Shining with Solar Power

Deep in the heart of farming land near Chinhoyi, in a place colloquially known as Poverty Valley, Wayne “Scrappy” Rouse, is productively harnessing the sun’s energy and is using it to power his irrigation. Three years ago, he was fed up with repeated and drawn out power cuts (one lasting for three months). Power grid failures meant large diesel bills for the generator, as well as falling behind on farming schedules and not being able to irrigate. The bottom line was reduced cereal crop yields. A chance chat about the frustrations of this situation with an Austrian friend out on holiday in Zimbabwe, led to a defining moment for Scrappy.

Image by Julie Havercroft

The friend connected him with someone from Austria, working for a firm specialising in solar-powered (photovoltaic) energy, with one sector being irrigation. Innovation is key to staying on top of successful farming and this particular one has turned around Scrappy’s irrigation. He decided to take a leap of faith and build a self-sufficient system which works completely autonomously from the power grid.

The company was given the specifications of his easiest and hardest centre pivots to work with. The most difficult pivot cycle sees water being pumped from the Hunyani river to a height of 90m. The simplest cycle pumps from the dam. The company came up with a solution suited to each scenario. Each setup has its own set of solar powered panels, its own computer and pump. The systems are “smart” and a full set of data from the pumps can be accessed via a special app on a mobile phone. Local company Valley Centre Pivots came on board to supply and connect the pivots and it was all systems go from there on. Making use of the sun Now, he has a daily output in an average month from 875m3 at the first pivot and 913m3 from the other pivot, and this is solely from the strength of the sun. At the moment, this may be the only solar powered irrigation setup within Zimbabwe.

Image by Julie Havercroft

 In a country known for its sunshine, the reasons for this may be the challenges of finance and forex. Initial setup fees were large, but the system has been easy to run, has been low maintenance and has now paid for itself. It also has a long lifespan (the panels’ lifespan is 25 years) and has presented Scrappy with no insurmountable problems so far. Large parts of the summer crops (150ha soya beans and 250ha Maize) and the winter wheat crop (350ha) are watered by the setup and its efficiency is nearly 100%. The photovoltaic panels track the course of the sun. In winter, they work for 11 hours and in summer, they work for up to 14 hours. The system’s output is maximised by this. The panels can generate an output voltage from up to 850 volts and a power of 65 kWp. This gives a flow rate of up to 450m3/ha. Scrappy works on five mm/day to water his wheat, but this output of this system has averaged out at 8mm, well above the crop needs.

Image by Julie Havercroft

 For Scrappy, this gamble has paid dividends. Going bananas As well as the cereals, bananas are grown. The climate in Poverty Valley is warm and perfectly suited to the year round growing of bananas. This section is run separately and has 34 full time employees, all being women. Scrappy’s wife Rachel directly markets the bananas herself and supplies the town of Chinhoyi with the produce, which averages between 28-30 tons weekly. Conservation agriculture Scrappy combine harvests his summer maize and soyas and immediately plants his winter wheat crop into the land. The planter has discs which finely shred the stover and plants directly into the land, at a rate of 35ha/day. This conservation agriculture is built on three principles: minimum soil disturbance, permanent soil cover and crop rotation. These are known to reduce erosion, improve soil quality, conserve water, reduce fuel costs and above all, improve yields. Labour saving, soil and water conservation are benefits of this system, but weeds grow faster in the undisturbed soil and need more effort to keep fields clean.

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