Building Integrated Photo Voltaics
The Sun is an inexhaustible, reliable and non-polluting source of power. Since the inception of life on earth, the only energy that was available came from the sun. The time is now approaching when mankind will again depend upon the sun as dominant energy source.
· Solar radiation is the largest energy resource. Approximately 0.1 % of the world's area utilised by solar photovoltaic plants would be sufficient to generate the world's entire electricity demand.
· The solar energy is more evenly distributed in the world than wind or bio-mass.
· It is well proven and demonstrated technology.
· It promises to be the most effective renewable power at high volume of production.
With escalation in energy prices, shortages, concerns over pollution, environment degradation and resource depletion, the awareness around the world has dramatically
increased. Inefficiency in use of energy, dependence on fossil fuels causing green house emissions, acid rain and release of pollutants to the atmosphere must now be addressed seriously in modern buildings.
Architects with vision have come to realise that designing aesthetically pleasing buildings are not enough. The building of the future must be environmentally friendly as well.
Photovoltaics is a truly elegant means of producing electricity at site directly from the sun. It has no moving parts, no environmental pollution and no depletion of materials. Photovoltaics are also exceedingly versatile. It can pump water, operate lights and house hold appliances, can operate communication equipment and any electrical gadgets. The photovoltaics can be used for village electrification in the developing countries and electricity for the buildings and distribution grids for cities and commercial areas.
Nearly 50%of world production of solar PV cells are used in building integrated photovoltaics (BIPV) projects, however, we in India are yet to initiate the promotion of BIPV:
Barrier to BIPV projects in India
Due to the attractive incentives offered by the governments in countries like Germany, Japan, USA and Europe as a whole, the business in Building Integrated Photovoltaics (BIPV) has increased rapidly in the last 3 years. In Germany, every KWH of electricity fed to the grid from solar photovoltaic system earns Euro 0.51 /kWh (Rs.21.0/kWh). In Japan and USA, attractive subsidies and net metering is provided that has resulted in pushing the photovoltaic market up.
In India, government subsidy to power sector is estimated to be over Rs 40,000 crore for the current fmancial year and about Rs 20,000 crore on petroleum products. A small portion of 10% (Rs 6000 crore) of this amount if allocated to subsidize photovoltaic projects in the country, it will amount to promoting 200 MWac of solar PV projects. This would provide boost to the PV business and help government reduce its recurring and increasing subsidy burden on power and petroleum sector as investment on PV will provide free for 30 years.
Major benefits of solar PV:
1. Demand side management:
Solar photovoltaic systems on commercial buildings will help shave peak power requirements during the day as most offices have large air-conditioning, lighting and computer loads during the day. This would help offset over loading of power plants and transformers apart from saving emission and pollution from coal based thermal power plants.
2. Reduction in transmission and distribution line losses:
The transmission and distribution line losses in India is one of the highest in the world that ranges from 30-50%. By having building integrated photovoltaics the power is generated close to the point of use that will result in substantial savings in the losses in transmission and distribution.
3. Reduction in emissions and pollutants:
Nearly 75% of electricity generation in India is from coal based thermal plants. The installation of solar photovoltaic systems will reduce emission of green house gases causing global warming. Also there are other pollutants added to the atmosphere that cause acid rain and have detrimental effect on the health of people and destroy flora and fauna.
It is estimated that a 1MWac solar photovoltaic installation will prevent the following emissions to the atmosphere:
i. CO2: 2100.0 tons
ii. SO2 : 13.4 tons
iii. NOx : 10.2 tons
iv. Fly Ash : 120.0 tons
v. Dust : 0.8 tons
The Kyoto protocol signed by 30 countries in 199 7 makes it obligatory to all signatories to reverse the emission to 1993 level. Photovoltaics will play a major role in reducing emissions. It will be possible for PV systems owners to trade carbon emissions with polluters in other countries that will contribute to repay the cost of PV system installed by them.
4. Reductiou iu foreign exchange outflow:
Due to power shortages many industries and commercial complexes have installed oil based captive power generators. Since India is not self sufficient in oil, large quantity of oil must be imported. By installing 1 MWac photovoltaic systems country would save about 2,25,000 litres of diesel fuel per year. The use of photo voltaic systems will protect from sudden oil price increase with changing international solutions and exchange rates.
BIPV projects executed by Tata BP Solar in India
a. 6KwP BuiIdiug integrated photovoltaic project for Mamata machinery, Ahmedabad
The system consists of 80 nos of 75Wp solar modules mounted on the sloped roof of the building. The system can support up to 18kva domestic electrical load and is designed to provide 20 kwh per day. The power from solar PV panels is stored in a deep cycle, tubular plate battery bank for use any time of the day and to take care of three continuous cloudy days. The system was commissioned in June 1997.
b. 10kWp Building integrated photovoltaic project for TERI, Gual Pahadi, Haryana
The system consists of 3kWp roof mounted solar PV modules and 7kWp of triple glass modul with spaces between solar cells to pass daylight. The system can support up to 36kVa load using a special power conditioning unit that can feed power from a wood gasifier engine in case of shortfall in power from solar PV array. A battery bank is provided to store power from solar array for use any time of the day. The system was commissioned in April 1999.
c. 25kWp Building Integrated Photovoltaic Project for NEDA, Luckuow, Uttar Pradesh
The system consists of 25kWp roof mounted solar PV array that feeds DC power to a power conditioning unit (PCU). The PCU then delivers power at 415V; 3phase, 50Hz that is synchronised to the grid. Two way electronic metering system records the export and import of power to/from SEB's grid. The system is supplied with data logger that records all electrical parameters and solar radiation data. The system was commissioned in April 1999.
d. 50kWp Buildiug lutegrated Photovoltaic Project for Puujab Mini Secretariat, Chandigarh
The PV array is mounted on the rooftop of the Punjab Mini-Secretariat Building. To ensure that the building is not affected by additional weight, the solar PV array is mounted on an elevated structure to transfer load to the pillars. The PCU output is 415V; 3Phase, 50Hz synchronized to the grid. Metering and data logger is provided to record all electrical and solar data. This project was commissioned in October 1999.
BIPV products and services available from TATA BP Solar:
a. Single glass/ Double Glass/ Triple glass with vacuum Solar PV Modules with light spaces:
These solar modules are suitable for fixing in the building facade to replace conventional glass. The modules generate electricity as well as pass day light. These modules are equally suited to use in an Atrium structure that can pass light and replace glass or polycarbonate material.
b. Aluminium Frames with space for concealed wiring:
Tata BP Solar offers special aluminium sections for mounting BIPV solar modules that have concealed cable duct to carry electrical power from solar PV array to the required point. These have flexible gaskets to take care of thermal expansion of the solar expansion of the solar modules.
c. DPR,System Design, Turn-key Projects, Training and Operation & Maintenance:
Building Integrated Photo- voltaic (BIPV) being a new technology which is being constantly updated, Tata BP Solar offers its services for preparation of detailed project reports (DPR), system design, executing the project on turn-key basis, training architects, builders, designers and users. Tata BP Solar also undertake operation and maintenance on short or long term basis as desired by the users.
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