Climate Change Mitigation Strategy through Membranes Replacement and Determination Methodology of Carbon Footprint in Reverse Osmosis RO Desalination Plants for Islands and Isolated Territories

Abstract

This article shows a climate change mitigation strategy by means of membranes replacement and determination methodology of carbon footprint in reverse osmosis (RO) desalination plants, valid for all the islands, and even isolated territories in the continent. This study takes the case of study of Canary Islands, where there are more than 320 desalination plants with different sizes, private, and public. The objective is to propose a new method which integrates this analysis with the replacement of membranes, from 0% to 20% per year in sea water reverse osmosis desalination plants, to reduce the carbon footprint and ecological footprint. If it is considered a replacement of 20% of the elements per year, the carbon footprint could be reduced to between 5% and 6% and even more if it is introduced low energy consumption membranes instead of high rejection elements. The factor mix in Canary Islands, according to the technological structure of the generation park that uses oil products, is around 0.678 kgCO2/kWh, much higher than in the Spanish mainland where it is 0.263 kgCO2/kWh. Therefore, it is estimated in Canary Islands 5,326,963 t CO2/year can be emitted, which represents 2.4 tCO2/person/year, 12 times more the admissible admissions per inhabitant in the Canary Islands, only considering the seawater desalination sector. This document shows the different results of the analysis of energy efficiency and the environmental footprints. This study may serve as a tool for the decision-making processes related to how to improve energy efficiency in desalination plants.

Study of the Ecological Footprint and Carbon Footprint in a Reverse Osmosis Sea Water Desalination Plant

“…The methodology to calculate the carbon footprint of the current and future energy mix, considering the sum of the energies of each technology and its emissions mix factor is the following [ 8 ]: HC MIX = ΣE i FM i …”

“…The current energy and future energy of the technologies of the energy mix are the following: E 1 t MIX = ΣE i in the initial moment E 2 t MIX = ΣE i in the final moment being HC MIX : carbon footprint of the energetic mix (tCO 2 ), E 1 t MIX : actual energy of the energetic mix technologies (kWh), E 2 t MIX : future energy of the energetic mix technologies (kWh), E i : energy of each technology (kWh), P t : percentage of use of each technology in the energetic mix and FM is the factor mix, calculated for each technology and island with the total consume of energy per island, associated to the carbon footprint and the percentage of one technology in the energetic mix, including renewable and non-renewable energies [ 8 ].…”

“…A reduction in energy consumption will have a direct impact on environmental improvement and we study this through the carbon footprint produced by these desalination plants and their ecological footprint, the latter as a future line of action [ 8 , 9 ].…”

“…Performance factors in each country seek to quantify the relationship between a biologically productive zone and the global average of the same bio productive zone. In other words, it implies the relationship between the production of goods in a given category of a country, nation, or territory, with their national yields and the amount of territory that would have to be established to produce the same goods with average global yields; therefore, each country has its own set of performance factors, which must be recalculated each year [ 8 , 9 ].…”

“…Finally, this indicator assumes that soil productivity on farms and livestock does not decrease over time; obviously if it decreases, using these itself and by erosion and pollution [ 8 , 9 , 10 ].…”