Analysis of the Benefits Associated with the Development of Photovoltaic Self-Consumption Systems.

In the coming years, significant growth is expected in the development of photovoltaic self-consumption systems for installation and use across all sectors, including commercial, residential and industrial applications. Photovoltaic self-consumption systems can significantly reduce electricity bills for end users of these installations. However, an advanced technical analysis of the development and implementation of these systems is required, taking into account the benefits associated with their correct and accurate sizing. This enables the efficient use of the technology and more appropriate and optimal payback periods for the end user. The proper development and integration of photovoltaic self-consumption systems require in-depth knowledge and extensive analysis of the actual circumstances of the electricity consumer or end user of the installation, in order to maximise the savings that these systems can achieve and thus attain high levels of efficiency and savings in electricity consumption.

With the new electricity tariffs introduced on 1 July 2021, electricity prices for low-voltage consumers are divided into three periods: peak, off-peak and standard. The peak period runs from 8 a.m. to 2 p.m. and from 6 p.m. to 10 p.m., when the highest prices apply. Therefore, any consumption during these periods can significantly increase the electricity bill for low-voltage end users. This is where self-consumption systems with photovoltaic modules can provide significant savings, as many hours of the solar irradiance curve coincide with the peak-price periods. However, it is important to carry out a rigorous analysis to ensure the correct sizing of the peak power to be installed, the number of panels required and the way they are electrically connected to the other components of the system, particularly the selected inverter.

Our analysis must take into account factors relating to the shape of the end user’s consumption profile, based on a rigorous study of the consumer’s historical daily load profiles over recent years, as well as an analysis of their consumption habits, types of loads or electrical equipment connected, peak power levels, number of hours of use, etc. In this regard, we also consider differences in consumption between seasons or periods of the year, since the use, for example, of air-conditioning equipment in summer or electric heating in winter can result in significantly different profiles. It is also necessary to analyse the days of the week, as in many cases the consumption profile differs between weekdays and weekends. Another factor taken into account is any increases in consumption that the user may anticipate in the medium or long term, since the service life of a properly sized photovoltaic solar installation for direct self-consumption can easily be around 25 years. All this analysis is essential when establishing an efficient and effective installation design that enables the end user to achieve the greatest possible savings on their electricity bill each month.

Our expertise and knowledge in the correct and efficient sizing of photovoltaic solar self-consumption systems can be applied to all three electricity consumer sectors: residential, commercial and industrial.

Our advisory, analysis and photovoltaic installation design services can be aimed at both project offices and engineering firms, as well as companies installing electrical and renewable energy systems. We can also provide direct advice to small low- and medium-voltage consumers, as well as commercial and industrial businesses. Our technology offer and consultancy services for the efficient design of these systems therefore cover all areas and sectors involving low- and medium-voltage electrical installations.

There are currently separate devices that perform specific functions, such as photovoltaic modules for generating electricity during periods of solar irradiance, inverters for converting direct current into alternating current, and batteries for storing a certain amount of energy for use during periods of non-generation. However, there are no systems specifically adapted and integrated for different uses and consumption levels.

Other research centres and universities focus more on converting the photovoltaic effect of the solar cell and improving its performance, rather than on analysing the development of integrated photovoltaic self-consumption systems as advanced electricity generation and energy-saving systems.

Due to the recent regulatory framework promoting the installation of photovoltaic self-consumption systems, the proper design, calculation and sizing of these installations are associated with quality indicators and factors such as the levels of efficiency achieved (self-consumption rates of the photovoltaic installation), electricity savings resulting from reduced grid consumption, installation payback periods, etc. However, achieving good ratios for these factors requires an analysis of the end user’s consumption profiles (confidence bands, power peaks, profile seasonality, etc.) to ensure the proper development and implementation of these systems.

The photovoltaic solar self-consumption installation sector is currently undergoing significant development and therefore has strong prospects for future demand for this type of analysis to support the correct sizing of installations. In this regard, our research group has extensive experience in advising companies on the efficient design of this type of installation.

• Project Offices and Engineering Firms (as a specialised consultancy service).
• Companies Installing Electrical and Renewable Energy Systems.
• Industrial Sector (medium- and low-voltage consumers).
• Commercial Sector (small and medium-sized businesses).
• Residential Sector (residential communities and households).

Sergio Valero Verdú – University Research Institute for Engineering