Jet fuel blooms in seawater

A project to produce high-grade biofuels from saltwater-tolerant salicornia plants is under way at the Masdar Institute of Science and Technology in Abu Dhabi.

The integrated approach, which includes fish farming and a mangrove plantation, has the potential to make the project carbon negative.

The project's leaders claim that their techniques enable biofuel to be produced without using arable land or large amounts of fresh water, which are largely seen as the downside of much conventional biofuel production.

The Sustainable Bioenergy Research Project (SBRP) will use technology provided by UOP Honeywell to convert the oil from pressed salicornia into biofuels, including a blend that can be used as jet fuel. Hence the project is also funded by Boeing and Etihad Airways, the national airline of the United Arab Emirates.

“This project will for the first time demonstrate the commercial viability of using integrated saltwater agriculture to provide biofuels for aviation," said Dr John Perkins, Provost of the Masdar Institute.

Producing biofuel from salicornia in an integrated low-carbon, low-pollution circuit was originally tested in Eritrea by Carl Hodges, the founder and chairman of the Seawater Foundation.

The Masdar Institute's setup involves three stages. First saltwater from the sea is fed into a fish farm. The effluent from the fish farm is then used to irrigate salicornia plants.

Normally the effluent from fish farms is considered a pollutant as it is higher in salt than normal seawater and contains fish faeces. Releasing it back into the ocean can create disastrous algae blooms. But it acts as a fertilizer for the salicornia, obviating the need to use fossil-based fertilisers, which increases the carbon footprint of conventional biofuel production.

Run-off from the salicornia plants is then 'cleaned' through the mangroves, which can grow in salt water and sequester carbon in their root systems. The mangrove leaves can be used as fish food, completing the cycle.

Salicornia seeds are processed in much the same way as similar oil-rich crops for biofuel. UOP Honeywell has a proprietary process that can blend the resulting oil with jet fuel. The remainder of the salicornia plant can be used to make lower-grade fuels or be burned as biomass to generate electricity from steam turbines.

Per acre yields of oil from salicornia are on par with soybeans, say researchers at the Masdar Institute, but are only one-eighth the yield of palm oil.

An element of the Masdar Institute's research will be calculating how much carbon the process consumes rather than emits.

"To meet the growing demand for energy worldwide, we must identify regional biofuel solutions that are not only sustainable, but can actually regenerate the ecosystems where they are produced,” said Jennifer Holmgren, vice president and general manager of renewable energy and chemicals for Honeywell’s UOP. “This project is a unique opportunity to showcase the viability of a geographically-optimised solution and the availability of technology that produces high-quality green transportation fuels.”

The salicornia plants can be harvested much like any other arable crop, but as they are highly saline, it is likely they will damage conventional machinery.

The Masdar Institute is part of a zero-emissions city being built in Abu Dhabi, the largest emirate in the UAE.