Large companies risk expensive loss of production when the municipal or utility power supply fails. Such failures become more frequent as infrastructure ages, but can also result from other factors such as cable theft, severe weather conditions, etc. Companies can protect themselves from such losses by installing a private microgrid at their factory site.

One company which decided to take this precaution is Eaton. Energize interviewed Eugen Ranft, Eaton’s operations manager, who explained how the system works, as well as the benefits companies derive from installing a private microgrid.

In Eaton’s case, the company experiences, on average, four outages per year which last for about four hours at a time. The company has two large sites in Wadeville, Germiston and, faced with every-increasing electricity tariffs and being supplied from an ageing distribution infrastructure, the company decided to invest in a microgrid system which would provide reliable power to the factory.

Ranft says that the company installed a renewable-energy plus battery-storage type of microgrid at its factory. This system enables the company to isolate itself from the power utility’s supply should it need to do so – or during an outage – without loss of electricity to the facility. The microgrid consists of rooftop PV panels which provide 233 kW of electricity on a sunny day, a battery storage system which is rated at 275 kVA and a 400 kW diesel generator.

The whole system is managed by a computer-based controller. Apparently, the microgrid’s controller automatically selects the appropriate power source according to prevailing requirements. For example, during the day, when the utility’s electricity tariffs are high, the system draws power from the PV panels as well as from the batteries if necessary. At night, when the tariffs are lower, the utility’s supply is used to recharge the batteries. Should more power be required than what can be supplied by the PV-battery combination, the diesel generator will provide the difference.

According to Ranft, although a 400 kW diesel generator may seem large, it is smaller than would have been required by the factory during a power outage, if the microgrid did not have a battery storage system. Buying a smaller-than-needed generator saved the company money and the unused diesel fuel saves it even more.

The PV panels are mounted onto the factory’s roof and require no additional space on the site.

The batteries are “second-life” electric vehicle (EV) batteries. These batteries were previously fitted to EVs and although they still have plenty of life in them, they are deemed to be unsuitable for continued use in an EV. Ranft pointed out that the idea of extending the life of EV batteries by using them in stationary instead of mobile applications offers a number of advantages.

Firstly, he says, extending the life of these batteries has an environmental benefit. It removes the problem of disposing batteries which are no longer suitable for use in EVs, and secondly, the availability of these “second-life” batteries removes the need for more material to be mined for the manufacture of additional batteries for use in stationary applications.

Furthermore, the price of second-life batteries is about 30% lower than similar new ones. This helps to keep the overall cost of a microgrid down. Also, in Eaton’s application, the pay-back period is expected to be between four and five years.

According to Ranft, these second-life batteries still have an expected life of between seven and ten years depending on load and how they are recharged. There are, apparently, enough second-life batteries in the market to support this purpose, and as EVs become more popular the number of them will continue to increase.

Ranft says that to ensure that the microgrid system would meet the factory’s current and future needs, the company implemented an energy-efficiency programme which included replacing certain pieces of equipment and lighting with more modern energy-efficient types. Furthermore, to reduce its overall electricity demand, the company replaced its electric furnaces with gas-fired ones.

In Eaton’s case, the installation of this microgrid resulted in a reduction of 40% in the company’s electricity bill in June 2018. Savings during peak tariff periods could be as high as 65%, Ranft says.

Eaton manufactures most of the equipment used at the company’s factory. The installation is therefore useful as a demonstration site for those companies which are interested in investing in a microgrid for their facilities too. To run a factory efficiently, Ranft says, a reliable supply of electricity with high power quality specifications is essential. This can be assured from the microgrid system which has been installed at his site, he says.

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WHEN SATELLITES TRAIN their cameras onto Africa at night, it is almost as if they are peering back to an age before electricity. The rich world is awash with great glowing orbs for the main population centres and orange tentacles for the roads that link them. But apart from speckles of light around the biggest cities, much of Africa is dark.
Of all the measures of the continent’s poverty, few are starker than that about two-thirds of its people have no access to reliable electricity. The Africa Progress Panel (APP), a group of experts led by Kofi Annan, a former UN secretary-general, puts the number of Africans without any power at 620m, most of them in villages and on farms. The panel found that in nine African countries fewer than one in five primary schools had lights. A study by the World Health Organisation found that about a quarter of clinics and hospitals in 11 African countries have no power of any kind, and many of the rest get it from generators that often break down or run out of fuel.
Such power shortages cost lives. In Nigeria each year an estimated 36,000 women die during pregnancy or childbirth, many because they deliver their babies in the dark in clinics such as the one in Makoko, a slum perched on stilts above a lagoon in Lagos, Nigeria’s biggest commercial city. It has just a few rough wooden beds in a small room with a doorway so low that people have to stoop to enter it. Straightforward deliveries are done by candle and torchlight, says one local resident, a fisherman. If anything goes wrong, the mother is carefully passed down to a small fishing canoe and taken to a bigger hospital across the lagoon. By then it is sometimes too late. Without power even the simplest health precautions can become difficult. “If you don’t have electricity you don’t have a fridge, and if you don’t have a fridge you can’t store vaccines,” says Jasper Westerink, who runs the African business of Philips, a Dutch multinational firm.
Businesses across the continent have to contend with frequent blackouts, known as dumsor in Ghana, from the Asante words for “off and on”. They rely on expensive backup generators, so the electricity they use is among the costliest in the world. The full impact of intermittent and high-cost energy on Africa’s economy and society is hard to measure, but it seems safe to say that this is the biggest single barrier to development.

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A confluence of innovation, risk taking, and public and private effort has created a five-year, $1.5 billion microgrid market opportunity in Kenya, leading Germany’s TFE Consulting to dub the East African nation, “The World’s Microgrid Lab.”
International startups are deploying innovative mobile ‘pay as you go’ (Pay-Go), home solar, and microgrids in off-grid rural areas across the East African nation and far beyond. Their work is backed by development agencies, regional governments, non-government organizations (NGOs), venture capitalists and corporations.
It’s still early to know, but the rapid development of zero- or low-emissions microgrids and distributed energy could prove to be the linchpin of an emerging new model for environmentally friendly energy and socioeconomic development.
“Globally, microgrids for electrification have a market potential of $400 billion,” says the report, “Kenya: The World’s Microgrid Lab.”
Looking ahead, TFE estimates that over the next five years the number of microgrids installed in Kenya, alone, will surge to between 2,000 to 3,000.
As a result, Kenyans are taking their first steps up the sustainable energy ladder.

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Mini-grid Definition
In this publication we define mini-grids as involving small-scale electricity generation (from 10kW to 10MW), and the distribution of electricity to a limited number of customers via a distribution grid that can operate in isolation from national electricity transmission networks and supply relatively concentrated settlements with electricity at grid quality level.
​“Micro-grids” are similar to mini-grids but operate at a smaller size and generation capacity (1-10 kW). 

The Mini-grid Policy Toolkit is for policy makers to navigate the mini-grid policy design process. It contains information on mini-grid operator models, the economics of mini-grids, and necessary policy and regulation that must be considered for successful implementation. The publication specifically focuses on Africa.
​Time has obviously moved on since its publication in 2014 and as the policy and regulatory landscape for mini-grids continues to remain highly dynamic, IRENA picked up on the topic again last year.​

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