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In the next week or so, I will write some articles that break the solar myth, because if I have learned from 25 years of Internet use, it is easier to complain about something than to try to do something useful. Today, I am solving the problem of solar output during the winter in Australia.
Internet commentators told me that as far as my Internet face is concerned, solar energy does not work in winter. These statements don't even have conditions, exceptions, and warnings. They are bald lies facing the Internet. Although my initial reaction was to roll my eyes vigorously, I could count all my four brain cells1 and ignore these idiots, but if I didn't object to them, their nonsense might infiltrate people's brains.
To prevent idiots from infiltrating people's brain cells, I will show...
When you finish reading this article, your brain should be able to resist idiots. This is because the idiot exposed to me is like a vaccine.
It is easy to see solar energy working in winter. This is the daily power generation of the 10.56 kW solar system in Adelaide since it was launched in early April:
As you can see, although some days are clearly better than others, few days produce zero solar energy. This includes the winter of June, which is the worst month for solar production in most parts of Australia. The worst day was June 12, when only 8.3 kWh was produced. This is 19% of the average daily output of a system of this size in Adelaide. Only 19% is not very good, but if "solar energy does not work in winter" is true, it will provide an infinite number of 0 kWh.
Although July is the coldest month, in most parts of Australia, June has the worst solar output due to the winter solstice. This is the shortest day of the year. It is usually the 22nd, but this year it is the 21st.
If you are considering using solar energy, the winter solstice is the best time to check if your roof is obviously shaded by nearby trees or buildings, because the shadows are the longest. If your roof has no shade during the winter solstice, it will have no shade all year round—unless you have some fast-growing trees or buildings nearby.
This is a graph showing the average daily power generation of a 6.6 kW north-facing solar power system and its average daily power generation in each Australian capital in June:
Darwin’s solar output is higher in winter than in summer. This is because:
In other capitals, June’s figures are much lower. As a percentage of the annual daily average, the June daily average is:
The further the city goes south, this percentage will decrease. Hobarts live the worst in winter, have the lowest total power generation, and have the largest relative decline. For those who agree with some modern theories about the shape of the world, this is not surprising.
But winter is not all bad for Hobart.
No, wait, all this is terrible. If you consider the average electricity consumption in winter, Apple's capital is even worse.
The figure below shows the average daily electricity consumption of each capital in June compared with the average daily output of an ordinary 6.6 kW north-facing solar system in June:
In Darwin, Brisbane, Perth and Sydney, solar power generation in June exceeded the average household electricity consumption on average, but there was a gap in other capital cities. The mainland capital with the biggest power shortage is Canberra, thanks to its high power consumption in the cold winter. But the worst capital city so far is Hobart, where the average solar output of a 6.6-kilowatt solar system accounts for only 37% of the average household consumption.
The easiest way to improve this is to install a larger solar system—provided that there is space on your roof. Under the same conditions, a 10 kW solar system will provide 52% more energy than a 6.6 kW solar system. If you can't choose more solar panels, you can consider alternatives, such as improving the gaps, glass and insulating materials in the house, using energy-efficient reverse cycle air-conditioning for heating, or trembling violently.
When a boring sadist on the Internet tried to find someone to annoy him and said that solar energy didn't work in winter, there was a small piece of real corn hidden in this foul lie. Although solar energy is certainly effective, there will be a few days of poor output. Below I have created a chart showing the worst day so far this year, the output of a 6.6 kW north facing solar system. The numbers below are only approximate values, because I got them by observing the curve-I usually don't do this 3:
So far this year, Darwin, Brisbane, Perth and Adelaide have not experienced a bad day, but Canberra's daily output is very low, and Sydney, Melbourne and Hobart have all experienced terrible dark days. Although a day with low solar output is not good, if you connect to the grid, it is not a disaster. Even if you are off the grid, the good news is that periods of abnormally low solar output usually don’t last long, as shown in the first chart near the top of this article, which shows the daily output of solar systems in the past three calendars moon.
However, if you are off the grid, you must be prepared for the unusually severe weather and/or high power consumption.
There are four main ways to solve the problem of low winter yield. If I had to sum up everyone in one word, I would describe them as:
But, thank goodness, I have a lot of words here, so there is no need to be too concise.
1. Moving north: Approaching the equator can reduce the angle at which the sun shines on the clouds in winter. This will cause Brisbane, otherwise the same cloud cover, to reduce solar output less than Melbourne. However, due to the high cost of moving, most people don't think this is a practical method. If you travel to the far north, you will have to fight for territory with giant spiders.
2. Increase the tilt of the panel: The panel can be tilted to maximize its winter output. This may be a brilliant idea for off-grid systems installed on the ground. But because the inclined rack on the roof is a major expense, rooftop solar panels are almost meaningless. The ideal angle (from the horizontal direction) to obtain the maximum winter output from the north panel is:
3. Purchase batteries: Install batteries to store excess solar energy for use on days with poor output. Although it is not currently cost-effective, hopefully we don’t have to wait a long time to make it financially meaningful.
4. Install more solar energy: Installing more solar panels allows you to generate more electricity, not only in winter, but also throughout the year. For most households, this method will provide the best financial return due to annual savings in electricity bills. But unless you live in the far north, the yield of south-facing panels will be particularly low in winter.
5. Reducing electricity consumption in winter: a penny saved... hardly worth the effort. But improving your home’s thermal envelope through better insulation and sealing gaps, or using energy-efficient reverse cycle air conditioning for heating, can save hundreds or even thousands of dollars each year.
Hope I have convinced you that solar energy works in winter. The combination of large solar energy and high thermal efficiency houses will bring a pleasant low winter cost and a comfortable home, allowing you to spend the days when the Australian winter is not particularly dark.
Ronald Brakels was born in Toowoomba many years ago. When his township collected a collection and sent him to Japan, he became famous internationally for the first time. This was the furthest place they could manage with the funds raised. When the local mayor greeted him at the airport and explained that it was too dangerous for him to return to Toowoomba due to climate change and mutations attacking goats. After returning to Australia, he developed a keen interest in environmental issues. Ronald then moved to a property in Adelaide Hills, where he now lives with his horse Tonto 23.
At least here in Brisbane it is balanced.
The reverse cycle air conditioner heats up to 20°C from 7pm to 7am in winter (about 3 times higher than the cooling efficiency), plus the almost cloudless sky, our energy costs are zero.
In summer, the temperature drops to 26°C in the late afternoon and at night, only occasionally overnight on very humid days, we are still at nett Credit back then.
"Internet commentators told me that as far as my Internet face is concerned, solar energy does not work in winter."
I want to know how they think about Tooth Fairy, Santa Claus or climate change? Since June 2009, I have kept a daily spreadsheet record that shows power generation, consumption, and more importantly (for me) my panel supply as a percentage of consumption.
Everyday generation. In the past 12 months, I did not generate electricity one day. That was because I had to rewire my meter box, so I completely disconnected all the connections.
Percentage of monthly consumption. Even though I own three electric or hybrid cars that get all their electricity from solar energy, in the past three years, I have only one month (including June 2021) of solar panels to meet less than 60% of my household needs for the past three years Power.
The monthly generation. In the past 7 years, only one month my panel generated less than 100 kWh-and that month was June 2021.
Of course solar panels work in winter.
I think the degree of "mythology" about the "solar panels don't work in winter" story depends on where you live.
In the northern hemisphere, about 1 billion people rely on a lot of heat to spend the winter, and at the same time of the year, the sun hardly leaves the horizon for more than a few hours a day, and the total output reaches 20 to 30 full load a few months a month Hour.
In the other half of the year, the panel generated amazing energy...but we don't need much. It is light enough to read from 5:00 in the morning to 10:00 in the evening. Although it may reach 35 C in the afternoon, the family room in the basement will reach 23 C.
This is a corner case that will benefit you. The story of "solar panels not working in winter" is very convincing in the Arctic Circle, even south of the Arctic Circle, where solar panels may have 1 foot of snow. But my brother calls me every week from Sydney, and his 19 kW system has been meeting domestic demand and exported all afternoon, all winter so far.
In Dandenongs, we had no main power supply in the second half of June and no internet for 8 weeks. Self-sufficiency cannot be underestimated. My mantra is: more roofs, more panels!
The seasonal variation at 52 degrees latitude ranges from 300 kWh per month in December to 1500 kWh in summer. From 10 KWp system
Yes, snow and ice on the panel may be a problem, but the biggest impact is the simple geometry and the tilt of the earth.
Sydney is around 33 degrees, and the Arctic Circle is around 66 degrees, so the ypur friends are still closer to the equator than the polar regions.
One billion people living in the high latitudes of the northern hemisphere between 40 and 50 degrees may be surprised to find that they are "edge cases," because a billion is a lot of people, and the earth is more like a sphere than a flat surface.
I am also struggling with the dilemma of ignoring the trolls spreading BS or fighting with them. The former will treat my blood pressure much better
Yes, for my old 2.5kWp system, things have been very bad in Adelaide in the past two weeks. But I am very happy to tremble violently. I postponed the activation of the heat pump this winter in a strange self-imposed pursuit. The crankcase heater has been warmed up and ready, but so far I have been very determined.
D2 left the lair last year and SWMBO was ecstatic about her passion for throwing gifts. Unfortunately, my furry foot warmer abandoned me for my wife's heating blanket. traitor.
So far, the combination of our solarium, beanie and relatively efficient living area is enough to delay any mechanical heating, and we expect net electricity in June to be approximately 35 kWh
I live in the Adelaide Hills and thought for a while we tend to design solar systems suitable for roofs, but never (almost never) have designed a roof suitable for solar panels, let alone for winter rather than summer Design the system. Therefore, the east-west blocks have long north-facing roofs with a pitch of 45° to 60°, and the roof space is used as the second floor. By heating the heat pump cycle to a high thermal quality plate, one can spend a bad day or two with the system shut down! Thanks, great post.
Solar energy works in the winter in Australia. This is not necessarily the case in other regions. For example, there are too many clouds in the United Kingdom (52North), and almost no output is recorded in cloudy or sunny days [Warning: fixed angle installation]
I want to add (I know you have discussed it elsewhere) if you are looking for the lowest cost, "filling up your roof" does not need to include an additional (relatively expensive) inverter, because you have an existing inverter The extra power is cut when it is not needed. Regarding the tariff feed, there are some complicated calculations to be done, I just simply do...
For me, the key question is why we are not allowed to connect more solar panels to the inverter. In my case, the nominal 10kW of the inverter only really limits the output during the noon period of about 4 to 5 months. I simulated that I can easily add about 25% to 40% of the panels to the string in 6 months without violating the inverter's maximum capacity of 13.33kW. This investment will have a great return for me and the environment, and there will be no technical defects-if we are allowed. Think about the installed capacity of inverters across the country. I feel sick if I use less in winter! But maybe this is what our government wants.
I suspect this is to make it easier for the grid to balance the supply/load of all three stages, because your ordinary family home is only connected to one stage.
I have no evidence and no engineering background to investigate (I am just a humble electrician), but this makes sense when you consider that three-phase operating buildings do not have the same restrictions. With a three-phase photovoltaic system, it is much simpler to balance the energy produced by all phases!
Unfortunately, we don’t have a vaccine against stupidity.
The "Average daily power generation of a 6.6 kW north-facing solar power system vs. June's average daily power generation" chart is quite interesting and informative, but I am not sure how to convert it to a 10 kW inverter system. Is this just a doubling of statistics? This is still not correct for me.
As a solar novice, I don’t have any complete months to compare, but here are my east-west + north system data for June, in case anyone is interested and/or use them:
Worst day so far this month: 11.9 kWh (Uh!!!) Best day so far this month: 51.5 kWh
The average daily power generation in June claimed by the installer: 32 kWh
Actual average from June to present: 42.7 kWh
Average production in May (partial months): 45.9 kWh
I'm still trying to determine if I have a flat increase over the installer's estimate-the most beneficial in winter, or a percentage increase-the most beneficial in summer.
In any case, according to the data I have seen, solar power is pretty good in winter-most of the time.
The size of a 10-kilowatt system is 152% of that of a 6.6-kilowatt system, so under the same other conditions, it will generate about one-third of the energy. Note, however, that the numbers in the article apply to solar energy facing north. The production in the east and west will be a little less.
I don't know where you are, but it looks like your system is running well in winter.
Ah sorry, I should say inverter, not inverter system-my fault. Our goal is 13.3 kW panel + 10 kW inverter, but we cannot fully manage the roof space, so there is a "non-standard" size version.
Yes, I know North=/= East\West. I'm not sure if North is always 15% better than East\West, or whether it depends on the month, but I am still satisfied with how our system matches your North number.
I'm a little north of Brisbane, but I think the results I got are better than what your graph shows. 🙂
So far, my 10.8 kW system in Canberra has produced 500.9 kWh in the first 20 days of June. Well, not as much as we consume, and not as much as the 1,191 kWh generated in the first 20 days of January, but it is still better to have 500 kWh than nothing!
I have a 2kw system and 8kw lithium battery on my truck. There is no other power source. This is indeed a difficult month. I am glad to know that the worst has passed because I was hiding in a small room with a 13-inch battery. The laptop and a lamp for such a long time are a bit close to what I call roughing.
Coincidentally, today is the first full sunny day in at least two weeks, and I am now at 100%, so I have time to turn on the large external monitor/stereo and subwoofer for some movies tonight🙂
In colder months, the negative temperature coefficient of solar cells also significantly improves efficiency.
Be careful when using EXCEL to generate charts to illustrate one point. The vertical scale of the middle series of your first chart is different from the other two. This is something generated by EXCEL auto-scaling. In this case, it's not much, but manual scaling can make them exactly the same. This will completely avoid any accusations that try to mislead, and is good scientific practice.
RE: If there is a way to tilt the panel to the level you recommend, do you estimate it will increase?
Excellent article. We have entered the third year of using solar energy from batteries. I was surprised by the low net usage. Last month, the EW of our 5Kw system in Adelaide was about 30 Kwh. The net input is negligible, but we obviously get a lot of solar energy. Although the cost of the battery is still not feasible without some useful rebates, solar energy in winter is still quite good, and if you have a plan, it will never be cancelled...😎👍
Yesterday our shortest day in Adelaide received 9kWh from an old 2.5kWp array and 17kWh on a good summer day
Yes, solar energy works very well in winter
Good article Ron but... please mark the axis. The horizontal (x) is obvious, but the vertical should be clearly marked as kWh. Hope this will help educate some people (especially media writers) to understand the difference between power and energy.
I live in Rockhampton in central Queensland and installed a 6.6 kW solar edge system about 18 months ago. Due to the roof style, I have 3.6kw for NE and 3.0kw for sw. In the past 12 months, my system has generated an average of 790kwh per month, totaling 9500kwh throughout the year. In the past 3 months, I averaged 620 kWh per month
Some strategic logging was carried out in April, and now our June output has increased by 10kWh/day compared to the same period last year. The shade can absorb the life of winter solar energy!
I did more than 5kWh/kW in January and June, and only 2.37kWh/kW, which is less than half. Due to its large size, it still has a peak of 7.4kW in sunny days, but has a flat 10kW for 5 hours in summer. It's certainly worth a try, but this is one of the reasons I installed it in September, just before the cash season. Covering the entire roof, so tilting is not an option, it may be the last row, but it may increase compared to the cost of the rack, so it is not worth installing. In general, since my meter was registered and moved to Origin, I have been in credit status (somehow, all retailers only provide reasonable quotations up to 5kW), the credit limit in June is 2 US dollars, I may be in First payment in July. However, only when my house decides to turn on the heating because I leave these decisions to my house😛
Every year, my electricity bill is reduced by half during sunny days and winter hours, 60% capacity and 10% capacity in cloudy days
We live in Melbourne and purchased a 6.6kw system (22 panels) in January 2019. So far, it has worked well and I am happy to purchase it. Our north and west are affected by some shadows, but overall it is positive.
June = 11.78kwh July = 11.89kwh. (We suspect this is due to greater cloud coverage in July) December = 33.81kwh
Regarding winter solar work, we have negative values in June and July (average consumption> average output). Also due to the low FIT relative to the grid price, our financial position in May and August was also negative.
Because we consume 65% of the total electricity from the grid (mainly at night), what we really need are batteries, but they are still too expensive for us at the moment. This will have a huge impact on us, especially in winter.
Please keep the SolarQuotes blog constructive and useful through the following 4 rules:
1. Preferred real name-you should be happy to add your name to your comment. 2. Put down the weapon. 3. Assume positive intentions. 4. If you are in the solar industry-try to understand the truth instead of selling. 5. Please keep the theme.
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