一、光伏發電是什么意思
光伏(fu)發(fa)電(dian)(dian)(dian)是利用(yong)半導(dao)體界面(mian)(mian)的光生伏(fu)特效應而(er)將光能(neng)直接轉(zhuan)變(bian)為電(dian)(dian)(dian)能(neng)的一種(zhong)技術。主要(yao)由太(tai)陽(yang)(yang)電(dian)(dian)(dian)池板(組件(jian)(jian))、控制器(qi)(qi)和逆變(bian)器(qi)(qi)三大(da)部分(fen)組成,主要(yao)部件(jian)(jian)由電(dian)(dian)(dian)子元器(qi)(qi)件(jian)(jian)構成。太(tai)陽(yang)(yang)能(neng)電(dian)(dian)(dian)池經(jing)過串聯后進行封裝保護可(ke)形成大(da)面(mian)(mian)積(ji)的太(tai)陽(yang)(yang)電(dian)(dian)(dian)池組件(jian)(jian),再配合上功率控制器(qi)(qi)等部件(jian)(jian)就形成了光伏(fu)發(fa)電(dian)(dian)(dian)裝置。
二、太陽能光伏發電對人體有輻射嗎
光(guang)伏(fu)(fu)系統有(you)電磁輻(fu)射,但(dan)比較(jiao)少(shao),采用合格(ge)(ge)的(de)設備(bei),不(bu)會(hui)(hui)對人體造成傷害(hai)和對家用電器(qi)造成干擾。光(guang)伏(fu)(fu)組件是直流電,不(bu)會(hui)(hui)產生輻(fu)射,逆變器(qi)的(de)輻(fu)射嚴格(ge)(ge)控制在安全范圍內(nei)。
光伏(fu)(fu)發電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)是(shi)將(jiang)光能(neng)通(tong)過(guo)半導體(ti)的(de)(de)(de)特性(xing)(xing)直(zhi)(zhi)接(jie)轉(zhuan)化(hua)為直(zhi)(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)的(de)(de)(de),再通(tong)過(guo)逆變(bian)(bian)器(qi)(qi)將(jiang)直(zhi)(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)轉(zhuan)換成可(ke)以(yi)被(bei)我(wo)們(men)使用(yong)的(de)(de)(de)交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。光伏(fu)(fu)系統是(shi)由光伏(fu)(fu)組(zu)件(jian),支架(jia),直(zhi)(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜,逆變(bian)(bian)器(qi)(qi),交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜,配電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)柜(ju),變(bian)(bian)壓器(qi)(qi)等組(zu)成,其中支架(jia)不帶電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),自然不會(hui)(hui)產(chan)(chan)(chan)(chan)生電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁干擾。光伏(fu)(fu)組(zu)件(jian)和直(zhi)(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜,里面是(shi)直(zhi)(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu),方向沒有變(bian)(bian)化(hua),只能(neng)產(chan)(chan)(chan)(chan)生電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場,不能(neng)產(chan)(chan)(chan)(chan)生磁場。輸出變(bian)(bian)壓器(qi)(qi)雖然是(shi)交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),但頻率很(hen)低,只有50Hz,產(chan)(chan)(chan)(chan)生的(de)(de)(de)磁場很(hen)低。逆變(bian)(bian)器(qi)(qi)是(shi)把直(zhi)(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)轉(zhuan)為交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)設備(bei),里面有電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子變(bian)(bian)換,頻率一般為5-20KHz,因此會(hui)(hui)產(chan)(chan)(chan)(chan)生交(jiao)變(bian)(bian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場,所以(yi)也會(hui)(hui)產(chan)(chan)(chan)(chan)生電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁輻(fu)射(she)。但國(guo)家對光伏(fu)(fu)逆變(bian)(bian)器(qi)(qi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁兼容性(xing)(xing)有嚴格的(de)(de)(de)標準。光伏(fu)(fu)逆變(bian)(bian)器(qi)(qi)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁輻(fu)射(she),同家用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)相比,大約和筆記(ji)本電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)腦差不多,低于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁爐,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)吹風,冰箱。
因(yin)此,太陽(yang)能(neng)光(guang)伏(fu)發電不僅不會(hui)對(dui)人(ren)的健康產(chan)生危害,還可以為地(di)球(qiu)提供綠色(se)清潔的優質能(neng)源,是人(ren)類未(wei)來(lai)能(neng)源發展方向。
三、太陽能光伏發電的優點
1、太陽(yang)能資源取之不(bu)盡,用之不(bu)竭(jie),照射到地(di)(di)球上的(de)太陽(yang)能要比人類(lei)目前(qian)消耗的(de)能量大6000倍。而且太陽(yang)能在地(di)(di)球上分布廣泛(fan),只要有光(guang)(guang)照的(de)地(di)(di)方(fang)就可以使用光(guang)(guang)伏(fu)發電系統(tong),不(bu)受地(di)(di)域、海(hai)拔等因(yin)素的(de)限制。
2、太陽能資源隨(sui)處(chu)可得(de),可就(jiu)近供電,不(bu)必長距(ju)離輸送,避免了長距(ju)離輸電線路所(suo)造成的電能損失。
3、光(guang)伏發(fa)電(dian)的能(neng)量轉(zhuan)換(huan)過程簡單,是直接從光(guang)能(neng)到(dao)電(dian)能(neng)的轉(zhuan)換(huan),沒有(you)中間過程(如熱能(neng)轉(zhuan)換(huan)為機械(xie)(xie)能(neng)、機械(xie)(xie)能(neng)轉(zhuan)換(huan)為電(dian)磁(ci)能(neng)等)和機械(xie)(xie)運動,不存在機械(xie)(xie)磨損(sun)。根據熱力(li)學分析,光(guang)伏發(fa)電(dian)具有(you)很高的理(li)論發(fa)電(dian)效率,可達80%以上(shang),技(ji)術開發(fa)潛力(li)巨(ju)大。
4、光伏發電本身不(bu)使用燃料(liao),不(bu)排(pai)放包括溫室氣(qi)體和其它廢氣(qi)在內的(de)任何物質,不(bu)污(wu)染(ran)空(kong)氣(qi),不(bu)產(chan)生噪聲,對環(huan)境友好(hao),不(bu)會(hui)遭受能源危機或燃料(liao)市(shi)場不(bu)穩定而造成的(de)沖擊,是真正綠(lv)色環(huan)保的(de)新型可再生能源。
5、光(guang)伏(fu)(fu)發電(dian)(dian)過(guo)程不需(xu)要(yao)冷卻水,可(ke)以安(an)裝在沒(mei)有水的(de)荒漠戈壁(bi)上(shang)。光(guang)伏(fu)(fu)發電(dian)(dian)還可(ke)以很(hen)方便地與建(jian)筑(zhu)物結合(he),構成(cheng)光(guang)伏(fu)(fu)建(jian)筑(zhu)一(yi)體化發電(dian)(dian)系統,不需(xu)要(yao)單(dan)獨占地,可(ke)節(jie)省寶貴的(de)土(tu)地資(zi)源。
6、光伏發電無機械傳動部(bu)件,操作、維護簡(jian)單,運行穩定可靠。一套光伏發電系統只要有太陽能(neng)電池組件就(jiu)能(neng)發電,加(jia)之自動控制技術的廣泛采用,基本上可實現無人值(zhi)守,維護成本低。
7、光(guang)伏發(fa)電系(xi)統工作性能(neng)穩定(ding)可(ke)靠,使(shi)用壽命(ming)長(30年(nian)以(yi)上(shang))。晶體硅太(tai)陽能(neng)電池壽命(ming)可(ke)長達20~35年(nian)。在光(guang)伏發(fa)電系(xi)統中,只要設計合理、選(xuan)型適當,蓄電池的壽命(ming)也(ye)可(ke)長達10~15年(nian)。
8、太陽能(neng)電池組件結構簡單(dan),體積(ji)小(xiao)、重量輕,便(bian)于運輸和安裝(zhuang)。光伏發電系統建設周(zhou)期短,而且根據用(yong)電負荷容量可大可小(xiao),方便(bian)靈活,極易組合、擴容。
四、太陽能光伏發電的缺點
1、能量密度低
盡管太(tai)(tai)陽(yang)(yang)(yang)投向地球的(de)能(neng)量(liang)總(zong)和(he)極(ji)其巨大(da)(da),但由于地球表(biao)(biao)面(mian)積(ji)也很大(da)(da),而且地球表(biao)(biao)面(mian)大(da)(da)部(bu)分(fen)被海洋覆蓋,真(zhen)正能(neng)夠(gou)到(dao)達(da)陸(lu)地表(biao)(biao)面(mian)的(de)太(tai)(tai)陽(yang)(yang)(yang)能(neng)只有到(dao)達(da)地球范圍太(tai)(tai)陽(yang)(yang)(yang)輻射(she)能(neng)量(liang)的(de)10%左右,致使在陸(lu)地單位(wei)面(mian)積(ji)上能(neng)夠(gou)直(zhi)接(jie)獲得的(de)太(tai)(tai)陽(yang)(yang)(yang)能(neng)量(liang)較少。通常以太(tai)(tai)陽(yang)(yang)(yang)輻照度來(lai)表(biao)(biao)示(shi),地球表(biao)(biao)面(mian)輻照度最高值約(yue)為1.2kw/㎡,且絕大(da)(da)多數(shu)地區和(he)大(da)(da)多數(shu)日照時間內都低于1kw/㎡。太(tai)(tai)陽(yang)(yang)(yang)能(neng)的(de)利用實際(ji)上是低密度能(neng)量(liang)的(de)收集(ji)、利用。
2、占地面積大
由(you)于太陽能能量密(mi)度低,這就使得光(guang)伏(fu)發電(dian)(dian)系(xi)統的占(zhan)地面(mian)(mian)積會很大,每10kw光(guang)伏(fu)發電(dian)(dian)功(gong)率占(zhan)地約需100㎡,平(ping)均(jun)每平(ping)方米面(mian)(mian)積發電(dian)(dian)功(gong)率為100w。隨著光(guang)伏(fu)建筑(zhu)一體(ti)化發電(dian)(dian)技(ji)術的成熟和(he)發展,越來越多的光(guang)伏(fu)發電(dian)(dian)系(xi)統可以(yi)利(li)用建筑(zhu)物、構筑(zhu)物的屋頂和(he)立(li)面(mian)(mian),將逐漸克(ke)服光(guang)伏(fu)發電(dian)(dian)占(zhan)地面(mian)(mian)積大的不足(zu)。
3、轉換效率低
光伏(fu)發(fa)(fa)電(dian)的(de)(de)最基本單元是(shi)太陽能電(dian)池組件。光伏(fu)發(fa)(fa)電(dian)的(de)(de)轉(zhuan)(zhuan)換(huan)效率(lv)(lv)指光能轉(zhuan)(zhuan)換(huan)為電(dian)能的(de)(de)比率(lv)(lv)。目(mu)前(qian)晶體(ti)硅(gui)光伏(fu)電(dian)池轉(zhuan)(zhuan)換(huan)效率(lv)(lv)為13%~17%,非晶硅(gui)光伏(fu)電(dian)池只有5%~8%。由于光電(dian)轉(zhuan)(zhuan)換(huan)效率(lv)(lv)太低,從而(er)使光伏(fu)發(fa)(fa)電(dian)功率(lv)(lv)密(mi)度低,難以形成高功率(lv)(lv)發(fa)(fa)電(dian)系統(tong)。因此,太陽能電(dian)池的(de)(de)轉(zhuan)(zhuan)換(huan)效率(lv)(lv)低是(shi)阻礙光伏(fu)發(fa)(fa)電(dian)大面積推廣的(de)(de)瓶頸(jing)。
4、間歇性工作
在地球(qiu)表(biao)面(mian),光伏(fu)發(fa)(fa)電(dian)(dian)系統只能(neng)在白天(tian)發(fa)(fa)電(dian)(dian),晚上不(bu)能(neng)發(fa)(fa)電(dian)(dian),除(chu)非在太(tai)空中(zhong)沒(mei)有晝夜(ye)之分的(de)(de)情況下,太(tai)陽能(neng)電(dian)(dian)池才(cai)可以連續發(fa)(fa)電(dian)(dian),這與(yu)人們的(de)(de)用(yong)電(dian)(dian)需求不(bu)符。
5、受氣候環境因素影響大
太(tai)(tai)陽能光伏發(fa)電的(de)(de)能源直(zhi)接來源于太(tai)(tai)陽光的(de)(de)照(zhao)射,而地(di)球表面(mian)上(shang)的(de)(de)太(tai)(tai)陽照(zhao)射受氣候(hou)的(de)(de)影響(xiang)(xiang)很大(da),長(chang)期的(de)(de)雨雪天(tian)、陰天(tian)、霧天(tian)甚至(zhi)云層的(de)(de)變化都會(hui)嚴(yan)重影響(xiang)(xiang)系統的(de)(de)發(fa)電狀態。另外,環境因素的(de)(de)影響(xiang)(xiang)也很大(da),比較(jiao)突出的(de)(de)一點是,空氣中的(de)(de)顆粒物(如(ru)灰塵(chen))等(deng)沉落在太(tai)(tai)陽能電池組(zu)件的(de)(de)表面(mian),阻擋了部(bu)分光線的(de)(de)照(zhao)射,這(zhe)樣會(hui)使電池組(zu)件轉換(huan)效率降低,從而造成發(fa)電量減(jian)少甚至(zhi)電池板的(de)(de)損壞。
6、地域依賴性強
地(di)理位置不同,氣(qi)候不同,使各地(di)區日(ri)照資源(yuan)相(xiang)差很大。光伏(fu)發電(dian)系統只有應(ying)用在(zai)太陽能資源(yuan)豐富的地(di)區,其效果才(cai)會(hui)好。
7、系統成本高
由于(yu)太陽(yang)能光(guang)伏發(fa)電(dian)(dian)的(de)(de)效(xiao)率較低,到目前為止,光(guang)伏發(fa)電(dian)(dian)的(de)(de)成本(ben)仍然是(shi)(shi)其他常(chang)規發(fa)電(dian)(dian)方式(shi)(如火力(li)和水力(li)發(fa)電(dian)(dian))的(de)(de)幾倍,這(zhe)是(shi)(shi)制(zhi)約其廣泛應用(yong)的(de)(de)最(zui)主(zhu)要因素。但是(shi)(shi)也(ye)應看到,隨著太陽(yang)能電(dian)(dian)池產能的(de)(de)不斷擴大及電(dian)(dian)池片光(guang)電(dian)(dian)轉換效(xiao)率的(de)(de)不斷提高,光(guang)伏發(fa)電(dian)(dian)系(xi)統的(de)(de)成本(ben)也(ye)下降得非常(chang)快。太陽(yang)能電(dian)(dian)池組件的(de)(de)價格幾十年來已(yi)經從(cong)最(zui)初的(de)(de)每瓦(wa)70多美(mei)元(yuan)下降至目前的(de)(de)每瓦(wa)2美(mei)元(yuan)左右。
8、晶體硅電池的制造過程高污染、高能耗
晶(jing)(jing)體硅電(dian)池的(de)(de)主(zhu)要原料是純凈的(de)(de)硅。硅是地球上含量僅次(ci)于氧的(de)(de)元素,主(zhu)要存在形式(shi)是沙子(sio2)。從(cong)硅砂一步步變成(cheng)純度為99.9999%以上的(de)(de)晶(jing)(jing)體硅,要經(jing)過多道化學(xue)和物理工序(xu)的(de)(de)處理,不(bu)僅要消(xiao)耗大量能(neng)源,還會造成(cheng)一定的(de)(de)環境(jing)污染。