## 1 Introduction  
Renewable energy sources (RES) [1] can be coupled with several energy systems to produce the heat or power needed for different plants in order to reduce the primary energy demand of the included components. RES systems may be integrated into agricultural waste conversion processes [2; 3] to provide the energy required for the process and significantly reduce the energy conversion of the process. The exploitation of biomass as a renewable source is widely investigated in the literature [4]. In fact, biomass can be used to produce biogas by means of the anaerobic digestion process [5], and the biogas may be upgraded into biomethane and injected into the gas grid [6]. Furthermore, digestate is a by-product of the anaerobic digestion process which can be used as a fertilizer in agriculture [7]. Agriculture biomass conversion is a pivotal solution for farmers considering that their agricultural activities can be modified in order to obtain energy-efficient plants [8]. In this framework, the waste-to-energy (WTE) approach is considered as a viable strategy for the management of waste considering that in comparison to other methods, this approach provides renewable energy outputs and end products [9]. According to this strategy, by using low/negative-value organic waste, the production of renewable heat or power as well as fuel is possible. This allows for a minimal environmental impact to be made and also a significant decrease in organic waste volume [10]. Implementing this paradigm, agricultural waste (or other sources of biomass) can be globally recognized as resources, more than simply waste, producing renewable outputs in an efficient manner. This environmental-friendly approach also implies a reduction in fossil fuel dependence [11]. Thanks to agricultural waste conversion, it is possible to produce useful energy for specific users such as farms, single buildings, and groups of both. However, for the efficient and economic use of agricultural waste for the production of energy vectors, clear guidelines and possible obstacles to be overcome in order to use agriculture biomass in the coming years [8] have to be identified. In particular, solar systems--namely, photovoltaic (PV) panels [12], solar thermal collectors (STC) [13], or PV/thermal (PVT) collectors [14]--can be absolutely coupled with greenhouse systems [15]. This option seems very smart for the adoption of natural gas boilers and electricity from the national grid. For example, the installation of PV panels for power production [16] can easily be a sustainable energy source to supply water pumps for irrigation farming purposes; solar thermal collectors can be employed to provide heat for the heating system of greenhouses with the aim of maintaining the operating temperature of the greenhouse within the designed temperature range [17]. For prediction and the increase in solar power plants, the tracking of solar power data can assist in determining the rate of performance loss in their systems. In addition, artificial intelligence is one strategy that has recently grown in popularity [18]. Several authors have investigated this issue. For example, a non-linear integrated controlled environment agriculture model was developed in order to define a correlation between several factors and the conditions of the crop being grown [19]: humidity and temperature control, the impact of weather disturbances, irrigation, and fertilization. The simulation results are related to a renewable-energy-powered semi-closed greenhouse situated in Ithaca, New York. Tomato growing was considered. The authors suggest that a model able to control the environment where the crops grow can be useful to increase the efficiency of renewable energy utilization from 4.7% to 127.5%. In the work of ref. [20], a mathematical model to simulate a greenhouse was developed and validated vs. experimental data. The equations regard four elements of the greenhouse, i.e., the inside air, cover, bare soil surface, and canopy surface.