The recent spate of load shedding left many businesses in South Africa reeling as they tried to make plans to `keep the lights on’ whilst Eskom failed to deliver power. Fish farmers felt the pain rather severely as South Africa is a temperate climate and virtually all fish farming here is conducted in recirculating systems (RAS) which are dependent on stable power supply. Most seem to feel that additional hardware and diesel were the main expenses this added to the debit column of their financials, but there are some more insidious costs that we should not overlook.
Power is required to run a RAS and this must be supplied 24/7/365. Due to the elevated densities at which our fish are stocked they will only survive for a short while without aeration, where after devastating losses occur quickly. Therefore, part of the cost of investing in a RAS is the cost of backup power. Most of us opt to install a generator fitted with an ATS which starts automatically after 30 seconds or so of power failure. Once the power returns the generator is again turned off automatically. The power supply to small systems such as hatcheries is often supported by a bank of batteries that provide seamless power to the pumps and blowers during a power outage. Either of these options naturally adds to the capital costs of financing an aquaculture operation.
During a power outage the generators consume fuel, and running generators is far more expensive than paying for Eskom power. This fuel needs to be paid for, and if you opted for batteries then these too have a limited life span after which they need to be replaced. In both cases this adds to the operational costs of running the farm.
On our Grahamstown farm we have utilised both options to cater for power outages. However, we found that due to the frequency of the Eskom load shedding, the batteries were not yet fully recharged by the time the next load shedding event occurred. This has two consequences for us; firstly, the sequential partial charging of the batteries means that the charge gets lower and ultimately the batteries are incapable of carrying the load allocated to them, so at some point the system fails and the fish die anyway. Secondarily, the batteries have been discharged to beyond the safe limit for extended battery life, and as such the batteries themselves are now irreparably damaged and their life span severely reduced. Furthermore, we have lost (read `they failed’) 5 generators over the past 2 years due to failures of various sorts, 3 of these were during the past 2 weeks of load shedding as they simply could not cope with the frequency and load they were being required to carry.
As fish farmers, a compounding factor is that our fish have a 9 to 15 month growth cycle and a single 30 minute power failure to any of these systems at any stage of the growth cycle can result in a total loss of those fish. In short, despite having invested more than R100k in backup power systems we currently have no generators and two badly comprised battery systems, we have lost a pile of fish, and are very vulnerable should further load shedding occur.
The solution we opted for is to downscale and restructure. All the trout and tilapia are being sold off, as they are vulnerable to power outages, and we are now focussing on catfish, which are air breathing and merely inconvenienced by power outages. On the aquaponics side we have reduced our crop range to only cucumbers and lettuce, again sticking to the crops that can be produced in the decoupled system which is not as vulnerable to power failure. Sadly, these means that some of our staff have had to be laid off; viva Eskom and viva ANC.
Large fish farms are less vulnerable as the proportional cost of power supply is much lower than it is for a small scale producer. We have said for years that in order to be economically viable aquaculture needs to be done on a large scale. Given the mounting costs and risks associated with load shedding, the minimum size of an aquaculture investment in South Africa just got a whole lot bigger! So much for job creation; the real cost of load shedding is reduced profitability for the investor and job shedding!
We have scheduled the following Aquaculture Courses planned for 2019:
20 & 21 May Aquaponics Course, Pretoria
22 – 24 May Aquaculture Course, Pretoria
13 – 17 May Practical Aquaculture Course, Aquaculture Academy, Grahamstown – This is an excellent opportunity to obtain both the theory of fish farming as well as practical experience in spawning tilapia and catfish, feeding correctly, managing water quality, sorting fish, aquaponics plant care and many other related skills.
To obtain further information email us on email@example.com.
Catfish fry for Sale
We have catfish fry for sale to permit holders. Send us an email if you are interested in obtaining stock.
We offer a wide range of products to the Aquaculture Industry. These products can be viewed and purchased from our secure online store at Aquaculture Store.
Product promotion: Grommets 50mm at R99.00 each ex-Grahamstown.
If you need anything that is not listed, drop me an email and I will attempt to source it for you.