Clean Solar Energy DSSC Technology PRUTHIRAJ SWAIN 12PS21F
Outline Introduction(Present Scenario in India) Background on Solar Light Types of Solar cell How a Silicon-Based Solar Cell Works How a Dye-Sensitized Cell Works Comparison Summary
Introduction : Energy-starved India is becoming a vibrant market for renewable energy. This bodes well for a country that has often seen its industrial and economic growth inhibited by a truncated supply of conventional power. Currently faces energy shortage of 8 % & a peak demand shortage of 11.6 %. In order to sustain a growth rate of 8 %, it is estimated that the power generation capacity in India would have to increase to 306 GW in the next 10 years which is 1.7 times current levels. Grid-connected renewable power accounts for as much as 20.2 GW – or 11% – of Indias 182.3 GW of installed power capacity. ◦ The majority share (55% or 99.8 GW ) – by coal-based thermal power. ◦ Gas-fired thermal power, (10% or 17.7 GW), ◦ Hydropower (21% or 38.7 GW) and nuclear 2.6% with 4780 MW. ◦ India just had 2.12 megawatts of grid-connected solar generation capacity
Under the 11th Five Year Plan (ended March 2012), Only 52 GW of the 78.6 GW originally envisaged has been added,. The 10th Plan (2002-07) only saw a meagre 21.2 GW capacity added, against a target of 41.1 GW. The 12th Plan (2012-17) now aims for a capacity addition of 103.3 GW which includes commensurate transmission and distribution capacities. Clean energy investments in India reached a record US$10.3bn in 2011, up 52% from the US$6.8bn invested in 2010 .This was the highest growth figure of any significant economy in the world, with the country accounting for 4% of global investments in clean energy. The large growth was driven by a 7-fold increase in funding for grid-connected solar projects. Solar photovoltaic (PV) power plants totalling over 180 MW were set up in the country and off-grid installations of over 50 MW were completed as well.
What is Solar Energy? Energy produced by the Sun Conversion of Sunlight into usable energy such as electricity and heat. ◦ Clean(No green house gases), ◦ renewable source of energy, ◦ Decentralization of power Photovoltaic (solar) panel ◦ Saving eco-systems and livelihoods. Harnessed by solar collection methods such as solar cells & Concentrators Conversion of Sunlight into usable energy such as electricity and heat. Set of solar panels
Energy from the Sun is Abundant Solar power systems installed in the areas defined by the darkdisks could meet the worlds current Total energy demand
Solar Panel Use Today Solar panels being tested on WalMart store Solar panels on Microsoft building
Photovoltaic Solar Cells Generate electricity directly from sunlight 2 Main types:– Single-crystal silicon Silicon Based Solar Cell (traditional) Widespread Expensive to manufacture– Dye-sensitized (“nano”) Newer, less proven Inexpensive to manufacture Flexible Dye Sensitized Solar Cell
Solar Cells are Converters ofEnergy Solar cells are devices that take light energy as input and convert it into electrical energy
A Little Background on LightDifferent colours of light have different wavelengths and different energies
Absorption of Light by Atoms Absorption occurs only when the energy of the light equals the energy of transition of an electronSingleelectrontransition inan isolatedatom
Absorption of Light by IonicCompounds Electrons can jump between “bands” Incident light with energy >= than the “band gap” energy can be used to excite the electrons
So What Does this Mean for SolarCells ? In dye-sensitized solar cells– Talk about highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital(LUMO) In single-crystal silicon solar cells– Talk about “conduction band” (excited states) and “valence band”(ground states)
How a Silicon-Based Solar CellWorks Light with energy greater than the band gap energy of Si is absorbed Energy is given to an electron in the crystal lattice. The energy excites the electron; it is free to move. A positive “hole" is left in the electron’s place. This separation of electrons and holes creates a voltage and a current.
Silicon-Based Solar CellAttributes Expensive – Made in high vacuum at high heat – High manufacturing costs Need TLC – Fragile, rigid, thick Long return on investment – Takes 4 years to produce energy savings equivalent to cost of production
How a Dye-Sensitized Cell Works Light with high enough energy excites electrons in dye molecules Excited electrons infused into semiconducting TiO2, transported out of cell Positive “holes” left in dye molecules Separation of excited electrons and “holes” creates a voltage and hence current.
Dye-Sensitized Solar Cells Relatively inexpensive – Made in non-vacuum setting mainly at room temperature – Relatively simple manufacturing process Need little TLC – Thin, lightweight, flexible Short return on investment – Takes approx 3 months to produce energy savings equivalent to cost of production
Dye-Sensitized and Silicon-basedSolar Cells Compared Dye-Sensitized Traditional Relatively Expensive inexpensive – Need little TLC – Need TLC – Short return on – Long return on investment investment
Summary The DSSC has a number of attractive features. Although its conversion efficiency is less than the best thin-film cells, in theory its price/performance ratio should be good enough to allow them to compete with fossil fuel electrical generation by achieving grid parity. North-western University researchers announced a solution to a primary problem of DSSCs, short useful life of the device.. The current efficiency is about half that of silicon cells, but the cells are lightweight and potentially of much lower cost to produce.
Further ReadingKonarka Technologies (Graetzel cells) http://www.konarkatech.com/PV Power Resource Site http://www.pvpower.com/US DOE Photovoltaics http://www.eere.energy.gov/pv/Key Center for Photovoltaic Engineering http://www.pv.unsw.edu.au/National Center for Photovoltaics http://www.nrel.gov/ncpv/