A look at Microgrids, the pros and cons of localised power generation

Most countries rely on a large infrastructure and grids in order to power homes, schools and businesses. In most cases across the continent those power generating facilities are overwhelmed by population explosion. Even in places like rural areas where population figures haven’t changed and could be decreasing because of people moving into urban areas, electricity is still a far off dream. An alternative to hooking up massive lines that span great distances are microgrids.

Microgrids are power generating installations that can be connected to a main grid but can function independently. In a 2011 report by the International Energy Agency an estimated 1.1 billion people don’t have access to modern electricity services and 600 million of them are in Sub-Saharan Africa. Achieving universal access by 2030 was going to need an investment of US$45 billion.

The investment is a sizable one, and countries have been trying to make strides in this respect. Here in Zimbabwe one of the means to tackling this problem was ZERA’s licensing Independent Power Producers (IPPs). Beyond looking at the conventional power generating methods like thermal and hydroelectric. ZERA has over the years licensed companies looking to build renewable power plants.

What are the benefits of Microgrids

They provide efficient low cost energy. The assumption here is that a localised grid will use the local energy resources already available. It can be a small hydro plant that is installed on the area’s water body.

Being that they are localised, they can operate independently which increases the resiliency of the power infrastructure as a whole. There won’t be unitary points of failure in the case of natural disasters like the recent Cyclone Idai.

Microgrids can for example, serve a rural community as well as add power into the national grid. This also means that conventional power infrastructure can make its way to rural areas while communities already have a source of power. In this way it’s not an either or situation but microgrids actually compliment the national grid.

Even when we assume a national grid that has enough capacity for the whole country, microgids reduce grid congestion and thus alleviate stress on the national grid. Existing infrastructure can then get the servicing and maintenance they sorely need. Existing infrastructure won’t always have to operate at full capacity even during seasons where power consumption is high.

Microgrids reduce fossil fuel dependency. The cost of extracting or buying fossil fuels in order to burn them to produce electricity increases the cost of the service. With renewable technologies powering microgrids, the cost will fall, again making the service affordable and accessible.

Having such critical infrastructure deployed at community level may add to the retention of critical skills in that community. An engineer has the option of working at the local plant instead of making the usual trek to bigger cosmopolitan areas for a job.

Drawbacks of microgrids

The synchronisation with the main power grid can be difficult. But there have been ways to make this process more efficient using Distributed Generators.

Energy may need to be stored in batteries depending on the power demands of the community that it is serving. Batteries, if they are employed, will need servicing and regular maintenance.

Protecting the infrastructure is also a hurdle. It isn’t uncommon to hear reports of vandalism and theft when it comes to electrical infrastructure. The components of microgrids are expensive, and any theft would result in a community being without power until the components are replaced.

Are there any microgrids already operational in Zimbabwe?

In May of this year an initiative backed by Econet saw the completion of a 100KW solar plant that will support businesses in Ndolwane, Matebeleland South.

Zera listed a number of IPPs that have been registered to start work on Solar Plants. The most recent is Triangle Solar Systems which is looking to build a power generating facility in Chiredzi.

There are currently, according to Zera: