Illuminating the night by day – Solar Street Lights

Street lights are essential public amenities at night, illuminating the way home. However, these tiny lights, while providing convenience and safety, also incur significant electricity bills and consume precious energy.

According to statistics, there are over 100,000 street lights in Taipei City. Every two months, the city's electricity bills total approximately NT$14 million, resulting in an annual streetlight electricity budget of nearly NT$200 million. This is after a 50% discount. This demonstrates the significant energy consumption of street lights. For some local governments, streetlight electricity costs can even become a significant burden, creating safety concerns for the public.

Independent Systems

An alternative approach would be to equip each street light with a small power generator, generating its own power, eliminating the need for additional electricity. However, this power generation method must be clean and pollution-free to meet the needs of a high-density streetlight system.

Solar street lights are a particularly suitable system. Utilizing the principle of solar photovoltaics, photovoltaic panels absorb sunlight during the day and convert it into electricity, which is stored in batteries. At night, the lights can use the energy generated during the day for lighting, drawing entirely from nature, eliminating the need for electricity bills!

What happens when solar power is unavailable during rainy or cloudy weather? Modern solar street lights are equipped with a deep-storage battery, ranging from a basic 100AH ​​to larger capacities, to effectively keep the battery fully charged during good weather. Under typical usage, most solar street lights can provide three to five days of illumination with a full day's sunlight, allowing them to survive rainy periods.

Diverse Choices

The primary component of a solar powered street light is the solar module, the core that converts sunlight into electricity. Its power level affects the brightness and operating time of the light. Currently, both polycrystalline and monocrystalline modules are used. Polycrystalline silicon is less efficient and therefore more affordable, while monocrystalline silicon offers higher efficiency and a higher price.

Since solar modules generate direct current (DC), they require a power controller to steadily charge the battery and discharge it, providing power for light generation. Regarding lighting, the more energy-efficient the bulb, the longer the solar street light will operate, compensating for lower solar energy conversion efficiency.

Currently, solar street light bulbs, including energy-saving lamps and PL lamps, all offer low power consumption and high brightness. Energy-saving, high-brightness, and long-life LED lamps are also available as solar street light components, but their high unit price has limited market acceptance.

Save money, save energy, and provide disaster prevention.

In practice, the price of solar street lights has dropped from over 300,000 yuan a few years ago to around 50,000 yuan today. With this declining cost trend, local governments are increasingly considering solar street lights, which eliminate the need for wiring, electricity bills, and the worry of unexpected power outages and natural disasters.

While solar streetlights still can't compete with traditional streetlights in terms of brightness and stability, they are quite suitable as a supplementary lighting source. Looking ahead, these uniquely designed streetlights, equipped with solar modules, will become increasingly commonplace, transforming daytime sunlight into a new way to illuminate the night sky.