How Do Solar Cells Support Rural Electrification | Access, Reliability, Independence

Solar energy batteries through distributed photovoltaic systems support rural electrification.

For example, every household installs a 100W solar panel, which can provide lighting and mobile phone charging, realize all-weather electricity use, improve power reliability (power outage rate drops to 10% below), and at the same time no need to rely on remote power grids, realize energy autonomy.

Access

Cannot reach electricity

Traditional's alternating current high voltage transmission line in crossing hills and desert terrains takes time, single kilometer's erecting hardware and manual budget usually high reaches 25,000 US dollars to 45,000 US dollars. When tropical remote villages distance national main power grid's physical straight line distance exceeds 15 kilometers time, merely building a 110 kilovolts turn 10 kilovolts' step-down substation, basic civil construction and transformer purchasing expenses just break through 1.2 million US dollars.

High's early stage asset input lets local electricity department in population density lower than every square kilometer 50 people's region, its investment return evaluation cycle forcedly stretched long to 45 years above. Long-reaching tens of kilometers' overhead transmission aluminum stranded wire exposed in outdoor environment inside, its physical line loss rate will along with temperature rising and sharply climb. When summer afternoon's environment temperature breaks through 35 Celsius degrees, due to metal conductor resistivity increasing, terminal 220 volts alternating current's actual measured arriving voltage often will drop to 180 volts below. This kind of exceeding 18% voltage deviation rate will let conventional 50 hertz alternating current motor's starting failure probability increase to 60% above.

Off-grid independent photovoltaic system patched up power supply network's most terminal's blank gap, installed capacity in 15 watts to 300 watts' small type direct current power generation equipment thoroughly crossed long's geographical cable paving restriction, will ordinary farmer household obtain basic lighting's every kilowatt-hour comprehensive power supply cost rigidly compress to 0.12 US dollars' extremely low interval.

Parts list

A set satisfying 5 mouths of family daily life lighting and communication needs' micro solar energy power supply equipment, in carton packed state, under's total volume is only 0.15 cubic meters, including packaging material inside's total physical weight is strictly controlled at 12.5 kilograms within, farmer households can completely rely on a single non-powered bicycle, which has only a width of 0.8 meters, on a muddy dirt road on the last 5 kilometers' material transportation. Tearing open moisture-proof corrugated paper outer shell, whole set system's rated operating parameter covers below specific's quantified hardware modules:

· One piece nominal maximum output power is 50 watts' polycrystalline silicon photovoltaic module, its external physical size is fixed at 670 millimeters multiply 540 millimeters, four surroundings surrounding's aluminum alloy fixing frame thickness is 25 millimeters, front side covered has a layer 3.2 millimeters thick's low iron high light transmittance tempered glass, in every square meter 1000 watts' standard testing lighting condition under, its photoelectric conversion rate stable at 18.5%'s benchmark value on.

· One machine internally placed 12 volts working voltage, rated capacity is 15 ampere-hours lithium iron phosphate cell cell's control host, its cell cell's 100% charging and discharging depth cycle number upper limit set as 3000 times, outer shell adopts flame retardant ABS industrial plastic injection molded, seam place's silicone sealing ring makes its protection rating reach IP54's dust-proof splash-proof standard.

· 4 lamps single body power consumption is 3 watts' LED bulb lamps, lamp bead's emitting color temperature set at 6000 Kelvin's cold white light parameter segment, single lamp luminous flux reaches 350 lumens, matched's insulated polyvinyl chloride pure copper conducting wire length is 8 meters, internal copper wire cross-sectional area is 0.75 square millimeters, cable terminal uniformly crimped fool-proof design's DC5521 circular direct current plug, mechanical plugging and unplugging testing lifespan exceeds 5000 times.

· One root equipped has 5 kinds of different mold interfaces' mobile equipment charging cable, the mainboard's step-down chip will maximum output current constantly limit at 5 volts 2 amperes, in lighting sufficient's noon time, can in 2.5 hours inside will a equipped has 4000 milliampere-hours lithium cell's non-smart mobile phone from 15%'s remaining electricity amount charge to 100%'s full electricity state.

How to pay money?

Daily average per capita living expenses less than 2 US dollars' farming family, absolutely unable to take out 150 US dollars' hardware full payment purchasing budget. Current's pay-as-you-go installment business model will initially power connecting fund threshold drop to a dozen US dollars' extreme point. User purchasing machine time only needs to towards local dealer pay 10 US dollars to 15 US dollars' first phase hardware deposit, just can will whole set packaging box bring back to adobe house to conduct wiring installation.

Host internal's circuit board on in advance welded a piece supporting 2G and 3G wireless cellular network frequency band's Internet of Things SIM communication module, this chip uses every day 1 time to 2 times' fixed frequency, with service provider set at capital's cloud database conduct 20 bytes size's encrypted state data packet interactive communication.

Farmer households through handheld button mobile phone's USSD code pop-up window function, towards specified's mobile payment digital wallet inside recharge 0.3 US dollars to 0.5 US dollars equivalent value's local circulating currency. Deducting money success after, cloud server in 10 seconds inside generates a string of 15 digits' random unlocking number and through short message sends down. The user in the host panel's physical rubber keyboard one by one inputs this string number, the mainboard's internal micro relay recognizes no mistake after will emit a "click" sound, close circuit, release future 24 hours' usable discharging permission.

If the timer continuously walked past 72 hours and did not receive a new round's recharging password input, the mainboard chip will forcibly disconnect the 12-volt direct current output port's physical conducting connection, forcibly interrupt all bulbs' power supply, until next a sum of 0.3 US dollars' remittance instruction is cloud confirmed. The whole set of equipment's payment cycle usually is shared at 18 months to 24 months' time axis, with a total number of installments roughly distributed at 540 sums to 720 sums around.

When the user completes the electronic contract agreed's 100% funds settling clear after, the system backend automatically sends down a piece including 20 digits number's permanent unlocking code, host internal's timing locking program is thoroughly erased, farmer household immediately obtains this set hardware's complete physical ownership, towards later long reaching 10 years' equipment life span period inside, solar photons transform into electrons' process cost thoroughly returns to zero.

Do it yourself

Alternating current main power grid's indoor entering household construction must hire holding professional electrician operation license's technical workers, single day's construction manual expense generally quoted price at 30 US dollars above, construction specification still requires brick wall inside cut groove and bury in diameter 20 millimeters' insulated flame retardant threading tube. Off-grid solar energy kit's design system voltage highest not exceeds 24 volts direct current, far lower than 36 volts' human body safety tolerance voltage red line indicator, will construction process inside's electric shock causing injury probability drop to 0%.

· Photovoltaic panel back side's metal bracket crossbeam on factory left in advance 4 diameter is 8 millimeters' standard installation round holes, ordinary labor force only needs use following carton additionally gifted's hexagon wrench and 4 pieces M6 specification's galvanized expansion bolts, consume about 15 minutes around's time, just can will it firmly lock dead at corrugated iron sheet roof or wood quality load-bearing crossbeam on.

· From solar energy panel junction box led out's 5 meters long black color main power supply cable terminal, injection molded has bringing elastic buckle's waterproof aviation plug. The installer only needs to plug the aim at control host backplate on bringing fool-proof notch's input port forcefully push in, hear crisp's mechanical plastic biting sound, namely represents positive and negative terminal conducting finish. This docking port's maximum safe bearing current is set at 5 amperes.

· Single root lighting cable middle segment equipped has physical pressing style mechanical switch button, laboratory environment under's fatigue testing confirms its average pressing connecting-disconnecting lifespan reaches 20000 times. A user casually will redundant cable wind at house internal's supporting wood pillar or iron wire on then can, due to power supply circuit extremely short and load extremely low, by conducting wire internal resistance caused's end to end voltage drop is strictly controlled at 0.3 volts within, guaranteed distance host furthest terminal's that piece bulb its emitting lumen parameter will not appear any naked eye visible's physical decay.

Reliability

Can withstand rain

The International Electrotechnical Commission issued IEC 61215 standard towards solar energy panel's mechanical load, making clear quantified stipulations. In leaving factory before's hail impact destructive testing inside, every piece of mono-crystalline silicon panel's 3.2 millimeters thickness high light transmittance tempered glass surface layer, must be able to bear a diameter of 25 millimeters, and weigh about 7.53 grams' ice ball using every second 23 meters' speed conduct front side impact, and glass surface shattering's probability is 0%.

In tropical rain forest or equator desert climate, daytime earth surface temperature often breaks through 50 Celsius degrees, arriving early morning will suddenly drop to 10 Celsius degrees below. Cell panel back side's junction box adopted polycarbonate material, internal completely poured flame retardant level's epoxy resin sealing glue, makes its dust-proof waterproof rating fixed at IP68's highest level standard line on.

Even if in continuous long-reaching 72 hours, accumulated rainfall amount breaks through 150 millimeters' extraordinarily big rainstorm washing under, junction box internal's positive and negative copper quality terminal appearing short circuit oxidation or electricity leaking's discrete probability is also rigidly controlled at ten thousandth one's extremely low deviation range inside. Aiming at local tree leaves blocking or bird droppings covering causing hot spot effect, module manufacturer at every interval 18 pieces or 24 pieces silicon cell series connection unit between, reversely parallel connection installed rated passing current is 15 amperes to 20 amperes' Schottky bypass diode.

When the mainboard detects a certain one-piece silicon wafer due to physical blocking causing a short circuit, the current output violently drops to 15% below normal value's time, a bypass diode will in microsecond level's time delay automatically conduct, forcefully cut off the damaged block's current circuit. One whole piece installed nominal power is 400 watts' panel, in lost one third's working area after, still can maintain at least 260 watts above's direct current output, thoroughly blocked high reaching 150 Celsius degrees' local high temperature point will internal EVA packaging film burn through's physical catching fire risk.

Cell durable

Early period's flooded type lead-acid cell in discharging depth reaches 80% time, its physical nominal capacity decay rate will in short 150 days and night alternating cycles after soar to 40% above's astonishing ratio. Currently, mainstream configured lithium iron phosphate cell positive pole material possesses an extremely stable olivine crystal structure. When a single body cell is in a 25 Celsius degrees' standard room temperature environment, using 0.5C's constant rate conduct daily charging and discharging operation time, its 100% full charging full discharging's statistical physical cycle number upper limit is high reaches 6000 times to 8000 times.

One residing at the equator near a farmer's household, every night, fixedly consumes away cell total capacity's 75%, configured at home inside's rated voltage is 12.8 volts, nominal capacity is 100 ampere-hours' energy storage module, can guarantee whole house load in a long reaching 13.5 years' time span inside no need to replace any internal cell cell module.

Lithium iron phosphate cell's physical self-discharging rate in storing environment temperature lower than 30 Celsius degrees time, every month only loses about 1.5% to 2.0% of electricity, long-term idling caused's voltage too low scrapping risk is vastly weakened. Hardware system internal integrated a piece including ARM architecture microprocessor's cell management system mainboard. Mainboard on carrying's high precision voltage sampling chip uses every second 10 times' ultra high frequency, uninterruptedly scans by 4 strings cell cells composed's cell pack physical state indicator:

· Overcharging blocking protection: when any single body cell's internal terminal voltage climbs to 3.65 volts' upper limit safety threshold time, the management mainboard will instantly emit a cutting off instruction, in 50 milliseconds, forcibly disconnect the field effect tube's charging circuit, put an end to internal electrolyte boiling spilling out triggering plastic outer shell volume expansion.

· Low temperature heating compensation: in altitude height exceeding 3500 meters' plateau winter time, when NTC thermistor detects environment temperature drops below minus 5 Celsius degrees, system will automatically extract photovoltaic panel emitted total electric energy's 8% transfer to patch heating silicone pad, using every minute rising 2 Celsius degrees' constant rate will cell cell preheat to 0 Celsius degrees above's safety working interval.

· Overload limiting current power off: facing user suddenly connecting in rated load power 200% above's violating regulation alternating current electricity using equipment time, shunt collected arriving's current numerical value once exceeds 50 amperes' maximum allowed range, electronic circuit breaker will in 10 milliseconds thoroughly cut off outward electric energy output, prevent internal cable due to overheating melting down.

Mainboard not burn

Hardware engineer at input and output terminal both parallel connection nominal discharging current reaching 10000 amperes' zinc oxide varistor. When outdoor open wire circuit suffers thunderstorm weather inside, the indirect induction lightning strike time, instantly soaring to 4000 volts' high voltage peak pulse will be varistor in 25 nanoseconds' extremely short time window inside, forcefully limited at 60 volts' safety protection interval inside, redundant static electricity energy will through cross-sectional area reaching 4 square millimeters' brass grounding cable fast led into underground moist soil inside.

In a long-reaching 10-year continuous natural operation cycle, mean time between failures is one item extremely severe's checking indicator. Adopting all aluminum die-cast outer shell as passive heat dissipating carrier's controller, thoroughly abandoned containing mechanical bearing easily accumulating dust stuck dead's ball bearing heat dissipating fan. When the mainboard's internal DC-DC synchronous rectification circuit is situated at full load operating state, the electric energy conversion efficiency reaches 98.5% at its highest peak value time, its own produced heat power consumption can still maintain at overall passing energy's 1.5% around.

Wide big's wave shape metal heat dissipating fin piece makes equipment's air contact surface area multiply expanded 3.5 times, even if external air relative humidity reaches 95%, and daytime environment temperature continuously hovering at 45 Celsius degrees' high position, internal electronic modules' junction temperature from beginning to end is dead dead suppressed at 85 Celsius degrees' safety benchmark line below, internal electrolytic capacitor's liquid state evaporation decay rate is controlled at every year two thousandths' tiny proportion inside.

Independence

Not rely on the big power grid

Far away from the city's remote tropical savanna, relying on 500 kilometers outside the national thermal power plant transmitting electric energy, needs to long term endure high reaching 25.5% circuit voltage drop amplitude and every year exceeding 120 hours' unplanned power outage accidents. Through the village center zone, paving one installed nominal capacity is 50 kilowatts to 150 kilowatts' solar energy micro power grid, containing 80 households to 150 households permanent resident population's community thoroughly cut off with that root extremely unstable's public high voltage transmission aluminum wire's physical contact.

All direct current power generation equipment, chemical energy storage module, and low voltage alternating current distribution network are completely concentrated in a radius not exceeding 3 kilometers' physical circumference range inside. Placed at 20 feet standard container inside's three-phase micro grid inverter, all-weather towards outside outputs waveform smooth's 220 volts alternating current, its physical output frequency is microprocessor accurately locked at 50 hertz, voltage fluctuation's standard deviation forever not exceeds plus minus 3%.

Even if a field instantaneous wind speed reaching 120 kilometers' tropical cyclone blew down provincial road both sides' tens of roots high voltage electricity poles, causing the surroundings tens of square kilometers' region to sink into a long-reaching 15 days' physical power off state, this independent micro power grid internal that group total capacity high reaching 200 kilowatt-hours' lithium iron phosphate cell pack, matching occupying land 350 square meters' mono-crystalline silicon photovoltaic array, still can every day on time towards village town clinic's 200 liters vaccine cold storage cabinet and public water pump transmit 4500 watts' continuous operating power. This kind completely stripped external physical circuit's power supply network, its local area inside 10 kilovolts distribution transformer's no-load loss is strictly controlled at rated capacity's 0.2%.

Farm machinery casually drive

A set total installed effective power is 3 kilowatts' independent solar energy frequency conversion irrigation system, will this kind of towards far distance fossil fuel supply chain's heavy reliance probability directly dropped to 0%. This set system by 8 to 10 pieces standard 450-watt polycrystalline silicon panel series connection drive, as long as the early morning earth's surface's sunlight radiation intensity climbs to every square meter 200 watts' starting physical threshold, down well caliber is 4 inches' submersible pump just will automatically start operating.

From a vertical depth of 45 meters underground, the aquifer towards pumping water, equipment can maintain a constant physical flow rate of 8 to 12 cubic meters every hour, every day's effective continuous working time reaches 6.5 standard hours.

Solar energy direct drive water pump in hardware topology architecture on directly cleared chemical energy storage cell this one cumbersome link, panel produced's 400 volts high voltage direct current through MPPT frequency converter directly converts as driving three-phase alternating current asynchronous motor's physical rotating power.

Every day, exceeding 50 cubic meters of continuous fresh water injection, lets occupy land 5 hectares' tomato dry land soil relative humidity from beginning to end maintain at 60% to 70% 's agronomy growing interval. Comparing completely relying on natural rainfall's adjacent statistical land plot, its farm crop final per mu yield's median vastly leaped 38.5%. The farm owner also needs no diesel because a truck transporting diesel fuel 60 kilometers outside on a muddy dirt road broke down, and forcedly interrupted field inside high reaching 40 Celsius degrees high temperature under daily irrigation operation.

Account book self-calculate

Towards large public power companies continuously purchasing alternating current grid electricity, must silently endure every year's average 4.5% to 6.2% commercial electricity price compound interest growth rate. Choosing investing in a set completely independent's off-grid roof photovoltaic hardware, will future 25 years physical life span cycle's electricity using unit price in advance conducted rigid locking.

An ordinary farming family takes out 850 US dollars' initial budget fund, purchasing a set including 1000 watts poly-crystalline silicon light emitting panel and 2400 watt-hours energy storage host's off-grid kit after, thoroughly ending every month towards town on grocery store boss paying 18 US dollars kerosene fee and lead-acid cell acting charging fee's financial running water cycle.

From the long-term financial report statement model, this sum fixed asset investment's principal recovery period will at 47th month's node punctually finish. From the 48th month, until the whole set of equipment arrives at the 300th month's operating endpoint, the farmer household every obtaining 1 kilowatt-hour of electric energy's marginal cost strictly keeps at 0 US dollars' horizontal line.

Regardless of the local legal currency's inflation rate soaring 15%, or is the international crude oil futures market's single barrel settlement price 30% above the violent shaking, towards this group's roof panel's daily power generation spare parts operating budget, there is no financial data on's relevant interference. Panel surface's photoelectric effect does not produce any bill late fee.

Data big inventory

Different power supply obtaining channels at physical independent distribution, later period maintaining expense and operating time stability on's quantified statistical sample, in comparing inside presents out completely not same's numerical value discrete state.

Will this kind of off-grid, independently operating topology architecture enlarge to cover 500 households residents' remote market town? A set of 500 kilowatts mono-crystalline silicon photovoltaic panel array and 1.5 megawatt-hours container energy storage unit's large type independent power grid can support a town's 2 strips wood processing assembly lines' 30 kilowatts three-phase asynchronous motor every day continuously cut logs 8.5 hours.

The whole local area power grid's peak load redundancy capability reaches 400 kilowatts, physically completely shielded external provincial level high voltage power grid at summer electricity using peak period implemented's pulling switch limiting electricity instruction, guaranteed processing factory's handling goods on time achieving rate whole year maintains at 98.5%'s statistical high position. The whole set's grounding resistance is copper clad steel grounding rod controlled at 4 ohms below, in thunderstorm season lightning strike probability rises 300% under, still keeps zero downtime's high intensity operation.