Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/827133
20 In Site June 2017 Water. desalination + reuse We are stressing our membranes above the recommendation, of course only for a few seconds, but for how long is it viable? Joachim Käufler, managing partner, Synli Technology provider has a background in renewables Flexible process • The concept is to adapt processes and pumping to match power output • The product water will be stored in a reservoir as an alternative to storing renewable energy • Company has conducted extensive membrane testing to discover limits of operational flexibility The Figures • RO output will average at 90,000 m3/d, and will flex from low to high output • The financial optimum requires 80 per cent of power to be sourced from solar PV TeChnology Solar power in Chile Solar capacity mega watt peak (MWp) 2015 Chile wants to generate 19 per cent of energy from solar by 2050. The combined capacity of photovoltaic plants installed, under construction, and presented for assessment was 19,000 MWp at end-2105. Source: Centro Nacional para la Innovación y Fomento de las Energías Sustentables 83% Presented for environmental assessment 4% Installed capacity 13% Under construction German technology provider Synli has focused on developing systems that enable industrial processes to run on renewable energy. One of its early projects, in 2003, was to install the first wind turbine in Abu Dhabi, on Sir Bani Yas Island, eight kilometres off the shore in the Arabian Gulf, primarily to power desalination. The company toured the international water conferences scene about five years ago, but found the market relatively unreceptive to its ideas. "Now we take the market as ready," says Synli managing partner Joachim Käufler, and a new company was established in 2015. Synli's conceptual approach is to develop flexibility in industrial processes enabling them to power up and down to match a fluctuating power supply, and to store product that's produced during peak operations, rather than to store the energy generated during peak sun or wind hours. The ENAPAC project envisages building a new reservoir to store produced water in Tierra Amarillo, about 45 miles from the treatment plant. The water will be conveyed by a twin system of glass fibre reinforced pipes, of 1.4 metres diameter, across a height span of 700 metres, by way of five pumping stations. The first pumping station will be at the intake, the second at the desalination plant, two on the piping route, and the final pumping station will be situated at the reservoir. A dedicated solar photovoltaics plant will be constructed to power the treatment plant and water conveyance network, producing up to 100 megawatts (MW). The water treatment system is to be conventional reverse osmosis, and this will be expected to flex up and down in production levels from about 84,000 m3/d, potentially up to 216,000 m3/d at peak times; and averaging at around 90,000 m3/d. The project hinges on the Synwater load management system, which reads the real-time signal output from the power generation facility, calculates the probability of the power output increasing within the next second, and then signals to the pumps to adapt as closely as possible to this power output. "The more the power output and the power consumption is in balance, the higher the share of renewable energy used. This sounds very simple, but in reality it's not so simple," says Käufler explains. "The challenge for the desalination system is to operate across such a wide variation of flux. How long can you stress your membranes when the wind velocity is high? We are stressing our membranes above the recommended long-term value, of course it is only for a few seconds, but for how long is it recommended? We have tested membrane behaviour under extremely fluctuating process conditions, particularly how long you can run a membrane with peak flux, and then come down to low flux. What is the fatigue behaviour of such a membrane? What are the limits?" The ENAPAC project requires about 3.5 KwH/m3 of desalinated water, including pre and post- treatment, and about the same energy again to pump the water to the mining industry up in the mountains. The financial optimum for the project will be for solar to provide 80 per cent of the power, while the remainder will come from the grid during the cheaper, off-peak hours (Chile's energy pricing changes hourly). The load management system will aim optimally to adapt the operations of the water treatment plant and the water transport system to fluctuating power output levels and energy pricing. "We believe that this is the future for medium or large scale systems with high wind or solar penetration. We are working with 80 per cent, and in upgrade versions 95 per cent renewable energy," says Käufler. million, to cover a photovoltaics plant, water conveyance system including five pumping stations, a new reservoir, and the RO plant. Gleisner points to "viable expressions of interest from German banks" to finance 85 per cent of the cost, as well as support from the German government, and credit insurance specialist Euler- Hermes. The remaining 15 per cent must be provided by the project owner in equity capital. continued from p18