Solar energy in india:

India is densely populated and has high solar insolation, an ideal combination for using solar power in India. India is already a leader in wind power generation. In the solar energy sector, some large projects have been proposed, and a 35,000 km2 area of the Thar Desert has been set aside for solar power projects, sufficient to generate 700 GW to 2,100 GW.

In July 2009, India unveiled a US$19 billion plan to produce 20 GW of solar power by 2020.[1] Under the plan, the use of solar-powered equipment and applications would be made compulsory in all government buildings, as well as hospitals and hotels.[2] On November 18, 2009, it was reported that India was ready to launch its National Solar Mission under the National Action Plan on Climate Change, with plans to generate 1,000 MW of power by 2013.[3]

Contents

[hide]

1 Current status o 1.1 Installed capacity o 1.2 Still unaffordable o 1.3 Solar engineering training

2 Future applications o 2.1 Rural electrification o 2.2 Agricultural support o 2.3 Solar water heaters

3 Challenges and constraints o 3.1 Land scarcity o 3.2 Slow progress

4 Latent potential 5 Government support 6 See also 7 Notes 8 External links

[edit] Current status

With about 300 clear, sunny days in a year, India's theoretical solar power reception, on only its land area, is about 5 Petawatt-hours per year (PWh/yr) (i.e. 5 trillion kWh/yr or about 600 TW).[4][5] The daily average solar energy incident over India varies from 4 to 7 kWh/m2 with about 1500–2000 sunshine hours per year (depending upon location), which is far more than current total energy consumption. For example, assuming the efficiency of PV modules were as low as 10%, this would still be a thousand times greater than the domestic electricity demand projected for 2015.[4][6]

[edit] Installed capacity

The amount of solar energy produced in India is less than 1% of the total energy demand.[7] The grid-interactive solar power as of December 2010 was merely 10 MW.[8] Government-funded solar energy in India only accounted for approximately 6.4 MW-yr of power as of 2005.[7] However, as of October 2009, India is currently ranked number one along with the United States in terms of solar energy production per watt installed.[9]

India's largest photovoltaic (PV) power plants

Name of Plant

DCPeak Power

(MW)

GW·h/year[10] Capacity

factorNotes

Sivaganga Photovoltaic Plant[11] 5

Completed December 2010

Kolar Photovoltaic Plant[12] 3 Completed May 2010Itnal Photovoltaic Plant, Belgaum[13] 3 Completed April 2010

Azure Power - Photovoltaic Plant[14] 2 2009

Jamuria Photovoltaic Plant[15] 2 2009NDPC Photovoltaic Plant[16] 1 2010Thyagaraj stadium Plant-Delhi[17] 1 April, 2010

Gandhinagar Solar Plant[18] 1 January 21, 2011Tata - Mulshi, Maharashtra[19] 3

Commissioned April 2011

Azure Power - Sabarkantha, Gujarat[20] 10

Commissioned June 2011

Moser Baer - Patan, Gujarat[21] 30

To Be Commissioned July 2011

Tata - Mayiladuthurai, Tamil Nadu[22] 1

Commissioned July 2011

REHPL - Sadeipali, (Bolangir) Orissa [23] 1

Commissioned July 2011

Total 58

[edit] Still unaffordable

Solar power is currently prohibitive due to high initial costs of deployment. To spawn a thriving solar market, the technology needs to be competitively cheaper (i.e. attaining cost parity with fossil or nuclear energy). India is heavily dependent on coal and foreign oil, a phenomenon likely to continue until non-fossil/renewable energy technology becomes economically viable in the

country.[24][25] The cost of production ranges from 15 to 30 per unit compared to around

5 to 8 per unit for conventional thermal energy.[26]

[edit] Solar engineering training

The Australian government has awarded UNSW A$5.2 million to train next-generation solar energy engineers from Asia-Pacific nations, specifically India and China, as part of the Asia-Pacific Partnership on Clean Development and Climate (APP).[27] Certain programmes are designed to target for rural solar usage development.[28]

[edit] Future applications

[edit] Rural electrification

Lack of electricity infrastructure is one of the main hurdles in the development of rural India. India's grid system is considerably under-developed, with major sections of its populace still surviving off-grid. As of 2004 there are about 80,000 unelectrified villages in the country. Of these villages, 18,000 could not be electrified through extension of the conventional grid. A target for electrifying 5,000 such villages was set for the Tenth National Five Year Plan (2002–2007). As of 2004, more than 2,700 villages and hamlets had been electrified, mainly using solar photovoltaic systems.[4] Developments in cheap solar technology are considered as a potential alternative that allows an electricity infrastructure consisting of a network of local-grid clusters with distributed electricity generation.[7] It could allow bypassing (or at least relieving) the need to install expensive, lossy, long-distance, centralised power delivery systems and yet bring cheap electricity to the masses.

Projects currently planned include 3000 villages of Odisha, which will be lighted with solar power by 2014.[29][30][31][32]

[edit] Agricultural support

Solar PV water pumping systems are used for irrigation and drinking water. The majority of the pumps are fitted with a 200–3,000 watt motor that are powered with 1,800 Wp PV array which can deliver about 140,000 liters of water per day from a total head of 10 meters. By 30 September, 2006, a total of 7,068 solar PV water pumping systems had been installed.[7]

Solar driers are used to dry harvests before storage.[33]

[edit] Solar water heaters

Bangalore has the largest deployment of rooftop solar water heaters in India. These heaters will generate an energy equivalent of 200 MW every day .[34]

Bangalore is also the first city in the country to put in place an incentive mechanism by

providing a rebate (which has just been[when?] increased to 50) on monthly electricity bills for residents using roof-top thermal systems. These systems are now mandatory for all new structures.

Pune, another city in the western part of India, has also recently made installation of solar water heaters in new buildings mandatory.[35]

[edit] Challenges and constraints

[edit] Land scarcity

Land is a scarce resource in India and per capita land availability is low. Dedication of land area for exclusive installation of solar arrays might have to compete with other necessities that require land. The amount of land required for utility-scale solar power plants—currently approximately 1 km2 for every 20–60 megawatts (MW) generated[7]—could pose a strain on India's available land resource. The architecture more suitable for most of India would be a highly-distributed set of individual rooftop power generation systems, all connected via a local grid.[7] However, erecting such an infrastructure, which does not enjoy the economies of scale possible in mass, utility-scale, solar panel deployment, needs the market price of solar technology deployment to substantially decline, so that it attracts the individual and average family size household consumer. That might be possible in the future, because PV is projected to continue its current cost reductions for the next decades and be able to compete with fossil fuel.[4]

[edit] Slow progress

While the world has progressed substantially in production of basic silicon mono-crystalline photovoltaic cells, India has fallen short of achieving the worldwide momentum. India is now in 7th place worldwide in PV cell production and 9th place in solar thermal systems, with nations such as Japan, China, and the US currently ranked far ahead. Globally, solar is the fastest growing source of energy (though from a very small base) with an annual average growth of 35%, as seen during the past few years.[36]

[edit] Latent potential

Some noted think-tanks[4][37][38] recommend that India should adopt a policy of developing solar power as a dominant component of the renewable energy mix, since being a densely populated region [39] in the sunny tropical belt,[40][41] the subcontinent has the ideal combination of both high solar insolation [40] and therefore a big potential consumer base density.[4][42][43][44][45] In one of the analyzed scenarios,[38] India can make renewable resources such as solar the backbone of its economy by 2050, reining in its long-term carbon emissions without compromising its economic growth potential.

[edit] Government support

The government of India is promoting the use of solar energy through various strategies. In the

latest budget for 2010/11, the government has announced an allocation of 10 billion (US$223 million) towards the Jawaharlal Nehru National Solar Mission and the establishment of

a clean energy fund. It is an increase of 3.8 billion (US$84.7 million) from the previous budget. This new budget has also encouraged private solar companies by reducing customs duty on solar panels by 5% and exempting excise duty on solar photovoltaic panels. This is expected to reduce the cost of a roof-top solar panel installation by 15–20%. The budget also proposed a coal tax of US$1 per metric ton on domestic and imported coal used for power generation.[46] Additionally, the government has initiated a Renewable Energy Certificate (REC)[47] scheme, which is designed to drive investment in low-carbon energy projects. The Ministry of New and Renewable Energy (MNRE)provides 70 percent subsidy on the installation cost of a solar photovoltaic power plant in North-East states and 30 percentage subsidy on other regions. The detailed outlay of the National Solar Mission highlights various targets set by the government to increase solar energy in the country's energy portfolio.

The development of wind power in India began in the 1990s, and has significantly increased in the last few years. Although a relative newcomer to the wind industry compared with Denmark or the US, India has the fifth largest installed wind power capacity in the world.[1] In 2009-10 India's growth rate was highest among the other top four countries.

As of 31 March 2011 the installed capacity of wind power in India was 14550[2] MW, mainly spread across Tamil Nadu (5904.40 MW), Maharashtra (2310.70 MW), Gujarat (2175.60 MW), Karnataka (1730.10 MW), Rajasthan (1524.70 MW), Madhya Pradesh (275.50 MW), Andhra Pradesh (200.20 MW), Kerala (32.8 MW), Orissa (2MW),[3][4] West Bengal (1.1 MW) and other states (3.20 MW) [5]. It is estimated that 6,000 MW of additional wind power capacity will be installed in India by 2012.[6] Wind power accounts for 6% of India's total installed power capacity, and it generates 1.6% of the country's power.[7] India is currently preparing a wind atlas.[8]

Contents

[hide]

1 Overview 2 State-level wind power

o 2.1 Tamil Nadu (5904.40 MW) o 2.2 Maharashtra (5310.70 MW) o 2.3 Gujarat (2175.60 MW) o 2.4 Karnataka (1730.10 MW) o 2.5 Rajasthan (1524.70 MW) o 2.6 Madhya Pradesh (275.50 MW) o 2.7 Kerala (32 MW) o 2.8 West Bengal (1.10MW)

3 Projects in India

4 Barriers 5 Future 6 See also 7 References 8 External links

[edit] Overview

India is the world's fifth largest wind power producer, with an annual power production of 8,896 MW.[9] Shown here is a wind farm in Kayathar, Tamil Nadu.

The worldwide installed capacity of wind power reached 197 GW by the end of 2010. China (44,733 MW), US (40,180 MW), Germany (27,215 MW) and Spain (20,676 MW) are ahead of India in fifth position.[10] The short gestation periods for installing wind turbines, and the increasing reliability and performance of wind energy machines has made wind power a favored choice for capacity addition in India.[11]

Suzlon, as Indian-owned company, emerged on the global scene in the past decade, and by 2006 had captured almost 7.7 percent of market share in global wind turbine sales. Suzlon is currently the leading manufacturer of wind turbines for the Indian market, holding some 52 percent of market share in India. Suzlon’s success has made India the developing country leader in advanced wind turbine technology.[12]

[edit] State-level wind power

There is a growing wind energy installations in the number of the states across the India.

[edit] Tamil Nadu (5904.40 MW)

India is keen to decrease its reliance on fossil fuels to meet its energy demand. Shown here is a wind farm in Muppandal, Tamil Nadu.

Tamil Nadu is the state with the most wind generating capacity: 5502.90 MW at the end of the December 2010. Not far from Aralvaimozhi, the Muppandal wind farm, the largest in the subcontinent, is located near the once impoverished village of Muppandal, supplying the villagers with electricity for work.[13][14] The village had been selected as the showcase for India's $2 billion clean energy program which provides foreign companies with tax breaks for establishing fields of wind turbines in the area.

Wind turbiness in Tamil Nadu

In February 2009, Shriram EPC bagged INR 700 million contract for setting up of 60 units of 250 KW (totaling 15 MW) wind turbines in Tirunelveli district by Cape Energy.[15] Enercon is also playing a major role in development of wind energy in India. In Tamil Nadu, Coimbatore and Tiruppur Districts having more wind Mills from 2002 onwards,specially, Chittipalayam, Kethanoor, Gudimangalam, Poolavadi, Murungappatti (MGV Place), Sunkaramudaku, KongalNagaram, Gomangalam, Anthiur, Edyarpalayam, Bogampatti, Puliya Marathu Palayam, Chandrapuram are the high wind power production places in the both districts.

[edit] Maharashtra (5310.70 MW)

Maharashtra is second only to Tamil Nadu in terms of generating capacity. Suzlon has been heavily involved.[11] Suzlon operates what was once Asia's largest wind farm, the Vankusawade Wind Park (201 MW), near the Koyna reservoir in Satara district of Maharashtra.[16]

[edit] Gujarat (2175.60 MW)

Samana & sadodar in jamanagar district is set to host energy companies like China Light Power

(CLP) and Tata Power have pledged to invest up to 8.15 billion ($189.5 million) in different

projects in the area. CLP, through its India subsidiary CLP India, is investing close to 5 billion for installing 126 wind turbines in Samana that will generate 100.8 MW power. Tata

Power has installed wind turbines in the same area for generating 50 MW power at a cost of 3.15 billion. Both projects are expected to become operational by early next year, according to government sources. The Gujarat government, which is banking heavily on wind power, has identified Samana as an ideal location for installation of 450 turbines that can generate a total of 360 MW. To encourage investment in wind energy development in the state, the government has introduced a raft of incentives including a higher wind energy tariff. Samana has a high tension transmission grid and electricity generated by wind turbines can be fed into it. For this purpose, a substation at Sadodar has been installed. Both projects are being executed by Enercon Ltd, a joint venture between Enercon of Germany and Mumbai-based Mehra group.[17]

ONGC Ltd has commissioned its first wind power project. The 51 MW project is located at Motisindholi in Kutch district of Gujarat. ONGC had placed the EPC order on Suzlon Energy in January 2008, for setting up the wind farm comprising 34 turbines of 1.5 MW each. Work on the project had begun in February 2008, and it is learnt that the first three turbines had begun

production within 43 days of starting construction work. Power from this 308 crore captive wind farm will be wheeled to the Gujarat state grid for onward use by ONGC at its Ankleshwar, Ahmedabad, Mehsana and Vadodara centres. ONGC has targeted to develop a captive wind power capacity of around 200 MW in the next two years.[18]

[edit] Karnataka (1730.10 MW)

There are many small wind farms in Karnataka, making it one of the states in India which has a high number of wind mill farms. Chitradurga, Gadag are some of the districts where there are a large number of Windmills. Chitradurga alone has over 20000 wind turbines.[citation needed]

The 13.2 MW Arasinagundi (ARA) and 16.5 MW Anaburu (ANA) wind farms are ACCIONA’S first in India. Located in the Davangere district (Karnataka State), they have a total installed capacity of 29.7 MW and comprise a total 18 Vestas 1.65MW wind turbines supplied by Vestas Wind Technology India Pvt. Ltd.[citation needed]

The ARA wind farm was commissioned in June 2008 and the ANA wind farm, in September 2008. Each facility has signed a 20-year Power Purchase Agreement (PPA) with Bangalore Electricity Supply Company (BESCOM) for off-take of 100% of the output. ARA and ANA are Acciona’s first wind farms eligible for CER credits under the Clean Development Mechanism (CDM).[citation needed]

ACCIONA is in talks with the World Bank for The Spanish Carbon Fund which is assessing participation in the project as buyer for CERs likely to arise between 2010 and 2012. An environmental and social assessment has been conducted as part of the procedure and related documents have been provided. These are included below, consistent with the requirement of the World Bank's disclosure policy.[citation needed]

[edit] Rajasthan (1524.70 MW)

Gurgaon-headquartered Gujarat Fluorochemicals Ltd is in an advanced stage of commissioning a large wind farm in Jodhpur district of Rajasthan. A senior official[who?] told Projectmonitor that out of the total 31.5 mW capacity, 12 mW had been completed so far. The remaining capacity would come on line shortly, he added. For the INOX Group company, this would be the largest wind farm. In 2006-07, GFL commissioned a 23.1-mW wind power project at Gudhe village near Panchgani in Satara district of Maharashtra. Both the wind farms will be grid-connected and will earn carbon credits for the company, the official noted.[citation needed] In an independent development, cement major ACC Ltd has proposed to set up a new wind power project in

Rajasthan with a capacity of around 11 mW. Expected to cost around 60 crore, the wind farm will meet the power requirements of the company's Lakheri cement unit where capacity was raised from 0.9 million tpa to 1.5 million tpa through a modernisation plan. For ACC, this would be the second wind power project after the 9 mW farm at Udayathoor in Tirunelvelli district of Tamil Nadu.[citation needed] Rajasthan is emerging as an important destination for new wind farms, although it is currently not amongst the top five states in terms of installed capacity. As of 2007 end, this northern state had a total of 496 mW, accounting for a 6.3 per cent share in India's total capacity.[citation needed]

[edit] Madhya Pradesh (275.50 MW)

In consideration of unique concept, Govt. of Madhya Pradesh has sanctioned another 15 MW project to MPWL at Nagda Hills near Dewas. All the 25 WEGs have been commissioned on 31.03.2008 and under successful operation.[19]

[edit] Kerala (32 MW)

The first wind farm of the state was set up at Kanjikode in Palakkad district. It has a generating capacity of 23.00 MW. A new wind farm project was launched with private participation at Ramakkalmedu in Idukki district. The project, which was inaugurated by chief minister V. S. Achuthanandan in April 2008, aims at generating 10.5 MW of electricity.[citation needed]

The Agency for Non-Conventional Energy and Rural Technology (ANERT), an autonomous body under the Department of Power, Government of Kerala, is setting up wind farms on private land in various parts of the state to generate a total of 600 mW of power. The agency has identified 16 sites for setting up wind farms through private developers. To start with, ANERT will establish a demonstration project to generate 2 mW of power at Ramakkalmedu in Idukki

district in association with the Kerala State Electricity Board. The project is slated to cost 21 crore. Other wind farm sites include Palakkad and Thiruvananthapuram districts. The

contribution of non-conventional energy in the total 6,095 mW power potential is just 5.5 per cent, a share the Kerala government wants to increase by 30 per cent. ANERT is engaged in the field of development and promotion of renewable sources of energy in Kerala. It is also the nodal agency for implementing renewable energy programmes of the Union ministry of non-conventional energy sources.[citation needed]

[edit] West Bengal (1.10MW)

The total installation in West Bengal is just 1.10 MW as there was only 0.5 MW addition in 2006-2007 and none between 2007–2008 and 2008–2009

Bengal - Mega 50 MW wind energy project soon for country[citation needed]

Suzlon Energy Ltd plans to set up a large wind-power project in West Bengal Suzlon Energy Ltd is planning to set up a large wind-power project in West Bengal, for which it is looking at coastal Midnapore and South 24-Parganas districts. According to SP Gon Chaudhuri, chairman of the West Bengal Renewable Energy Development Agency, the 50 MW project would supply grid-quality power. Gon Chaudhuri, who is also the principal secretary in the power department, said the project would be the biggest in West Bengal using wind energy. At present, Suzlon experts are looking for the best site. Suzlon aims to generate the power solely for commercial purpose and sell it to local power distribution outfits like the West Bengal State Electricity Board (WBSEDCL).[citation needed]

Suzlon will invest around 250 crore initially, without taking recourse to the funding available from the Indian Renewable Energy Development Agency (Ireda), said Gon Chaudhuri. He said there are five wind-power units in West Bengal, at Frazerganj, generating a total of around 1 MW. At Sagar Island, there is a composite wind-diesel plant generating 1 MW. In West Bengal, power companies are being encouraged to buy power generated by units based on renewable energy. The generating units are being offered special rates. S Banerjee, private secretary to the power minister, said this had encouraged the private sector companies to invest in this field.[citation needed]

[edit] Projects in India

India's Largest Wind power production facilities (10MW and greater)[20]

Power Plant

Producer

Location

State

Total Capacity

(MWe)Vankusawade Wind Park

Suzlon Energy Ltd. Satara Dist. Maharashtra 259

Cape ComorinAban Loyd Chiles Offshore Ltd.

Kanyakumari Tamil Nadu 33

Kayathar Subhash Subhash Ltd. Kayathar Tamil Nadu 30Ramakkalmedu Subhash Ltd. Ramakkalmedu Kerala 25

Muppandal Wind Muppandal Wind Farm Muppandal Tamil Nadu 22Gudimangalam Gudimangalam Wind Farm Gudimangalam Tamil Nadu 21

Puthlur RCI Wescare (India) Ltd. PuthlurAndhra Pradesh

20

Lamda Danida Danida India Ltd. Lamda Gujarat 15

Chennai MohanMohan Breweries & Distilleries Ltd.

Chennai Tamil Nadu 15

Jamgudrani MP MP Windfarms Ltd. DewasMadhya Pradesh

14

Jogmatti BSES BSES Ltd.Chitradurga Dist

Karnataka 14

Perungudi NewamNewam Power Company Ltd.

Perungudi Tamil Nadu 12

Kethanur Wind Farm

Kethanur Wind Farm Kethanur Tamil Nadu 11

Hyderabad APSRTC

Andhra Pradesh State Road Transport Corp.

HyderabadAndhra Pradesh

10

Muppandal Madras Madras Cements Ltd. Muppandal Tamil Nadu 10Poolavadi Chettinad

Chettinad Cement Corp. Ltd.

Poolavadi Tamil Nadu 10

Shalivahana WindShalivahana Green Energy. Ltd.

Tirupur Tamil Nadu 20.4

[21]

[edit] Barriers

Initial cost for wind turbines is greater than that of conventional fossil fuel generators per MW installed. Noise is produced by the rotor blades. This is not normally an issue in the locations chosen for most wind farms and research by Salford University[22] shows that noise complaints for wind farms in the UK are almost non-existent.

[edit] Future

The Ministry of New and Renewable Energy (MNRE) has fixed a target of 10,500 MW between 2007–12, but an additional generation capacity of only about 6,000 MW might be available for commercial use by 2012Solar panels use light energy (photons) from the sun to generate electricity through the photovoltaic effect. The structural (load carrying) member of a module can either be the top layer or the back layer. The majority of modules use wafer-based crystalline silicon cells or thin-film cells based on cadmium telluride or silicon. The conducting wires that take the current off the panels may contain silver, copper or other conductive (but generally not magnetic) transition metals.

The cells must be connected electrically to one another and to the rest of the system. Cells must also be protected from mechanical damage and moisture. Most solar panels are rigid, but semi-flexible ones are available, based on thin-film cells.

Electrical connections are made in series to achieve a desired output voltage and/or in parallel to provide a desired current capability.

Separate diodes may be needed to avoid reverse currents, in case of partial or total shading, and at night. The p-n junctions of mono-crystalline silicon cells may have adequate reverse current characteristics that these are not necessary. Reverse currents waste power and can also lead to overheating of shaded cells. Solar cells become less efficient at higher temperatures and installers try to provide good ventilation behind solar panels.[1]

Some recent solar panel designs include concentrators in which light is focused by lenses or mirrors onto an array of smaller cells. This enables the use of cells with a high cost per unit area (such as gallium arsenide) in a cost-effective way.[citation needed]

Depending on construction, photovoltaic panels can produce electricity from a range of frequencies of light, but usually cannot cover the entire solar range (specifically, ultraviolet, infrared and low or diffused light). Hence much of the incident sunlight energy is wasted by solar panels, and they can give far higher efficiencies if illuminated with monochromatic light. Therefore another design concept is to split the light into different wavelength ranges and direct the beams onto different cells tuned to those ranges.[2] This has been projected to be capable of raising efficiency by 50%. The use of infrared photovoltaic cells has also been proposed to increase efficiencies, and perhaps produce power at night.[citation needed]

Currently the best achieved sunlight conversion rate (solar panel efficiency) is around 21% in commercial products[3], typically lower than the efficiencies of their cells in isolation. The Energy Density of a solar panel is the efficiency described in terms of peak power output per unit of surface area, commonly expressed in units of Watts per square foot (W/ft2). The most efficient mass-produced solar panels have energy density values of greater than 13 W/ft2 (140 W/m2).

[edit] Crystalline silicon modules

Main article: Solar Cell

Most solar modules are currently produced from silicon PV cells. These are typically categorized into either monocrystalline or multicrystalline modules.

[edit] Thin-film modules

Main articles: Thin film solar cell, Third generation solar cell, and Low-cost photovoltaic cell

Third generation solar cells are advanced thin-film cells. They produce high-efficiency conversion at low cost.

[edit] Rigid thin-film modules

In rigid thin film modules, the cell and the module are manufactured in the same production line.

The cell is created on a glass substrate or superstrate, and the electrical connections are created in situ, a so called "monolithic integration". The substrate or superstrate is laminated with an encapsulant to a front or back sheet, usually another sheet of glass.

The main cell technologies in this category are CdTe, or a-Si, or a-Si+uc-Si tandem, or CIGS (or variant). Amorphous silicon has a sunlight conversion rate of 6-12%.

[edit] Flexible thin-film modules

Flexible thin film cells and modules are created on the same production line by depositing the photoactive layer and other necessary layers on a flexible substrate.

If the substrate is an insulator (e.g. polyester or polyimide film) then monolithic integration can be used.

If it is a conductor then another technique for electrical connection must be used.

The cells are assembled into modules by laminating them to a transparent colourless fluoropolymer on the front side (typically ETFE or FEP) and a polymer suitable for bonding to the final substrate on the other side. The only commercially available (in MW quantities) flexible module uses amorphous silicon triple junction (from Unisolar).

So-called inverted metamorphic (IMM) multijunction solar cells made on compound-semiconductor technology are just becoming commercialized in July 2008. The University of Michigan's solar car that won the North American Solar challenge in July 2008 used IMM thin-film flexible solar cells.

The requirements for residential and commercial are different in that the residential needs are simple and can be packaged so that as solar cell technology progresses, the other base line equipment such as the battery, inverter and voltage sensing transfer switch still need to be compacted and unitized for residential use. Commercial use, depending on the size of the service will be limited in the photovoltaic cell arena, and more complex parabolic reflectors and solar concentrators are becoming the dominant technology.

The global flexible and thin-film photovoltaic (PV) market, despite caution in the overall PV industry, is expected to experience a CAGR of over 35% to 2019, surpassing 32 GW according to a major new study by IntertechPira.[4]

[edit] Module embedded electronics

See also: Microinverter

Several companies have begun embedding electronics into PV modules. This enables performing Maximum Power Point Tracking (MPPT) for each module individually, and the measurement of performance data for monitoring and fault detection at module level. Some of these solutions make use of Power Optimizers, a DC to DC converter technology developed to maximize the power harvest from solar photovoltaic systems.

[edit] Module performance and lifetime

Module performance is generally rated under standard test conditions: irradiance of 1,000 W/m², solar spectrum of AM 1.5 and module temperature at 25°C.

Electrical characteristics include nominal power (PMAX, measured in W), open circuit voltage (VOC), short circuit current (ISC, measured in amperes), maximum power voltage (VMPP), maximum power current (IMPP), peak power, kWp, and module efficiency (%).

Nominal voltage refers to the voltage of the battery that the module is best suited to charge; this is a leftover term from the days when solar panels were used only to charge batteries. The actual voltage output of the panel changes as lighting, temperature and load conditions change, so there is never one specific voltage at which the panel operates. Nominal voltage allows users, at a glance, to make sure the panel is compatible with a given system.

Open circuit voltage or VOC is the maximum voltage that the panel can produce when not connected to an electrical circuit or system. VOC can be measured with a meter directly on an illuminated panel's terminals or on its disconnected cable.[5]

The peak power rating, kWp, is the maximum output according under standard test conditions (not the maximum possible output).

Solar panels must withstand heat, cold, rain and hail for many years. Many crystalline silicon module manufacturers offer a warranty that guarantees electrical production for 10 years at 90% of rated power output and 25 years at 80%.[6]

[edit] Production

15.9 GW of solar PV system installations were completed in 2010, with solar PV pricing survey and market research company PVinsights reporting growth of 117.8% in solar PV installation on a year-on-year basis. With over 100% year-on-year growth in PV system installation, PV module makers dramatically increased their shipments of solar panels in 2010. They actively expanded their capacity and turned themselves into gigawatt GW players. According to PVinsights, five of the top ten PV module companies in 2010 are GW players. Suntech, First Solar, Sharp, Yingli and Trina Solar are GW producers now, and most of them doubled their shipments in 2010.[7]

[edit] Top ten

The top ten solar panel producers (by MW shipments) in 2010 were:[7]

1. Suntech 2. First Solar 3. Sharp Solar 4. Yingli 5. Trina Solar 6. Canadian Solar 7. Hanwha Solarone 8. Sunpower 9. Renewable Energy Corporation 10. Solarworld

The windwheel of the Greek engineer Heron of Alexandria in the 1st century AD is the earliest known instance of using a wind-driven wheel to power a machine.[4][5] Another early example of a wind-driven wheel was the prayer wheel, which was used in ancient Tibet and China since the 4th century.[6] It has been claimed that the Babylonian emperor Hammurabi planned to use wind power for his ambitious irrigation project in the 17th century BC.[7]

Horizontal windmills

The Persian horizontal windmill

The first practical windmills had sails that rotated in a horizontal plane, around a vertical axis.[8] They were invented in eastern Persia (what is now Afghanistan), as recorded by the Persian geographer Estakhri in the 9th century.[9][10] The authenticity of an earlier anecdote of a windmill involving the second caliph Umar (AD 634–644) is questioned on the grounds that it appears in a 10th-century document.[11] Made of six to twelve sails covered in reed matting or cloth material, these windmills were used to grind grain or draw up water, and were quite different from the later European vertical windmills. Windmills were in widespread use across the Middle East and Central Asia, and later spread to China and India from there.[12]

A similar type of horizontal windmill with rectangular blades, used for irrigation, can also be found in 13th-century China (during the Jurchen Jin Dynasty in the north), introduced by the travels of Yelü Chucai to Turkestan in 1219.[13]

Hooper's Mill, Margate, Kent. An 18th Century European horizontal windmill

Horizontal windmills were built, in small numbers, in Europe during the eighteenth and nineteenth centuries,[8] for example Fowler's Mill at Battersea in London, and Hooper's Mill at Margate in Kent. These early modern examples seem not to have been directly influenced by the horizontal windmills of the Middle and Far East, but to have been independent inventions by engineers influenced by the Industrial Revolution.[14]

Vertical windmills

There is an ongoing debate among historians on whether and how the windmill from the middle East influenced the development of the early European windmill.[15][16][17][18] In northwestern Europe, the horizontal-axis or vertical windmill (so called due to the plane of the movement of its sails) is believed to date from the last quarter of the 12th century in the triangle of northern France, eastern England and Flanders. The earliest certain reference to a windmill in Europe (assumed to have been of the vertical type) dates from 1185, in Weedley, Yorkshire, although a number of earlier but less certainly dated twelfth century European sources referring to windmills have also been found.[19] These earliest mills were used to grind cereals.

Post mill

A windmill on the background of the 1792 Battle of Valmy, France.Main article: Post mill

The evidence at present is that the earliest type of European windmill was the post mill, so named because of the large upright post on which the mill's main structure (the "body" or

"buck") is balanced. By mounting the body this way, the mill is able to rotate to face the wind direction; an essential requirement for windmills to operate economically in North-Western Europe, where wind directions are variable. The body contains all the milling machinery. The first post mills were of the sunken type where the post was buried in an earth mound to support it. Later a wooden support was developed called the trestle. This was often covered over or surrounded by a roundhouse to protected the trestle from the weather and to provide storage space. This type of windmill was the most common in Europe until the 19th century when more powerful tower and smock mills replaced them.

Hollow-post mill

In a hollow-post mill the post on which the body is mounted is hollowed out, to accommodate the drive shaft.[20] In this way it is possible to drive machinery below or outside the body while still being able to rotate the body into the wind. Hollow-post mills driving scoop wheels were used in the Netherlands to drain wetlands from the 14th century onwards.

Tower mill

Main article: Tower mill

By the end of the thirteenth century the masonry tower mill, on which only the cap is rotated rather than the whole body of the mill, had been introduced. The spread of tower mills came with a growing economy that called for larger and more stable sources of power though they were more expensive to build. In contrast to the post mill, only the cap of the tower mill needs to be turned into the wind, so the main structure can be made much taller, allowing the sails to be made longer, which enables them to provide useful work even in low winds. The cap can be turned into the wind either by winches or gearing inside the cap or from a winch on the tail pole outside the mill. A method of keeping the cap and sails into the wind automatically is by using a fantail, a small windmill mounted at right angles to the sails, at the rear of the windmill. These are also fitted to tail poles of post mills and are common in Great Britain and English-speaking countries of the former British Empire, Denmark and Germany but rare in other places. Tower mills with a fixed cap are found around the Mediterranean Sea. They are built with the sails facing the prevailing wind direction.

Smock mill

Main article: Smock mill

The smock mill is a later development of the tower mill where the tower is replaced by a wooden framework, called the "smock." The smock is commonly of octagonal plan, though examples with more, or fewer, sides exist. The smock is thatched, boarded or covered by other materials like slate, sheet metal or tar paper. The lighter construction in comparison to tower mills make smock mills practical as drainage mills as these often had to be built in areas with unstable subsoil. Having originated as a drainage mill, smock mills are also used for a variety of purposes. When used in a built-up area it is often placed on a masonry base to raise it above the surrounding buildings.

Smock mill De 1100 Roe, Amsterdam, Netherlands, built in 1757, type called a grondzeiler ("ground sailer") by the Dutch , since the sails almost reach the ground.

Post mill of Talcy, France with medieval style sails

Groenendijkse Molen. A hollow post drainage mill

Wilton Windmill. A tower mill with fantail

Beacon Mill, a smock mill of 1802

A smock mill with a stage on a brick base in Sønderho, Fanø, Denmark

Tower mill with jib sails in Antimahia, Kos, Greece

Sails

Main article: Windmill sail

Common sails consist of a lattice framework on which a sailcloth is spread. The miller can adjust the amount of cloth spread according to the amount of wind available and power needed. In medieval mills the sailcloth was wound in and out of a ladder type arrangement of sails. Post-medieval mill sails had a lattice framework over which the sailcloth was spread, while in colder climates the cloth was replaced by wooden slats, which were easier to handle in freezing conditions.[21] The jib sail is commonly found in Mediterranean countries, and consists of a simple triangle of cloth wound round a spar. In all cases the mill needs to be stopped to adjust the sails. Inventions in Great Britain in the late 18th and 19th century led to sails that automatically adjust to the wind speed without the need for the miller to intervene, culminating in Patent sails invented by William Cubitt in 1813. In these sails the cloth is replaced by a mechanism of connected shutters. In France, Berton invented a system consisting of longitudinal wooden slats connected by a mechanism that lets the miller open them while the mill is turning. In the 20th

century increased knowledge of aerodynamics from the development of the airplane led to further improvements in efficiency by German engineer Bilau and several Dutch millwrights. The majority of windmills have four sails. Multi-sailed mills, with five, six or eight sails, were built in Great Britain (especially in and around the counties of Lincolnshire and Yorkshire), Germany and less commonly elsewhere. Earlier multi-sailed mills are found in Spain, Portugal, Greece, parts of Romania, Bulgaria and Russia [22] A mill with an even number of sails has the advantage of being able to run with a damaged sail and the one opposite removed without resulting in an unbalanced mill.

Machinery

Main article: Mill machinery

Interior view, Pantigo windmill, East Hampton, New York. Historic American Buildings Survey

Gears inside a windmill convey power from the rotary motion of the sails to a mechanical device. The sails are carried on the horizontal windshaft. Windshafts can be wholly made of wood, or wood with a cast iron poll end (where the sails are mounted) or entirely of cast iron. The brake wheel is fitted onto the windshaft between the front and rear bearing. It has the brake around the outside of the rim and teeth in the side of the rim which drive the horizontal gearwheel called wallower on the top end of the vertical upright shaft. In grist mills the great spur wheel, lower down the upright shaft, drives one or more stone nuts on the shafts driving each millstone. Post mills sometimes have a head and/or tail wheel driving the stone nuts directly, instead of the spur gear arrangement. Additional gear wheels drive a sack hoist or other machinery. The machinery differs if the windmill is used for other applications than milling grain. A drainage mill uses another set of gear wheels on the bottom end of the upright shaft to drive a scoop wheel or Archimedes' screw. Sawmills use a crankshaft with to provide a reciprocating motion to the saws. Windmills have been used to power many other industrial processes, including papermills, threshing mills, and for example to process oil seeds, wool, paints and stone products [3]

An isometric drawing of the machinery of the Beebe Windmill.

Diagram of the smock mill at Meopham, Kent

Cross section of a post mill

Windshaft, brake wheel and brake blocks in smock mill d'Admiraal in Amsterdam

Spread and decline

Oilmill De Zoeker, paintmill De Kat and paltrok sawmill De Gekroonde Poelenburg at the Zaanse Schans

The total number of wind powered mills in Europe is estimated to have been around 200,000 at its peak, compared to some 500,000 waterwheels.[21] With the coming of the industrial revolution, the importance of wind (and water) as primary industrial energy source declined and was eventually replaced by steam (in steam mills) and internal combustion engines, although windmills continued to be built in large numbers until late in the 19th Century. More recently windmills have been preserved for their historic value, in some cases as static exhibits when the antique machinery is too fragile to put in motion, and in other cases as fully working mills. There are around 50 working mills in operation in Britain as of 2009.[23]

Of the 10,000 windmills in use in the Netherlands around 1850,[24] about 1000 are still standing. Most of these are being run by volunteers though there are some grist mills still operating commercially. Many of the drainage mills have been appointed as backup to the modern pumping stations. The Zaan district has been said to have been the first industrialized region of the world with around 600 operating wind powered industries by the end of the 18th century.[24] Economic fluctuations and the industrial revolution had a much greater impact on these industries than on grain and drainage mills so only very few are left.

Construction of mills spread to the Cape Colony in the 17th century. The early tower-mills did not survive the gales of the Cape Peninsula, so that in 1717 the Heeren XVII sent carpenters, masons and materials to construct a durable mill. The mill was completed in 1718 and became known as the Oude Molen and was located between Pinelands Station and the Black River. Long since demolished, its name lives on as that of a Technical school in Pinelands. By 1863 Cape Town could boast eleven mills stretching from Paarden Eiland to Mowbray. [25]

Windpumps

Windpump in South Dakota, USAMain article: Windpump

Windpumps are used extensively on farms and ranches in the central plains and South West of the United States and in Southern Africa and Australia. These mills feature a large number of blades so that they turn slowly with considerable torque in low winds and be self regulating in high winds. A tower-top gearbox and crankshaft convert the rotary motion into reciprocating strokes carried downward through a rod to the pump cylinder below. The farm wind pump was invented by Daniel Halladay in 1854.[26][27] Eventually steel blades and steel towers replaced wooden construction, and at their peak in 1930, an estimated 600,000 units were in use.[28] The multi-bladed wind turbine atop a lattice tower made of wood or steel hence became, for many years, a fixture of the landscape throughout rural America. Firms such as Star, Eclipse, Fairbanks-Morse and Aermotor became famed suppliers in North and South America.

Wind turbine

Main article: Wind power

A windmill used to generate electricity is commonly called a wind turbine. The first windmills for electricity production were built by the end of the 19th century by Prof James Blyth in Scotland (1887),[29][30] Charles F. Brush in Cleveland, Ohio (1887–1888)[31][32][33] and Poul la Cour in Denmark (1890s). La Cour's mill from 1896 later became the local powerplant of the village Askov. By 1908 there were 72 wind-driven electric generators in Denmark from 5 kW to 25 kW. By the 1930s windmills were widely used to generate electricity on farms in the United States where distribution systems had not yet been installed, built by companies like Jacobs Wind, Wincharger, Miller Airlite, Universal Aeroelectric, Paris-Dunn, Airline and Winpower and by the Dunlite Corporation for similar locations in Australia.

Rønland Windpark in Denmark

Forerunners of modern horizontal-axis utility-scale wind generators were the WIME-3D in service in Balaklava USSR from 1931 until 1942, a 100 kW generator on a 30 m (100 ft) tower,[34] the Smith-Putnam wind turbine built in 1941 on the mountain known as Grandpa's Knob in Castleton, Vermont, USA of 1.25 MW[35] and the NASA wind turbines developed from 1974 through the mid 1980's. The development of these 13 experimental wind turbines pioneered many of the wind turbine design technologies in use today, including: steel tube towers, variable-speed generators, composite blade materials, partial-span pitch control, as well as aerodynamic, structural, and acoustic engineering design capabilities. The modern wind power industry began

in 1979 with the serial production of wind turbines by Danish manufacturers Kuriant, Vestas, Nordtank, and Bonus. These early turbines were small by today's standards, with capacities of 20–30 kW each. Since then, they have increased greatly in size, with the Enercon E-126 capable of delivering up to 7 MW, while wind turbine production has expanded to many countries.

As the 21st century began, rising concerns over energy security, global warming, and eventual fossil fuel depletion led to an expansion of interest in all available forms of renewable energy. Worldwide there are now many thousands of wind turbines operating, with a total nameplate capacity of 194,400 MW.[36] Europe accounted for 48% of the total in 2009.

A wind turbine looking like a windmill is De Nolet in Rotterdam.

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