SMILE SOLAR ENERGY CO., LTD.

       According to ASTM (American Society of Test and Material) No. E892 testing standard, solar panels in the lab are 1000 W/m² output. Therefore, the higher the power generation is, the bigger the solar panes are. Generally, now all brands of commercially available solar panels’ generation efficiency has no great differences. As far as the crystalline silicon PV panels are concerned, if the power generation capacity is about 120W/m²~150 W/m², then setting 1kw solar power system need approximately 7~9m² (75.6~97.2 square feet).

Considerations are as follows:

1. Solar system engineering is experience and knowledge-intensive industry. You should consider past reputation and performance.
2. Whether the system components provided by system supplier can operate for 20 years and have good warranty program.
3. The system supplier’s long-term assurance program for power performance.
4. Whether the service is complete and fast.
5. You should compare the highest performance with price, instead of just pursuing the lowest price.

       Solar conversion efficiency is a symbol of ratio of power generation and power consumption. The sunlight generates energy in a very broad spectrum. But for now, we learn to get small part of the spectrum by using solar PV cells and converse it into available power. So the efficiency of commercially available solar PV modules is about 7~17% which seems low. Many of the solar system efficiency will reduce gradually by years based on the extended exposure to the sunlight. By contrast, the power conversion efficiency by the conventional fossil fuels is about 28%. 

The following are the main factors affecting the generation capacity: shade. The solar panels cannot generate electricity without sunlight. Therefore, we should rule out this factor while choosing the location and planning for the construction.

1. Poor quality of the solar panelsChoosing the products of low price or small factory will cause the efficiency reduce quickly after 6-month installation, and will reach the desired power generation.

2. Poor heat resistance of the solar PV system.The efficiency of the solar PV system will reduce by 0.4%~0.5% with the temperature of the modules increase per degree Celsius, so the system should have good heat dissipation design.

3. Poor construction qualityPoor connection of the contact and the connector, exposed pipes, and other factors will increase system failure possibility and reduce the power generation efficiency.

4. Poor pipe configuration and matchesThe line length of each site is different. If the line is not long enough will cause voltage drop, and then the power transmission will drop, too.

5. DustIf the solar PV system locates in areas with high dust amount, the shade caused by dust may result in 30% power loss. Medium and large system should be equipped with cleaning device to clean the dust regularly.

6. No monitoring devicesThe equipment failure or system performance degradation may not be discovered timely without monitoring devices, and then cause large amount of power loss because of delayed maintenance.

Types are as follows:
       Crystalline silicon, the mainstream product. It’s also divided into single-crystal silicon and multicrystalline silicon. The efficiency of single-crystal silicon is better. Its lab chip conversion efficiency may reach to 25%~26%, while the commercially available modules are about 15%~16%. The multicrystalline silicon lab chip’s conversion efficiency is about 21%~23%, while the commercially available modules are near 13%~15%. Therefore, with same power generation modules, multicrystalline silicon may slightly larger than single-crystal silicon.
        Membrane: Using sputtering or printing production. Based on different materials, it can be classified into Amorphous (5%~10%), CdTe(10%~12%), CIGS(10%~14%), and so on. Amorphous membrane was quite popular few years ago. At that time, amorphous membrane had price advantage, so a lot of large factories were competing to invest it. Then, because of low conversion efficiency, large installation area, and significant decline of crystalline silicon’s price, current users are very few. First Solar, the American firm, is on behalf of manufacture of CdTe. CdTe membrane’s efficiency is medium, but its cost is controlled under US$ 0.9/W. Therefore, CdTe membrane is the most competitive membrane product. As for CIGS, it is the latest product. Many domestic and foreign large factories including Taiwan TSMC are competing to invest and develop. Only due to mass production process’s yield rate is still low, so the Markey visibility remains to be strengthened.

       Concentrating: The chip uses GaAs as generating material which is also known as III-V. Its feature is high power generation efficiency (Up to 35%~40%), but it needs precise solar to align the chip to the sun. Therefore, the overall cost is still high when comparing with crystalline silicon system. Besides, the maintenance for long-term operation is also an issue to be discussed. In addition, because dye-sensitized solar cells or other new type materials are not widely used, it still depends on long-time development.
       Grid-tie－the mainstream system with over 90% market share. This system will converse solar DC power into AC power, and then transport to power company network directly in order to achieve the purpose of saving overall power consumption.
       Alone－used in area where electricity network cannot reach or difficult to reach. In that area, batteries need to storage electricity for irregular electricity load. Because of the batteries’ lifetime, the batteries need regular replacement.
       Anti-disaster (Hybrid)－used in area where electricity network is frequently disconnected. In that area, it also needs batteries to storage part of electricity for grid-tie operation for usual normal electricity network. Once the electricity network is interrupted, the battery will release electricity for critical equipment use.

       “Hours of sunshine” is usually used for agriculture purposes or construction. It’s defined as the time cumulative value when insolation amount is over 120W/ m². Insolation amount higher than 120W/ m² is usually firmly good, and this will contribute to crop photosynthesis or construction time for the work. In Taiwan this value is about 2,000~3,000 hours for the whole year. As for “Equivalent insolation hours,” it is an important factor for assessing solar power. The higher value it is, the stronger the local insolation it is and more electricity it can generate. It’s defined as the effective exposure time that the local insolation is converted to standard condition of 1000W/ m². In Taiwan this value is about 900~1,650 hours for the whole year, if the daily average value is about 2.5~4.5 hours. The following table is “Equivalent insolation hours” based on estimates of Central Weather Bureau and our company: 

Equivalent insolation hours
2.5	3	3.5	4	4.5
Taipei, Keelung, and Ilan	Taoyuan, Hsinchu, and Hualien	Miaoli, Taichung, Changhua, Nantou, and Yunlin	Chiayi, Tainan, Kaohsiung Penghu	Pingtung

The above is overview table, as far as the same latitude, usually the equivalent insolation hours in seaside are better than that in the plains, and equivalent insolation hours in plains are better than that in hillside and mountain regions.

        The solar PV cell can converse solar energy into electricity. The typical solar PV cell is a kind of crystalline silicon. Through a special treatment, it will become a dual-type layer wafer with one side the dissociative electrons swim freely in the internal (N-type layer), and the other side is hole lacking of electrons (P-type layer). When the sunlight irradiate at the silicon chip, it will cause the interaction flow of electrons and holes, and pass through N-type and P-type layer, thus causing electric current.

Thevenin’s theorem: open-circuit voltage (The voltage between two points, it is resistance.) If you want to know the open-circuit voltage resistance, follow the electric circuit and find the parallel connection resistance, or if the voltage source is parallel connection resistance, you can calculate the voltage drop with partial pressure theorem.

Thevenin’s theorem: short-circuit current (Current between two points, it is short course.) If you have already known the voltage drop between A and B, connect it with the short course. If the electric circuit doesn’t have resistance, then using the internal resistance as resistance to calculate for electric current which is short-circuit current.