Effective power saving of load shedding on irrigation.

It seems like they could irrigate at night when the peak demand is low. Or switch to solar - which is well suited to irrigation.

SA is an arid country and for some months the irrigation must go at 24/7.

Replacing a 80ha irrigation with solar running only 1/3 of the day. 240KVA would mean a lot of cells.

Some farmers irrigate at night time only (less evaporation and wind losses)

Load shedding at night is also possible. Imagine getting up at 3 and go through a starting sequence.

I guess the simple answer is to automate the starting sequence.

installing a rudimentary SCADA system to restart the pumps, treat then like sub-stations. The farmers could even form a co-operative and build a single system that covers several farms. Another option that could be used in conjunction or as a stand alone would be install some sort of transmission between the motor and the pump to lessen the initial start spike, starting the motor under no load and then increasing it to full production mode. Have they considered their own generation, possibly wind? Load shedding stoppages could be avoided by switching from the grid to their own power source and any excess power could be sold back to the grid operator.

Just a couple of thoughts, my $0.02 (cdn) worth

An automated starter would only save him from getting out of bed but would not save much time. $$$ vs Laziness?

Please remember that SA cannot be compared to America.

At more than R8 to the $ , Prime rate 8x of that of America, High inflation rate, BEE sword, runaway crime rate, 40 to 50% unemployment, massive numbers of illegal immigrants, Little to no subsidisation etc - we are 3rd world,

As you brought the subject up of economic and social situations in SA, how do you compare it to let's say 10 years ago, which was the last time I was there for several weeks for work and play. I almost packed everything up here and moved I loved it so much.

You forgot the Government controlled monopolies. Everything is regulated/controlled by Government. Our energy supplier will not let anyone in on the supplying of the energy cake. They are of course the only one's supplying the country and they fail to provide. YET they export energy to our neighbouring countries. So we don't have enough for us but still they export and for cheaper than we can buy electricity for ourselfs. And to top it all, now they want a 60% increase in tariffs. Hell this place is getting to me. Hendrik, are you sure we still qualify as being 3rd world? I think it is heading more in the direction of 5th or 6th. About 3 Mil taxpayers carrying 49 Mil people. Excluding illegal immigrants. Don't even want to elaborate on the 2010 soccer comming?????

Hopefully more of you will get out soon. A lot of SA citizens are arriving on OZ mostly tradesmen. The Govt isn't doing enough for skilled workers and don't have the guts to even mention refugee status, which is the reality.

The problem with large Capex projects like suggested, is the lack of security of tenure. It will not be long before the farm siezures like Mug-ape promotes in Zim start.

I could say a lot about meddling overfed middle class western liberals, but I won't.

I agree trying to boost the power output to compensate for decreased pumping windows is self defeating, as the overloaded worn out system isn't gonna like concentrated heavy loading at all. Wind and sun may help make up some of the shortfall, but I just don't know how solar can be sourced with foreign exchane being as it is. If wind has any reliability in the affected areas, it is at least farm buildable technology. Solar is too technology dependant to foster self help.

You damn NUTS! No wonder you contain traces of shit

Just like bureaucrats to cut off power to their food supply so the can sit in their offices and homes in relative comfort. They don't have to worry about paying more for food stuffs. Just give themselves a raise and pay with the taxpayers money.

Around here the power company has a device connected to the HVAC units. Under an agreement you allow them to shut down the unit I believe its 10 to 15 minutes on the hour. They cycle through the neighborhoods if they need to which helps them to regulate the demand. It's all voluntary and if you agree to the shut down they credit you $10.00 on your bill.

we have signed up for a heat control thermostat, the utility can turn it down to 19 degrees C in peak during the heating season, 25 degrees C in the cooling season, fits fine for us since we rarely have the winter temp above 18 degrees, and cooler that 28 in summer, and we get a discounted power bill every month for doing nothing and changing nothing.

WHATS THE AVAILABLE HP?

WHATS THE HEAD?

WHATS THE WATER REQUIREMENT?

HOW MUCH AREAS HE WANT TO IRRIGATE PERDAY?

WHETHER HE INSTALLED ANY MICRO IRRIGATION SYSTEM?

WHATS THE CROP?

IF WE KOW THE DETAILS WE CAN SORT TEHE PROBLEM.

All the detail is immaterial because it will stay constant on both sides of the equation.

The only change is that to apply the same amount of water in a shorter time the flow rate and power required must be increased.

He chose 50% increase because he anticipated further cuts.

The system was developed when the water was allocated according to a maximum flow rate and with 24/7 irrigation the most area could be irrigated.

The current allocation is in m³/year but it is based on the use under the old system. He replaced his equipment about 18 months ago but the design essentially stayed the same.

All the farmers in the country are in the same position. Unfortunately I don't know the total area under irrigation.

More industries are in the same boat.

For your information the current shortage was caused because planing, maintenance, investment, development, replacement etc has been neglected for more than 10 years.

The plant water requirement in the area is about 5mm/day for the normal 3 month dry period. I think he can apply 8mm/day but that is barley sufficient to carry him through in dryer spells.

He now want to increase the capacity to 12mm/day.

He measure and schedule properly and will of course not apply any excessive water just because he can.

Changing from Centre pivot to micro he may save 650m³/ha/year but he will increase his area by about 5 ha not to forfeit some of his precious allocation. (new irrigation licences can be obtained by paying 200 x more for the water).

What will be the cost in your country of scrapping a 80ha pivot and replacing it with 85ha micro?

is this for paddy cultivation (12mm/day)

No - It is for completing the job in a shorter time.

His system will be capable of applying 12mm per day but he wont and cant use it that way.

Hi Hendrik

Do a search for Floppy sprinklers or Floppy irrigation. Just maybe something that could help.

Pivot irrigators as Hendrik listed are installed because of their energy efficiency and water use efficiency. They deliver the water from above at low pressure requiring less power at the pump, as we all know pressure requires energy. Pivots and linears have replaced soft hose and hard hose reelers despite much higher capital cost because there is a business case to do so.

One possibility that pivots can open up is the ability to use pumped storage to operate during downtime. This method is used in OZ for a different reason, water harvesting.

A turkey's nest dam is installed on top of a rise and harvested water pumped there and released through the pivot as required. The adjustable low pressure sprays allow this quite well. The only N in the woodpile is, the power required to propel the pivot during the load shedding. Many of the pivots and linears I've installed use about a 12kva diesel genset for this task as there isn't a viable way to connect mains power especially with linears.

Hi Emjay

"The Floppy Sprinkler ® has no moving and wearing parts and therefore requires little or no maintenance."

Maybe with the low pressure use, it can be adapated to suit areas where power is a problem. Don't know, never been involved with irrigation on a large scale. A friend of someone I know grows about 100mx100m lucern, irrigated with the floppy system. Works great they say.

Linears and Pivots are designed for Hectares to Square Km. Look up Valley from Valley Nebraska who are probably the leaders and for hard hose reelers try Idrofoglia from Italy and soft hose reelers Waterwinch. It will give an idea of the scale and the issues regarding energy, time, dosage etc.

can you please inform the availability/discharge/pressure required /specifications.

Hello,

If your friend has not yet purchased his additional 50% capacity pumps, I have two suggestions.

Alternative 1: Suggest that he purchase instead a generator set to product his own electricity during the outages (to run his existing pumps), or else a motor/pump set to run while the power is off or in parralel to the electrical operated pumps.

Alternative 2: (Lower cost also) we often ran our pumps using "PTO" drive from tractor. If he has a farm tractor, it is likely to be of suitable size to run a substantial pump. I can remember building a "V" belt drive where PTO ran 36" pulley running down to 6" pulley to drive the pump.

Hi

He did consider both options but in his situation it would not have been sound economics.

He already is competing against heavily subsidised food imports.

etc.