No more headache, weed harvesters are here

The silent but immense cost of siltation, weed infestation and sedimentation along the Shire River basin to the country’s power sector is just overwhelming.

The current prolonged and incessant power outages may be as a result of a combination of factors. But weeds and severe soil erosion, coupled with resultant sedimentation along the Shire River have a significant contribution or share to these blackouts.

The Weed Harverster harvesting weed and debris in Shire River

Tellingly, many are familiar with water hyacinth or Namasipuni, but there are other invasive weeds that are also tormenting and clogging the intake screens of most hydropower stations along the River Shire.

They include papyrus, hippo grass (Nsenjere), water lecture, water lettuce, and reeds (Bango).

Extreme cases are evidenced by a myriad of floating islands visible along the Shire River basin, caused by these undesirable plants.

What happens is that when weeds and trash clog the intake screens, they restrict required quantities of water from going to the turbines; hence, a reduction of power generated.

Furthermore, debris, trash and weeds pass through the unprotected tunnel and damage the turbines, in the process.

Besides, smaller weeds pass through the screens and block the cooling water system for the generation units and this makes machines to overheat.

Here is a slice of a specimen of how weeds can be precarious to Malawi’s power sector.

Firstly, severe environmental degradation and poor farming practices in the river catchment area led to the mushrooming of weed islands floating in the Shire River in 1991, affecting power generation in the process by chocking the intake screens.

Secondly, in 2001 Malawi lost both Tedzani I and II due to collapse of the intake screens after they got blocked with aquatic weeds.

Such a damage to infrastructure is estimated to have cost $12 million (K8.7 billion) to repair the damaged infrastructure.

This prompted Escom (before the unbundling process took place) to launch the Liwonde Weed Management in 2005 to manage the aquatic weeds that were so rampant then.

“Since then main interventions were tried including manual harvesting using locals with pangas and bare hands to harvest the weeds, hire of Plant and Vehicle Hire Organized (PVHO) grab crane, hire of Malawi Defence Force navy and all this to no avail,” laments Electricity Generation Company (Egenco) chief executive officer William Liabunya.

In 2005, Electricity Supply Corporation of Malawi (Escom) procured a set of one weed harvester, one shore and trailer conveyor, one weed cuter, and service boat to help reduce the machine outages due to weeds.

But still, there was no end in sight of the hassles unleashed by the weeds and silt to hydropower generation. It meant that there was complete shutdown of weed harvesting operations during machine equipment breakdowns, knowing that it was one set of harvesting equipment.

“The set of equipment we bought has been in operation now for 13 years against its lifespan of 10 years,” said Liabunya.

Over the years along the Shire River, weeds have continued to grow even heathier, greenish and plumb, thanks to the daily nourishment from nitrogen, calcium, potassium and other nutrients that cascade through the Shire River basin and emanate from the inorganic or synthetic fertilisers applied by communities cultivating along the river banks.

The genesis of optimism

Then came a ray of hope from the Millennium Challenge Account-Malawi (MCA-Malawi) on September 20 2013 when its $350.7 million (K257 billion) five-year project.

To address the problem of siltation and weed infestation that has over the years strained Escom’s efforts to generate enough power, MCA-Malawi bought mechanical equipment to help Egenco manage weeds and sediments.

This was one key mitigation measures of the impact of the weeds and sedimentation through mechanical means, in accordance with international best practices.

According to the compact agreement, Millennium Challenge Corporation (MCC) funding was earmarked towards supporting the purchase of dredgers, trash rakes, diversion booms, conveyers, disposal trucks and weed harvesting equipment at existing hydropower plants and the Liwonde barrage.

The promise that is honoured

Fast forward to the April 17 2018, Malawi indeed witnessed the commissioning and handover of two weed harvesters to Egenco in Liwonde, Machinga District.

The two harvesters named Rukuru and Linthipe as well as shore conveyors and a tipper truck are va lued at $2 million (about K1.4 billion).

Each harvester has a maximum loading capacity of 4.5 tonnes.

This is a fulfillment of one of the promises by MCC.

“The commissioning of Rukuru and Linthipe shows us what we [USA and Malawi] can do in partnership and the great impact we can have together,” says USA Ambassador to Malawi, Virginia Palmer.

The commissioning of the two weed harvesters is the first of the many milestones to come under the Malawi compact, adds Palmer.

But to Liabunya, it is a sigh of relief to Egenco.

“The procurement of two new harvesters, a shore conveyor and two tipper trucks under the MCC compact, will go a long way in improving the weed harvesting operations by Egenco,” he says.

Already, Liabunya states that the new equipment has increased the harvesting capacity and will improve the disposal volume and processes.

Egenco is also committed to working together and supporting other stakeholders that are taking care of the Shire River catchment areas, said Liabunya as he received the equipment on behalf of Egenco.

To government, the handing over of the harvesting equipment to Egenco is a timely gesture.

“It [the commissioning] comes at a time Malawi is facing challenges in power generation,” said Minister of Natural Resources, Energy and Mining Aggrey Masi.

Todate, MCA-Malawi continues to work closely with local communities living along the Shire River basin to improve land management practices as a way of combating erosion that culminates into sedimentation.

MCA-Malawi is also working with 11 non-governmental organisations (NGOs) or grantees under MCA’s Environmental and Natural Resource Management (ENRM) project and the Social and Gender Enhancement Fund (SGEF) aimed at addressing the dual challenges of increased sedimentation and weed infestation in the Shire River Basin.

It is highly believed that the success of such mitigation measures under the Compact’s ENRM project, will improve hydropower generation capacity downstream.

But the fact still remains that sedimentation, siltation and weed infestation as a result of catchment degradation, are all wreaking serious havoc to the power sector and these efforts by MCA-Malawi Compact are critical but not sufficient enough to totally thwart power outages plaguing Malawi.

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