Vegetable Power: How the Green Fields of Kenya are Leading an Off-Grid Revolution

Oct 11, 2013 10:45 AM ET

“If you don’t have power, it is difficult to achieve economic growth and better living standards,” observes George Njenga, GE Distributed Power Regional Leader, Sub-Saharan Africa.

It is estimated that more than two-thirds of the population of Sub-Sahara Africa is without electricity, and more than 85% of those living in rural areas lack access to the grid. (Source: International Energy Agency)

Electrifying the region is a huge challenge with no single solution. However, localized off-grid energy solutions whereby power is generated at or near the point of use—sometimes known as distributed power—are increasingly playing a big role in bridging the sub-Saharan “power gap.”

Just as the development of mobile phone networks in Sub-Saharan Africa reduced the need for fixed telecom infrastructure, off-grid energy is also a technological leapfrog. “Off-grid,” or distributed power, solutions such as standalone combined-heat-and-power (CHP) engines, micro-turbines, advanced battery technologies, and solar and wind energy systems can be more cost-effective and practical for many remote sub-Saharan locations that big centralized power schemes find difficult to reach.

The large-scale vegetable fields found in the Kenya highlands seem an unlikely frontier for this new energy revolution. However, Tropical Power, a UK-based biomass energy company, has developed a project using GE Jenbacher J420 technology for Vegpro, one of Kenya’s largest exporters of fresh vegetables and flowers to supermarkets across Europe. Vegpro’s 700 hectare farm near Naivasha currently produces 10,000 tons of vegetable matter per year.

Producing that much vegetable matter results in a large amount of waste material: up to 45,000 tons of waste annually at the Naivasha farm. A great untapped energy resource, the combined technological know-how of GE and Tropical Power will convert this previously underutilized by-product into electricity and heat for the farm as well as for the local community.

The waste vegetable matter is placed into an anaerobic digester, a low-oxygen environment that causes the biomass to rot and produce natural gas. It is this methane and carbon dioxide that is then burned in a low-emission GE Jenbacher J420 engine to produce electricity.

The process is extremely efficient as the only by-product of the anaerobic digestion itself is nutrient-rich sediment that can be used as fertilizer or converted into charcoal. Equally, the Jenbacher is a highly efficient and reliable CHP engine. The heat generated during the burning of the natural gas is not wasted, as it is then used in heating and cooling systems.

Two J420 GE Jenbacher engines will be installed at the Naivasha farm, allowing for the production of up to 2.8 MW of electricity, enough to power the farm and 5,000–6,000 homes in the surrounding area.

Vegpro is even moving its vegetable-packing facility from Nairobi to Naivasha to take advantage of this new source of power. It will also use the heat produced by the Jenbachers in the packing center’s cooling systems.

The company will reap significant savings as a result of being energy self-sufficient, and its agricultural production will become more environmentally friendly by utilizing a previously discarded waste product.

Carol Koech, a GE sales and solutions engineer for Distributed Power, East Africa sees the project as a milestone:

“The Vegpro project will become a reference point for distributed power in sub-Saharan Africa, demonstrating the great applicability of this technology in promoting more reliable and cleaner energy production.

“Such technology has a wider importance in safeguarding Africa’s energy security through its potential use in other sectors. For example, we see great potential for the sustainable production of off-grid energy in a wide range of areas, from industrial processing to municipal waste.”

As is often the case with any complex infrastructure project, there are challenges to be surmounted in the off-grid revolution.

GE’s Njenga explains:

“The challenge is not just the technology, you need to support the full project chain. You have to have the technological expertise and knowledge but there are many other things to take into consideration such as the social impact, flora and fauna, and other environmental impacts. For community projects, long-term viability also needs to be ensured with the right training and maintenance programs. Training local people to operate and maintain facilities on an ongoing basis is important.”  

Effective metering and payment programs are also critical once the off-grid schemes are operational in local communities. However, the benefits are immense. “Getting power to communities via these off-grid projects can help empower them and create economic growth,” says Njenga. “It helps to power local businesses, hospitals and the mobile phone network. It can make a real difference in people’s lives.”