The Energy Challenge and Introduction to Solar Cells

Burhan Saifaddin

Splash program for High School Students, MIT 2011

Outline

• The importance of Energy • The energy Challenge• Introduction to Solar Cells• Organic Photovoltaic Research

What is Energy !!

• Brain storm the importance of energy and its uses: Examples on the impact of energy : – Transportation– Housing– Industry

• Materials • Manufacturing

– Information Technology – Food– People and every living being

The Sun is the main source of energy at our planet.

What is Energy !!

• Discovery of Energy. • Matter is Energy. Everything is Energy.– The Big bang started the universe.– Biological Life is based on the consumption of energy.– Fire discovery ended Stone AgeMore recently :– Steam Engine started the industrial revolution– Electricity started communication, tranportation and

information revolution– Nuclear energy started the nuclear age.

Do we consume Energy more than we drink water *?!

• How are we spending energy ?• World wide : ~0.5 Zetta-Joules (10^21)– What does one Joule means ?!

• ~ 2.9 MJ to boil 1 kg of water from zero degrees.

• In the US 100 Quadrillions(10^15) BTU – 5% consumes 22% of global energy use.In lay terms– this is 1.5 Gallon /person/day.– Average US is 7.5 Gallon/person/day.– How much water do you drink a day ? But more than 1.6B people have Zero electricity

* Ignore other industrial, agricultural etc… uses of water

Adopted from Prof Tonio Buonassisi

Units 101

Units 101

Adopted from Prof Tonio Buonassisi

Adopted from Prof Tonio Buonassisi

Adopted from Prof Tonio Buonassisi

100 MW Solar Cells Power Planet

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The Energy Challenge

1- Meet Huge Energy Demands Sustainably:

• 2010, 6.8 Billion People 12TW– 2kW/person over the year. – 1.5 Gasoline Gallon/day.

• Increasing population. By 2050, 10-12 Billion People 20-24TW (conservative estimate).

• Raising standards of Living for over than 2 Billions people.• Nations wants energy security and green energy.

The Energy Challenge 2- Risks of Global Warming. Is it real ?

3-National Security.

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Why meet the Energy Challenge

• Meet Global Energy Demands in a sustainable way.

• Big economic growth: Energy is a Trillions of Dollars Industry. – 30% growth in photovoltaic market in the past 6

years. • Enable cheap and distributed power sources. • Empower people around the world.– 25 % of humanity have no electricity.

The developing World

The World at night.

PV and the developing WorldWorld

http://eosweb.larc.nasa.gov/sse/Adopted from Prof. Tonio Buonassisi

PV and the developing WorldWorld

The Sun is the Primary energy source on Earth

Solar Insolation: Incoming Solar Radiation

Summer

Solar Insolation: Incoming Solar Radiation

Winter

Review

• What are the main energy challenges facing our world ?

• Design a Solar System to Generate – 10KWh/day at peak sun conditions.

• How much area , roughly, we need to generate

1 TW ?

Difficulties with the sun’s light spectrum:

-Very Wideband

-Low power density , Maximum (peak) ~ 1000 W/m2

-Capacity factor ~ 20%.

Three generation of Photovoltaic in 50 Years

Main Problem for wide adoption is Cost $$

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Polymer and Silicon PV

• TTwo

Based on A Heeger et all. Science (1995)

Polymer PV

Early Applications in Space

Crystalline Silicon in Bell Labs in the 1950s

Basic Photovoltaic Energy Conversion

What is the maximum limit for a single junction PV ?

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PV Technology Status

NREL, 2009

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PV Technology Status

NREL, 2009

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Motivation for Cheap Solar Cells

• Meet Global Energy Demands in a sustainable way.

• Big economic growth.– 30% growth in photovoltaic market in the past 6 years.

• Enable cheap and distributed power sources. • Empower people around the world.– 25 % of humanity have no electricity.

Why Polymers or Organic Materials ?

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Additionally Huge Economic Advantages.

• Big economic growth.– Potentially trillions of dollars market size.– 30% growth in photovoltaic market in the past 10

years. – DOE expect grid parity for PV tech. in 2020.

• Empower people around the world.– 25 % of humanity have no electricity.

africa-charity-project.org

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Basic Overview of the Organic PV Technology

• Setbacks – Low life time (2-5 years) – and low efficiency (4-5%).

• Key patents :Konarka (2001) and Solarmer (2006).

BHJ Cells manufacturers Claims:Roll to Roll processing. Cheap abundant Materials. Light weight.Flexible. Larger acceptance angle.

www.osa-opn.org

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PV Researchers and entrepreneurs dream

• Covers large area of land with PV cells. – 1 % of US land to satisfy US electricity needs.– Spain size to satisfy 20TW increase in demand.– Small contribution to global warming , comparable to US

black highways. – Reasonable fraction Targets by 2030 and by 2050.

• However to be competitive in the grid parity market– 5c/KWh at around 1$/W for the whole system.– Improve lifetime in outdoor conditions.

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Components of BHJ PV

• Active materials cost is a small fraction of the total cost. • Similar cost structure to Thin Films. . Kalowekmao et al., 2007

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PV Electricity Markets

• Market Size double every 3y. Currently ~$40 Billion. • Competitors will reach Grid parity at some locations (8-10

c/kwh) before by 2015.

Thin Films are leading the way nowExs. First Solar

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Solar systems cost

• Balance of System (>50%)– 1- Light weight plastic substrate. – Glass substrate • Cost is Different in developing nations

• Balance of Materials – In crystalline silicon materials cost is 10% , 2-3

C/KWh(1).

(1) Nathan S. Lewis. SCIENCE 9 FEB 2007 VOL 315.

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Niche Markets: What would be the consumer reaction?

• Opportunities is determined by– $/kWh, life time, efficiency.

• Light Weight and low light suitability. • Portable Electronics: Mobiles , laptops, ipods• Watches.

• Flexibility lead to – Clothing. – Fabrics. – Tents

• Transparency lead to– Tinted Glass.– Building integrated materials.– Automobiles.

Premium to 100$