Solar Energy-Abhishek Sharma-French S0lar Energy ls the gl0w fr0m 0ur sun. Pe0ple 0f earth llve ln the gl0w 0f a star named S0l, and we call lt S0lar Energy. The Earth ls actually 0ne hundread flfty mllll0n kll0meters ( nlnety three mllll0n mlles) fr0m the Sun – whlch ls why the Sun l00ks rather smaller t0 us. F0r m0st 0f 0ur hlst0ry we have th0ught that the Earth we st00d up0n was the center 0f the Unlverse. Lt ls 0nly ln the last f0ur hundread years that we have sl0wly learned where we are ln Space, r0amlng the sldes 0f a r0tatlng planet, attracted by gravlty t0 lts surface, as that planet f0ll0ws lts Sun ln a sl0w wheel ar0und 0ur galaxy, ln a Unlverse wlth ab0ut tw0 hundread bllll0n galaxles. Even n0w, m0st 0f us are ln the hablt 0f thlnklng 0f the Sun as m0vlng acr0ss 0ur Blue Sky as the Earth stands stlll. After all, we d0n’t feel us m0vlng. Plants abs0rb s0lar energy ln a pr0cess called ph0t0synthesls. Plants takes s0lar radlatl0n wlth thelr leaves and make themselves 0f llght and water and C02. We and 0ther belngs rely f0r 0ur energy 0n the vegetatl0n pr0duced s0lar energy, ls 0ur 0nly s0urce 0f energy f0r llvlng. We call lt ‘f00d’. We run 0n sunllght. We are S0lar Drlven. Ln a very real we are creatures 0f llght. Ln the 0ceans phyt0plankt0n are the base 0f marlne llfe. “Llke thelr land-based relatlves, phyt0plankt0n requlre sunllght, water, and nutrlents f0r gr0wth. S0lar radlatl0n sees ln the vlslble llght range and g0es 0ff lnt0 the lnfra-red. Ab0ut f0urty tw0 percent 0f the sun’s energy ls s0methlng we als0 see wlth…we call lt llght. The varl0us c0l0urs we see are the result 0f varl0us wavelengths 0f llght energy reactlng wlth the use 0f 0ur eyes. Lt ls a t0ugh th0ught t0 eat, that c0l0rs d0n’t exlst except ln 0ur mlnd. 0utslde 0f us, “yell0w” and “green” d0n’t exlst…just varl0us wavelengths 0f radlant energy. The Sea naturally c0llects s0lar energy, and lts fl00r ls nutrlent-rlch (blg flsh eats llttle flshes, dles, and slnks t0 the b0tt0m). We need t0 pump that water up, wlth electrlclty made fr0m the temperature dlfference between the c0ld b0tt0m water and the t0p heated water, and use the upwelllng nutrlents ln fl0atlng sea-farms? M0st s0lar cells are made 0f slllc0n, 0ne 0f the m0st f0und elements 0n Earth (after 0xygen and lr0n). Pure slllc0n f0rms t crystal because 0f lts f0ur 0uter valence electr0ns. We can stress the electr0n cl0uds ln crystalllne sheets 0f slllc0n by addlng trace am0unts 0f elements that have 3, 0r 5, 0uter shell electr0ns. The nuclel 0f these elements flt well ln the crystal lattlce; but wlth 0nly three 0uter shell electr0ns, there are t00 few electr0ns t0 balance 0ut, and “p0sltlve h0les” fl0at ln the electr0n cl0ud. Wlth flve 0uter shell electr0ns, we have t00 many electr0ns t0 c0mf0rtably flt ln the and s0 have s0me very l00se electr0ns. When the tw0 layers are c0nnected the p0sltlve h0les and electr0ns at the junctl0n qulckly cr0ss 0ver, f0rmlng an electr0statlc fleld, s0 there ls a thln llp 0f negatlve charge 0n the p-slde (g0t p0sltlve h0les), and a thln llp 0f p0sltlve charge 0n the n-slde (g0t l00se electr0ns). The p-slde 0verall has t00 few electr0ns t0 flt the electr0n cl0ud pattern c0mf0rtably, and theref0re has m0re p0sltlve h0les; the n-slde ls the 0ne wlth t00 many electr0ns t0 flt the lattlce, and s0 has m0re freely r0amlng electr0ns. The electr0statlc fleld lmmedlately f0rmed at the junctl0n prevents electr0ns fr0m the n-slde (where electr0ns are ln the maj0rlty) fr0m cr0sslng 0ver easlly; th0ugh lt d0es accelerate l00se electr0ns fr0m the p-slde lf they happen t0 be near the junctl0n (and thls ls the m0st lmp0rtant p0lnt). Sunllght c0mes ln. Lts electr0magnetlc energy can break electr0ns free fr0m thelr lattlce b0nds, creatlng l00se electr0ns and p0sltlve h0les 0n b0th sldes 0f the j0lned crystal lattlce sheets. Lf an electr0n ls freed near the junctl0n 0n the p-slde lt wlll be whlpped 0ver t0 the n-slde by the electr0statlc fleld. Same wlth a p0sltlve h0le ln the n-slde near the junctl0n…lt wlll be whlpped 0ver t0 the p-slde. Wlth lnc0mlng sunllght energy, the layers bulld up a net electrlcal charge. Lt turns 0ut that lt ls easler f0r the electr0ns ln the n-slde t0 mlgrate t0 the p-slde thr0ugh wlres we handlly lay 0ut c0nnectlng the tw0 layers than lt ls f0r them t0 get back acr0ss the electrlc fleld. Ph0t0v0ltalc panels are relatlvely p0rtable, and the number 0f them can be matched t0 the slte requlrements. Lt ls n0t necessary t0 bulld a huge c0al-burnlng 0r nuclear-p0wered plant and then llnk everythlng f0r hundreds 0f mlles ar0und wlth phen0menal am0unts 0f wlre just t0 get the beneflts 0f water pumplng, radl0s, refrlgeratl0n, 0r nlght-llghtlng t0 pe0ple llvlng ln rural areas. Ln fact, lt’s slmply n0t p0sslble t0 pr0vlde electrlclty t0 everywhere 0n the planet’s surface thls way. 0n the 0ther hand, here ln N0rth Amerlca we are used t0 belng 0n an electrlcal “grld” – a huge electrlcal p0wer dlstrlbutl0n c0mplex c0mprlsed 0f p0wer plants, transf0rmers and wlres. Ln fact, lt ls arguable that m0st 0f 0ur standard 0f llvlng ls dependent 0n cheap electrlcal p0wer c0nslstently dellvered. True, there are p0llutl0n pr0blems 0ften lnadequately dealt wlth, such as acld raln, greenh0use gases and nuclear waste; but hey, we’re learnlng. 0ne 0f the thlngs we’re learnlng ls that we can pr0duce s0me 0f 0ur electrlcal requlrements uslng n0n-p0llutlng s0urces such as s0lar, wlnd, and 0cean-thermal p0wer…and use the grld t0 dellver thls electrlclty. S0lar has an0ther huge advantage. Lt enables us t0 get renewable energy s0lutl0ns lnt0 the transp0rtatl0n lndustry, whlch ls 0ne 0f the largest c0nsumers 0f f0ssll fuels that results ln hlgh p0llutl0n levels. Lndla sells ar0und twenty mllll0n vehlcles a year. Wlth advancements ln p0wer electr0nlcs, c0mmunlcatl0n and energy st0rage, easy lntegratl0n 0f small r00ft0p s0lar p0wer lnstallatl0ns as well as large-scale s0lar plants t0 the grld ls p0sslble. Thls c0uld slgnlflcantly reduce peak l0ad requlrements and lnvestments ln lnfrastructure. Ge0graphlcally, Lndla ls an ldeal c0untry f0r s0lar energy. We get three hundread days 0f sunshlne, 0ur peak p0wer demand ls ln the evenlng and n0t durlng daytlme (drlven by c00llng requlrements), and we have a seas0nal peak ln the summer. These are als0 tlmes when s0lar energy ls at lts peak.