Is it worth installing a solar energy system at home? Part 2

Is it worth installing a solar energy system at home? This is a question that, in order to provide an appropriate answer, we are analyzing various parameters for you.

In order to give you a complete overview of the topic we are addressing, we invite you to read the article Is it worth installing a solar energy system at home? Part 1.

Here we will address the most obvious disadvantage of photovoltaic systems. It consists of the fact that they cannot generate electricity during the nights, and their performance is significantly reduced on cloudy days.

Additionally, due to the availability of sunlight based on sunrise and sunset times, the solar energy system alone cannot meet the electrical demand at certain times of the day.

As this is the most critical disadvantage, we have decided to create a post exclusively dedicated to it. It is called Disadvantages of the solar energy system and reading it will be very beneficial for you.

What is electricity demand?

Electric demand is the factor by which electric companies determine your consumption and charge you accordingly.

It is expressed in kWh (kilowatt-hour), which represents the amount of watts divided by 1000 consumed during one hour.

To illustrate this concept, if the average electric demand of your home between 8:00 PM and 11:00 PM is 15 kWh, then the consumption would be this value divided by 3 hours, resulting in 5 kW.

These average electric demand values are added to obtain a daily average, which is then multiplied by 30 to obtain the monthly consumption. You should know that the electric company uses the highest demand for billing.

If you want to know the electric demand of your home, there are two ways. The most accurate but cumbersome way is to take note of the electric consumption of each of your appliances. Then, you multiply it by the hours of use and add them all up. This will give you the daily value..

Finally, to get the monthly value, simply multiply this number by 30.

The simpler way is to take this data from your electricity bill, as shown in the image below.

What is the disadvantage of the photovoltaic system regarding not producing enough electricity during the peak hours of household electric demand?

Several studies have identified the highest electric demand of households during the approximate hours between 07:00 AM to 09:00 AM, 12:00 PM to 02:00 PM, and 08:00 PM to 11:00 PM.

During these times, family members are typically at home, and it is understandable as it is when electrical appliances such as heating, air conditioning, washing machines, lights, entertainment devices, clothes dryers and others, are commonly used.

In the graph below, the household electric demand is indicated in red. The rest of the time, these values are relatively low as families are usually at their workplaces or schools.

On the other hand, the electricity generation by solar panels starts to become significant from around 10:00 AM to 05:00 PM, depending on whether it is summer or winter. This trend is depicted in green in the graph provided below.

As you can observe, the problem lies in the fact that when the solar energy system is at its peak electricity generation, the household electric demand is at its lowest, and vice versa.

So, what can be done? Let’s see.

Possible solutions

a. Install a hybrid photovoltaic system that can provide electricity from the commercial grid when the electric demand exceeds the energy that the photovoltaic system can generate at certain times.

b. Change consumption habits; with current automation, it is possible to schedule some appliances such as dishwashers, washing machines, clothes dryers, coffee makers, etc., to operate during the period of highest solar system production.

c. Add a battery system to the solar energy installation, which, although increasing the cost, will guarantee you access to electricity at any time of the day without depending on the commercial electric grid.

In our upcoming post titled Is it worth installing a solar energy system at home? Part 3, , we will analyze the feasibility of these proposals and choose the best among the three.

For a better understanding of this topic, we invite you to read our previously published posts in the Solar Energy category on our website, energydcac.

If you have enjoyed this article or have any questions, feel free to leave your comments or contact us. It will be our pleasure to respond to you.

Image sources

• energydcac.com
• totalenergies.es