Analysis of solar LED street lights
The overall cost of a solar-powered high-power LED street light is much lower than the overall cost of an AC-powered high-power LED street light system.
Although the initial installation cost of solar LED street lamps is high, the cost of cabling for AC power supply and long-term electricity bills are much higher than those for solar systems.
Let's do a detailed analysis below.
1. The cost of the LED head and pole of the two systems is roughly the same, the main difference is the solar panel. Usually the power of a solar panel is about three times that of an LED luminaire. If the LED is 100 watts, then a 300 watt solar panel is required. At present, the price of solar panels has been reduced to 23 yuan / watt, 300 watts is 6900 yuan. In addition, solar systems require batteries, but their cost is equivalent to the cost of switching power supplies in AC power. So the two can be offset. Therefore, the difference in cost of the lamps themselves is mainly solar panels.
2. The maximum cost of AC power supply high-power LED street lights during initial installation is the laying of cables.
The average person thinks that the cost of the cable itself is mainly, but in addition to the cable itself, its laying, auxiliary facilities (inspection wells, power distribution equipment), etc., are much more expensive than the cable itself. Now suppose that a road of 10 kilometers long is taken as an example. Every 30 meters, the opposite side is placed. A total of 666 high-power LED street lights are needed. If solar street lights are used, in addition to recovering the cost within five years, it can save 430,000 yuan in electricity costs. After five years, the annual electricity bill will save 1.22 million yuan.
Solar high-power LED street light has no such shortcomings. Its composition is very simple. It consists of only five parts: and its installation is very simple. Just make a cement base, stand up the light pole, and install the anchor screw. In particular, people who do not have to worry about the power system are designed to install and construct, dig trenches, lay cables, dig inspection wells, install transformers,... This is a very important advantage.
The lead storage battery in the solar high-power LED street lamp is a problem. On the one hand, it has a life problem. The life of the lead-acid battery is only 2 years, but now there is a type of lead-type lead battery that has a life of up to 6- 8 years. It's just a little more expensive.
Another problem with lead storage batteries is the pollution of the environment. In fact, the largest user of lead storage batteries is automobiles. China now produces and sells 7 million vehicles per year, and each vehicle uses at least one lead storage battery. The lead battery of the car has a very complete recycling system, and the lead plates will be recycled and recycled. Therefore, the lead storage battery in the solar LED street lamp system can be completely recovered by using the existing automobile battery recovery system without causing environmental pollution. Moreover, the cost of lithium iron batteries has now been reduced to the extent that they can be practically used. This is a completely non-polluting battery. There are already electric bicycles that use lithium-iron batteries instead of lead batteries. In Taiwan, a company that makes solar high-power LED street lamps (KESC) has developed street lamps using lithium-iron batteries. Domestic Dongguan also has factories to produce lithium-iron car batteries. It can be guaranteed for five years. So this problem can also be solved.
One of the only problems with solar streetlights today is the cost of solar panels, but at present its price is declining at an alarming rate. In 2008, it has already cut the price by 1/3. The price of its main raw material polysilicon has dropped from $300 per kilogram in 2007 to $200 in 2008. It is expected that the price of polysilicon will drop to $100 per kilogram by 2009. In particular, China's polysilicon production is growing rapidly. After all 33 projects under construction are put into production, its output will reach more than 146,000 tons, while the current domestic demand is only 8,000 tons. Therefore, how to expand domestic demand is a top priority. Vigorously developing solar high-power LED street lights is undoubtedly the best way. The current price of solar panels has been reduced to 20 yuan / watt. And it is still decreasing at an extremely fast speed.
In addition, the use of PWM dimming controller and PWM dimmable constant current driving module is also an effective way to reduce the area of solar panels. As shown in the figure below, after PWM dimming control, it can save more than 40%, which means that the area of solar panels can be reduced by 40%. This is undoubtedly a great reduction in the cost of solar high-power LED street lights. Make it more competitive with AC high-power LED street lights!
All street lights changed to solar street lights can save the power generation of a Three Gorges hydropower station
High-power LED street lamps are more energy-efficient than high-pressure sodium lamps and have long been recognized. However, there may be some quantitative concepts. It can now be considered that a 100-watt high-power LED street light can replace a 250-watt high-pressure sodium lamp, so it can be simply assumed that each high-power LED street light can save 150 watts of electricity.
However, if it is changed to solar power, then even this 100W of electricity can be saved, that is, each street lamp can save 250 watts. According to estimates, the total number of existing street lamps in China is about 100 million baht and is growing at a rate of 20% per year. In 2008, 20 million new LED street lamps were added. If the 100 million street lamps can be converted into 60 million sets 250 watt street lamps, and then the 60 million street lamps are all converted into solar high-power LED street lamps, a total of 15 million kilowatts of power can be saved. Assuming that every street lamp works 12 hours a day, it will save 65.7 billion kWh in one year. The total power generation of the Three Gorges Hydropower Station in 2007 was 61.603 billion kWh. Therefore, the amount of electricity saved in one year after the national street lights are all changed to solar street lights will exceed the annual power generation of a Three Gorges hydropower station. This is an extremely amazing number. Even if we don't renovate the original street lights, we will add about 20 million new street lights every year and 60 million new ones in three years. The same method can be used to save a Three Gorges power station after three years. There is no need to mobilize the power of the country, invest hundreds of billions, and immigrate millions to achieve.
Not only that, solar energy is a clean renewable energy source that not only saves electricity but also reduces carbon dioxide emissions. Each 250-watt high-pressure sodium lamp will produce 1,290 kilograms of carbon dioxide in a year, so after 60 million street lamps are all converted to solar street lights, it will reduce 77.4 million tons of carbon dioxide. Therefore, after changing to solar energy, it not only saves electricity costs, but also saves carbon dioxide reduction costs. The cost per ton of carbon dioxide is $345-404. A reduction of 77.4 million tons of carbon dioxide is equivalent to saving $31 billion in carbon dioxide reduction costs!
The previous figures are just a comparison of high-power LED street lights and high-pressure sodium lamps. For high-power LED street lamps with the same 100W, the energy consumption comparison between AC and solar energy is only required by dividing the above data by 2.5. That is to say, 60 million watts of 100 watt high-power LED street lights, if all powered by solar power, can save 26.28 billion kWh of electricity when all AC power is used, and the carbon dioxide emission reduction cost is 12.4 billion US dollars.