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Daily solar energy pickup

Falling  solar prices will lead to mass installation of solar energy, which will have a negative impact on distribution networks. There will be imbalance and oveto theoading of electricity supply networks. This had already happened in California in 2012

Anyone can be an electricity producer

It has already become a  frequent phenomenon that pensioners in Germany and Switzerland, the USA and other developed countries, invest in small solar plants on their plots instead of keeping savings in banks or real estate. Their calculation
is clear: energy needs will increase rapidly globally. Investors will have a certain inflow of funds from the sale of clean energy every year. In 7 years, their investment will be repaid, and they will have something to leave to their descendants. Their mini solar power plants are not large; they occupy the roof of the house or the space of an unusable part of the yard, or they can still be part of a
 carport or garage.

Daily solar energy pickup

Using the SPAC application, we will analyze this example. Let’s imagine a married couple of pensioners from Germany near Frankfurt who decided to invest in the installation of solar panels on the barn of their farm. Suppose they have a well-built barn with one side facing south-southeast at 10 degrees
east, and the dimensions of that part of the roof are 10m x 5m. After randomly selecting the panels, from the Chines manufactured   JA SOLAR with 400 Wp, that cost  $283.55  calculation tells us that they can install 16 panels with a roof utilization rate of 63%. 


Setting parameters for calculation

For that configuration, they need two inverters, for example, Growat.Investment and return are given in the image of the report that we get after entering the price of electricity (let’s set $0.152 per
kilowatt). Before we click the button for the final calculation, let’s see, for example, how much production is expected in April. We see that the production of electricity increases during the day and
reaches a maximum around noon, which is logical. 

Example: Investment and expected profit
Daily pickup from solar

Let’s assume that we have a lot of other investors who came up with a similar idea and that they all have maximum production around noon. What should be done with such a large amount of electricity? That leads us to the next step: Duck curve problem

What is the duck curve problem

The origin of the problem with uneven production of electricity from solar was registered for the first
time in California in 2012. A lot has been written about it. Until now, electricity producers have produced and delivered electricity to households evenly during the day, and at night when consumption was low, the price of electricity was lower. If we rely on the traditional production of electricity from fossil fuels, this is a logical approach. Burners in nuclear and thermal power plants cannot be switched off and on at will. Their production is constant during the day. The biggest consumers of electricity in the household are boilers, washing machines, refrigerators, air conditioners, and freezers, respectively. Cheap nighttime electricity was used to turn on household appliances that consume more electricity, such as washing machines and water heaters, during those hours. That’s how savings were made on household electricity bills. However, with the mass appearance of solar, there was a disturbance both in the price of electricity during the day and in the load on the electricity network globally.

More about Duck curve problem you can read there : Wikipedia, Energy Shift, Synergy


Methods for overcoming the duck curve problem (duck curve flattering)

There is no clear strategy to overcome this problem. For now, two main directions are proposed, which have shortcomings: Storage of excess electricity produced in high-capacity home batteries.This proposal requires investing in batteries and switching to a hybrid inverter, which is an additional financial intervention for the household budget. 

how to choose inverter   more about batteries) 

Global approach: converting excess electricity into some other form of energy that would be used at night. The main type of this procedure is pumping water to a certain altitude and then putting hydroelectric power plants (reversible) into operation at night. This intervention is not easily feasible because it requires a large amount of water reserves and hilly terrain due to the accumulation of potential water energy. 

Another global approach is the transfer of excess electricity to the west or east over several time zones. For example, excess electricity obtained by solar power at noon is transferred six time zones to the west, where the sun sets. This approach also requires huge investments in electricity distribution networks and is only partially applicable

Solar homeowners against Duck

Electrical appliances in households should switch to a new mode of operation: switching on at the time of peak production, when electricity is most available. This endeavor can already be carried out by setting timers on smart machines. However, further improvement of electrical devices that use heat engines (pumps), such as refrigerators, freezers, and cooling (heat) devices, is needed. They would have to have an additional heat storage system that they would use during the night (similar to thermal storage furnaces).



For now, this real problem with excessive electricity production in the midday hours is solved by turning off the solar panels. This is a necessary method of protecting the network from overload. Because, as I mentioned, it is easier to switch off a solar panel than a power plant combustion chamber.

Miroslav Mitić

Mechanical engineer and programmer for 25 years. Solar energy expert

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