一、光伏發電是什么意思
光(guang)伏發電(dian)(dian)(dian)是利用半導體界面(mian)(mian)的(de)光(guang)生伏特效應而(er)將光(guang)能直接轉變為電(dian)(dian)(dian)能的(de)一(yi)種技術。主(zhu)要(yao)由太陽(yang)電(dian)(dian)(dian)池板(ban)(組件(jian))、控制(zhi)器(qi)和(he)逆變器(qi)三大(da)部分組成,主(zhu)要(yao)部件(jian)由電(dian)(dian)(dian)子元器(qi)件(jian)構成。太陽(yang)能電(dian)(dian)(dian)池經過串聯后進行封裝(zhuang)保護可形(xing)成大(da)面(mian)(mian)積的(de)太陽(yang)電(dian)(dian)(dian)池組件(jian),再配合上功率控制(zhi)器(qi)等部件(jian)就形(xing)成了光(guang)伏發電(dian)(dian)(dian)裝(zhuang)置。
二、太陽能光伏發電對人體有輻射嗎
光伏系統有電磁(ci)輻(fu)(fu)(fu)射(she),但比較少,采(cai)用(yong)(yong)合格(ge)的設備,不(bu)會對人體(ti)造(zao)成傷害和對家用(yong)(yong)電器(qi)造(zao)成干擾。光伏組件(jian)是(shi)直流(liu)電,不(bu)會產生輻(fu)(fu)(fu)射(she),逆變器(qi)的輻(fu)(fu)(fu)射(she)嚴格(ge)控制在安全(quan)范圍(wei)內。
光(guang)(guang)伏(fu)(fu)發電(dian)(dian)(dian)(dian)(dian)(dian)是(shi)(shi)將光(guang)(guang)能(neng)通過半導(dao)體的(de)特性(xing)直(zhi)(zhi)(zhi)接轉(zhuan)化(hua)為直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)能(neng)的(de),再通過逆(ni)變(bian)(bian)(bian)(bian)(bian)器(qi)將直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)轉(zhuan)換(huan)成(cheng)可以被我們使(shi)用(yong)的(de)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)。光(guang)(guang)伏(fu)(fu)系統是(shi)(shi)由光(guang)(guang)伏(fu)(fu)組件,支架(jia),直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)纜,逆(ni)變(bian)(bian)(bian)(bian)(bian)器(qi),交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)纜,配(pei)電(dian)(dian)(dian)(dian)(dian)(dian)柜,變(bian)(bian)(bian)(bian)(bian)壓(ya)器(qi)等組成(cheng),其中支架(jia)不帶電(dian)(dian)(dian)(dian)(dian)(dian),自然不會產(chan)(chan)生(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)干擾(rao)。光(guang)(guang)伏(fu)(fu)組件和直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)纜,里面是(shi)(shi)直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu),方向沒有變(bian)(bian)(bian)(bian)(bian)化(hua),只能(neng)產(chan)(chan)生(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)場,不能(neng)產(chan)(chan)生(sheng)(sheng)磁(ci)場。輸出(chu)變(bian)(bian)(bian)(bian)(bian)壓(ya)器(qi)雖然是(shi)(shi)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian),但頻率很(hen)低(di)(di),只有50Hz,產(chan)(chan)生(sheng)(sheng)的(de)磁(ci)場很(hen)低(di)(di)。逆(ni)變(bian)(bian)(bian)(bian)(bian)器(qi)是(shi)(shi)把直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)轉(zhuan)為交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)的(de)設備,里面有電(dian)(dian)(dian)(dian)(dian)(dian)力電(dian)(dian)(dian)(dian)(dian)(dian)子變(bian)(bian)(bian)(bian)(bian)換(huan),頻率一般為5-20KHz,因此會產(chan)(chan)生(sheng)(sheng)交(jiao)變(bian)(bian)(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)(dian)場,所以也會產(chan)(chan)生(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)輻射(she)。但國(guo)家(jia)對光(guang)(guang)伏(fu)(fu)逆(ni)變(bian)(bian)(bian)(bian)(bian)器(qi)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)兼(jian)容性(xing)有嚴格的(de)標準。光(guang)(guang)伏(fu)(fu)逆(ni)變(bian)(bian)(bian)(bian)(bian)器(qi)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)輻射(she),同家(jia)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)相比,大約和筆記本電(dian)(dian)(dian)(dian)(dian)(dian)腦(nao)差不多,低(di)(di)于電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)爐(lu),電(dian)(dian)(dian)(dian)(dian)(dian)吹風,冰箱(xiang)。
因此,太陽能光(guang)伏發(fa)電(dian)不僅不會對人(ren)的健康產生危害,還(huan)可以為地球提(ti)供綠色清潔的優質能源(yuan),是人(ren)類未來能源(yuan)發(fa)展方向(xiang)。
三、太陽能光伏發電的優點
1、太(tai)陽(yang)能資源(yuan)取之(zhi)不盡,用之(zhi)不竭(jie),照射到地(di)球(qiu)上的(de)太(tai)陽(yang)能要比(bi)人類目前(qian)消耗(hao)的(de)能量大6000倍。而(er)且太(tai)陽(yang)能在地(di)球(qiu)上分布廣(guang)泛(fan),只要有光(guang)(guang)照的(de)地(di)方就可(ke)以(yi)使用光(guang)(guang)伏發電系統(tong),不受地(di)域、海拔等(deng)因素(su)的(de)限(xian)制。
2、太(tai)陽能資源隨處可得,可就近供電(dian)(dian),不必(bi)長距離(li)輸送,避免了長距離(li)輸電(dian)(dian)線路所造成的(de)電(dian)(dian)能損失。
3、光(guang)伏發(fa)(fa)電的(de)(de)能(neng)(neng)量轉(zhuan)(zhuan)換(huan)(huan)過(guo)程(cheng)簡單,是直接從(cong)光(guang)能(neng)(neng)到電能(neng)(neng)的(de)(de)轉(zhuan)(zhuan)換(huan)(huan),沒(mei)有中(zhong)間過(guo)程(cheng)(如熱(re)能(neng)(neng)轉(zhuan)(zhuan)換(huan)(huan)為(wei)機(ji)械(xie)能(neng)(neng)、機(ji)械(xie)能(neng)(neng)轉(zhuan)(zhuan)換(huan)(huan)為(wei)電磁(ci)能(neng)(neng)等)和(he)機(ji)械(xie)運動(dong),不存在機(ji)械(xie)磨損。根據熱(re)力學分析,光(guang)伏發(fa)(fa)電具有很高的(de)(de)理(li)論發(fa)(fa)電效率,可(ke)達80%以上,技術(shu)開發(fa)(fa)潛力巨(ju)大。
4、光伏發電本身不(bu)使用(yong)燃料,不(bu)排放包括溫室氣體(ti)和(he)其(qi)它廢氣在(zai)內的任何物質,不(bu)污染空氣,不(bu)產生(sheng)噪聲(sheng),對(dui)環(huan)境友好,不(bu)會遭受能源危(wei)機或燃料市場不(bu)穩定而造成(cheng)的沖擊,是真正綠色(se)環(huan)保的新(xin)型(xing)可再(zai)生(sheng)能源。
5、光伏(fu)(fu)發電過(guo)程(cheng)不需(xu)要(yao)冷(leng)卻水,可(ke)(ke)以安裝在沒(mei)有水的(de)荒(huang)漠戈壁上。光伏(fu)(fu)發電還可(ke)(ke)以很方便地與建筑物(wu)結合,構成光伏(fu)(fu)建筑一體化(hua)發電系統,不需(xu)要(yao)單獨(du)占地,可(ke)(ke)節省寶(bao)貴的(de)土(tu)地資源(yuan)。
6、光伏發(fa)電無機械傳動部件(jian),操(cao)作、維護簡單,運行(xing)穩定可靠。一套光伏發(fa)電系(xi)統(tong)只要有(you)太(tai)陽能電池組件(jian)就能發(fa)電,加之自動控制技術的廣泛(fan)采用,基本上可實現(xian)無人值守,維護成本低。
7、光伏(fu)發電(dian)(dian)系統工作性能穩定可(ke)靠,使用壽(shou)命長(chang)(30年以(yi)上)。晶體(ti)硅太陽(yang)能電(dian)(dian)池壽(shou)命可(ke)長(chang)達(da)20~35年。在(zai)光伏(fu)發電(dian)(dian)系統中,只要設(she)計合(he)理、選型適(shi)當,蓄電(dian)(dian)池的壽(shou)命也可(ke)長(chang)達(da)10~15年。
8、太陽能電池組(zu)(zu)件結構簡單,體積小(xiao)、重量輕(qing),便(bian)于(yu)運輸和安裝。光伏發電系統建設周(zhou)期短(duan),而且根據(ju)用電負荷容量可大(da)可小(xiao),方便(bian)靈活,極易組(zu)(zu)合、擴容。
四、太陽能光伏發電的缺點
1、能量密度低
盡(jin)管太(tai)陽(yang)投向地(di)(di)(di)球的(de)能(neng)量總和極其巨大(da)(da),但由于地(di)(di)(di)球表(biao)面(mian)積也很大(da)(da),而且地(di)(di)(di)球表(biao)面(mian)大(da)(da)部分被(bei)海(hai)洋覆蓋(gai),真正能(neng)夠到達陸地(di)(di)(di)表(biao)面(mian)的(de)太(tai)陽(yang)能(neng)只有到達地(di)(di)(di)球范圍太(tai)陽(yang)輻射能(neng)量的(de)10%左右,致使在(zai)陸地(di)(di)(di)單位(wei)面(mian)積上能(neng)夠直接(jie)獲得的(de)太(tai)陽(yang)能(neng)量較少。通常以太(tai)陽(yang)輻照度(du)來表(biao)示,地(di)(di)(di)球表(biao)面(mian)輻照度(du)最高值約為1.2kw/㎡,且絕大(da)(da)多(duo)數(shu)地(di)(di)(di)區和大(da)(da)多(duo)數(shu)日照時間內都低(di)于1kw/㎡。太(tai)陽(yang)能(neng)的(de)利用實(shi)際上是低(di)密度(du)能(neng)量的(de)收集、利用。
2、占地面積大
由于太(tai)陽能能量密度低,這就使得光伏(fu)(fu)(fu)發(fa)電(dian)系統(tong)的(de)(de)占(zhan)地面(mian)(mian)積(ji)會很大,每10kw光伏(fu)(fu)(fu)發(fa)電(dian)功率占(zhan)地約需100㎡,平(ping)均每平(ping)方米面(mian)(mian)積(ji)發(fa)電(dian)功率為(wei)100w。隨著光伏(fu)(fu)(fu)建筑(zhu)一體化(hua)發(fa)電(dian)技術的(de)(de)成熟和發(fa)展,越(yue)(yue)來越(yue)(yue)多的(de)(de)光伏(fu)(fu)(fu)發(fa)電(dian)系統(tong)可以利用建筑(zhu)物、構筑(zhu)物的(de)(de)屋頂(ding)和立面(mian)(mian),將逐漸克服光伏(fu)(fu)(fu)發(fa)電(dian)占(zhan)地面(mian)(mian)積(ji)大的(de)(de)不足(zu)。
3、轉換效率低
光(guang)(guang)伏(fu)發(fa)(fa)電(dian)(dian)的(de)最基本(ben)單元(yuan)是太(tai)(tai)陽(yang)能(neng)電(dian)(dian)池組件。光(guang)(guang)伏(fu)發(fa)(fa)電(dian)(dian)的(de)轉(zhuan)換(huan)效(xiao)率(lv)(lv)(lv)(lv)指光(guang)(guang)能(neng)轉(zhuan)換(huan)為電(dian)(dian)能(neng)的(de)比率(lv)(lv)(lv)(lv)。目前晶體硅(gui)(gui)光(guang)(guang)伏(fu)電(dian)(dian)池轉(zhuan)換(huan)效(xiao)率(lv)(lv)(lv)(lv)為13%~17%,非晶硅(gui)(gui)光(guang)(guang)伏(fu)電(dian)(dian)池只有5%~8%。由于(yu)光(guang)(guang)電(dian)(dian)轉(zhuan)換(huan)效(xiao)率(lv)(lv)(lv)(lv)太(tai)(tai)低,從而使光(guang)(guang)伏(fu)發(fa)(fa)電(dian)(dian)功率(lv)(lv)(lv)(lv)密度(du)低,難以形成(cheng)高功率(lv)(lv)(lv)(lv)發(fa)(fa)電(dian)(dian)系統(tong)。因此,太(tai)(tai)陽(yang)能(neng)電(dian)(dian)池的(de)轉(zhuan)換(huan)效(xiao)率(lv)(lv)(lv)(lv)低是阻礙光(guang)(guang)伏(fu)發(fa)(fa)電(dian)(dian)大(da)面積(ji)推廣的(de)瓶頸。
4、間歇性工作
在地(di)球表面,光伏發電(dian)系統(tong)只能(neng)在白天發電(dian),晚上不能(neng)發電(dian),除非在太空中沒有(you)晝夜之分的情況下,太陽能(neng)電(dian)池才可以連續發電(dian),這與人們(men)的用電(dian)需(xu)求不符(fu)。
5、受氣候環境因素影響大
太(tai)陽(yang)(yang)(yang)能(neng)(neng)光伏發(fa)電(dian)(dian)的(de)(de)(de)能(neng)(neng)源(yuan)直接(jie)來(lai)源(yuan)于太(tai)陽(yang)(yang)(yang)光的(de)(de)(de)照射(she),而地球表(biao)面上的(de)(de)(de)太(tai)陽(yang)(yang)(yang)照射(she)受氣候的(de)(de)(de)影響很大(da),長期的(de)(de)(de)雨雪天、陰天、霧天甚(shen)至云層的(de)(de)(de)變化都會嚴重影響系統的(de)(de)(de)發(fa)電(dian)(dian)狀態。另外,環境(jing)因素的(de)(de)(de)影響也(ye)很大(da),比較突(tu)出的(de)(de)(de)一點是,空氣中的(de)(de)(de)顆(ke)粒物(wu)(如灰塵)等沉落在太(tai)陽(yang)(yang)(yang)能(neng)(neng)電(dian)(dian)池組(zu)件(jian)的(de)(de)(de)表(biao)面,阻擋(dang)了部分光線的(de)(de)(de)照射(she),這樣(yang)會使電(dian)(dian)池組(zu)件(jian)轉換效率降低(di),從(cong)而造(zao)成發(fa)電(dian)(dian)量(liang)減少甚(shen)至電(dian)(dian)池板的(de)(de)(de)損壞(huai)。
6、地域依賴性強
地(di)理(li)位置不同,氣候不同,使各地(di)區(qu)日照資源相差很大。光伏發電系統(tong)只有應用在太陽能資源豐富的地(di)區(qu),其效果才會好。
7、系統成本高
由于(yu)太陽能(neng)光(guang)(guang)伏發電(dian)(dian)(dian)(dian)的(de)(de)效(xiao)率較低,到(dao)目(mu)前為止,光(guang)(guang)伏發電(dian)(dian)(dian)(dian)的(de)(de)成本(ben)仍然是(shi)其(qi)他(ta)常規(gui)發電(dian)(dian)(dian)(dian)方式(如火(huo)力(li)和(he)水力(li)發電(dian)(dian)(dian)(dian))的(de)(de)幾倍,這是(shi)制約其(qi)廣泛(fan)應用(yong)的(de)(de)最(zui)主要因素。但是(shi)也(ye)應看(kan)到(dao),隨著太陽能(neng)電(dian)(dian)(dian)(dian)池產能(neng)的(de)(de)不(bu)斷擴大及電(dian)(dian)(dian)(dian)池片光(guang)(guang)電(dian)(dian)(dian)(dian)轉(zhuan)換效(xiao)率的(de)(de)不(bu)斷提(ti)高,光(guang)(guang)伏發電(dian)(dian)(dian)(dian)系統的(de)(de)成本(ben)也(ye)下(xia)降得非常快(kuai)。太陽能(neng)電(dian)(dian)(dian)(dian)池組件(jian)的(de)(de)價格幾十(shi)年來(lai)已經從最(zui)初(chu)的(de)(de)每瓦(wa)70多美(mei)元(yuan)下(xia)降至目(mu)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)體硅(gui)電池(chi)的(de)主(zhu)要(yao)原料(liao)是純凈的(de)硅(gui)。硅(gui)是地球上含量僅次(ci)于氧的(de)元素,主(zhu)要(yao)存在(zai)形(xing)式(shi)是沙子(sio2)。從硅(gui)砂一步(bu)步(bu)變成(cheng)純度(du)為99.9999%以(yi)上的(de)晶(jing)體硅(gui),要(yao)經(jing)過多道化(hua)學和物理工(gong)序的(de)處理,不僅要(yao)消(xiao)耗大量能源(yuan),還會造成(cheng)一定的(de)環境污染。