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ScienceDirectEnergy Procedia 00 (2017) 000–000

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1876-6102 © 2017 The Authors. Published by Elsevier Ltd.Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling.

The 15th International Symposium on District Heating and Cooling

Assessing the feasibility of using the heat demand-outdoor temperature function for a long-term district heat demand forecast

I. Andrića,b,c*, A. Pinaa, P. Ferrãoa, J. Fournierb., B. Lacarrièrec, O. Le Correc

aIN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, PortugalbVeolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France

cDépartement Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France

Abstract

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 heatsales. 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.

© 2017 The Authors. Published by Elsevier Ltd.Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling.

Keywords: Heat demand; Forecast; Climate change

Energy Procedia 146 (2018) 3–11

1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved.Selection and peer-review under responsibility of the publication committee of the International Carbon Conference 2018.10.1016/j.egypro.2018.07.002

10.1016/j.egypro.2018.07.002 1876-6102

Copyright © 2018 Elsevier Ltd. All rights reserved.Selection and peer-review under responsibility of the publication committee of the International Carbon Conference 2018.

Available online at www.sciencedirect.com

ScienceDirect

Energy Procedia 00 (2018) 000–000 www.elsevier.com/locate/procedia

1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the publication committee of the International Carbon Conference 2018.

International Carbon Conference 2018, ICC 2018, 10–14 September 2018, Reykjavik, Iceland

The lungs of the Earth: Review of the carbon cycle and mass extinction of species

Andrew Gliksona,*

aEarth and paleoclimate science, Australian National University, Canberra, A.C.T. Australia

Abstract

The ability of carbon to combine with oxygen or/and hydrogen, leading to the formation of complex molecules such as amino acids, carbohydrates, lipids, proteins and nucleic acids, in the presence of water, forms the basis of the chemistry of advanced life. The carbon, oxygen, nitrogen and sulphur cycles, mediated by the atmosphere-ocean-land system, constitute the “lungs of the biosphere”, allowing the exchange of essential components of biological molecules. The capture of atmospheric carbon dioxide through photosynthesis, release of oxygen, respiration and burial of carbon produce the balance on which the biosphere depends. The atmospheric concentration of carbon-dominated greenhouse gases plays a key role regulating terrestrial temperatures. The mean global temperature of ~14.9 °C allows the existence on the Earth surface of aqueous media where metabolic microbiological processes are performed, among other by chemo-bacteria, microbes and algae. The geological record displays a close correspondence between paleo-CO2 levels and paleo-temperature trends, allowing the identification of environmental factors that underlie the evolution and extinction of species. Unoxidizing atmospheric and low-pH hydrosphere conditions on the early Earth, dominated by methane, CO2 and CO, constrained the appearance of oxygenating organisms, with the exception of minor oxygen release by stromatolites. An increase in photosynthetic oxygen about 2.45 Ga was associated with proliferation of phytoplankton. Glaciation followed by the “Cambrian Explosion” of life at 543 Ma is considered responsible for development of complex proteins and abundant marine life. The anthropogenic extraction and transfer from the Earth’s crust to the atmosphere of carbon, including coal, oil, tar sand, shale oil, methane gas, coal seam gas and other forms of hydrocarbon, constitutes the most significant shift in composition of the atmosphere since the PETM hyperthermal event (~56 Ma) and the K-T boundary extinction (~66 Ma), with worrying consequences for the planetary habitat. Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the publication committee of the International Carbon Conference 2018.

Keywords: Atmosphere; carbon; methane; temperature; greenhouse

* Corresponding author. Tel.: +61 02 6296 3853. E-mail address: geospec@iinet.net.au

Available online at www.sciencedirect.com

ScienceDirect

Energy Procedia 00 (2018) 000–000 www.elsevier.com/locate/procedia

1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the publication committee of the International Carbon Conference 2018.

International Carbon Conference 2018, ICC 2018, 10–14 September 2018, Reykjavik, Iceland

The lungs of the Earth: Review of the carbon cycle and mass extinction of species

Andrew Gliksona,*

aEarth and paleoclimate science, Australian National University, Canberra, A.C.T. Australia

Abstract

The ability of carbon to combine with oxygen or/and hydrogen, leading to the formation of complex molecules such as amino acids, carbohydrates, lipids, proteins and nucleic acids, in the presence of water, forms the basis of the chemistry of advanced life. The carbon, oxygen, nitrogen and sulphur cycles, mediated by the atmosphere-ocean-land system, constitute the “lungs of the biosphere”, allowing the exchange of essential components of biological molecules. The capture of atmospheric carbon dioxide through photosynthesis, release of oxygen, respiration and burial of carbon produce the balance on which the biosphere depends. The atmospheric concentration of carbon-dominated greenhouse gases plays a key role regulating terrestrial temperatures. The mean global temperature of ~14.9 °C allows the existence on the Earth surface of aqueous media where metabolic microbiological processes are performed, among other by chemo-bacteria, microbes and algae. The geological record displays a close correspondence between paleo-CO2 levels and paleo-temperature trends, allowing the identification of environmental factors that underlie the evolution and extinction of species. Unoxidizing atmospheric and low-pH hydrosphere conditions on the early Earth, dominated by methane, CO2 and CO, constrained the appearance of oxygenating organisms, with the exception of minor oxygen release by stromatolites. An increase in photosynthetic oxygen about 2.45 Ga was associated with proliferation of phytoplankton. Glaciation followed by the “Cambrian Explosion” of life at 543 Ma is considered responsible for development of complex proteins and abundant marine life. The anthropogenic extraction and transfer from the Earth’s crust to the atmosphere of carbon, including coal, oil, tar sand, shale oil, methane gas, coal seam gas and other forms of hydrocarbon, constitutes the most significant shift in composition of the atmosphere since the PETM hyperthermal event (~56 Ma) and the K-T boundary extinction (~66 Ma), with worrying consequences for the planetary habitat. Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the publication committee of the International Carbon Conference 2018.

Keywords: Atmosphere; carbon; methane; temperature; greenhouse

* Corresponding author. Tel.: +61 02 6296 3853. E-mail address: geospec@iinet.net.au

4 Andrew Glikson / Energy Procedia 146 (2018) 3–112 Author name / Energy Procedia 00 (2018) 000–000

1. Introduction

Evidence of major trends and distinct events in the atmosphere-ocean-land system during the Paleozoic, Mesozoic and Cenozoic eras indicate an alternation of tropical high-greenhouse periods (CO2 ~ 2,000–5,000 ppm) and glacial low-greenhouse phases (CO2<500 ppm), controlling the biosphere. During the Palaeozoic low solar luminosity allowed glacial phases to occur even under high atmospheric CO2. Isotopic and other proxies such as 13C/ C12, 34S/32S isotopic indices, relic organic compounds and leaf pore stomata define periods of peak biological productivity. Phanerozoic geochemical models of the carbon, oxygen and sulphur cycles [1] underpin the breakdown of plant matter and the separation of organic carbon through burial under anoxic conditions, represented by major carbon isotope excursions, including δ13C anomalies associated with uptake of methane by clathrates. Major external forcing of mass extinction events included volcanic and asteroid impact episodes, exerting abrupt effects on the carbon cycle (Fig. 1).

Fig. 1. Phanerozoic mass extinctions, volcanic events and asteroid impacts: (A) Extinction intensity; (B) Impact events; (C) Volcanism. Stratigraphic subdivisions and numerical ages are after Gradstein and Ogg [2]. The extinction record is based on genus-level data [3]. The number of impact events, size and age of craters follows largely the Earth Impact Database [4], with modification from a figure courtesy of Gerta Keller.

2. Climate History

The Cenozoic era, for which detailed paleoclimate data are available, includes several stages [5] (Fig. 2 and 3): A. K-T boundary impact and mass extinction at ~66 Ma: Negative δ13C excursion (+1 to -1.5‰) signify accumulation

of extinguished biological debris. B. Post-KT boundary warming culminating with the ~55 Ma Paleocene-Eocene hyperthermal. Negative δ13C

excursion of +1.5 to -10‰ represents buried organic debris. C. Long-term cooling followed by a sharp temperature plunge toward formation of the Antarctic ice sheet from ~32

Ma, with atmospheric CO2 declining from 1100 ppm to 700 ppm.

Andrew Glikson / Energy Procedia 146 (2018) 3–11 5 Author name / Energy Procedia 00 (2018) 000–000 3

D. A post-32 Ma era dominated by the Antarctic ice sheet, including moderate thermal rises at the end-Oligocene, mid-Miocene and end-Pliocene, with CO2 ranging between 700 and 400 ppm.

E. Miocene-Pliocene (~23-2.6 Ma): Transition from tropical to dry climates punctuated toward the Pliocene by cyclic orbital forcing events, appearance and variability selection of Hominins in Africa. CO2 levels of ~400 ppm.

F. Pleistocene (~2.6-0.0117 Ma) glacial-interglacial cycles. CO2 ~180-280 ppm. G. Hominids. From ~2 Ma mastery of fire, allowing the genus to increase its energy output by orders of magnitude,

heralding civilization and combustion, splitting of the atom and the 6th mass extinction of species. CO2 ~280-410 ppm.

H. The mining and drilling of coal and liquid and gas hydrocarbons at a rate reaching ~9 GtC/year (1GtC = 1 billion tons of carbon) (Fig. 4), reaching a total of >600 GtC, just under the pre-industrial atmospheric inventory of carbon, with atmospheric concentration of CO2 of ~410 ppm, threatening to shift the state of the planetary atmosphere into uncharted territory.

Fig. 2. A summary plot of Phanerozoic evolution from 540 Ma, displaying (1) Palaeozoic and Mesozoic oscillations between tropical greenhouse eras and ice ages (blue squares); (2) the descent of mean global temperature from the Paleocene toward the late Eocene to Pleistocene Antarctic ice ages; (3) Late Pleistocene glacial-interglacial cycles; (4) The Holocene and Anthropocoene. Modified after Wikimedia commons.

The onset of vascular plants on land in the Silurian led to flammable land surfaces, heralding a fundamental shift in the composition of the atmosphere in terms of enrichment in photosynthetic oxygen and an onset of wildfires ignited by lightning, incandescent fallout from volcanic eruptions and meteorite impacts, consuming vast quantities of biomass. Subsequent burial of carbon in sediments stored the fuel over geological periods, affecting the carbon and oxygen cycle in favor of oxygen. Experiments suggest fire is suppressed below 18.5% O2, switched off below 16% O2 and enhanced between 19% and 22% O2 [6]. Changes in atmospheric chemistry result in variations in acidity (pH) and oxidation/reduction state (Eh) of the hydrosphere and thereby of the marine food chain.

6 Andrew Glikson / Energy Procedia 146 (2018) 3–114 Author name / Energy Procedia 00 (2018) 000–000

Fig. 3. (A) A model Phanerozoic proxy-based average atmospheric CO2 variations. Green diamonds correspond to peak CO2 levels associated with mass extinction events. LD - late Devonian; PT - Permian-Triassic boundary; LT - late Triassic; LJ - late Jurassic; KT - Cretaceous-Tertiary boundary. (B) Blue squares corresponding to Ice ages and low CO2 periods, excepting the late Ordovician when weak solar radiation resulted in ice ages despite high CO2 levels. Modified after Royer et al. [1].

Fig. 4. Estimates of fossil fuel resources and equivalent atmospheric CO2 levels, including (1) emissions to date, (2) estimated reserves, and (3) recoverable resources (1 ppm CO2 ~ 2.12 GtC). After Hansen et al. [10].

Andrew Glikson / Energy Procedia 146 (2018) 3–11 7 Author name / Energy Procedia 00 (2018) 000–000 5

3. Anthropocene Global warming

The ice core evidence of greenhouse gas (GHG) concentrations and temperatures over the last 740 kyr suggests that the rise rate of GHG reached up to 3 ppm CO2/year and 409 ppm in March 2018 [7] constitutes a unique spike in the history of the atmosphere. Global carbon emissions from fossil fuel use were 32.5 GtCO2/yr in 2017. The extreme warming of the polar regions, reaching a mean of +4 °C, and near +8 °C in 2015-2016, relative to 1951-1980, over large parts of the northern hemisphere and Antarctica [8], threatens the stability of vast reserves of methane locked in permafrost and clathrates in shallow seas and of carbon in vegetation and dissolved in the oceans. These CO2 growth rates exceed even those of the Paleocene-Eocene Thermal Event (PETM), when CO2 growth rates were about an order of magnitude less than at present [9] (Fig. 5 and 6).

The accumulation of unoxidized organic matter, in particular in the Polar Regions, has resulted in the build-up of reserves of methane, in permafrost and shallow water clathrates. Some 650 GtC occur in vegetation worldwide from where CO2 is released to the atmosphere through decay and bush fires. Warming of the oceans releases part of their dissolved CO2 and methane hydrates.

Mean atmospheric CO2 levels have risen from 280 ppm prior to the industrial age to 410 ppm in April 2018, and of methane from ~800 ppb in pre-industrial times to ~1800-1900 ppb at present (Fig. 7), lead to extreme increases in temperature (Fig. 8). Over the short term, the greenhouse gas effect of methane up to 90 times that of CO2, degrading to about 20 times of CO2 over the longer term. This equals more than 36 ppm CO2 over the longer term. Current mean warming in the Arctic of +2 to +8 oC [8] induces thawing of continental and submarine permafrost and the destabilization of marine hydrates, causing massive CO2 and methane release into the atmosphere (Fig. 7). Given estimates of ice sheet stability of approximately ~500 ppm CO2 [12], the rise of CO2e (CO2+CH4 equivalent) toward 500 ppm threatens advanced melting of the Greenland and Antarctic ice sheets and a rise of sea level toward the scale of tens of meters. Advanced melting occurring in the CO2 range of 500-700 ppm threatens to flood coastal and river valleys where the bulk of population, industry and agriculture are concentrated [9] (Fig. 9).

Fig. 5. CO2 increase rates vs temperature rise rates during the Cenozoic compared with rates during the Anthropocene [5, 9]. (D-O cycles: Dansgaard-Oeschger intra-glacial cycles).

8 Andrew Glikson / Energy Procedia 146 (2018) 3–116 Author name / Energy Procedia 00 (2018) 000–000

Fig. 6. Temperature increase rates and the rate of carbon release (ton carbon/year) atmospheric carbon enrichment as a function of time during the PETM hyperthermal [11], the last glacial termination and the Anthropocene, compared to carbon release triggered by an asteroid impact.

4. Conclusions According to Wallace Broecker [13] “The inhabitants of planet Earth are quietly conducting a gigantic experiment.

We play Russian roulette with climate and no one knows what lies in the active chamber of the gun”. According to Hansen et al. [14] “Burning all fossil fuels would create a different planet than the one that humanity knows. The palaeoclimate record and ongoing climate change make it clear that the climate system would be pushed beyond tipping points, setting in motion irreversible changes, including ice sheet disintegration with a continually adjusting shoreline, extermination of a substantial fraction of species on the planet, and increasingly devastating regional climate extremes”. In 2009 Joachim Hans Schellnhuber, Director of the Potsdam Climate Impacts Institute and Climate Advisor to the German Government, stated: “We’re simply talking about the very life support system of this planet” [15]. The author concurs with these statements.

Andrew Glikson / Energy Procedia 146 (2018) 3–11 9 Author name / Energy Procedia 00 (2018) 000–000 7

Fig. 7. (A) Atmospheric CO2 concentration. Red reflects high concentrations, blue reflect lower concentrations and green intermediate concentrations; (B) monthly average concentration of methane for January 2016; (C) atmospheric methane concentrations with time [7].

10 Andrew Glikson / Energy Procedia 146 (2018) 3–118 Author name / Energy Procedia 00 (2018) 000–000

Fig. 8. Mean global temperatures over the last two millennia and future projections (modified after Steffen 2012), together with temperature variations for the period 1880-2018 [7, 8]. Inset: Mean global temperatures 1850-2017 [7, 8].

Fig. 9. Evolution of the climate during the Cenozoic and the choice humanity is facing [5, 10].

Andrew Glikson / Energy Procedia 146 (2018) 3–11 11 Author name / Energy Procedia 00 (2018) 000–000 9

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