一、光伏發電是什么意思
光(guang)(guang)(guang)伏發電(dian)(dian)是利用半導體界(jie)面的光(guang)(guang)(guang)生伏特效應而將光(guang)(guang)(guang)能(neng)直接轉變(bian)為電(dian)(dian)能(neng)的一種技術。主(zhu)要由太陽(yang)電(dian)(dian)池板(組件(jian))、控(kong)(kong)制器(qi)和逆變(bian)器(qi)三大部分(fen)組成(cheng)(cheng),主(zhu)要部件(jian)由電(dian)(dian)子元器(qi)件(jian)構成(cheng)(cheng)。太陽(yang)能(neng)電(dian)(dian)池經過串聯后(hou)進行封(feng)裝(zhuang)保護可形(xing)成(cheng)(cheng)大面積的太陽(yang)電(dian)(dian)池組件(jian),再配合(he)上功率(lv)控(kong)(kong)制器(qi)等部件(jian)就(jiu)形(xing)成(cheng)(cheng)了光(guang)(guang)(guang)伏發電(dian)(dian)裝(zhuang)置。
二、太陽能光伏發電對人體有輻射嗎
光伏系統有電(dian)磁輻射,但比(bi)較少(shao),采用合格的設備(bei),不(bu)會(hui)對人體造成傷害(hai)和(he)對家用電(dian)器(qi)造成干(gan)擾。光伏組(zu)件是直流電(dian),不(bu)會(hui)產(chan)生輻射,逆(ni)變器(qi)的輻射嚴(yan)格控制在安全范圍內。
光(guang)伏(fu)發電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)是將光(guang)能(neng)(neng)通過半導體的(de)(de)特性直(zhi)接轉(zhuan)化為直(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)的(de)(de),再通過逆(ni)(ni)變(bian)(bian)器(qi)將直(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)轉(zhuan)換成可以(yi)被我們使用的(de)(de)交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。光(guang)伏(fu)系(xi)統(tong)是由光(guang)伏(fu)組件(jian)(jian),支(zhi)架(jia),直(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan),逆(ni)(ni)變(bian)(bian)器(qi),交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan),配(pei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)柜(ju),變(bian)(bian)壓(ya)器(qi)等組成,其中(zhong)支(zhi)架(jia)不帶(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),自然不會產(chan)生(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)干擾(rao)。光(guang)伏(fu)組件(jian)(jian)和(he)直(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan),里面(mian)是直(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu),方向沒有變(bian)(bian)化,只能(neng)(neng)產(chan)生(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場,不能(neng)(neng)產(chan)生(sheng)磁(ci)(ci)場。輸出變(bian)(bian)壓(ya)器(qi)雖然是交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),但頻率(lv)很(hen)低,只有50Hz,產(chan)生(sheng)的(de)(de)磁(ci)(ci)場很(hen)低。逆(ni)(ni)變(bian)(bian)器(qi)是把直(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)轉(zhuan)為交(jiao)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)設(she)備,里面(mian)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(lv)一般為5-20KHz,因此(ci)會產(chan)生(sheng)交(jiao)變(bian)(bian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場,所以(yi)也會產(chan)生(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)輻射(she)(she)。但國家對(dui)光(guang)伏(fu)逆(ni)(ni)變(bian)(bian)器(qi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)兼(jian)容性有嚴格的(de)(de)標準。光(guang)伏(fu)逆(ni)(ni)變(bian)(bian)器(qi)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)輻射(she)(she),同家用電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)相(xiang)比(bi),大(da)約和(he)筆記本電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)腦差不多,低于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)爐,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)吹(chui)風,冰(bing)箱。
因(yin)此,太陽能光(guang)伏發電不僅(jin)不會對人的健(jian)康產(chan)生危害,還可以(yi)為地球提供綠(lv)色清(qing)潔的優質能源(yuan),是人類未(wei)來能源(yuan)發展方向(xiang)。
三、太陽能光伏發電的優點
1、太陽(yang)能(neng)(neng)資源取之不盡,用之不竭,照(zhao)射到地(di)球(qiu)上的(de)(de)太陽(yang)能(neng)(neng)要比(bi)人類(lei)目前消耗的(de)(de)能(neng)(neng)量大6000倍。而且太陽(yang)能(neng)(neng)在地(di)球(qiu)上分布廣(guang)泛,只要有光照(zhao)的(de)(de)地(di)方就可以使用光伏發電系統,不受地(di)域(yu)、海拔(ba)等因素的(de)(de)限制。
2、太(tai)陽(yang)能(neng)資(zi)源隨處可(ke)得,可(ke)就近(jin)供電,不(bu)必長距離輸送,避免了長距離輸電線路所(suo)造(zao)成的電能(neng)損失。
3、光伏發(fa)電(dian)的能量(liang)轉換(huan)過(guo)程簡(jian)單(dan),是(shi)直接(jie)從光能到電(dian)能的轉換(huan),沒有(you)中間過(guo)程(如熱能轉換(huan)為機(ji)械(xie)(xie)能、機(ji)械(xie)(xie)能轉換(huan)為電(dian)磁能等)和機(ji)械(xie)(xie)運動,不存在機(ji)械(xie)(xie)磨損(sun)。根據熱力學分析(xi),光伏發(fa)電(dian)具有(you)很高的理論發(fa)電(dian)效率,可達80%以上(shang),技術開(kai)發(fa)潛力巨大。
4、光伏發(fa)電本身不(bu)使用(yong)燃料(liao),不(bu)排放包括溫(wen)室氣(qi)(qi)體和其它廢氣(qi)(qi)在內的(de)任何物質,不(bu)污染空氣(qi)(qi),不(bu)產生(sheng)噪聲,對環境友好,不(bu)會遭受能源危機或燃料(liao)市場(chang)不(bu)穩定而造(zao)成的(de)沖擊,是真正綠色環保的(de)新(xin)型可再生(sheng)能源。
5、光(guang)伏發電過(guo)程(cheng)不需(xu)要(yao)冷卻(que)水(shui),可以安裝在沒有水(shui)的(de)荒漠戈壁上。光(guang)伏發電還可以很(hen)方便地(di)與建筑物(wu)結合,構成光(guang)伏建筑一(yi)體化發電系統,不需(xu)要(yao)單獨占(zhan)地(di),可節省寶貴的(de)土地(di)資(zi)源(yuan)。
6、光(guang)伏發(fa)電無(wu)機(ji)械傳(chuan)動部件,操作(zuo)、維護簡單(dan),運行穩(wen)定可(ke)靠。一套(tao)光(guang)伏發(fa)電系統只要有(you)太(tai)陽能(neng)(neng)電池組件就能(neng)(neng)發(fa)電,加(jia)之自動控制技術的(de)廣泛采(cai)用,基本(ben)上可(ke)實現(xian)無(wu)人(ren)值(zhi)守,維護成本(ben)低。
7、光伏(fu)發(fa)電(dian)系統(tong)工作性能(neng)(neng)穩(wen)定可(ke)靠,使用壽(shou)命長(30年以上(shang))。晶(jing)體硅(gui)太陽能(neng)(neng)電(dian)池(chi)壽(shou)命可(ke)長達(da)20~35年。在光伏(fu)發(fa)電(dian)系統(tong)中,只(zhi)要設計(ji)合理(li)、選型適(shi)當,蓄(xu)電(dian)池(chi)的壽(shou)命也可(ke)長達(da)10~15年。
8、太陽能電(dian)池組件結構簡(jian)單(dan),體積小、重量輕,便于運輸和安裝。光伏發電(dian)系統建設周期短,而且根(gen)據用電(dian)負(fu)荷容(rong)量可(ke)大可(ke)小,方便靈活,極易(yi)組合、擴容(rong)。
四、太陽能光伏發電的缺點
1、能量密度低
盡管太陽(yang)投向地(di)球的(de)能(neng)量總(zong)和極其巨大(da),但由(you)于地(di)球表面(mian)積也(ye)很大(da),而且地(di)球表面(mian)大(da)部(bu)分被海(hai)洋覆蓋(gai),真正能(neng)夠到(dao)達陸地(di)表面(mian)的(de)太陽(yang)能(neng)只有到(dao)達地(di)球范圍太陽(yang)輻(fu)射能(neng)量的(de)10%左(zuo)右,致使在陸地(di)單(dan)位面(mian)積上(shang)能(neng)夠直(zhi)接獲得的(de)太陽(yang)能(neng)量較少。通(tong)常(chang)以太陽(yang)輻(fu)照(zhao)度(du)(du)來表示(shi),地(di)球表面(mian)輻(fu)照(zhao)度(du)(du)最高值約為1.2kw/㎡,且絕大(da)多(duo)數(shu)地(di)區和大(da)多(duo)數(shu)日照(zhao)時間內都低于1kw/㎡。太陽(yang)能(neng)的(de)利用(yong)實際上(shang)是低密度(du)(du)能(neng)量的(de)收集、利用(yong)。
2、占地面積大
由于太陽(yang)能能量密度低,這就使得光(guang)伏(fu)發(fa)電(dian)(dian)系統的(de)(de)占地面積(ji)會很大(da),每10kw光(guang)伏(fu)發(fa)電(dian)(dian)功(gong)率(lv)占地約(yue)需100㎡,平(ping)均每平(ping)方(fang)米面積(ji)發(fa)電(dian)(dian)功(gong)率(lv)為100w。隨著光(guang)伏(fu)建筑一體(ti)化發(fa)電(dian)(dian)技術的(de)(de)成熟(shu)和發(fa)展,越(yue)來越(yue)多的(de)(de)光(guang)伏(fu)發(fa)電(dian)(dian)系統可(ke)以利用(yong)建筑物(wu)、構筑物(wu)的(de)(de)屋頂(ding)和立(li)面,將逐漸克服光(guang)伏(fu)發(fa)電(dian)(dian)占地面積(ji)大(da)的(de)(de)不足。
3、轉換效率低
光(guang)(guang)伏發(fa)(fa)(fa)電(dian)的(de)最基本單元(yuan)是太陽能電(dian)池(chi)組(zu)件。光(guang)(guang)伏發(fa)(fa)(fa)電(dian)的(de)轉(zhuan)換效率(lv)(lv)指光(guang)(guang)能轉(zhuan)換為電(dian)能的(de)比率(lv)(lv)。目前晶(jing)體硅光(guang)(guang)伏電(dian)池(chi)轉(zhuan)換效率(lv)(lv)為13%~17%,非晶(jing)硅光(guang)(guang)伏電(dian)池(chi)只有5%~8%。由于光(guang)(guang)電(dian)轉(zhuan)換效率(lv)(lv)太低,從(cong)而(er)使光(guang)(guang)伏發(fa)(fa)(fa)電(dian)功率(lv)(lv)密度(du)低,難(nan)以形成高功率(lv)(lv)發(fa)(fa)(fa)電(dian)系統。因此,太陽能電(dian)池(chi)的(de)轉(zhuan)換效率(lv)(lv)低是阻礙(ai)光(guang)(guang)伏發(fa)(fa)(fa)電(dian)大面(mian)積(ji)推廣的(de)瓶頸。
4、間歇性工作
在地(di)球(qiu)表面,光(guang)伏發電系統只能在白(bai)天(tian)發電,晚上不能發電,除非在太(tai)空(kong)中沒有晝夜之分的情況下,太(tai)陽能電池才可以連(lian)續發電,這與人們的用電需求(qiu)不符。
5、受氣候環境因素影響大
太(tai)陽能光(guang)伏發電(dian)(dian)的(de)(de)(de)(de)能源直接(jie)來源于太(tai)陽光(guang)的(de)(de)(de)(de)照(zhao)射,而地球表(biao)面上的(de)(de)(de)(de)太(tai)陽照(zhao)射受氣候的(de)(de)(de)(de)影(ying)(ying)響(xiang)(xiang)很大,長期的(de)(de)(de)(de)雨雪天、陰天、霧天甚至(zhi)云層的(de)(de)(de)(de)變化(hua)都會嚴重影(ying)(ying)響(xiang)(xiang)系統的(de)(de)(de)(de)發電(dian)(dian)狀態。另外,環境因(yin)素的(de)(de)(de)(de)影(ying)(ying)響(xiang)(xiang)也很大,比較(jiao)突出的(de)(de)(de)(de)一點是(shi),空氣中的(de)(de)(de)(de)顆粒物(如(ru)灰塵)等(deng)沉落在太(tai)陽能電(dian)(dian)池組(zu)件(jian)的(de)(de)(de)(de)表(biao)面,阻(zu)擋(dang)了部分(fen)光(guang)線的(de)(de)(de)(de)照(zhao)射,這樣(yang)會使電(dian)(dian)池組(zu)件(jian)轉換效率(lv)降(jiang)低,從而造成(cheng)發電(dian)(dian)量減少(shao)甚至(zhi)電(dian)(dian)池板的(de)(de)(de)(de)損壞。
6、地域依賴性強
地理(li)位置不(bu)同,氣候不(bu)同,使(shi)各地區(qu)日照資源相差很大。光(guang)伏發(fa)電(dian)系統(tong)只有應用(yong)在太(tai)陽能(neng)資源豐富的地區(qu),其效果才會好。
7、系統成本高
由于太(tai)陽能(neng)光伏發(fa)電(dian)(dian)的(de)(de)效(xiao)率較(jiao)低,到(dao)目(mu)前(qian)為(wei)止,光伏發(fa)電(dian)(dian)的(de)(de)成(cheng)本(ben)仍然是(shi)其(qi)(qi)他(ta)常規(gui)發(fa)電(dian)(dian)方式(shi)(如火力和(he)水(shui)力發(fa)電(dian)(dian))的(de)(de)幾倍(bei),這是(shi)制約其(qi)(qi)廣泛應用(yong)的(de)(de)最主要因(yin)素。但是(shi)也應看到(dao),隨著太(tai)陽能(neng)電(dian)(dian)池(chi)產(chan)能(neng)的(de)(de)不斷(duan)擴大及電(dian)(dian)池(chi)片光電(dian)(dian)轉換效(xiao)率的(de)(de)不斷(duan)提(ti)高,光伏發(fa)電(dian)(dian)系(xi)統(tong)的(de)(de)成(cheng)本(ben)也下降得非(fei)常快(kuai)。太(tai)陽能(neng)電(dian)(dian)池(chi)組件(jian)的(de)(de)價格幾十年來已經(jing)從最初的(de)(de)每瓦70多美(mei)元下降至(zhi)目(mu)前(qian)的(de)(de)每瓦2美(mei)元左右。
8、晶體硅電池的制造過程高污染、高能耗
晶(jing)(jing)體(ti)硅(gui)電池的(de)(de)主要(yao)原料是純(chun)凈的(de)(de)硅(gui)。硅(gui)是地球上(shang)含量僅(jin)次于氧(yang)的(de)(de)元(yuan)素,主要(yao)存(cun)在形式是沙(sha)子(sio2)。從硅(gui)砂一步(bu)步(bu)變成純(chun)度為99.9999%以(yi)上(shang)的(de)(de)晶(jing)(jing)體(ti)硅(gui),要(yao)經過多道化學和物理工(gong)序(xu)的(de)(de)處理,不僅(jin)要(yao)消耗大量能源,還(huan)會造成一定的(de)(de)環(huan)境污染。