Do self-sufficency equal to save money?

· PV Industry News

Rising energy prices are making the general public suffer, especially during the cold winter months. There are many ways to make your house more energy efficient , and we have suggested 8 in our previous article. But simply "cutting back" is not the answer. We also need to "open up" - to produce our own electricity. At the moment, the best way to "open source" is to install photovoltaic panels on your home.


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Is It Necessary To Pursue “Self-Sufficiency”? 

Self-sufficiency” in electricity consumption is what we want. This means reducing dependence on the public grid and consuming only self-generated solar energy for everyday use. So, can we say that the higher self-sufficiency rate, the better? 

It depends. But, increasing self-sufficiency has 3 advantages you probabaly want to know.

First is to save electricity costs. As electricity prices rise, using free, clean energy and drawing less electricity from the grid can save money in the long term. 

Second is to reduce Co2 emissions. Protecting the environment can also be a reason to be self-sufficient. To achieve that, you could reduce your own electricity consumption and adapting to the production cycle of PV systems. 

Third is to use electricity freely. You can turn your house into a green power plant by installing PV, while being protected from regional power outages and power restrictions. 

What Is Good Self-Sufficiency?

Cost-effective is always the point of self-sufficiency or not.

For private customers, the morning and evening are the peak times for electricity consumption, while the PV system generates most of its power in the middle of the day.

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But buying PV with energy storage seems like an expensive investment. So, is it worth it? 

In my opinion, energy storage is the trend of the future. We know that the cost of using PV is made up of investment in equipment, installation costs, maintenance costs and power purchase costs. Revenue is made up of feed-in tariffs and electricity savings.

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Let’s take the example of a single household in Germany consuming 4000 KWH of electricity per year. A 5KW PV module and a 5KWH storage tank would be sufficient, saving approximately €800 per year, which is expected to pay for itself in 10-15 years. At the same time, the price of electricity storage has fallen by around 80% since 2011. It is believed that the future self-sufficiency of PV will be even more cost-effective. 

From low self-sufficiency to 100%, which PV system is the better choice?

There are three mainstream PV systems: on-grid system, zero feed-in system and off-grid system, which benefit different users.

Speaking of on-grid system, it’s commonly found on the rooftops of private homes, connected to the public grid. With the help of energy storage, the self-consumption can be increased to as high as 75%. One of its major advantages is that it can generate a stable income from the feed-in, but since the feed-in price is much lower than the price of electricity, increasing the self-consumption and self-sufficiency is the more economical option today.

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The second is Zero feed-in system which is used in households with high electricity consumption and must have energy storage systems. Although connected to the public grid, they are not used to feed electricity into the grid, but only to purchase electricity from the public grid. Such a system can rely more on solar energy, and in addition there are no feed-in costs such as calibrated meters. However, the drawback is the lack of profit potential and poor scalability. 

The third is off-grid system with 100% self-sufficiency. They are commonly found in remote mountain cabins, electronic road signs, etc. off-grid systems are often used when connection to the grid is not possible or too costly. In addition they can be used as emergency generators. Because they are not connected to the grid, they require larger storage sizes, which results in relatively high acquisition costs.

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Therefore, in order to achieve cost-effective self-sufficiency, choosing a suitable size of energy storage is important! 

The size of the storage capacity depends on the power of the PV system as well as the power consumption for individual use. Simply increasing the storage capacity does not effectively increase the self-consumption. An example is a 5 kW PV system installed in a home with an annual electricity consumption of 4,500 kWh. We can see that as the storage capacity rises to 8 kWh, the increase in self-consumption slows down significantly.

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In common, storage capacities of 0.9 to 1.6 times the PV capacity, but the size still needs to be selected according to users habits. 

However, what is needed to increase self-sufficiency for those who do not have energy storage? 

In short, it means consuming as much electricity as possible When there is sufficient sunlight. For example, to use the washing machine’s timer to wash the laundry in the midday hours.

In Conclusion

Self-sufficiency describes the ability of a solar system to meet the electricity consumption of the system owner. The higher the degree of self-sufficiency, the less power is drawn from the grid.

There are a number of ways to increase self-sufficiency with or without purchasing energy storage tanks. In most cases, however, it does not make economic sense to strive for a higher level of self-sufficiency. This is because it would require much larger power storage, which would result in very high acquisition costs. 

In common, storage capacities of 0.9 to 1.6 times the PV capacity, but the size still needs to be selected according to users habits. 

As a PV module manufacturer with 14 years of expertise, Maysun Solar is ready to partner with you to help the energy transition. Contact us to open the door to green energy.