Environmetal Earth Science Research Papers (original) (raw)

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. Abstract The concept of energy from waste is getting popular nowadays across the globe, as being capable of producing multi fuels and value-added products from different fractions of municipal solid waste (MSW). The energy recovery technologies under this concept are anaerobic digestion (AD), pyrolysis, transesterification, refuse derived fuel (RDF) and incineration. This concept is very relevant to implementation in countries like Saudi Arabia, who wants to cut their dependence on oil. Moreover, the waste to energy becomes the imperative need of the time because of new governmental policy 'Vision 2030' that firmly said to produce renewable energy from indigenous sources of waste, wind and solar and due to given situations of Hajj and Umrah with massive amounts of waste generation in a short period. This study focused on two waste to energy technologies, AD and pyrolysis for food (40% of MSW) and plastic (20% of MSW) waste streams respectively. The energy potential of 1409.63 and 5619.80 TJ can be produced if all of the food and plastic waste of the Madinah city are processed through AD and pyrolysis respectively. This is equivalent to 15.64 and 58.81 MW from biogas and pyrolytic oil respectively or total 74.45 MW of continuous electricity supply in Madinah city throughout the whole year. It has been estimated that the development of AD and pyrolysis technologies will also benefit the economy with net savings of around US 63.51andUS63.51 and US 63.51andUS53.45 million respectively, totaling to an annual benefit of US 116.96million.Therefore,inSaudiArabiaandparticularlyinHoliestcitiesofMakkahandMadinahthebenefitsofwastetoenergyareseveral,includingthedevelopmentofrenewable−energy,solvingMSWproblems,newbusinesses,andjobcreationandimprovingenvironmentalandpublichealth.AbstractTheconceptofenergyfromwasteisgettingpopularnowadaysacrosstheglobe,asbeingcapableofproducingmultifuelsandvalue−addedproductsfromdifferentfractionsofmunicipalsolidwaste(MSW).Theenergyrecoverytechnologiesunderthisconceptareanaerobicdigestion(AD),pyrolysis,transesterification,refusederivedfuel(RDF)andincineration.ThisconceptisveryrelevanttoimplementationincountrieslikeSaudiArabia,whowantstocuttheirdependenceonoil.Moreover,thewastetoenergybecomestheimperativeneedofthetimebecauseofnewgovernmentalpolicy′Vision2030′thatfirmlysaidtoproducerenewableenergyfromindigenoussourcesofwaste,windandsolarandduetogivensituationsofHajjandUmrahwithmassiveamountsofwastegenerationinashortperiod.Thisstudyfocusedontwowastetoenergytechnologies,ADandpyrolysisforfood(40116.96 million. Therefore, in Saudi Arabia and particularly in Holiest cities of Makkah and Madinah the benefits of waste to energy are several, including the development of renewable-energy, solving MSW problems, new businesses, and job creation and improving environmental and public health. Abstract The concept of energy from waste is getting popular nowadays across the globe, as being capable of producing multi fuels and value-added products from different fractions of municipal solid waste (MSW). The energy recovery technologies under this concept are anaerobic digestion (AD), pyrolysis, transesterification, refuse derived fuel (RDF) and incineration. This concept is very relevant to implementation in countries like Saudi Arabia, who wants to cut their dependence on oil. Moreover, the waste to energy becomes the imperative need of the time because of new governmental policy 'Vision 2030' that firmly said to produce renewable energy from indigenous sources of waste, wind and solar and due to given situations of Hajj and Umrah with massive amounts of waste generation in a short period. This study focused on two waste to energy technologies, AD and pyrolysis for food (40% of MSW) and plastic (20% of MSW) waste streams respectively. The energy potential of 1409.63 and 5619.80 TJ can be produced if all of the food and plastic waste of the Madinah city are processed through AD and pyrolysis respectively. This is equivalent to 15.64 and 58.81 MW from biogas and pyrolytic oil respectively or total 74.45 MW of continuous electricity supply in Madinah city throughout the whole year. It has been estimated that the development of AD and pyrolysis technologies will also benefit the economy with net savings of around US 116.96million.Therefore,inSaudiArabiaandparticularlyinHoliestcitiesofMakkahandMadinahthebenefitsofwastetoenergyareseveral,includingthedevelopmentofrenewable−energy,solvingMSWproblems,newbusinesses,andjobcreationandimprovingenvironmentalandpublichealth.AbstractTheconceptofenergyfromwasteisgettingpopularnowadaysacrosstheglobe,asbeingcapableofproducingmultifuelsandvalue−addedproductsfromdifferentfractionsofmunicipalsolidwaste(MSW).Theenergyrecoverytechnologiesunderthisconceptareanaerobicdigestion(AD),pyrolysis,transesterification,refusederivedfuel(RDF)andincineration.ThisconceptisveryrelevanttoimplementationincountrieslikeSaudiArabia,whowantstocuttheirdependenceonoil.Moreover,thewastetoenergybecomestheimperativeneedofthetimebecauseofnewgovernmentalpolicy′Vision2030′thatfirmlysaidtoproducerenewableenergyfromindigenoussourcesofwaste,windandsolarandduetogivensituationsofHajjandUmrahwithmassiveamountsofwastegenerationinashortperiod.Thisstudyfocusedontwowastetoenergytechnologies,ADandpyrolysisforfood(4063.51 and US 53.45millionrespectively,totalingtoanannualbenefitofUS53.45 million respectively, totaling to an annual benefit of US 53.45millionrespectively,totalingtoanannualbenefitofUS116.96 million. Therefore, in Saudi Arabia and particularly in Holiest cities of Makkah and Madinah the benefits of waste to energy are several, including the development of renewable-energy, solving MSW problems, new businesses, and job creation and improving environmental and public health.