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Las Palmas de Gran Canaria, Spain

Medina-Dominguez E.J.,Canary Islands Institute of Technology ITC | Medina-Padron J.F.,University of Las Palmas de Gran Canaria
Energies | Year: 2015

The stability and security of small and isolated power systems can be compromised when large amounts of wind power enter them. Wind power integration depends on such factors as power generation capacity, conventional generation technology or grid topology. Another issue that can be considered is critical clearing time (CCT). In this paper, wind power and CCT are studied in a small isolated power system. Two types of wind turbines are considered: a squirrel cage induction generator (SCIG) and a full converter. Moreover, the full converter wind turbine's inertia emulation capability is considered, and its impact on CCT is discussed. Voltage is taken into account because of its importance in power systems of this kind. The study focuses on the small, isolated Lanzarote-Fuerteventura power system, which is expected to be in operation by 2020. © 2015 by the authors.

Carta J.A.,University of Las Palmas de Gran Canaria | Gonzalez J.,University of Las Palmas de Gran Canaria | Cabrera P.,University of Las Palmas de Gran Canaria | Subiela V.J.,Canary Islands Institute of Technology ITC
Applied Energy | Year: 2015

Given the significant water-energy problems associated with many remote and arid areas of the planet, most studies, projects and developments of installations for the production of fresh water using desalination technologies powered by renewable energy sources have focussed on small-scale stand-alone systems. The most commonly used energy sources have been solar photovoltaic and wind and the most widely applied desalination technology that of reverse osmosis (RO). Most of the systems use batteries as a means of mass energy storage and the RO plants normally operate at constant pressure and flow rate. This paper presents a small-scale prototype SWRO (seawater reverse osmosis) desalination plant designed to continuously adapt its energy consumption to the variable power supplied by a wind turbine (WT), dispensing with mass energy storage in batteries and proposing the use of a supercapacitor bank as a dynamic regulation system. A description is given of the tests performed to date with the SWRO desalination plant connected to the conventional grid while controlling the number of pressure vessels that are connected/disconnected to/from the system and regulating their operating pressures and flow rates (within predetermined admissible limits) to maintain a constant permeate recovery rate and adapt the energy consumption of the plant to a widely varying simulated wind energy supply.One of the most important conclusions that can be drawn from the studies undertaken is the feasibility of adapting the consumption of the prototype of the SWRO desalination plant to widely varying WT-generated power. Despite using various time interval lengths in which it was assumed that the WT output power remained constant, a perfect fit was not obtained between the theoretical WT-generated power and the power consumed by the SWRO desalination plant, nor was it possible to maintain a constant permeate recovery rate at each instant. © 2014 Elsevier Ltd.

Abreu-Acosta N.,University of La Laguna | Vera L.,Canary Islands Institute of Technology ITC
Ecological Engineering | Year: 2011

Two wastewater natural reclamation systems (WWNRS) have been compared regarding their efficiencies on faecal bacteria removal and the persistence of enteric pathogens. These WWNRS are constituted of a combination of anaerobic treatment, small sub-surface flow constructed wetland refilled of volcanic ashes and a final pond as water reservoir. Faecal coliforms, enterococci, Escherichia coli, Clostridium perfringens, somatic coliphages, Salmonella sp., Campylobacter sp., Cryptosporidium sp., Giardia sp. and helminth eggs were analyzed in constructed wetlands inlet and outlet and storage pond effluent. Low numbers of protozoan positive samples (4.54% in Albergue de Bolico for both protozoa, and 19.05% in Carrizal Alto for Giardia sp.) and absence of helminth eggs were found. Both systems demonstrated efficient reduction of faecal contamination indicators in the wastewaters (removal rates values of 2log10). The natural systems for wastewater treatment used to be efficient in Salmonella abatement, this fact was confirmed in the reported systems, since enterobacteriaceae were found in only one of the effluents. Campylobacter species associated with the access of animals to storage ponds were detected in the reclaimed water. © 2010 Elsevier B.V.

Penate B.,Canary Islands Institute of Technology ITC | Garcia-Rodriguez L.,University of Seville
Desalination | Year: 2012

Seawater reverse osmosis technology is fully mature at industrial scale which has been installed in all coastal areas around the world with limited natural hydrological resources. There are many technological advances and innovations which are trying to improve the reverse osmosis desalination process. In particular, all pursue to reduce the process energy consumption, as well as to minimize the harmful effects of scaling and fouling on membranes and to obtain higher water flux membranes. This paper presents a comprehensive review of the main innovations and future trends in the design of seawater reverse osmosis desalination technology. These are intended to improve the process performance and the efficiency of this technique for high production. Special focus is placed on the use of renewable energies as an innovation in the medium-term for medium and large production capacities. It supports desalination with renewable energies as an attractive combination in many regions with the possibility of reducing stress on existing water supplies. © 2011 Elsevier B.V..

Penate B.,Canary Islands Institute of Technology ITC | Garcia-Rodriguez L.,University of Seville
Desalination | Year: 2011

Water resources available in the island of Lanzarote, the furthest east of the Canary Islands Archipelago, come mostly from sea water desalination. Desalted water demand in the island has grown considerably in the last decade forcing managers to adapt desalinated water supply constantly. Additionally, the energy dependence of the water cycle in the island is relevant, so any corrective measures over the water supplies will be welcome if it gets more resource with the lowest energy cost. In this way, the authors described in detail and simulate the possible use of hybrid interstage element design of pressure vessels and Pelton retrofits in the Lanzarote IV SWRO plant by comparing the current situation. This desalination plant, one of the largest public desalination plants of the island, has an installed capacity of 30,000m3/day and more than 8years of operation. It is an excellent example to propose changes in order to reduce the process energy consumption, as well as to obtain another series of operation and maintenance advantages. This paper is focused on capital costs savings through the use of new generation membranes and replacing the existing Pelton turbines by other more efficient energy recovery systems based on isobaric chambers. © 2010 Elsevier B.V.

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