Skip to 0 minutes and 8 secondsWelcome to week 2 of How to Survive on Earth, Energy Materials for a Sustainable Future. We are here at a beautiful beach in Wollongong, Australia, surrounded by three materials that are used to generate energy on Earth-- water, the material that we think of as essential to all life that could also be the source of the fuel of the future, a material that's almost everywhere on the planet, is easily recyclable, and would produce little to no greenhouse gas. Now that would be truly sustainable. But more on that later in the course. Our second energy material-- sand, the essence of silicon solar cells.

Skip to 0 minutes and 53 secondsRefining this to highly pure silicon provides the solar cells that are currently producing 1% of all electricity in the world from the Sun. This is the energy material that has shown us the path to a sustainable future, but it takes a lot of energy and very expensive factories to produce silicon. And would we want to start digging up beautiful beaches like this to produce the other 99% of world electricity? Here on the beach is our third energy material, a material that we see so often polluting our environment, one that is clogging beautiful oceans like this-- plastic.

Skip to 1 minute and 38 secondsOf course, the reason that plastic has become public environmental enemy number one is because it can be produced so easily and cheaply and in enormous amounts. Yet, despite all the pollution, it can be so easily recycled.

Skip to 1 minute and 56 secondsBut if we can put aside our concerns about pollution for a moment and imagine if plastic could be turned into solar cells, imagine how much energy could be generated from thin layers of lightweight, inexpensive plastic solar cells that could cover all the bare roofs and even walls of our houses and buildings-- plastic solar cells that could be integrated into awnings, blinds, curtains, and even our clothes-- solar cells that could even work indoors. And if you think that's crazy, remember, plants are already doing it-- harvesting light both indoors and outdoors.

Skip to 2 minutes and 42 secondsAs you might guess, you can't make solar cells with just any old plastic. It needs to be conductive plastic, which in itself sounds remarkable because we all know that when we turn on a switch, we rely on plastic being an insulator. So this week, we will explore the remarkable story of the discovery of conducting plastics or polymers and how they can be used to make plastics solar cells, as well as be used in other energy applications. Can these amazing energy materials help us to survive on Earth? Let's go and find out.

Welcome to Week 2

The sun and solar energy.

The sun is a free and near-infinite power source of energy. But how do we capture this energy and convert it into electricity? There are different ways to get electricity from solar irradiation, including solar-thermal. Even hydro and wind energy are ultimately driven by energy from the sun. Here we will focus our attention specifically on systems which operate based on the photovoltaic (PV) effect.

On the arid lands there will spring up industrial colonies without smoke and without smokestacks; forests of glass tubes will extend over the plains and glass buildings will rise everywhere; inside of these will take place the photo-chemical processes that hitherto have been the guarded secret of the plants, but that will have been mastered by human industry which will know how to make them bear even more abundant fruit than nature, for nature is not in a hurry and mankind is. And if in a distant future the supply of coal becomes completely exhausted, civilization will not be checked by that, for life and civilization will continue as long as the sun shines! –Giacomo Ciamician, Science Magazine, Friday, September 27, 1912(1)

History of Solar Power

  • Edmund Bequerel wrote as far back as 1839 that exposure to light can cause certain materials to produce small electric currents. (2)

  • 1888, Edward Weston applies for US Patent – Apparatus for utilizing solar radiant energy (3)

  • Albert Einstein won a Nobel prize in physics for his 1905 work on describing the nature of light and the photoelectric effect. (4)

  • Bell Laboratories developed the first practical silicon solar cell in 1954 (5).

  • 1964 NASA launches the first satellite equipped with solar equipped panels that track the sun, Nimbus 1. (6)

From their initial development, photovoltaic and related technologies have continually gained efficiencies in how well they are able to capture the sun’s energy and convert it into electricity. There is a multitude of solar cell research happening globally, investigating the use of different PV technologies and materials to gain efficiencies in solar energy production.

The graph below illustrates this range of PV research happening globally and the efficiencies gained over time. It is notable that in the last 5 years that this trend of increasing efficiency is accelerating for all these competing PV technologies. The remarkable observation is that this is happening despite the diverse range of materials and cell structures suggesting that researchers are solving many of the key technology problems.

We won’t cover all of these technologies, but we will focus on traditional silicon (Si) PV cells and how conductive plastic (emerging PV) may be able to resolve some of the issues with silicon.

Alt text: Solar cells have become more efficient over time. From near 0% efficiency in the mid-1970s through to cells reaching nearly 50% efficiency heading into 2020

A full sized PDF version of this chart is available in the additional links below


Reference

  1. Ciamician G. The Photochemistry of the Future. Science [Internet]. 1912 [cited 21 May 2019];(926):394. Available from: Science Mag (PDF)

  2. First photovoltaic Devices PVEducation [Internet]. Pveducation.org. 2019 [cited 10 May 2019]. Available from: PV Education (Web link)

  3. Patent Images [Internet]. Pdfpiw.uspto.gov. 2019 [cited 10 May 2019]. Available from: Patent Images (Web link)

  4. The Nobel Prize in Physics 1921 [Internet]. NobelPrize.org. 2019 [cited 10 May 2019]. Available from: Nobel Prize (Web link)

  5. This Month in Physics History [Internet]. Aps.org. 2019 [cited 10 May 2019]. Available from: Physics History (Web link)

  6. Nimbus: NASA Remembers First Earth Observations [Internet]. NASA. 2019 [cited 10 May 2019]. Available from: Nimbus (Web link)

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How to Survive on Earth: Energy Materials for a Sustainable Future

University of Wollongong

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