Selective-Absorption Solar Cells for Agrivoltaic Crop Light Transmission
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Solution Overview
Problem
Traditional solar energy farms shade underlying vegetation, preventing efficient crop growth due to the absorption of all sunlight by solar panels, limiting land use efficiency to less than 100%.
Innovation Solution
Development of solar/photovoltaic cells that are opaque to high-energy photons (e.g., green, blue, UV) and transparent to low-energy photons (e.g., yellow, orange, red, infrared) to generate electricity while allowing sunlight to reach crops, using materials like gallium phosphide (GaP) or silicon (Si) with adjusted thicknesses to achieve this spectral separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional solar cells absorb all sunlight to generate electricity, then power generation efficiency is improved, but underlying vegetation cannot receive sufficient solar flux for healthy growth
Solution Approach 1:
The solar spectrum is segmented into different energy ranges, with solar cells absorbing high-energy photons (UV, blue, green) for electricity generation while allowing low-energy photons (red, infrared) to pass through to vegetation. This spectral segmentation resolves the contradiction by separating the light absorption function for power generation from the light transmission function for plant growth.
Solution Approach 2:
The solar cells are designed with selective optical properties where different portions of the spectrum are treated differently - high-energy photons are absorbed while low-energy photons are transmitted. This local quality differentiation in photon interaction allows simultaneous optimization of both electricity generation and vegetation growth conditions.
2Productivity
If solar panels are installed close to the ground to maximize land use, then land use efficiency is improved, but underlying crops receive insufficient sunlight for efficient growth
Solution Approach 1:
By segmenting the solar spectrum and allowing low-energy photons to pass through the solar cells, crops can receive sufficient sunlight even when panels are installed close to the ground. This enables high land use efficiency without compromising crop growth requirements.
3Illumination intensity
If solar panels are elevated or spaced apart to allow sunlight for crops, then vegetation growth is improved, but land use efficiency decreases
Solution Approach 1:
The spectral segmentation approach allows solar panels to be placed close together or near the ground while still permitting beneficial low-energy photons to reach crops. This eliminates the need for spacing or elevation, maximizing land use efficiency.
Solution Approach 2:
The solar cell system performs multiple functions simultaneously: generating electricity from high-energy photons while transmitting low-energy photons for crop growth. This multi-functionality allows both power generation and agriculture to thrive on the same land without spatial separation.
4Power
If solar cells use materials with broader absorption spectrum to maximize power generation, then electricity output is improved, but transparency to growth-beneficial photons is reduced
Solution Approach 1:
The solar cell materials are selected and engineered to have specific absorption characteristics where high-energy photons are absorbed for electricity generation while low-energy photons maintain high transmission. This local quality differentiation in spectral response resolves the contradiction between power generation and crop growth support.
Solution Approach 2:
By changing the material composition and thickness parameters of the solar cells, the absorption spectrum is optimized to absorb only high-energy photons while maintaining transparency to low-energy photons. This parameter optimization allows simultaneous achievement of high electricity generation and high transparency to growth-beneficial light.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables simultaneous electricity generation and crop growth by allowing solar cells to be placed adjacent to each other without gaps, enhancing land use efficiency beyond 100% by providing the necessary light spectrum for crop growth while generating power.
Implementation Method 1
solar/photovoltaic cells that produce electrical energy from one or more portions of the impinging solar spectrum
Implementation Method 2
the solar cells are transparent to photons within other color ranges (e.g., yellow, orange, red, infrared) or having photon energies below the specified energy level
Data Source
AI summary
A system, apparatus and method are provided for assembling an agriphotovoltaic (APV) system in which solar/photovoltaic cells selectively absorb a first portion or portions of the terrestrial solar spectrum and allow a second portion or portions to pass through to underlying vegetation. For example, solar photons in the green, blue, and ultraviolet (UV) range of the spectrum may be absorbed and used to generate electricity, while other photons (e.g., orange, yellow, and/or red) may be allowed to reach the vegetation. Yet further, a fraction of the generated electricity may be used to generate elements of the first portion(s) of the spectrum (e.g., some blue photons), for transmission toward the vegetation.