By Jason Deign

Sundrop Farms, a specialist integrator of solar power and greenhouse-based agricultural systems, is believed to be preparing a stock exchange launch. The move comes amid growing interest in the use of CSP within standalone horticultural setups.

Sundrop Farms is one of at least two enterprises touting the integration of CSP with agriculture in desert environments. A spokesperson has confirmed the company is currently in “press quiet period,” which is understood to mean it is readying for an initial public offering (IPO).

The IPO is scheduled for next month, CSP Today understands. Sundrop Farms has built a pilot system in Port Augusta, South Australia.

Last August, the company secured an in-principle agreement from the Australian government’s Clean Energy Finance Corporation (CEFC) for funds to extend its greenhouse facility to cover 20 hectares, with a potential yield of more than 15,000 tonnes of vegetables a year.

At the time, Sundrop Farms said in a press statement that the CEFC financing would cover approximately a quarter of the costs of the project, “with remaining financing currently being finalised.”

The project is scheduled for completion in the middle of next year.

“Once implemented, this project would be a worldwide demonstration of sustainable horticulture practices that address growing food security, water and clean energy challenges,” said CEFC’s chief executive, Oliver Yates, in the press material.

Sundrop Farms uses parabolic trough CSP technology to provide power and heating for an integrated water desalination and greenhouse concept. Its Port Augusta pilot, operational since 2010, uses desalinated seawater to grow tomatoes.

Sahara Forest

In the Middle East, meanwhile, a similar concept is being commercialised by Sahara Forest, a company established in 2011.

Joakim Hauge, chief executive, says the firm is preparing to build a test and demonstration centre after opening a pilot facility in Qatar in December 2012, which effectively made it the first CSP entrant in the Qatari market. The 20-hectare test centre will be in Wadi Araba, Jordan.

“The Sahara Forest project is designed to utilise what we have enough of to produce what we need more of, using deserts, sunlight, saltwater and CO2 to produce food, water and clean energy,” Hauge says.

Sundrop Farms is one of Sahara Forest’s commercial partners, supplying the small-scale parabolic trough collector and thermal desalination unit used in the Qatar pilot, adds Virginia Corless, Sahara Forest’s science and development manager.

For CSP, she says: “Our primary partners during the study phases of the Sahara Forest project have been the German-based consultants Schlaich Bergermann.

“We are also in long-term dialogues with a number of CSP developers and providers based in the US, Europe, Australia and the Middle East.”

Although the company is using parabolic trough in its pilot, Corless says: “The Sahara Forest project concept is compatible with all major CSP technologies. We are technology agnostic in this respect, and will make the best technology choice for each project and location.”

One of the benefits claimed by the company is that its concept can make use of salty or brackish water for CSP cooling.

Co-locating CSP

Hauge says: “By co-locating CSP with a saltwater-based evaporative cooling infrastructure, the thermal cycles of electricity generation or thermal desalination can be completed with wet cooling efficiencies, utilizing saltwater instead of freshwater, without the need for cooling towers.

“This is very valuable in hot desert environments, where wet cooling with freshwater is usually not possible and dry cooling leads to efficiency losses in electricity production of up to 10%.”

Furthermore, he points out: “The combination of technologies also has advantages in addressing social and logistical challenges to project development.

“The Sahara Forest project creates a much wider range of economic activity and career opportunities than would a single-purpose facility. This makes the project better able to secure buy-in from a wide range of stakeholders at local, regional and national levels.”

A report derived from Sahara Forest’s pilot experience claims that the saltwater-cooled greenhouse can deliver at least 75 kilos of produce per square metre and “significantly higher yields can be achieved in a commercial setup.”

The company declined to give a timeframe for the completion of its test and demonstration plant. “We have a step-by-step approach and never promise anything within a day, until everything is in place,” explained a spokesperson.

Both the Sahara Forest and Sundrop Farms schemes represent solar-powered variations of a concept called the Seawater Greenhouse, which has been under investigation by a company of the same name since 1991 and has been tested in a number of locations.

Sundrop Farms, in fact, took over operation of a Seawater Greenhouse facility as the basis for its Port Augusta pilot.

While Seawater Greenhouse installations rely on the condensation of water inside the greenhouse for desalination, the integration of CSP into the plant can provide additional energy while taking advantage of saltwater cooling.

To respond to this article, please write to the author, Jason Deign.