Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics

Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics Volume 1 photovoltaic solar energy 1 04 – history of photovoltaics

1.04.1 Harnessing Solar Energy – A New Invention?

Many may think that the use of solar energy is a modern time phenomenon being a repercussion of the 1970s’ oil embargo; however, this is not the case The use of solar energy in different forms to support the growth and development of civilization has been around as long as mankind existed When modern society considers energy sources, normally what would come to mind first would be traditional energy sources such as coal, oil, and gas; however, our current biomass of wood, dried animal dung, and peat has traditionally been the choice of fuel of ancient cultures Obviously, the traditional and modern biofuels, as with other renewable energy forms, are all originally created from the sun with the biofuels acting like an early storage device of solar energy which was useful only during daylight hours Early humans did not have the scientific capability and knowledge that we have today, but they had a basic understanding of the power of the sun and they understood that from this ‘bright yellow star’ different forms of energy came to enhance their standard of living This is the reason why many ancient civilizations, such as the Native Americans, both north and south, the Babylonians, the Persians, ancient Hindus, and the Egyptians, had a great respect for the sun, even going to the extent

of worshipping it The Greeks, well known for their gods, were devoted to the sun gods Helios and Apollo, and with their traditions built temples to show their devotion This was also seen in the ancient Egyptian Civilization and their dedication to Ra, who was normally depicted with the sun disk of Wadjet placed on top of his falcon head However, it was really the Greeks and Romans who fully embraced the potential of the sun in the first instance as a free energy source [1]

The first known invention that captured the solar rays was in 600 BC (before Christ) when fire was initiated by focusing the solar rays onto wood via a magnifying material (Figure 1)

This principle was not abandoned but rather it was further used for light applications, specifically torch lighting in the third and second century BC However, as with many innovations, developments in solar energy are often not only used to improve human comfort but also developed and used by the military An ancient example of this was introduced by Archimedes in 212 BC when the Greeks used the magnifying principle of solar radiation to burn the sails on Roman ships that were attacking Syracuse (Figure 2), thus diversifying the potential of solar to include war as well as daily life [3]

Very rarely does any civilization move forward with a new idea or technology unless there is a growing need for advancement: Greece experienced a fuel shortage in the fourth century BC, and therefore the need to be innovative and initiate an idea that would provide heat and light for its communities was vitally important for their survival From as early as 400 BC, the Greeks implemented passive solar designs into their accommodations, thus being the first community to fully integrate solar energy into their society for reasons other than religious worship

The basic principle of passive solar design (Figure 3) was to protect the north side of the building from the elements (wind, rain, etc.) and ensure that the south was open to solar radiation in the winter but shaded in the summer

This simple principle was accepted widely and was implemented not only in private homes but also in public buildings and the

This ensured that the civilization captured the optimum amount of energy from the sun; even with a limited understanding of why this worked, the cultures constructed cities based on this principle Greeks and Romans were not the only two societies that embraced this abundant energy source, but also the Pueblo, Anasazi, and Chinese also used the idea for the same purposes of light and heat Although many societies had similar ideas, they were not generated together or the knowledge transferred, rather they were developed separately, as the sharing of knowledge was not as readily available as it is in today’s modern society Societies did however advance their designs and a good example of this was the improvement by the Romans to use glass to enclose the heat in the building, hence storing it and ensuring maximum warmth [1] The Roman Government went further by declaring the first law highlighting that it was illegal to block your neighbor’s sunlight, supporting the embracement of solar heating and lighting at both government and community level The Romans developed and embraced the greenhouse idea we depend on now to grow fruits and vegetables that they brought back from different countries as they were expanding their empire This idea is still used in much the same form today as it was in Roman times to ensure that we have sufficient supplies and varieties of food to feed the world, ensuring self-survival

After the turn of history into the anno Domini (AD) period, very little changes or developments occurred with solar energy until during the Industrial Revolution In the different centuries from the beginning of this era, acts by certain people/communities to use

Figure 1 Creating fire from the sun [2]

Figure 2 Archimedes mirror burning Roman military ships [4]

Figure 3 Passive solar design in Anasazi cliff [5]

the heat and light of the sun were noted but no improvements or breakthroughs were highlighted or noted In 100 AD, Pliny the

what we would consider today a conservatory, but as mentioned before this use of the sun was common in Greek and Roman times

so was not a new idea [7]

Furthermore, it was recorded that the North American Pueblo people in 1200 AD discovered and embraced the benefits of passive solar By the eighteenth century, it was accepted as normal for the upper classes to have greenhouses, and this was further expanded in the nineteenth century when people with wealth constructed conservatories (Figure 6) for people to relax, walk, and enjoy warmth in very pleasant surroundings

However, the next step proved to be the most complicated period with the move from the sun as the provider of light and heat to

a supplier of much more The mystery of energy from the sun truly eluded societies until the nineteenth century when one discovery opened many possibilities for the sun to be a future energy-supplying giant

Figure 4 Roman bathhouses [6]

Figure 5 Pliny the Younger [8]

Figure 6 Conservatories first initiated by Romans [9]

1.04.2 What Was the Catalyst for Photovoltaic Development?

As discussed previously, for centuries we have been using the power of the sun in a number of basic ways However, it was not until the 1800s that the scientific breakthrough happened to enable us to fully harness all the potential of this free, largely abundant fuel source The credit of this turnaround in the use of solar energy is due to a publication in 1839 by a physicist Edmund Becquerel (Figure 7) from France, who discussed an experiment he had undertaken with a wet cell battery [10]

Figure 7 Edmund Becquerel [11]

Thin membrane

Light

Acidic Solution

Blackened box

Pt electrodes

Figure 8 Photoelectric effect [14]

During his investigation, Becquerel discovered that when sunlight is made available to the silver plates, the output voltage of the battery increased (Figure 8) This discovery paved the way for other researches [12, 13]; however, it was not a priority at the time as fossil fuel was reasonably priced and in abundant supply

Some other support of this original discovery was undertaken during the 1800s, but progression to prove was slow until the mid-twentieth century Adams (Figure 9) and Day discussed in a publication the effect of sunlight on selenium, and later in 1883,

an electrician Charles Edgar Fritts from New York designed a very inefficient (1–2%) prototype cell that is similar to the typical cells used today [15]

The efficiency of this and all other cells is calculated by measuring the electricity produced from the total of possible energy that hits the photovoltaic (PV) surface The prototype held many of the characteristics of today’s solar cells – it had a glass cover beneath which was a mass of fine gold wires sandwiched between glass and a thin layer of selenium This was the first model for scientists to improve further, but it would take many decades before an increased efficiency was achieved and a true understanding of the reasons of the earlier low output was reached

Little development had occurred over the half century since the initial discovery and whether this was due to lack of knowledge, lack of interest, or the constant low price of fossil fuels is not clear The first half of the twentieth century was to follow much the same trend with the only real notable occurrences being Planck’s (Figure 10) new idea regarding his light quantum hypothesis [17] which supported Albert Einstein’s (Figure 11) 1905 paper [18] on the photoelectric effect that won him the Nobel Prize in 1921

Figure 9 William Grylls Adams [16]

Figure 10 Max Planck [19]

Figure 11 Albert Einstein [20]

Figure 12 Bell Labs scientists Daryl Chaplin, Calvin Fuller, and Gerald Pearson Courtesy of John Perlin Bell Labs silicon solar cell [24]

The second half of the twentieth century was to see faster progression, some of which was just natural scientific progression but also some historical occurrences helped to speed up the growth of PV cells Bell Labs researchers in America were responsible for one

of the largest discoveries that turned the solar industry into what we see today and unbeknownst to them it was their work in semiconductors that would actually support the development of solar cells [21, 22] Semiconductors are the middle ground between conductors and insulators and are made from silicon that is doped and the researchers at Bell Labs had seen silicon reaching better results than the previously tested selenium [23] They, for the first time, foresaw the possibility for solar cells with efficiencies of more than 20% compared with current levels of 1–2% The team (Figure 12), however, realized that they could not make this significant step with only the transition to a different material and they continued to undertake research to find an optimal p–n junction

Bell researchers discovered that they could achieve 6% (US$250 per watt versus approximately $3 per watt for coal) cell efficiency by mixing arsenic with silicon and placing a thin coat of boron on the cell [25] Probably unknown to the scientists they had started a revolution in energy supply that in less than 20 years would be needed worldwide even if their discovery was a spin off from their transistor technology and expertise Even with the advancement, the current product was too expensive for terrestrial use; however, for space power applications, it was the perfect solution as there was no other alternative, so despite its negative points it was still the best solution [16]

The first of many solar cells for powering space machines was placed on the Vanguard I space satellite in 1958 and this worked until it was decommissioned in 1964 [26] The huge success of PV cells as an endless and nonpolluting power supply has ensured a place for these cells in the space industry (Figure 13) independent of cost and efficiency [27]

As more improvements and developments have been made to cells so has the option of where they can be incorporated As the efficiency continues to improve, the efficiency of PV cells improved to 14% by Hoffman Electronics (1960) [29], so does the

Figure 13 Solar-powered space satellite [28]

government incentives that helped to support the acceptance of renewable energy [31, 32]

During the 15-year period from 1970 onward, PV cells saw a huge growth, which culminated in a breakthrough in the price of PV cells per watt to under one-tenth of its previous cost in this short period (1970 – $100 per watt to 1985 – $7 per watt) This could have continued if the oil price had not dropped again, which meant people quickly forgot about the issues of the decade before and went directly back to their old habits, meaning that for another extended period progress was limited and the world went back to embracing fossil fuels Even the government’s support during this period was somewhat focused in the wrong direction as it did not see the importance of supporting the PV companies to develop the systems that would have speeded the progression of solar technology; rather it directed its efforts to universities for large-scale R&D making the public’s access to this technology more difficult Another factor that played an important part in the slow development of this technology was the attitude of the fossil fuel providers which traditionally most communities and governments depend on for energy This industry did not support the development of alternative energy initially providing it with a challenging path; however, this has changed as nowadays most people widely accept the idea of renewable energy as a supporting source to the traditional source

The United States very much took the lead in solar cell development after the initial nineteenth century French discovery, and until

1990 they were the leaders in the market, R&D, and implementation Nevertheless, this changed at the end of the twentieth century with this domination moving and splitting between Europe and Japan In this decade, the world reached a huge milestone with one million homes integrating some type of solar power During this period, both Japan and Europe, particularly Germany, introduced government subsidies, increased public awareness, and invested in R&D In the 1990s, Japan had seen its market increasing 10-fold with Germany floundering initially but modifications to its subsidies had seen its output rise by a multiple of 40 even topping Japan’s success Other European countries such as Spain have followed their lead and achieved much the same growth

The PV market has completed an exciting part in its history with R&D still ongoing together with product development for tasks such as lighting, desalination, and pumping, and hence making it interesting not only to scientists and engineers but also to the general public (Figures 14 and 15)

Solar energy is now not only a more accessible power supply to satisfy the ever-growing demands but it also has lower costs, has higher efficiency, and is a clean alternative to fossil fuels

1.04.3 A Photovoltaic Modern Historical Timeline

The previous section discussed the major events that happened to develop solar energy to what it is today; however, many other smaller events played their part in the growth of this technology Table 1 outlines the year of the event, the person/company/ country responsible, if available, together with a summary of the discovery outlining the modern history of PV technology

Figure 14 PV on homes [33]

Figure 15 Large-scale PV plants [34]

Table 1 Glimpse of the modern PV history

Year Person/company/country Summary of discovery

1839 Alexandre Edmond Becquerel The photoelectric effect (light to electricity conversion) which saw both the conductance and

illuminance rise during an experiment he was undertaking with metal electrodes and electrolyte

1873 Willoughby Smith Selenium sensitivity to light was discovered during another experiment he was undertaking

promoting branching into selenium solar cell experiments

1876 Richard Day, William Adams Smith’s discovery of the photoelectric effect on selenium was further verified and advanced by

testing it with a platinum intersection which experiences the same phenomenon

1877 William Adams Constructed an initial solar cell from selenium

1883 Charles Fritts Explained the selenium wafer solar cell with his version having approximately 1–2% efficiency

1887 Heinrich Hertz The effect of ultraviolet light on reducing the minimum value of voltage capable of inducing

sparking between a pair of metal electrodes was tested

1888 Edward Weston ‘Solar Cell’ obtained first US patent [35]

1901 Nikola Tesla US Patent ‘Method of Utilizing and Apparatus for the Utilization of Radiant Energy’[36, 37]

1904 Wilhelm Hallwachs Further discoveries continued with regard to photosensitive material mixing specifically cuprous

oxide and copper

1905 Albert Einstein Published on the photoelectric effect – ‘On a Heuristic Viewpoint Concerning the Production and

Transformation of Light’[18]

1914 Goldman and Brodsky PV barrier layer was discovered

1916 Robert Milliken Proved Albert Einstein’s 1904 photoelectric effect theory

1918 Jan Czochralski Discovered a method to nurture single-crystal silicon, hence supporting the development and

future production of solar cells using monocrystalline silicon based material

1921 Albert Einstein Nobel Prize for 1904 paper on photoelectric effect

1932 Many scientists More material combinations were being observed to react to the photoelectric effect, specifically

cadmium selenide

1941 Development of the initial monocrystalline solar cell made from silicon was completed

1951 Primary solar cells using germanium were built as advancements enabling a p–n junction of a

single-crystal cell of this material to be grown

1953 Dan Trivich Completed research on theoretical solar cell material efficiency and the wavelength of the solar

spectrum [38]

1954 Reynolds, Leiess, Antes, and Published on the photoelectric effect of cadmium sulfide [39]

Marburger

1954 AT & T Solar cell operations were widely exposed to the American public

1954 Pearson, Chapin, and Fuller – Bell Solar cells produced using silicon with 4.5% efficiency This work was developed from a discovery

Laboratory that researchers made on the photoelectric effect on silicon when conducting another project on

semiconductors [23]

1954 Mort Prince and team Bell Labs broke its own efficiency record by 1.5%, raising the new level to 6% in a short time frame

1955 Initial research into powering satellites using solar cells commenced

1955 Western Electric Silicon solar cell production commercial license

1955 Hoffman Electronics – semiconductor Produced a PV with the following specification per cell: 14 mW peak power with 2% efficiency for

1955 In Chicago, a car powered by solar energy was unveiled

1957 Hoffman Electronics Efficiency of PV improved to 8%

1957 Chapin, Fuller, and Pearson AT & T Patent issued – ‘solar energy converting apparatus’[40]

1958 Hoffman Electronics Efficiency of PV improved to 9%

1958 Solar cell was designed to withstand the radiation in space

(Continued)

1961 United Nations Conference was held on solar energy applications in the developing world

1961 Defence Studies Institute First PV specialist conference

1962 Bell Labs Telstar telecommunications commercial satellite with 14 W peak power

1963 Sharp Corporation First viable silicon PV module

1963 Japan World’s largest 242 W PV array for powering a lighthouse was installed

1964 USA New largest 470 W PV array for powering a space project (Nimbus) was designed

1965 Tyco Labs Designed the edge-defined film-fed growth (EFG) process Tyco Labs were the first to create crystal

sapphire ribbons after the silicon version

1966 NASA 1 kW PV power astronomical observatory was launched and went into earthly orbit

1968 Peter Glaser The idea of a solar power satellite system was announced [41]

1968 Another satellite (OVI-13) was launched, but this time with two cadmium selenide panels as power

supplies

1969 Roger Little Founding of Spire Corporation, which was a company that aimed to continue to be important in

solar cell manufacturing

1970 All the historical developments to date and the high interest in research has ensured the constant

reduction of PV technology to approximately 80% of the original cost, hence making it more readily available for common low-power applications

1972 France Used a cadmium selenide PV to power a TV, which was used for educational purposes in Africa

(Niger)

1972 Solar Power Corporation Company founded

1973 Solar Power Corporation Beginning of commercial operation and opening of sales division

1973 Solarex Corporation Two NASA experts with experience in PV satellites founded this company

1973 Delaware University Development of initial domestic PV cells and thermal combined appliances

1974 Project Sunshine An initiative by the Japanese to further enhance, develop, and research in this area

1974 Tyco Labs One-inch EFG ribbon using the endless belt process

1975 Bill Yerkes Established Solar Technology International

1975 Jet Propulsion Laboratory Research and development for earth-based PV systems at this lab was supported by the US

Government This occurred from an industrial conference recommendation

1975 Exxon Established Solar Power Corporation

1976 Kyocera Corp Produces silicon ribbon crystal modules

1976 NASA From 1976 to 1985 and also from 1992 to 1995, the NASA Lewis Research Centre (LeRC) worked

on integrating PV cells into small power systems that could be used in many areas especially rural places with limited power

1976 RCA Lab Amorphous silicon cell was introduced

1976 Solec International Established

1977 US Department of Energy Established the National Renewable Energy Lab (NREL) in Colorado initially known as the Solar

Energy Research Institute (SERI)

1977 This year the sum of all the PV modules produced topped 500 kW

1977 NASA (LeRC) Six strategically placed meteorological stations in the United States were introduced for recording

data

1977 NASA (LeRC) Placed in a Papago Indian community the first PV system which supplied the power requirements

for the entire village The system was 3.5 kW and supplied power and pump water for 15 homes

1979 ARCO Solar This company based in California built the largest PV production facility to date

1979 NASA (LeRC) Installed a pumping station of 1.8 kW which was then upgraded to 3.6 kW in Burkina Faso

1979 60 kW diesel–PV hybrid system for powering a radar station was installed in Mount Laguna in

sun-drenched California

1980 ARCO 1 MW per year peak power PV module produced

1980 Luz Co For just more than 10 years they produced 95% of the world’s solar-based electricity However,

when the price of fossil fuels reduced, they closed due to lack of investor support

1980 Wasatch Electric 105.6 kW system built by a Utah company The system integrated modules produced by

Spectrolab, ARCO Solar, and Motorola An interesting fact is that this system is still operational

(Continued)

1981

1981

1982

1982

1982

1982

1982

1983

1983

1983

1983

1983

1983

1984

1984

1984

1984

1984

1984

1985

1985

1986

1989

1989

1989

1990

1990

1990

1991

1992

1992

1994

1994

1994

1995

1996

1996

Saudi Arabia

Helios Technology

ARCO

NASA LeRC

Volkswagen

Solarex Production

Solar Trek

ARCO Solar

Solar Power Corporation

NASA LeRC and Solarex

Solaria Corporation

David Carlson and

Christopher Wronski

ARCO

NASA LeRC

BP Solar Systems and EGS

BP Solar

University of New South Wales

Urs Muntwyler

ARCO Solar

Solarex

ARCO Solar

BP Solar

United Solar Systems Corporation

ARCO Solar

Germany

BP Solar Systems

Antarctica

Japan

National Renewable Energy Lab

ASE Americas Inc

World Bank and Indian Renewable

Energy Source Agency

BP Solar

Icar

modules 10.8 kW peak power desalination system in Jeddah, Saudi Arabia, powered by Mobil Solar First European PV manufacturer was established

Above 9.3 MW PV power produced worldwide

1 MW dual tracking PV plant called Solar’s Hisperia in California was grid connected Unveiled two PV-powered systems for testing a power supply for public lighting and for terrestrial satellite reception stations

A system used to start a car by placing 160 W peak power PV on the car roof top was tested Solar rooftop project of peak power 200 kW

21.3 MW peak power produced worldwide

1 kW powered vehicle which participated in the Australia Race driving for 20 days and 4000 km with

an average speed of 24 km and a maximum speed of 72 km However, later in the same year, the car outperformed itself by traveling further than 4000 km in 18 days on its journey between Long Beach and Daytona Beach

6 MW power plant grid subsystem for Pacific Gas and Electric Company which was enough to supply 2000/2500 homes

A Tunisian village was supplied with four systems with a combined power of 124 kW Built a system of 1.8 kW in Guyana to maintain power for basic hospital power requirements such

as lighting, radios, and medical refrigerators Other places were also provided with similar systems such as 4 kW in Ecuador and 1.8 kW in Zimbabwe

Merged with Amoco Solar, which was owned by Standard Oil They were presented the IEEE Morris N Liebmann Award for their work in “use of amorphous silicon in low cost, high performance photovoltaic solar cells”

Sacramento in California has a 1 MW PV power plant Amorphous modules first shown

Remote medical and school basic power supplies in Gabon by 17 separate systems Grid-connected 30 kW system in Southampton, UK

BP Solar expanded by purchasing Monosolar thin-film division 20% solar cell efficiency obtained

The Tour de Sol which ran from 1985 to 1993 based in Switzerland was another race for solar-powered vehicles As the years progressed, different classes opened providing not only direct solar-powered cars the right to participate but also other solar-powered vehicles Unveiled the first thin-film PV

Provided a PV system of 50 kW in Pakistan for projects the United Nations was undertaking

7 MW per year thin-film production possible In addition to production in California, the company expanded its production to Germany and Japan

Thin-film technology patent Company created out of the amalgamation of Energy Conversion Devices Inc (ECD) and Canon Inc Bought by Siemens and renamed Siemens Solar Industries

First country to launch a program that aimed to get community embracement of solar energy –

$500 million ‘100 000 solar roofs’ program This program focused not only on homes but any building including churches with the Cathedral in East Germany embracing this initiative Name changed to BP Solar International as well as being a new division in the BP company New location for remote power application

Patent of a 20% efficiency silicon cell Japan is the next country to follow Germany’s subsidy lead with its ‘70 000 Solar Roofs’ program Launched its website providing more access to information on renewable energy

German company ASE GmbH took over Mobil Solar Energy Corporation creating ASE Americas Inc The two groups along with Siemens Solar collaborated to support renewable energy projects which enhanced system commercialization in India

Expanded their business by taking over APS’s California production premises In the same year, they further expanded their product line to include the production of CIS

2 The Icar plane, which was powered by solar cells, had a total surface area of 21 m covered by 3000 cells

(Continued)