*1.1. LED Lights in Closed Plant Production Systems*

Agriculture in 2050 will have to produce almost 50% more output to meet the demand for food supplies, presenting it with a crucial challenge in meeting the increase in demand [1]. Technological development and innovation can offer alternatives to ensure food security sustainably. The use of closed growth environments, such as greenhouses, plant factories, and vertical farms [2–6], represents a sustainable alternative for fresh food production. In closed plant production systems (CPPSs), several variables can be controlled and optimized, such as water, fertilizers, CO2 injection, and temperature, as well as the quantity and quality of light thus ensuring minimum greenhouse gas emissions [3]. CPPSs allow growing of any plant variety, no matter the season of the year. Artificial lighting plays an essential role in CPPSs, as it promotes growth by providing optimal conditions for

**Citation:** Montes Rivera, M.; Escalante-Garcia, N.; Dena-Aguilar, J.A.; Olvera-Gonzalez, E.; Vacas-Jacques, P. Feature Selection to Predict LED Light Energy Consumption with Specific Light Recipes in Closed Plant Production Systems. *Appl. Sci.* **2022**, *12*, 5901. https://doi.org/10.3390/ app12125901

Academic Editors: Luis Hernández-Callejo, Sergio Nesmachnow and Sara Gallardo Saavedra

Received: 3 May 2022 Accepted: 26 May 2022 Published: 9 June 2022

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**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

plant development. LEDs are energy-efficient replacements that contribute to plant growth in agriculture. An outstanding advantage of LED lamps is their ability to operate with specific wavelengths (λ) that considerably reduce energy consumption. LEDs regularly generate continuous light. Likewise, they can radiate pulsed light (on/off in microseconds (μs)) with high power and low energy consumption at a specific frequency and duty cycle without upsetting the vegetative development of plants [4,7,8]. LED technology can produce different colors of light—that is, different qualities—called light recipes (different wavelength combinations). The wavelength combinations (red, blue, green, ultraviolet, and infrared) and the photosynthetic photon flux density (PPFD, given in μmol m−<sup>2</sup> s−1) are the components that constitute the light recipes. Light recipes impact crop growth from branching to flowering; optimize the biomass; and increase the antioxidant capacity levels of calcium, potassium, magnesium, chlorophyll, iron, vitamins A, B, and E, and other substances [7–9]. Crop quality and productivity rely upon the time and the light quantity supplied to the plants.

CPPSs can offer several advantages (improved management control of all variables involved—temperature, CO2, radiation—and increased productivity, growth, and yield) and generate an impact on humanity. Nevertheless, it is a model with a high demand for electricity for the artificial radiation systems needed to enhance the developing plants. Environmental control (refrigeration), the air required to remove the heat produced, and artificial lighting account for approximately 32%, 11%, and 57% of the total energy demand, respectively [10]. Furthermore, according to Avgoustaki and Xydis [11], the artificial lighting system accounts for 80% of the electrical demand, since the overall operability of the CPPS accounts for 40% of the total energy consumption.

Innovative approaches, such as fluid dynamics, evolutionary algorithms [12,13], the derivative integral model, and derivative model [14–16], control the resources in CPPSs. Artificial neural networks predict weather conditions and energy consumption [13–15,17]. Other techniques predict energy consumption performance for plant production [18,19]. Finally, other techniques focus on in the optimization of resources and reducing energy demand in CPPSs [20,21].
