Solar Self-Consumption Analysis with PVSyst: Importing and Analyzing Consumption Data

Solar self-consumption analysis is essential for anyone looking to maximize the value of their solar PV system. As feed-in tariffs have declined and the value of exporting electricity to the grid has dropped, analyzing and optimizing how much solar energy you use on-site has become crucial.

Today, maximizing the use of your own solar energy—rather than sending it to the grid—can significantly reduce your electricity bills and improve your system’s return on investment. This shift has made it essential to analyze and optimize self-consumption, often by adjusting when and how you use electricity during the day.

In this guide, I’ll show you how to import your consumption data into PVSyst and analyze self-consumption, so you can design a solar PV system that’s both efficient and cost-effective.

Why Solar Self-Consumption Analysis Matters

• Financial benefits: Energy you self-consume directly offsets retail electricity costs, which are typically higher than feed-in tariffs
• Grid independence: Higher self-consumption means less reliance on the utility grid
• System sizing: Proper consumption data helps you appropriately size both your PV system and potential battery storage
• Return on investment: Maximizing self-consumption often leads to faster payback periods

For commercial buildings or facilities with significant daytime loads, designing for optimal self-consumption can dramatically improve the economics of your solar investment.

What You’ll Need

• PVSyst 8 (download the trial version from pvsyst.com if you don’t have it)
• Your energy consumption data in spreadsheet format (hourly or daily values)
• Basic understanding of PV system design concepts

Step 1: Install and Set Up PVSyst

1. Download PVSyst 8 from the official website
2. Follow the installation wizard to complete setup
3. Launch the program and create a new project (File → New Project)

Step 2: Create a New Project and Simulation Variant

1. In the main PVSyst window, select “Project” and click “New”
2. Enter a project name and select your location
3. Choose appropriate meteorological data for your location
4. Navigate to the “Variant” tab and click “New” to create a simulation variant
5. Here is a great video explaining how to create your first project: PVsyst 8 _ My First Project (Grid Connected System)

Step 3: Prepare Your Consumption Data

There are two option to load your consumption data into PVSyst.

• Option 1. Generate a graph showing the average power consumption per hour and manually define a weekly load profile in PVSyst.
• Option 2. Transform your consumption data in a format that can be imported in PVSyst and import it.

Option 1 is much simpler and give a good enough idea of what your energy self consumption will be. Option 2, can get complicated to get the data in the correct format and one need a whole year worth of data as PVSyst only does calculations for the period of the year that the data is available for.

Step 3.1 Option 1, define a weekly load profile.

You can generate graphs from your consumption data or make use of this template that we created to generate graphs. Generate the average daily energy load profile for weekdays and for weekends. Once you have these figures you are able to enter it manually into PVSyst in the next step.

Example weekday load profile

Hour	Average Power (W)
0	4450
1	4933
2	4485
3	4596
4	4494
5	4538
6	3810
7	2476
8	4743
9	5902
10	7022
11	7058
12	6885
13	6490
14	5013
15	5094
16	5480
17	7632
18	5947
19	6600
20	6574
21	4381
22	3767
23	3729

Step 3.2 Option 2, load .CSV data into PVSyst

PVSyst requires consumption data in a specific format:

1. Open your energy consumption data in Excel or another spreadsheet program
2. Format your data with the following structure:
   • Column 1: Date/time (PVSyst accepts various formats)
   • Column 2: Power values in kW or energy values in kWh
3. Important formatting requirements:
   • Use consistent time intervals (hourly is recommended)
   • Ensure there are no gaps in your data
   • Use decimal points, not commas (e.g., 1.25 not 1,25)
   • Remove any headers or extra information
4. Save your file as CSV (Comma Separated Values)
5. A few example template CSV files are included with PVSyst and should be available under this folder on your PC: “Your User FolderApplicationDataPVSystPVsyst8.0_DataTemplates“

Example of properly formatted CSV:

Date;Load
01/01/2025 00:00;0.421
01/01/2025 01:00;0.398
01/01/2025 02:00;0.375
...

Step 4: Configure Self-Consumption in PVSyst

1. In your project variant, look for the “Self-consumption” button in the “Main parameters” section

Step 4.1 Manually defining a weekly load profile

1. Click on “Daily Profiles” then on “Weekly modulation“

2. Click on “Daily Profiles tab” then on enter the hourly values as calculated for week days.
3. In the dropdown box in “Show values of” select “Week-Ends”, enter the values for the week end days. 

Step 4.2 Importing a .CSV file (If using this option)

1. Under “Kind of load profile,” select “Load values from a CSV hourly/daily file”
2. Click “Choose CSV file” and navigate to your prepared consumption data
3. Once loaded, you’ll see a confirmation message with your average daily consumption

Step 5: Complete Your PV System Design and Run the Simulation

1. Configure your PV system parameters:
   • Define orientation and system components
   • Set up your PV array and inverter specifications
   • Configure any additional parameters like detailed losses
2. Run the simulation by clicking the “Run Simulation” button

Step 6: Analyzing Self-Consumption Results

After simulation, access your self-consumption data:

1. Go to the “Results” section and click on “Detailed results”
2. Select “Tables” from the right sidebar

1. Choose “Energy use and User’s needs” from the table options

1. Click “Table” to display the results

You’ll now see a table with the following key metrics:

• E_Avail (kWh): Total solar energy produced by your PV system
• E_User (kWh): Energy directly consumed from your solar production – this is your self-consumed energy
• E_Grid (kWh): Excess energy exported to the grid
• SolFrac (ratio): Solar fraction – the percentage of your energy needs covered by solar
• PR (ratio): Performance Ratio of your system

Understanding Your Solar Self-Consumption Analysis Results

Let’s break down what these numbers mean for your project:

Key Metrics to Focus On:

1. Self-Consumption Rate: Calculate this by dividing E_User by E_Avail. This shows what percentage of your solar production is used on-site.
2. Solar Fraction (SolFrac): This shows what percentage of your total energy needs are covered by your PV system.
3. Monthly Variations: Look for seasonal patterns in your self-consumption. You might see higher SolFrac values in summer months when solar production is higher.

Example Analysis:

If your yearly totals show:

• E_Avail = 13,186 kWh
• E_User = 1,000 kWh
• E_Grid = 12,573 kWh
• SolFrac = 0.613

This means:

• Your self-consumption rate is only 7.6% (1,000 ÷ 13,186)
• 61.3% of your energy needs are covered by solar
• 92.4% of your solar production is being exported to the grid

This indicates your system is significantly oversized for your consumption needs unless you’re intentionally exporting to the grid for revenue.

You can export this results to Excel and calculate all the information you  need and generate graphs. To export the table to Excel, click on “Export” then click on “Copy to Clipboard” then paste the data in Excel. From there you can calculate the “Solar Energy Used” as self-consumption energy.

From this data you can generate a various graphs like the following:

Optimizing Your System Based on Results

Based on your self-consumption analysis, consider:

1. Adjusting system size: If exporting most of your production, you might want to reduce system size unless feed-in tariffs are favorable
2. Adding battery storage: Batteries can increase self-consumption by storing excess daytime production for evening use
3. Load shifting: Moving consumption to daylight hours can increase self-consumption without additional hardware
4. Economic evaluation: Use PVSyst’s economic evaluation tools to compare different system configurations based on self-consumption rates

Advanced Tips

• Hourly Graphs: For deeper analysis, use the “Hourly graphs” feature to see the relationship between production and consumption at specific times
• Custom Reports: Generate custom reports focusing on self-consumption metrics
• What-If Scenarios: Create multiple variants with different consumption profiles to model various scenarios

Schlussfolgerung

Understanding and optimizing self-consumption is crucial for maximizing the value of your solar PV system. By properly importing your consumption data and analyzing the results in PVSyst, you can make informed decisions about system sizing, battery storage, and potential load shifting strategies. This approach allows you to design solar systems that aren’t just technically sound but also economically optimized for each specific use case.

Have you used PVSyst for solar self-consumption analysis? What insights did you gain from the process? Share your experiences in the comments below!

---

Want to learn more about PVSyst? Check out these recommended training videos:

• PVsyst 8 – My First Project (Grid Connected System)
• PVsyst 7 – Self Consumption (Grid Connected System)

Frequently Asked Questions about Solar Self-Consumption Analysis

What is solar self-consumption analysis?

Solar self-consumption analysis is the process of evaluating how much of your solar PV system’s energy production is used on-site versus exported to the grid, helping optimize system design and financial returns.

How do I perform solar self-consumption analysis in PVSyst?

You can perform solar self-consumption analysis in PVSyst by importing your consumption data, configuring the self-consumption settings, and reviewing the simulation results.