Agricultural irrigation in Spain is a highly consuming activity of electricity (5,000 GWh/year), fuel (300,000 t/year) and water (14,500 Hm3/year). Since 2008, the electricity tariffs for irrigators have increased dramatically (up to 1250%), reducing the competitiveness of many agriculture productive initiatives.
For some crops, the energy cost can represent up to 50% of the overall harvesting costs, putting in serious danger the survival of these crops and farmers in the market.
The employment of photovoltaic pumping in large scale agricultural irrigation represents an innovative, reliable and cost-effective alternative versus the conventional energy sources such as electric grid and diesel generators.
PV irrigation reduces the energy cost up to 60%. The technology applies to all kinds of irrigation (sprinkles, drip irrigation, pivots, water canyons and so on), different size of the pumps, from small to high power pumps (megawatts) and different energy source configuration (PV stand alone systems, hybridization with the electric grid or diesel generators).
PV pumping irrigation does not use batteries to cumulate energy. When the farm has an elevated water tank or an irrigation pond, pumped water can be stocked in these reservoirs to be used later for irrigation. Otherwise, if that is not possible, then the PV system is able to pump directly to the irrigation grid at a constant flow and pressure.
The core of the PV system is the frequency inverter, which adapts the motor-pump running (RPM or Hz) to the available PV energy at all times. Moreover, the inverter is programmed with the needed algorithms to control all the pumping performance: starting and stop of the motor-pump; detection of empty wells and full water tank; communication with irrigation controllers; management of power intermittency due to clouds, and so on.
PV modules, frequency inverters an water motor-pumps used in PV irrigation are standard market equipment and their quality and reliability is guaranteed by world-renowned manufacturers.
DIFFERENT KIND OF CONFIGURATION
- DIRECT AND CONSTANT PRESSURE PUMPING
- Stand alone system
- Electric hybridization
- Hydraulic hybridization
- DIRECT AND CONSTANT PRESSURE PUMPING
THE BENEFITS OF PV IRRIGATION
Low cost. PV irrigation systems can contribute to reduce the electricity bill up to 60% when replacing grid connected pumps and even more when replacing diesel generators, depending on the cases.
Energy costs independency. The most interesting benefit is that once the investment has been made, the cost of energy will be never affected by the conventional energy market, such as the usual increases of the electricity tariffs or the price of diesel.
Irrigation effectiveness. Unlike conventional systems (grid connected or diesel generators), PV irrigation works only during the daylight hours. Thus, PV systems need to be sized accurately to satisfy the water needs, taking into account the daylight available hours. Moreover, all the control algorithms must be adjusted to each particular pumping system in order to fit the farmer needs. For this reason, plug-and-play PV pumping systems do not work in large irrigation applications.
Reliability. PV irrigation systems are composed by reliable components which can guarantee a lifetime up to 25 years, provided that the O&M work is carried out properly.
Environment. PV irrigation assures cero CO2 emissions and the absence of disturbing noises, such as those produced by diesel generators.
Easy installation. Once the PV system has been designed and sized, the exiting pumps in the farm can be kept, adapting the system to them, as well as to the irrigation controller and its programmes. A flat and clear terrain must be available as close to the pumps as possible. The surface of that terrain varies according with the size of the PV generator. As reference, a fix mounted PV generator needs around 13 m2/kWp and a North-South axe horizontal tracker around 20 m2/kWp.