By Jason Deign

The Chilean government is hoping to cut highland crop irrigation costs by as much as 65% using CSP as a power source for water pumps.

A project run by the Chilean Ministry of Agriculture’s Agricultural Innovation Foundation (Fundación para la Innovación Agraria or FIA in Spanish) and the project developer Solartec Chile aims to see how CSP compares to traditional power, based on diesel generators.

The FIA says the concept, expected to apply across the centre and north of the country, is ‘unique in the world’.

If successful, “the plan is to start commercialising the system at the end of 2014, once we have tested and validated the prototype,” says Jorge Ortiz Lobo, technical project leader at San Felipe, Valparaiso-based Solartec, which was selected for the project following a tender in 2011.

The FIA estimates CSP-powered pumps could be used across 59,800 hectares of avocados, citrus fruits, grapes, vineyards and other fruit crops planted by around 800 agricultural concerns on steep slopes in the Atacama, Coquimbo, Valparaíso and Metropolitana regions of Chile.

Growers favour the slopes because the land is inexpensive, with a reduced risk of frost and high fertility. Water is a limiting factor for farmers, however, since it has to be pumped long distances uphill before it can reach the plants.

According to published figures, traditional pumping methods can cost from USD$400,000 to $3.5 million per hectare a month. In the case of avocados, this accounts for up to 60% of total production costs.

The FIA believes switching to CSP could reduce electricity costs by between 50% and 65%, and overall production costs by between 10% and 45%, depending on current energy consumption levels.

A $360,000 saving

For a fruit grower currently spending $600,000 per hectare a year on energy, this would translate into a $360,000 saving.

To validate these numbers, the FIA and Solartec are planning a 50kW prototype plant to supply a 10.5 hectare avocado plantation with a 75-metre elevation in the San Esteban commune of Los Andes, Valparaíso.

The FIA calculates the CSP technology will require an upfront cost of $2,500 per kilowatt of pumping power for a 300kW system, making it cheaper than a solar photovoltaic array at between $5,000 and $7,000 per kilowatt.

Local press reports suggest the payback for CSP would be of the order of one to three years, with a 49-trough installation, costing $37 million, covering 19 hectares where the cost of irrigation is $400,000 per hectare.

Another reason for choosing CSP, according to comments in the press by Rodolfo Cortés, former FIA agricultural innovation executive in charge of the project, is the potential for easy maintenance and local manufacturing of most components apart from the concentrator.

The FIA project employs small-scale parabolic trough technology to power a steam turbine. Dish Stirling was discounted because it was only deemed cost effective at small scale.

CSP Today understands the main components of the system have been imported from the USA and Germany, and the project has suffered delays owing to import hurdles. Ortiz declined to name the parabolic trough supplier involved.

Nevertheless, he says, currently “the project is ready to start operating, with a prototype of 40 troughs for the irrigation of 10 hectares of avocados.”

High profile project

It is understood the prototype will be in operation for two seasons, starting this year.

Cortés, who now works as an advisor on regional innovation strategy for the regional government of VI Libertador General Bernardo O'Higgins, says: “It is a project with a high profile nationally, but we will have to wait for the results to see how efficient it really is.

“The last calculations we did showed it was competitive with photovoltaics and other forms of energy and the payback was quick, with a return on investment of three or four years on the slopes with the highest energy expenditure.”

This return on investment is quickest on the steepest slopes, he adds, because of the added energy needed to pump water uphill.

Although the FIA prototype is deemed to be unique, it comes at a time of growing interest in the use of CSP for agricultural applications.

As previously reported in CSP Today, at least two companies are working on the idea of combining parabolic trough technology with greenhouses to provide all-in-one solar desalination and crop-growing facilities in desert regions.

One of them, Sundrop Farms, is believed to be preparing a stock exchange launch next month.

The company has built a pilot system in Port Augusta, South Australia and last August secured an in-principle agreement from the Australian government’s Clean Energy Finance Corporation for funds to extend its greenhouse facility to cover 20 hectares.

In the Middle East, meanwhile, a similar concept is being commercialised by Sahara Forest, a company established in 2011 that is preparing to build a test and demonstration centre after opening a pilot facility in Qatar.

 

CSP as a power source for water pumps in Chile

 

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