Semantic Sandbox

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Introduction

Solar energy is the energy the earth receives from the sun, primarily as visible light and other forms of electromagnetic radiation. Solar power is among the readily available renewable energy sources on earth, but its availability and characteristics vary strongly from one region to another.

The solar power potential is highest in regions close to the equator, which overlap with many countries of the Global South. Especially in off-grid areas, the use of solar energy in agriculture, can considerably enhance livelihoods, enabling access to irrigation, cooling, drying and other agri-food processing devices. Despite the suitability of these regions for solar power and the potential to improve living standards, many barriers still hinder end users from adopting this clean energy, among others, the lack of information and access to finance. To overcome these obstacles, different approaches have been developed with the aim of mainstreaming access to solar power. Read more ...

Solar energy can be utilised for agriculture in various ways (GIZ/Böthling).

Technologies

Depending on the solar resource potential and its quality, solar energy can serve different purposes, leading to a large diversity of solar technologies. They can be either passive or active, depending on how sunlight is captured, converted and distributed. Active solar technologies include solar photovoltaic and solar thermal systems; which convert sunlight into useful energy. Passive solar techniques involve designing buildings, materials and spaces in a way that allow optimizing the use of solar energy, such as orienting a building towards the sun or selecting materials with favourable thermal conductivity or insulation properties. Read more…

Solar photovoltaic energy can be used to power pumps in irrigation systems (see next section) , improving agricultural yields and saving costs for other fuels like diesel. It can also power refrigerators (see below), overcoming the problem of electricity shortages, which interrupt the cold chain, enhancing access to cooling equipment in ‘off-grid’ regions and reducing post-harvest losses. Read more…

Solar thermal energy is used in agri-food processes like drying. As opposed to sun-drying, solar drying avoids contamination of the harvest with impurities from the ground and increases energy efficiency. The latter can be enhanced by using photovoltaic energy to power artificial aeration systems .

Solar Powered Technologies for Irrigation

Among renewable energy, solar power is the most attractive option for irrigation. As prices for solar modules have fallen substantially in recent years, solar powered irrigation systems (SPIS) have become more attractive from an economic perspective.

Solar-Powered Water Pump

There are different approaches of integrating renewables in pumping systems. The solar powered water pump, running on photovoltaic energy, shows especially good results in equatorial regions, where insulation is highest all year long. It uses solar energy to pump up water from the source to an elevated storage tank. Once water is needed for irrigation, it is released gravitationally at a certain pressure dependent on the height difference from the tank to the irrigated area, which can be regulated by pipe diameter and length, and the type of emitters employed. As solar panels become cheaper, this technology is increasingly accessible to most smallholder farmers in the Global South, allowing expansion of agricultural production to originally off-grid areas, and enhancing stepwise rural electrification through mini-grid projects. Read more…

Micro-Solar Utilities for Small-Scale Irrigation

However, despite the abundance of solar resources in countries of the Global South, a lack of information and of financing options hinders especially smallholder farmers from adopting solar-powered irrigation systems. In Senegal, farmers currently use the labour-intensive method of flood irrigation with wells and buckets, or cost- and energy-intensive diesel-powered motor pumps. Nevertheless, the country has immense solar resources that can be used to provide clean energy for irrigation practices. Earth Institute’s solution allows a small group of farmers to use a central solar energy unit to power multiple AC pumps for irrigation. This approach takes advantage of the benefits of solar without the high costs associated with DC-powered pumps and battery storage. Being accessed by farmers with prepaid electricity cards, this micro solar utility allows customers to cover their appliance loans in small payments, overcoming the major obstacle that hinders farmers from the adoption of the technology, which is Financial Instruments and Financing for Sustainable Agrifood Systems. The three shared systems that were implemented until 2016 served 21 farms, which have experienced 29 percent average increase in agricultural production, and resulted in 24 tons of CO2 equivalent. The project is now seeking partnerships for scaling up, adoption and local maintenance contracts. Read more…