee (Exco) to formulate the direction of IEA-PVPS for the next 5 years. The Exco was meeting on the following two days, the 24th and 25th of April.

Geoff then travelled to Chambery, France, to attend the 6th European Hybrids and Mini-Grids conference. There were 175 delegates at the 2 day conference which included formal presentations and a number of poster sessions. A number of the presentations and posters related to the control issues within hybrids and mini-grids. There were also a number of presentations on actual systems installed around the world and the technical/physical issues involved in installing and maintaining those systems in remote regions. One point that was raised many times was the fact that diesel fuel is expensive in these remote regions while PV prices have dropped significantly in recent years thereby making the economics of PV more attractive for hybrids and mini-grids.


Susan Neill and Geoff had prepared a paper and poster titles: Applying lessons learnt from the implementation of Solar Home systems to the implementation of Hybrid systems in developing countries. Those with posters were able to present 2 slides only on their poster to entice people to visit their poster. Susan and Geoff's focus was that the main reasons for system failures in developing countries were generally not technical, and regardless of equipment quality, many other issues needed to be addressed to make the sustainable energy based hybrid systems sustainable!

Chambery is in the French Alps, and Geoff had a day off of driving through the Alps before flying home to Australia - though delayed 22 hours at Heathrow due to plane mechanical issues flying out of France!