The Balearic Water and Environmental Quality Agency (Abaqua), under the Balearic Ministry of Environment, has included in its energy transition plan, the installation of two turbogenerators on Ibiza to use the flow from the future sa Coma treatment plant, located at an altitude of about 100 meters, to produce electricity. This is intended to compensate for the extra energy cost of pumping water from the city of Ibiza and its surroundings to the sa Coma plant. The current treatment plant will be used as a pumping system to pump wastewater to the plant being built at the old sa Coma shooting range.

A few days ago, in the debate on the value of water organised by the Club Diario de Ibiza and sponsored by Aqualia to mark World Water Day, Abaqua’s secretary general, Juan Calvo, acknowledged that planning Ibiza’s wastewater treatment plant in sa Coma was “nonsense” due to the high energy consumption involved in pumping wastewater to a height of 100 metres. Calvo recalled that almost 20 years ago, when they were looking for land to build a new treatment plant, “nobody wanted it“, and no alternative was found other than Sa Coma despite its altitude. He then explained that Abaqua contacted the Ministry of Ecological Transition, which, as a work of general interest, is building the new treatment plant, to make provision for this possibility. The Institute for Energy Saving and Diversification, which depends on the Ministry, has drawn up a preliminary project to foresee this installation and evaluate the cost, which is estimated at 480,000 euros, according to Calvo.

138,240 euros per year from the sale of energy

The Govern’s public company plans to install two 160 kW turbogenerators in parallel that can generate about 1.4 million kWh per year, which would mean obtaining a total of 138,240 euros from the sale of the energy generated. In January 2019, an engineering firm prepared a technical proposal, which proposed that the hydroelectric system be located at a distance of four kilometers from the treatment plant with a net flow, depending on the flow treated, ranging from 82 meters (minimum flow) to 75 meters (maximum flow). From this point to the seawater discharge there would be a distance of 600 meters. It should be taken into account, however, that the Regional Ministry also plans to use the treated water to recuperate the old irrigation channels of ses Feixes. The Autonomous Community will draw up the project and carry out the work for the installation of the hydroelectric system after the treatment plant is finished and operational. For this reason, Abaqua has asked the Ministry to draw up the preliminary project and to prepare the channeling of the water downstream from sa Coma to connect it to the turbine that will generate electricity. The Balearic Govern intends to finance this work with Next Generation funds from the European Union. Although this project has been included in Abaqua’s energy transition plan, it does not add to the general calculation of the energy savings that will result from the adoption of all the planned measures because its purpose is to compensate for an increase in electricity consumption (the pumping of wastewater to sa Coma) that does not exist now. In any case, the plan points out that it must be borne in mind that the future treatment plant, “being more modern”, will have a lower energy consumption per cubic meter of treated water than the present one. According to data from 2019 (the last year before the pandemic), Ibiza’s desalination and purification plants generate an annual energy consumption of 53.2 million kWh and generate 25,538 tonnes of carbon dioxide emissions into the atmosphere. The island’s three desalination plants produce 84% of the total energy expenditure. The energy transition plan stresses that Ibiza has “a very high consumption of water and energy due to its registered population” because, in addition to seasonality, there is “a greater need to use these infrastructures” due to the situation of the island’s aquifers. With the measures planned by the Government (basically improvements in the energy efficiency of the facilities and, above all, the installation of solar panels) it is calculated that in 2026, the energy cost of Abaqua’s facilities should be reduced to 46.2 million kWh per year, with 22,201 tons of carbon dioxide emissions into the atmosphere.

A long history of delays to replace the old plant Since 2017, and already years behind schedule, when work began on the new Sa Coma wastewater treatment plant, there have been delays in the deadline for the execution of this infrastructure. The declaration of general interest of this facility was approved in 2010, due to the need to replace the current plant, which is totally obsolete and causing repeated spills. After the start of the works, first the obligation to modify the layout of the pipelines and then the appearance of archaeological remains (old cultivation channels) have further delayed the works, which are not expected to be completed for another two years. For the full article, please visit Diario de Ibiza website here.