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producing energy and saving water

Floating solar panels: generating power and saving water
The floating photo voltaic plant consists of 648 panels and occupies a 45m x 50m space. Picture: Wouter Kriel

Nico Laubscher and his sons, Nico Jr and Sybrand, farm wine grapes and cucumbers at Alzanne Boerdery close to Vredendal on the Cape West Coast.

“We’re at all times looking for methods to enhance issues on the farm, and we turned our consideration to renewable vitality in 2020,” says Laubscher.

He provides that farmers are more and more specializing in decreasing their carbon footprint to stay sustainable.

“Vredendal is thought for its many sunny days, and we thought photo voltaic vitality could be a great choice to discover on this regard. After making just a few cellphone calls, we have been launched to Paul Kotze of Photo voltaic Power Architects in Cape City, who got here out to our farm to do an analysis for us. He confirmed one thing we’d already suspected: photo voltaic might work for us. Nevertheless, we didn’t have sufficient roof area on our farm buildings to put in the required variety of photo voltaic panels.”

Laubscher says at that stage they have been additionally contemplating plans to assemble further cooling services, which might have solved the issue relating to the dearth of roof area, however they have been involved concerning the potential theft of the photo voltaic panels, as these buildings could be additional away from the household’s quick working and residing areas.

“We due to this fact put that plan on maintain, and as an alternative appeared on the farm dam, which is correct subsequent to my home and workplace. I’d been considering the problem now we have with our dam, which is water loss by means of evaporation. [South Africa is] a water-scarce nation, and as farmers in Vredendal, we’re aware of what occurs when the dams run dry. We have been many potential options to minimise evaporation, however then [Paul] urged we resolve two issues with one answer.

The Laubscher household farms wine grapes and cucumbers close to Vredendal within the Western Cape. From left: Sybrand, Nico, and Nico Jr.

“The dam’s floor space was sufficiently big to accommodate a floating solar energy plant that will generate the quantity of electrical energy we wanted, whereas concurrently decreasing the extent of evaporation. This gave delivery to our floating photo voltaic vitality challenge.”

Saving water and producing vitality

In accordance with Kotze, the idea of a floating photo voltaic farm is comparatively new in South Africa, and the Laubschers’ challenge was solely the second designed for a farm that he knew of at the moment.

“Designed for a 233 kilowatt peak (kWp), with its 648 panels that cowl an space of 45m x 50m, it was the most important floating photo voltaic challenge for a farm on the time,” he says.

They appeared into the water-evaporation problem and based mostly their calculations on European evaporation figures. In accordance with these, water evaporates at a price of 1m³ of water for every 1m² of water floor per yr.

“There are at present no correct figures accessible for South Africa, however one can assume that the speed could be increased than that in Europe,” says Kotze. “However even when it comes to European numbers, that’s a variety of water misplaced for any farmer in South Africa. Within the case of the floating plant for the Laubschers, it interprets into an space of two 250m² that may now be lined and subjected to minimal evaporation, leading to a big water saving.”

Kotze says they searched internationally for a corporation that would provide the {hardware} required for the Alzanne Boerdery challenge.

“Initially there was curiosity from France, however it turned out that the challenge would find yourself being too small for them. We ultimately managed to obtain the know-how from a Chinese language firm, which is smart in hindsight, as [China] is the world leaders in floating photo voltaic, particularly developed for his or her rice-farming programs and mine reclamation.”

The set up of the floating photo voltaic panels proved to be a means of studying for each Kotze and Laubscher, and several other modern options have been developed alongside the best way.

Set up

Kotze calculated that Alzanne Boerdery wanted a system that would present 233kWp. The dam was massive sufficient for a 400kWp set up, and whereas Laubscher thought of going larger, the prohibitive price of such an set up ultimately dissuaded him, and solely sufficient capability to fulfill the farm’s peak wants was thus put in.

In the course of the design part, it was found that the form of the dam when empty needed to be taken into consideration, because the system must be designed in order that the floating construction can sit stage on the underside of an empty dam.

As well as, your entire floating platform needed to be anchored. Static strains have been due to this fact put in, which have some slack factored in to permit for rising and falling water ranges.

“Though the float is a comparatively flat construction, it’s fairly a big one, and wind performs an enormous issue,” says Laubscher.

In accordance with Kotze, the panels are put in at a 12° angle attributable to limitations attributable to wind masses within the Vredendal area. This coincides nicely with Laubscher’s excessive summertime electrical energy consumption, because the smaller-than-normal tilt angle of the panels means they generate extra electrical energy in the summertime months than they might have at an incline appropriate for year-round optimum vitality era.

“With land-based installations, you’ll be able to set up panels on rotating frames that observe the solar; however with floating programs, mounted frames are the one doable answer,” says Kotze.

“Additionally, as a result of the set up floats on water, it advantages from the cooling impact of the dam, and cooler panels generate electrical energy extra effectively, thus balancing out a number of the compromise you make with a static set up.”

Cleansing and upkeep

For photo voltaic panels to function successfully, they should be clear. “Whereas we’re 40km away from the Atlantic Ocean, we get common visits from massive seabirds, and their droppings is usually a drawback,” says Laubscher.

Fowl droppings or another varieties of filth create soiling losses, which scale back the effectiveness of the panels. The 648 panels are divided into 36 teams, every making up a string of panels related to a land-based inverter. A person string can solely generate electrical energy as successfully because the weakest panel in that particular string, so panels need to be stored clear.

“This must be carried out early within the morning earlier than the warmth of the solar hits. We wash the panels with dam water, and Photo voltaic Power Architects additionally gives a upkeep and assist plan that ensures a sure stage of efficiency from the plant,” says Laubscher.

The corporate has a Cape City-based system that may monitor Laubscher’s plant in actual time.

“If a particular string isn’t performing, we see it within the system diagnostics. We are able to contact Nico, or do a website go to to troubleshoot the difficulty. However it’s usually so simple as eradicating just a few massive splats of seabird droppings,” says Kotze.

Laubscher says the floating photo voltaic plant challenge was an costly endeavor.

“The challenge price R5,7 million, and can repay itself in seven to 10 years. We opted to buy the system outright, with the advantage of free electrical energy from the beginning, as a result of I’m at a stage in my life have been I wish to preserve issues easy. If we will’t do one thing in money, we rethink very fastidiously.”

He admits, nevertheless, that money won’t have been the best choice on this case, primarily attributable to points with Eskom.

“We opted for a grid-tied system, and made our calculations on the idea that we’d be capable to feed vitality into the Eskom grid and promote the excess to offset the prices [of the project]. However Eskom is dragging its ft and now, over a yr later, we’re nonetheless not related to the grid, and we’re being throttled and might solely generate as a lot energy as we will use.”

Kotze, who’s managing the applying course of on behalf of Laubscher, says Eskom’s administrative capability is at present stretched, and it is rather tough to foretell how lengthy the method would take.

“There are tasks the place we will get approval and grid connection in a matter of months; different tasks take longer,” he says. Because of this, he encourages potential shoppers to finalise the Eskom course of up entrance the place doable, and likewise contemplate various funding approaches at present on supply.

Kotze explains that as an alternative of buying the system outright, as Laubscher did, potential shoppers ought to contemplate coming into into energy buy agreements with third events equivalent to Photo voltaic Power Architects.

“In such a state of affairs, we set up the system at our personal price, and the shopper purchases the generated electrical energy from us at an agreed tariff. The benefit is that we will worth it competitively in contrast with Eskom, and we will quantify and assure the annual escalations, which is an unknown with Eskom.”

Kotze says that the floating photo voltaic plant at Alzanne Boerdery is particular to him when it comes to his profession, because it was a primary in lots of elements.

“The challenge confirmed that these renewable vitality tasks are every distinctive, and there are lots of variables to have in mind earlier than you commit your cash. These embody the viability of solar energy, whether or not or to not be tied to the grid, and the assorted potential methods to finance it.”

Laubscher agrees, including that it’s dangerous to embark on such a challenge with out the assist of an knowledgeable service supplier.

“There are lots of technical issues we needed to study alongside the best way, and Paul is on my pace dial for that purpose!” he says.

E-mail Nico Laubscher at [email protected], or Paul Kotze at [email protected]



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