Energy efficiency measures and technical-economic study of a photovoltaic self-consumption installation at ENSA Kenitra, Morocco

Introduction

The oil blockade in the 1970s forced the world to realize its dependence on fossil fuels. Today, an awareness of the environmental damage caused by these energies and their hidden costs of use has shown that renewable energies could be a solution to this problem. As a result, we are more and more concerned by environmental issues. The solar solution, seems to be a good arrangement because the earth collects every day, under the aspect of solar energy, the equivalent of the electric consumption of 5.9 billion people during 27 years. The energy situation in Morocco is linked to the singularity of the local context. Morocco is faced with the virtual absence of identified fossil energy resources and a heavy dependence on imports which cover more than 90% of energy needs (Planètes énergies 2016). As a developing country, Morocco has experienced continuous growth in energy demand since the beginning of the twentieth century such an experience has been part of industrialization, the overall development of the economy and the increase in living standards. Over the last 25 years, the increase in demand has averaged 6–7% per year. At the same time, a new threat has emerged: climate change whose impact can be potentially catastrophic in a country where water plays a central role (Ministère de l’Aménagement du Territoire National, de l’Urbanisme, de l’Habitat et de la Politique de la Ville 2017). In this regard, Morocco considered the issue of climate change to be at the center of the country’s concerns, a fact that makes sustainability a matter of great importance in its development strategy, so as to ensure a strong and sustainable economic growth and an integrated human development. Energy efficiency is a priority axis of the State’s action aiming to mobilize all operators and stakeholders to limit global warming and control energy demand, with the objective of achieving an energy saving of 12% by 2020 and 15% by 2030 (Drissi Lamrhari and Benhamou 2018). In Morocco, energy efficiency is a major priority in the national energy strategy, alongside the development of renewable energy. For this reason, energy efficiency action plans have been put in place in all key sectors including transport, industry, building and agriculture. Energy Efficiency consists in the rational use of energy resources: it aims at reducing energy consumption to the maximum while keeping the same quality of service. The subject of energy efficiency in buildings has aroused the interest of several researchers around the world (Hamdaoui et al. 2018). On the Moroccan scale, we address an issue and we highlight a point but we come out with solutions and make recommendations studies aiming at improving building envelop performance, reducing energy consumption and enhancing occupants’ thermal comfort usually assess the effects of design and the architectural parameters of the building like building shape (compactness), walls and roof composition and insulation, windows to wall ratio, natural ventilation (air change per hour), envelope thermal mass and inertia. Hamdaoui et al. (Abdoua et al. 2021) assessed the energy demand and environmental impact of various construction scenarios of an office building in Morocco. The obtained results showed that the best construction scenario offers considerable reduction in annual energy loads compared to the base scenario (Allouhi, Rehmanb, and Krarti 2021). Renewable energy sources including solar photovoltaic (PV), solar thermal, geothermal, wind, biomass and hydro are considered promising alternatives for clean heat and power generation. These sources can provide sustainable energy to all populations irrespective of their geographical location and financial status. Due to the decentralized nature of these sources, small hybrid power systems can be deployed even for remote locations (Allouhi 2019). The growth in energy demand has highlighted the importance of energy efficiency. It reduces the pressure on natural resources and is now considered a fourth energy. Morocco is not left behind since it has adopted a law on energy efficiency, has established an agency for the latter and has started exploiting the interesting potential offered by this energy within the framework of a national strategy; the objective is being to follow the overall development dynamics of the country. In this context, Ibn Tofail University and more specifically ENSAK has been interested in assessing the contributions of energy efficiency to the development of its entire campus in terms of fighting against energy waste, reducing energy costs.

Measures and actions taken on user behavior at National School of Applied Sciences

When analyzing the bill of 04/2021, we have found that the power demand is lower than the subscribed power. This implies that the bill includes monthly charges due to this overage. To minimize these charges and pay only for what is consumed, we propose recalculating the optimal subscribed power from the powers called throughout the reference year. ENSA is a medium voltage customer, the billing of its subscribed power is done according to the power demand for each month. If the power demand does not exceed the subscribed power, the customer is subject to fixed charges that are multiplied by the subscribed power. If the power demand exceeds the subscribed power, the charges will be multiplied by 1.5. The goal is to find the optimal contracted power that guarantees us the maximum gain from this year’s bills. It must be exceeded 4–5 months per year to compensate for the other months when the power is not reached. First of all, we calculate the average power demand, then we proceed to search the subscribed power by suitable steps until we obtain the optimal subscribed power that brings us the maximum gain.

Energy efficiency – the air conditioning and heating station

In the framework of its international commitments, Morocco has expressed its willingness to reduce greenhouse gas emissions and to ensure a shift towards sustainable growth, especially since the country is strongly affected by a constantly growing energy consumption as well as by its almost total energy dependence on the outside world. In this context, Morocco has adopted the national energy strategy, outlined in March 2009, which defines as a priority objective by 2020 the reduction of energy dependence, estimated in 2009 at 97% (AMEE 2015).

The achievement of this objective, will pass essentially by the installation of 42% of the electrical production capacity from clean and renewable resources such as solar thermal and photovoltaic, wind and hydroelectric, and also by the implementation of a comprehensive policy for the promotion of energy efficiency in different sectors and particularly in the building sector by reducing energy consumption by 15% by 2030 (AMEE 2015). Thus, Morocco’s energy efficiency policy aims to clarify the relationship between the administration and other stakeholders by establishing an institutionalized energy efficiency governance system, a legislative and regulatory framework and standards.

Finally, the construction of energy-efficient housing appears to be one of the most urgent actions to be taken to implement the national strategy for renewable energy and energy efficiency (AMEE 2015, Nourdine and Abdallah 2021). A significant reduction in the heating and cooling needs of the building as well as an improvement in thermal comfort can be achieved through the use of certain building materials and appropriate architectural design, including better orientation, optimal window sizing, thermal insulation (Nourdine and Abdallah 2021).

Regarding our case study, while evaluating the school site, we have noticed that the air conditioning and heating station consumes the most energy; it represents almost 58% of the overall consumption, so it is necessary to reduce the energy consumption of this station. Since the air conditioning/heating system used in the different buildings of the school is a split system, the use of inverter technology was proposed as an action on this item, to improve significantly the energy efficiency of the buildings, to reduce the electric bill and to favor the comfort of the user (Sadeghifam, Meynagh, and Tabatabaee 2019).

Thermal insulation of the school buildings

In order to reduce or avoid the problem of heat loss, it has been thought to close all sources of leakage. This can only be achieved by means of insulation. Thermal insulation is an important technology to reduce the energy consumption of buildings by preventing heat gain/loss through the building envelope. Thermal insulation is a building material with low thermal conductivity, often less than 0.1 W/mK (Ashrafian et al. 2016).

These materials have no other purpose than to save energy, to protect and provide comfort to the occupants. Among the many forms and applications of thermal insulation, this section focuses on those commonly used for building envelopes, i.e., the floor, walls and roof, and which have potential for South-South technology transfer. These include industrial insulation products and the application of natural elements as thermal insulation (Aubin et al. 2017).

Photovoltaic self-consumption

Solar photovoltaics (PV) self-consumption can be defined as the setting in which a share of a certain PV system electricity production is consumed directly at the point of production (Pontes Luz et al. 2021; Stephant et al. 2018). Moreover, a PV system sized for self-consumption has the objective of increasing this share and to eliminate excess production and energy injected to the power grid. Therefore, self-consumption is an important model for consuming local renewable energy specially in markets without feed-in-tariffs (Pontes Luz et al. 2021).

Photovoltaic self-consumption occurs when individuals or businesses consume the energy produced by photovoltaic generation facilities located near where the energy is consumed. In addition to the solar panels themselves, self-consumption photovoltaic installations include other elements such as inverters, cables, connectors and possibly batteries. Not only does this type of consumption reduce electricity bills, but also contributes to reducing climate change since it uses renewable energy (Lienhart 2018).

PVSyst plant simulation

We used PVSyst for Kenitra region:

1. Geographical situation: Latitude: 34.26° N Longitude: −6.58° W

2. Collector plane correction: Tilt 30° Azimuth: 0° (Figures 1, 2, 3, 4 and 5).

Figure 1:

Choice of panels and inverters/grid connected system – main results.

Figure 2:

Meteorological data of the site and average monthly photovoltaic production - PVSYST.

Figure 3:

Daily input/output diagram.

Figure 4:

System output power distribution.

Figure 5:

Loss diagram over the whole year.

The profitability of the installation

The profitability of a photovoltaic installation is a concept that may seem complex, but to define whether the installation is profitable or not, it is necessary to calculate the amortization time of the installation in addition to the gain brought by the installation.

In order to determine the price per kWh produced by the installation, the number of kWh produced per day must be calculated. Given an installation with a power of 45 kWp, the results are as follows:

• kWh produced = 539 kWh/D;

• So, the price of the kWh of a photovoltaic installation of 25 years duration is: 1 kWh produced = 0.41 MAD;

• With, first investment = 495,000 MAD, we take:

• Maintenance costs = 40,000 MAD

• 1 EURO = 10.65 MAD

And also, with a degradation of performance of 5% per year which is equivalent to 10% in 25 years (Figure 6).

Figure 6:

PVCalc data simulation.

Calculation of the time of return on investment of the installation

In this part, it has been assumed that 100% of the equity is from ENSAK and without credit. According to the results found using PVCalc (Figure 7).

Figure 7:

PVCalc project summary.

We find that the amortization period of this installation according to our simulation PVCalc is four years.

The average price of kWh of the Autonomous Company of Kenitra (RAK) = 1.0101 MAD, according to the following consumption profile of ENSAK:

1. The weighting coefficient HC (off-peak hours) = 0.274

2. The weighting coefficient HP (peak hours) = 0.148

3. The weighting coefficient HN (normal hours) = 0.413

4. The average of the weighting coefficients is = 0.278

Thus, according to the previous part price of PV kWh produced = 0.41 MAD using the LCOE formula and knowing that the number of kWh produced/year = 196,861.5 kWh, we have: Return on Investment (ROI) = 4.52 years.

The difference between the Return on Investment calculated by the software and the manual calculation is due to the fact that PVcalc considers the inflation rate and other economic parameters.

We are profitable since the payback time is almost five years (Figure 8).

Figure 8:

PVCalc – simulation of cash flows.

Conclusions

Energy efficiency and technical-economic study of a photovoltaic self-consumption installation at ENSA Kenitra in order to optimize electricity consumption and reduce invoicing, the inventory of equipment and the analysis of invoices and energy-consuming items made it possible to detect anomalies in each of the energy-consuming items and to target potential sources of energy savings. With an installation of 45 kWp, ENSA Kenitra can produce almost 25% of its energy consumption with a price of 0.41 MAD per kWh produced. This photovoltaic installation with five years of return on investment will bring to ENSAK an annual gain of 80,713 MAD. Moreover, with regard to the environmental impact, we can reduce up to 164.25 KgeqCO2/kWh/d which is equivalent to a production of 59,951.25 KgeqCO2/kWh/year.

All the recommendations mentioned will only be useful if they are accompanied by the cooperation of the users, so long as the demand depends mainly on their behaviors. Awareness campaigns can be of great help in encouraging stakeholders of ENSAK to adopt good practices that will improve the energy efficiency of this institution.