See THE LIGHT OF LIFE at
[http://www.facebook.com/l/fAQCSLWiwAQBUYyGeHhmyOl93dq3hXPEcd7889Q6NfBO99A/www.youtube.com/watch?v=ziT3XYE2xSA&sns=fb]
Here is a brilliant use of solar energy as a light source, without using any conversion to heat or electricity.
Many hut and shanty structures have roofs and walls hat do not permit any natural illumination. Here, a light gathering water-lens was improvised with a plastic bottle was filled up with water and inserted through the roof. Given the protruding shape of the bottle's neck, sunlight from about any angle is absorbed into the bottle, concentrated via refraction and diffused by the lower part of the bottle glowing in the dark.
Tuesday, September 27, 2011
Monday, September 27, 2010
Sunday, September 26, 2010
Wednesday, September 15, 2010
Getting it right with photovoltaics
Few people and organisations appreciate the the best way forward in a power-deprived region is to give people the power to charge batteries via low-cost-low-power SPV panels - and next - to help make simple battery-powered flashlights and such battery-powered equipment locally. Invariably, political expediency and other factors put pressure on building large centralised power systems in these regions and run into conflicts of all kinds and at a huge cost.
In this light, it is heartening to see quite a few initiatives in Africa getting it right. The BioDesign Newsletter of 14th September 2010 informs us about the Noar Foundation http://noar.g3web.net doing exemplary work in distant Togo.
Mr Graham Knight of Biodesign UK http://biodesign.webeden.co.uk has encouraged several such initiatives by training and providing small quantities of single-digit wattage solar panels to enthisiasts and NGOs alike. In fact he is a major inspiration to The microPower Initiative.
In this light, it is heartening to see quite a few initiatives in Africa getting it right. The BioDesign Newsletter of 14th September 2010 informs us about the Noar Foundation http://noar.g3web.net doing exemplary work in distant Togo.
Mr Graham Knight of Biodesign UK http://biodesign.webeden.co.uk has encouraged several such initiatives by training and providing small quantities of single-digit wattage solar panels to enthisiasts and NGOs alike. In fact he is a major inspiration to The microPower Initiative.
Friday, December 18, 2009
Alternatives to solid-state invertors or UPS?
There is yet another unique solution that is still popular for critical installations like life support, airport signalling, etc., beyond about 50 KVA in load and for industrial loads of all values. It combines the benefits of all invertor-based solid-state battery-backed UPS systems. Called Rotary UPS, No-Break generator, short-break generator or MG Set, depending on the exact application-specific configuration, it is available in power ratings from fractional HP to Megawatts.
In larger power or high-current requirements, the battery bank used in inverter and UPS involves multiple joints. Even at few ohms, a high current can drop several volts from the line. Such drops add with each joint, causing high line loss. Next, the plates of lead-acid batteries (most commonly used) under hi-drain and hi-charge conditions tend to harden, especially in applications like telephone exchanges, which drain all stored current in 5 hours from C-5 Duty Class batteries. This means either total replacement of the battery bank in 3 years or 30% battery replacement per year. The only alternative is to use excess battery capacity by a higher Duty Class, say C-25 to C-100, but that means filling up a room instead of a stool as at present.
Either way, all this means high running cost. No inverter/UPS manufacturer will advise a buyer of this but will promptly blame the battery vendor in case of a failure. Invertor/UPS warranties exclude responsibility from battery performance. Likewise, the fine print also puts limits on the acceptable levels of EMI or Noise, transients and frequency changes, all of which together lower the reliability of inverter-UPS systems, even though SMPS and PWM-based circuits and IGBT bridges have brought in improvements. Besides, in India, these often need expensive airconditioned rooms.
On the other hand, a rotary UPS uses a motor to drive an alternator or dynamo via a flywheel. Despite the worst in interrupted power supply, flywheel momentum drives the generator steadily, delivering a smooth voltage and frequency as needed. During short failures too, flywheel momentum drives the generator but at gradually lowering voltage or frequency. However, if the supply from the mains fails for longer than a preset time limit, an engine, pneumatic or hydraulic motor gets ‘kicked’ by a clutch fitted on the flywheel. This prime mover in turn revs up the entire motor-flywheel-generator system, delivering the desired power output without a break.
A variety of prime mover choices as well as motor and alternator or dynamo choices can be exercised to match about any set of line and load regulation requirements. Petrol engines suit rapid starts and short runs, while diesel engines are heavy-duty workhorses. Hydraulic and pneumatic motors are used where fuel storage is infeasible, besides in small ratings. Likewise, DC and synchronous motors provide a precisely regulated voltage-frequency output, while squirrel-cage induction motors save on cost. In few cases, battery-banks are also used to drive DC motors during short interruptions. Larger No-break generator systems also use PLCs and microprocessor controls for sensing conditions and acting on them since all uninterrupted supplies can be hazardous in the face of a fault.
The race between solid-state and rotary UPS thus continues…
In larger power or high-current requirements, the battery bank used in inverter and UPS involves multiple joints. Even at few ohms, a high current can drop several volts from the line. Such drops add with each joint, causing high line loss. Next, the plates of lead-acid batteries (most commonly used) under hi-drain and hi-charge conditions tend to harden, especially in applications like telephone exchanges, which drain all stored current in 5 hours from C-5 Duty Class batteries. This means either total replacement of the battery bank in 3 years or 30% battery replacement per year. The only alternative is to use excess battery capacity by a higher Duty Class, say C-25 to C-100, but that means filling up a room instead of a stool as at present.
Either way, all this means high running cost. No inverter/UPS manufacturer will advise a buyer of this but will promptly blame the battery vendor in case of a failure. Invertor/UPS warranties exclude responsibility from battery performance. Likewise, the fine print also puts limits on the acceptable levels of EMI or Noise, transients and frequency changes, all of which together lower the reliability of inverter-UPS systems, even though SMPS and PWM-based circuits and IGBT bridges have brought in improvements. Besides, in India, these often need expensive airconditioned rooms.
On the other hand, a rotary UPS uses a motor to drive an alternator or dynamo via a flywheel. Despite the worst in interrupted power supply, flywheel momentum drives the generator steadily, delivering a smooth voltage and frequency as needed. During short failures too, flywheel momentum drives the generator but at gradually lowering voltage or frequency. However, if the supply from the mains fails for longer than a preset time limit, an engine, pneumatic or hydraulic motor gets ‘kicked’ by a clutch fitted on the flywheel. This prime mover in turn revs up the entire motor-flywheel-generator system, delivering the desired power output without a break.
A variety of prime mover choices as well as motor and alternator or dynamo choices can be exercised to match about any set of line and load regulation requirements. Petrol engines suit rapid starts and short runs, while diesel engines are heavy-duty workhorses. Hydraulic and pneumatic motors are used where fuel storage is infeasible, besides in small ratings. Likewise, DC and synchronous motors provide a precisely regulated voltage-frequency output, while squirrel-cage induction motors save on cost. In few cases, battery-banks are also used to drive DC motors during short interruptions. Larger No-break generator systems also use PLCs and microprocessor controls for sensing conditions and acting on them since all uninterrupted supplies can be hazardous in the face of a fault.
The race between solid-state and rotary UPS thus continues…
Thursday, August 27, 2009
Business in Solar Cells and Panels - opportunity or risk?
A lot of good and bad work by the various governments and industry make RE or renewable energy in India a promising yet risky venture. Otherwise, with about the highest bases of RE installations as well as globally leading manufacturers like Tata BP and Suzlon in India, we would have seen every other home powered, heated and fed via solar devices, every garden generating power from bio-gas and SPV for the neighbouring street, farmers and cooperative societies prospering as energy producers from biomass and wind.
The solar programme in India is as old as the 70s, with the CSIR first identifying this as a promising field in the early 70s, the setting up of CASE - Commission for Alternate Sources of Energy at Mrs Indira Gandhi's behest in 1980, leading to the DNES - Dept of Non-conventional Energy Sources by 1983-84 that finally got Ministry status as MNES under Narasimha Rao in 1992. Simultaneously, States set up Nodal Agencies to facilitate development, manufacture, marketing and installation of RE products and Gujarat took the lead with the establishment of GEDA about 1978-79 under the Janata Party Govt and visionary Chairmanship of Dr Nanubhai B Amin.
The spadework that lead to India becoming the largest installed base in solar energy was done by these relatively non-bureaucratic departments during that era. A large number of power, thermal equipment and systems engineering companies progressively entered this field, from the mid 70s to the 80s. I was also involved in installing about 1000 panels of solar-thermal panels for industrial and domestic heating and few scores of SPV systems. All RE systems were marketed under the SNAs' aegis and buyers, who had to be end users, got half or more their installed cost subsidised or reimbursed according to the policies of that day, between the Central and State Govts.
Although the Public Sector doggedly stuck to their protected monopoly in SPV cells and panels, companies like CEL and BHEL took the initiative to supply panels via the Nodal Agencies to systems integrators who installed SPV-based community lighting solutions in several thousand villages in each State.
In 1985, Rajiv Gandhi's Govt dealt a body blow to the RE industry, when perhaps his swish set of advisers made him slash the RE provisions in the 7th 5-yr Plan from Rs 400 Cr to just Rs 7 Cr. This put paid to all subsidised projects and murdered the market prospects of large companies, which were started with large projected demands endorsed by the licensing body, mostly the DNES and Industries Ministry. By then, SPV imports leading to phased manufacture manufacture of SPV panels were allowed. But Mr VP Singh, as Finance Minister sat over all foreign collaboration files citing the need to save forex.
Rajiv Gandhi Govt. had, by then also shot down the silicon foundry proposal of IPCL-Hemlock, asserting that there was enough silicon facility between Mettur Industries and Semiconductor Complex Ltd of Chandigarh, the latter of which was gutted in a fire before commissioning and never re-commissioned. Thus we never saw PV-grade silicon made in India in the required quantity. Otherwise solar panels would have perhaps been household commodities by now!
In 1989, VP Singh's Janata Dal coalition Govt came to power. It agreed on private sector importing solar cells towards a Phased Manufacturing Programme for panels but the refusal to involve the IMF etc again starved the economy of foreign exchange and imports, again restricting the import or manufacture of solar cells to the public sector. Hence a company like Tata BP Solar had to hand its know-how and import sources to BHEL and in exchange receive priority allotted deliveries of panels. This put severe restrictions on the industry and business opportunities.
Other companies are still reeling under losses inflicted by these whims to this date.
Meanwhile it took the clout and massive resources of the Tatas to continue to develop the 'balance of systems' including charge and load regulators, batteries, suitable lamps, fans, invertors, etc as needed to complete a SPV power system. They insisted on the highest quality standards and delivered only complete systems, initially under a 5-year comprehensive warranty. This inspired confidence and saw sustained growth, while its competitors were veritably wiped out.
Risk-hedging is perhaps one reason why manufacturers like Tata BP who started out as dedicated SPV panel and systems manufacturers felt and still feel the need to also manufacture or market solar-thermal panels and systems. The latter systems also have a faster pay-back period than SPV.
Yet others like Shell, Siemens, GE, Philips, National and several others have entered the field but lack the long-term perspective, perseverance and commitment to survive this market. However, we see some progress by smaller players like SELCO, Solite, Solkar and few others who rely on Chinese/East Asian imports of SPV panels.
Amorphous silicon offers tremendous opportunity to SMEs and MSMEs by being ready-made in large quantities, amenable to scaling, shadow-tolerance and although of a lower efficiency, available at half the cost per Wp compared to crystalline silicon. Small manufacturers can import these 'a-Si glass' sheets, cut them according to the desired rated voltage and current, frame and connect them as finished panels without any sophisticated production facilities.
The solar programme in India is as old as the 70s, with the CSIR first identifying this as a promising field in the early 70s, the setting up of CASE - Commission for Alternate Sources of Energy at Mrs Indira Gandhi's behest in 1980, leading to the DNES - Dept of Non-conventional Energy Sources by 1983-84 that finally got Ministry status as MNES under Narasimha Rao in 1992. Simultaneously, States set up Nodal Agencies to facilitate development, manufacture, marketing and installation of RE products and Gujarat took the lead with the establishment of GEDA about 1978-79 under the Janata Party Govt and visionary Chairmanship of Dr Nanubhai B Amin.
The spadework that lead to India becoming the largest installed base in solar energy was done by these relatively non-bureaucratic departments during that era. A large number of power, thermal equipment and systems engineering companies progressively entered this field, from the mid 70s to the 80s. I was also involved in installing about 1000 panels of solar-thermal panels for industrial and domestic heating and few scores of SPV systems. All RE systems were marketed under the SNAs' aegis and buyers, who had to be end users, got half or more their installed cost subsidised or reimbursed according to the policies of that day, between the Central and State Govts.
Although the Public Sector doggedly stuck to their protected monopoly in SPV cells and panels, companies like CEL and BHEL took the initiative to supply panels via the Nodal Agencies to systems integrators who installed SPV-based community lighting solutions in several thousand villages in each State.
In 1985, Rajiv Gandhi's Govt dealt a body blow to the RE industry, when perhaps his swish set of advisers made him slash the RE provisions in the 7th 5-yr Plan from Rs 400 Cr to just Rs 7 Cr. This put paid to all subsidised projects and murdered the market prospects of large companies, which were started with large projected demands endorsed by the licensing body, mostly the DNES and Industries Ministry. By then, SPV imports leading to phased manufacture manufacture of SPV panels were allowed. But Mr VP Singh, as Finance Minister sat over all foreign collaboration files citing the need to save forex.
Rajiv Gandhi Govt. had, by then also shot down the silicon foundry proposal of IPCL-Hemlock, asserting that there was enough silicon facility between Mettur Industries and Semiconductor Complex Ltd of Chandigarh, the latter of which was gutted in a fire before commissioning and never re-commissioned. Thus we never saw PV-grade silicon made in India in the required quantity. Otherwise solar panels would have perhaps been household commodities by now!
In 1989, VP Singh's Janata Dal coalition Govt came to power. It agreed on private sector importing solar cells towards a Phased Manufacturing Programme for panels but the refusal to involve the IMF etc again starved the economy of foreign exchange and imports, again restricting the import or manufacture of solar cells to the public sector. Hence a company like Tata BP Solar had to hand its know-how and import sources to BHEL and in exchange receive priority allotted deliveries of panels. This put severe restrictions on the industry and business opportunities.
Other companies are still reeling under losses inflicted by these whims to this date.
Meanwhile it took the clout and massive resources of the Tatas to continue to develop the 'balance of systems' including charge and load regulators, batteries, suitable lamps, fans, invertors, etc as needed to complete a SPV power system. They insisted on the highest quality standards and delivered only complete systems, initially under a 5-year comprehensive warranty. This inspired confidence and saw sustained growth, while its competitors were veritably wiped out.
Risk-hedging is perhaps one reason why manufacturers like Tata BP who started out as dedicated SPV panel and systems manufacturers felt and still feel the need to also manufacture or market solar-thermal panels and systems. The latter systems also have a faster pay-back period than SPV.
Yet others like Shell, Siemens, GE, Philips, National and several others have entered the field but lack the long-term perspective, perseverance and commitment to survive this market. However, we see some progress by smaller players like SELCO, Solite, Solkar and few others who rely on Chinese/East Asian imports of SPV panels.
Amorphous silicon offers tremendous opportunity to SMEs and MSMEs by being ready-made in large quantities, amenable to scaling, shadow-tolerance and although of a lower efficiency, available at half the cost per Wp compared to crystalline silicon. Small manufacturers can import these 'a-Si glass' sheets, cut them according to the desired rated voltage and current, frame and connect them as finished panels without any sophisticated production facilities.
Wednesday, August 12, 2009
Solar Lantern Programmes - A brief watchlist.
Too many people and bodies, unfortunately including media like NDTV Green Campaign, seem to carry an impression that a chargeable torch or battery-powered lamp is a solar lamp by itself and that, donating one to a village family means immortality to all concerned. To top it, some of them have displayed ignorance of the difference between a solar thermal and SPV or photovoltaic panel. Nothing is more damaging to the credibility of the solar energy programme than these amateur freebies.
The Barefoot College in Rajasthan under the stewardship of Bunker Roy is a good example, where local persons are first trained and micro-entrepreneurs enabled to service solar lanterns. So is GEDA in Gujarat, for community-owned lighting installations like streetlights.
The country's first State to take up solar energy in earnest saw good and bad cases too. While Gujarat's State Nodal Agency GEDA (www.geda.org.in) managed few hundred streetlights a year in the late 80s by providing solar stills for distilled water to refill lead-acid batteries (sealed batteries were not available locally then), training owners and incentivizing local monitors, the SEBs or State Electricity Boards including GEB bombarded the villages with 1000-3000 streetlights and never bothered to check, with the result that all had failed by 1991-92, causing a massive loss in monetary and credibility of the SPV program. However, on the other hand, a good proportion of the ones installed and facilitated by GEDA with the village administrations' enthusiasm, continue to light up their habitats, to this day.
- The lantern, most importantly, needs to be compatible to a solar SPV panel, which often costs more than the lamp itself, in the region of Rs 250 per Watt. Typical power ratings of crystalline silicon panels manufactured in India are 6W, 10W and 35W, for this purpose, by Tata BP, SELCO, Solkar, CEL, BHEL, Udhaya Semiconductors, etc. You may thus calculate the budgetary costs. More notes on techno-economic calculations for SPV systems can be found at http://micropower.blogspot.com/2003_11_23_archive.html
- The energy drained from the lamp's battery each night, in Watt-Hrs should match the panel power rating in Watts X 4.5 hrs, i.e. the solar panel must feed its power in 4.5 hours what has been drained all night by the lamp's battery. This calls for correct matching and supply of a solar panel of adequate capacity and correct voltage for safe and reliable charging.
- For battery durability and system-level reliability, the battery must not be drained for more than 20% of its stored capacity in a day, on average. While we provide for this in indoor and outdoor stationery lighting systems by using slow-drain Class-100 or Class-120 batteries, compact lantern manufacturers typically use a hi-drain, hi-charge C-5 battery which drains its full charge in just 5 hours. This is why batteries in solar lamps wear out in 3 years or less.
- Another issue is the light source. Reading and activities involving inspection require 300 Lux i.e. 300 Lumens per Sq Mtr. The recent trend is to use white LEDs, which deliver mostly in the region of 20-30 Lumens per watt consumed, as against a filament lamp that delivers 15 Lumens and a 230V Commercial-grade CFL that delivers 44 and a tube-light that delivers 40 Lumens per watt respectively. Often, the quality of LED lights are questionable for eye safety, unless certified by a manufacturer.
- Beside quality and quality of light, each light source has a limited life. A standard replacement should be available locally or provided for, the battery as well as LED, tube or bulb used.
- The beneficiaries need to be taught to connect and place the panel correctly and clean it daily, in order to get the right amount of power. Often, there is no indication of light source or output in Lux or Lumens of the lanterns in the manufacturer's information. We do not even know how for many hours the lamp will glow on full charge, in one day.
- The manufacturer or donor must address the above issues.
- In India, it may be wise to contact the appropriate State Nodal Agency for a list o0f their approved manufacturers, because State Nodal Agencies typically undertake execution and follow-up of such programmes, even privately and charitably funded.
- Alternately, I would suggest procuring the smallest rated but reliable, warranty-supported solar panel and approaching a manufacturer like Eveready, who have recently entered the solar lantern space and have a reasonably penetrated rural marketing network, for support in lantern servicing as well as replacement of battery and light source.
The Barefoot College in Rajasthan under the stewardship of Bunker Roy is a good example, where local persons are first trained and micro-entrepreneurs enabled to service solar lanterns. So is GEDA in Gujarat, for community-owned lighting installations like streetlights.
The country's first State to take up solar energy in earnest saw good and bad cases too. While Gujarat's State Nodal Agency GEDA (www.geda.org.in) managed few hundred streetlights a year in the late 80s by providing solar stills for distilled water to refill lead-acid batteries (sealed batteries were not available locally then), training owners and incentivizing local monitors, the SEBs or State Electricity Boards including GEB bombarded the villages with 1000-3000 streetlights and never bothered to check, with the result that all had failed by 1991-92, causing a massive loss in monetary and credibility of the SPV program. However, on the other hand, a good proportion of the ones installed and facilitated by GEDA with the village administrations' enthusiasm, continue to light up their habitats, to this day.
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