What are the key advances in mini-grid end-use technologies?

The use of light-emitting diodes (LEDs) has significantly decreased the amount of electricity required for basic household lighting. LED light bulbs use only about 10 percent of the energy required by traditional incandescent bulbs. As a result, the solar-lighting market has grown significantly. Similarly, efficient TVs and DVD players with LED screens and smartphones are changing electricity requirements for communications and entertainment.

In rural areas in developing countries, agricultural processing tasks such as grinding grain, milling rice, husking corn and shredding coconut are generally done by hand—often by women—or with the use of diesel-powered mills. New, more efficient agro-processing units for rice, corn, coconut and sweet potato, such as those developed by Village Infrastructure Angels, are in the early stages of commercial deployment.

For example, Village Infrastructure Angels helped install efficient mills in Sumba, Indonesia. By using solar mills, making 1 kg of milled corn for a family’s daily consumption, which previously took 1 hour to shell and smash corn with rocks, became a 5-minute job. The potential time saving of each mill over 5 years for a 100-household village is 100,000 hours, or the equivalent of 10 full-time jobs. This project is now scaling up to 2,500 households with support from the Millennium Challenge Account - Indonesia and other investors.

Conventional refrigeration relies on compression and expansion of a refrigerant such as freon. Magnetic refrigeration uses magnetocaloric alloys, which have a lower heat capacity in the presence of a magnetic field. Magnetic refrigerators expose the alloy to a magnetic field and then remove the field in a continuous cycle. By circulating a fluid with the changing magnetic field, the system can pump heat from one area to another.

Magnetic refrigerators are up to 35 percent more energy efficient than conventional refrigerators, and they are much quieter. As of January 2015, Haier, in collaboration with BASF and Astronautics Corporation of America, had developed the technology to proof-of-concept stage.

Peltier junctions, a new semiconductor technology, has enabled developers to create a refrigerator with no moving parts. Peltier junctions create a temperature differential when electrical current flows through them, known as the Peltier (or thermoelectric) effect. Refrigerators with Peltier junctions have no moving parts and have a longer lifespan, but they are less efficient than conventional compressor-based systems.

USAID’s Powering Agriculture: An Energy Grand Challenge for Development program has supported innovative biogas and solar chilling devices, with a particular focus on the dairy and horticulture industries.

Highly efficient, reliable DC appliances can stretch the limited electricity from mini-grids much further. Unfortunately, in addition to lacking good receptacles, most DC appliances manufactured for off-grid use are inefficient and low quality. In rural off-grid markets where electricity is expensive and limited, inefficient appliances increase household energy costs.

The Global Lighting and Energy Access Partnership (Global LEAP) Awards is addressing this challenge through an international competition to identify the world’s best low-voltage DC appliances for off-grid use. Products nominated for awards are evaluated for affordability, quality, durability and energy efficiency. Finalists are tested according to internationally accepted laboratory methods, and a panel of independent experts chooses the winners. So far, the Global LEAP Awards has held competitions for LED lighting products and flat-screen TVs. These awards, combined with media outreach, help create demand for higher-quality, super-efficient DC appliances.