Harnessing the Moon: How do solar panels work at night
- 02 Aug 2023
- 4 min
Solar panels have become synonymous with sunlight. But what happens after the sun goes down? Do solar panels work at night? Let’s shed some light on this somber issue.
Not quite a nocturnal creature
Solar panels are designed to capture and convert sunlight into electricity using the photovoltaic effect. At night, there is no sunlight, which is clear. What the night has to offer is moonlight, but it is much dimmer and has significantly lower energy. The intensity of moonlight is around 400,000 times fainter than direct sunlight on a clear day. So, solar panels cannot recognize and absorb it.
However, some experts believe that panels might produce at least 10W a night. It will be enough to keep the light on in the bathroom all night.
Daytime for harvest, nighttime for usage
In a grid-connected system, having no solar production is not a big problem because you can draw some power from the grid at any time. Electricity rates at night are usually lower anyway so your bills don’t grow as fast.
You can always go for some battery solutions to store the energy you have harvested during the day. There are off-grid and hybrid solar systems that comprise storage batteries. The principle is very simple: during the daytime solar panels generate energy, part of which is stored to be used at night or during power outages.
Best solar storage solution
There are two main types of solar batteries: lead-acid and lithium. The latter are undisputed leaders: they have a 85-95% efficiency (compared to 60-80% of lead-acid batteries), they last up to 10 years and their depth of discharge (DOD) reaches 100%.
Solar Installation Expert
The only problem I see with lithium-ion batteries is their high cost. It ranges from $2,000 to $15,000, while you can always find a lead-acid battery for less than a grand.
One of the most popular solutions with clients is a modular backup. Generac offers DC solar batteries with a storage capacity from 8.6kWh to 17.1kWh. They can be nicely fit in a special battery enclosure: from three to six batteries. As power needs grow, you simply add new modules to the cabinet.
Benefits and drawbacks of using stored solar energy at night
Well, here’s what we’ve learned so far. First, solar panels do not work at night. Second, you can still use solar energy stored in batteries. But is it always the best solution? Let’s take a look.
• Uninterrupted power supply. Solar energy storage systems provide a reliable backup at night or during power outages, reducing dependency on the grid.
• Environmentally friendly. Solar batteries help maximize the utilization of clean, renewable energy, reducing greenhouse gas emissions and contributing to a greener, more sustainable planet.
• Peak time energy usage. Using stored solar energy during peak electricity demand periods, like in the evening, allows homeowners to avoid higher energy costs.
• Initial cost. The upfront cost of installing solar energy storage systems can be relatively high, almost doubling the overall system price.
• Efficiency loss. Energy conversion and storage processes may result in some energy loss, reducing the overall efficiency of the system.
• Maintenance and replacement. Batteries require regular maintenance and eventually need replacement, adding to the overall cost of the solar energy storage setup.
Having batteries is mandatory when you go for an off-grid solar system. How do you size your battery bank correctly though? Read about it in our article: “How many batteries does it take to power a house?”
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