How to Harvest Solar Energy on Cloudy Days

Image credit: SunModo

Talking about solar energy without sunlight, it is interesting to see how solar energy can be harvest on cloudy days. 

Even on cloudy days, there’s still solar energy send down to earth from the sun. And although solar panels don’t produce as much electricity as they do on sunny days, they have been shown to produce 25% of what they produce on a sunny day, or 10% when it’s very cloudy. The exact amount will vary depending on the density of the clouds, and may also vary by the type of solar panel - some kinds of panels are better at receiving diffuse light. SunPower solar cells, for example, have been designed to capture a broader range of the solar spectrum. By capturing more red and blue wavelengths, their solar panels can generate more electricity even when it’s overcast.

We may assume that solar panels thrive in hot, sunny weather, but too much heat can also reduce solar panel output 10-15%. The very hot climate isn't the best condition for them. Most solar panels' power outputs start to degrade if the temperature of the panel goes over about 25°C. 

Solar power can work well in areas known for cloudy, cold weather. For example, New York, San Francisco, Milwaukee, Boston, and Seattle. These cites often have bad weather, from blizzards to rain and fog. However, each of these cities tops the list of those that see major savings due to solar power installations. And rain helps to keep the panels operating efficiently by washing away any dust, pollen, and dirt. Clean panels turn out the most electricity.

San Francisco is well known for its foggy days with cool weather but rooftop solar power systems in San Francisco do function well. The amount of direct sunlight is reduced by fog and clouds, but as already was said, solar panels function better at cooler temperatures, so the electricity output in San Francisco is still significant. Using a home solar power system there can save approximately $1,500 per year on utility bills.

Germany is the fourth-largest PV market in the world that's famous for its lack of sunlight. Germany accounts for about 25 percent of the world's solar power output and achieved its strongest growth in half a decade during 2018, according to a recent Greentech Media article. 

Going solar is about saving on your energy costs as well as helping our planet and the weather can’t be an obstacle.

And if we choose to rely on solar panels for our home electricity use, we can also use a solar battery system to save money by storing free energy for use when it’s cloudy or for night use. Solar batteries have been around for a while, but up until recently, the costs were very high, the equipment was bulky and they were difficult to use. Except for people who lived off the grid, they weren’t so good investment. But that has changed in recent years. The price of solar batteries has dropped and in many cases, they are now an excellent investment for homeowners in cloudy regions who want to reduce their electricity bills.

Sources: Cleantechnika & Powerhome

                     

Solar PV Power in Cold Climate

Many people interested in generating solar PV power for their household power needs are also interested to know how PV solar panels operate at colder temperatures or in cloudy conditions. Actually, PV solar panels work better at colder temperatures - some of the best efficiencies ever recorded were at the South Pole! This is because the solar cells in the panels are electronic devices that generate electricity depending on the amount of sunlight they receive, not heat. In cold climates, PV panels will generate less energy in the winter than in the summer, but this is due to the shorter days and less sunlight, not the colder temperatures.

Photo credit: altenergy.blog-city.com

PV solar panels continue to work even in cloudy conditions, although they do produce less electricity. On days with cloud cover or windblown snow, the PV panels' output power is reduced significantly. With sun angles approaching the highest limits and visibility being high, the PV panels reach their rated output power.

Many countries in the northwestern region of Europe, including Denmark and the rest of Scandinavia, make extensive use of solar power. Germany is the world's leading installer of photovoltaic (PV) solar cells, although its climate is mostly temperate. Japan is also a major installer of solar PV panels, and their climate is temperate.

An example of integrating PV technology in the daily life are solar powered parking meters which are fairly common in Germany and the Netherlands. The electricity which runs them is supplied by small solar panels on top of the parking meters, right there in the streets.

Canada is another cold-weather country where PV technology is quickly gaining ground. PV cells have been used in Canada over the last 20 years or more for many applications. Photovoltaic modules were used as standalone units, mainly as off-grid distributed electricity generation to power remote homes, telecommunications equipment, oil and pipeline monitoring stations and navigational applications. Over the last few years PV technology has also started to be introduced into urban areas, incorporated into the roofs and facades of homes, offices and factories. And the largest solar PV energy park in North America will be located on approximately 300 acres of land in the Township of Stone Mills, Lennox & Addington County, Ontario. The 19-megawatt project, known as First Light, is being built by SkyPower Corp and SunEdison Canada. The construction is anticipated to be completed by the end of 2009 and local communities will benefit from clean renewable energy sufficient to power more than 2,000 homes annually.