離網(wǎng)光伏電站是把太陽能發(fā)電儲存到蓄電池，然后通過逆變器轉(zhuǎn)換成家用的220V電壓。

并網(wǎng)光伏電站是指和市電連接在一起，并網(wǎng)光伏發(fā)電站沒有電能儲存裝置，直接通過逆變器轉(zhuǎn)換成國家電網(wǎng)需要的電壓要求，并優(yōu)先供家庭使用，家庭用不完的電可以賣給國家。

目前國家政策支持，正在大力扶持太陽能光伏發(fā)電，家庭光伏發(fā)電站只要發(fā)電，都會有國家補貼。不過并網(wǎng)的話要先跟當(dāng)?shù)貒译娋W(wǎng)部門申請。

并網(wǎng)，就是必須連接到公共電網(wǎng)，就是太陽能發(fā)電、家庭電網(wǎng)、公共電網(wǎng)聯(lián)系在一起了，這是必須依賴現(xiàn)有電網(wǎng)才能運行的發(fā)電系統(tǒng)。

主要由太陽能電池板和逆變器組成，太陽能電池板發(fā)出直接經(jīng)逆變器轉(zhuǎn)換成220V交流電并給家用電器供電，當(dāng)太陽能的發(fā)電量超過家用電器使用的電量時，多余的電就輸送到了公共電網(wǎng)；而當(dāng)太陽能的發(fā)電量不能滿足家用電器使用時，就自動從電網(wǎng)中補充。而這整個過程都是智能控制的，不需要人工操作。

由于這種光伏發(fā)電系統(tǒng)不需要使用蓄電池，也就大大節(jié)省了成本，特別是國家的并網(wǎng)政策已經(jīng)明確指明，家庭光伏電站可以免費入網(wǎng)，多余的電還可以賣給電力公司。

從投資的長遠角度，按家庭光伏電站25年的使用壽命計算，6-10年左右可以回收成本，剩下的十幾年就是賺到的。因此，如果想節(jié)省電費開支且電力供應(yīng)方便的話，就選擇并網(wǎng)太陽能發(fā)電系統(tǒng)，這也是目前主流的方式。

但是，并網(wǎng)也有其缺點，就是當(dāng)公共電網(wǎng)斷電時，光伏發(fā)電也不能運行。但是如果把其中的并網(wǎng)逆變器換成智能微網(wǎng)逆變器(并網(wǎng)與離網(wǎng)混合逆變器)，斷電時電站仍可以正常運轉(zhuǎn)。

那么，怎么才可以將白天發(fā)的電力儲存起來晚上用？這需要添加控制器和蓄電池等，白天控制器將光伏所發(fā)的電力儲存在蓄電池中，晚上控制器將蓄電池所儲電力釋放出來供照明使用。

離網(wǎng)光伏發(fā)電站也被叫做獨立光伏發(fā)電站，是不依賴電網(wǎng)而獨立運行的發(fā)電系統(tǒng)，主要太陽能電池板、儲能蓄電池、充放電控制器、逆變器等部件組成。太陽能電池板發(fā)出的電直接流入蓄電池并儲存起來，需要給電器供電時，蓄電池里的直流電流經(jīng)逆變器并轉(zhuǎn)換成220V的交流電。

這是一個重復(fù)循環(huán)的充放電過程。這種發(fā)電系統(tǒng)由于不受地域的限制，使用很廣泛，只要有陽光照射的地方就可以安裝使用，因此非常適合于偏遠無電網(wǎng)地區(qū)、孤島、漁船、戶外養(yǎng)殖基地等，也可以為經(jīng)常停電地區(qū)的應(yīng)急發(fā)電設(shè)備。

這種系統(tǒng)由于必須配備蓄電池，且占據(jù)了發(fā)電系統(tǒng)30-50%的成本。而且蓄電池的使用壽命一般都在3-5年，過后又得更換，這更是增加了使用成本。而經(jīng)濟性來說，很難得到大范圍推廣使用，因此不適合用電方便的地方使用。

但對于無電網(wǎng)地區(qū)或經(jīng)常停電地區(qū)家庭來說，又具有很強的實用性。特別是單純?yōu)榱私鉀Q停電時的照明問題，可以采用直流節(jié)能燈，非常實用。因此，離網(wǎng)發(fā)電系統(tǒng)是專門針對無電網(wǎng)地區(qū)或經(jīng)常停電地區(qū)場所使用的。

Off-grid photovoltaic power stations store solar power to batteries, and then convert it into 220V voltage at home through inverters.

Grid-connected photovoltaic power station refers to the power station connected with the municipal power. Grid-connected photovoltaic power station has no power storage device, and directly converts to the voltage requirements of the national grid through the inverter. It is given priority to the household use, and the household can sell the electricity that is not used up to the state.

At present, the national policy support is vigorously supporting solar photovoltaic power generation. As long as the household photovoltaic power station generates electricity, there will be state subsidies. But if you want to connect to the grid, you need to apply to the local state grid department first.

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Grid-connection means that it must be connected to the public grid, which means that solar power generation, home power grid and public power grid are all connected together. It is a power generation system that must rely on the existing grid to operate.

It is mainly composed of solar panels and inverters, which directly convert the solar panels into 220V alternating current through the inverters and supply power to household appliances. When the solar power generation exceeds the electricity used by household appliances, the excess electricity is sent to the public grid; And when solar power cannot produce enough electricity for household appliances, it is automatically replenished from the grid. The whole process is intelligently controlled and does not require manual operation.

Since the photovoltaic system does not require the use of batteries, it also saves a lot of costs, especially since the national grid-connection policy has clearly stated that the household photovoltaic power station can be connected to the grid for free, and the surplus electricity can be sold to the power company.

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From the long-term perspective of investment, based on the 25-year service life of the household photovoltaic power station, the cost can be recovered in about 6-10 years, and the remaining ten years is earned. Therefore, if you want to save the cost of electricity and the power supply is convenient, choose the grid connected solar power system, which is also the current mainstream way.

However, grid-connection also has a drawback, which is that when the public grid is cut off, the photovoltaic generation cannot operate. However, if the grid-connected inverter is replaced by intelligent micro-grid inverter (grid-connected and off-grid hybrid inverter), the power station can still operate normally when the power is cut off.

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So how do you store the electricity you generate during the day for use at night? This requires the addition of a controller and storage battery. During the day, the controller will store the electricity generated by the photovoltaic in the battery, and at night, the controller will release the electricity stored in the battery for lighting.

Off-grid photovoltaic power stations, also known as independent photovoltaic power stations, are power generation systems that do not rely on the power grid and operate independently. They are mainly composed of solar panels, storage batteries, charge and discharge controllers, inverters and other components. The electricity produced by the solar panels flows directly into the battery and is stored. When it is needed to power the electrical appliances, the direct current in the battery flows through the inverter and is converted into 220V alternating current.

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This is a repeating cycle of charge and discharge. This kind of power generation system is widely used because it is not limited by the region and can be installed and used wherever the sun shines. Therefore, it is very suitable for remote areas without power grid, isolated islands, fishing boats, outdoor breeding bases, etc., and can also be used as emergency power generation equipment in areas with frequent power outages.

Such systems, because they must be equipped with batteries, account for 30-50% of the cost of the generation system. And the service life of the battery is generally in 3-5 years, after which it has to be replaced, which increases the cost of use. Economically speaking, it is difficult to be widely promoted and used, so it is not suitable for use in places where electricity is convenient.

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However, it has strong practicability for households in areas without power grid or frequent power outage. Especially in order to solve the lighting problem when the power failure, you can use DC energy-saving lamps, very practical. Therefore, off-grid power generation system is specifically for the use of non-grid areas or frequent power outage areas.