Jessica Strefler

The value of bioenergy in low stabilization scenarios: an assessment using REMIND-MAgPIE

This study investigates the use of bioenergy for achieving stringent climate stabilization targets and it analyzes the economic drivers behind the choice of bioenergy technologies. We apply the integrated assessment framework REMIND-MAgPIE to show that bioenergy, particularly if combined with carbon capture and storage (CCS) is a crucial mitigation option with high deployment levels and high technology value. If CCS is available, bioenergy is exclusively used with CCS. We find that the ability of bioenergy to provide negative emissions gives rise to a strong nexus between biomass prices and carbon prices. Ambitious climate policy could result in bioenergy prices of 70

Scenarios towards limiting global mean temperature increase below 1.5 °C

/GJ (or even 430

Description of the REMIND Model (Version 1.5)

/GJ if bioenergy potential is limited to 100 EJ/year), which indicates a strong demand for bioenergy. For low stabilization scenarios with BECCS availability, we find that the carbon value of biomass tends to exceed its pure energy value. Therefore, the driving factor behind investments into bioenergy conversion capacities for electricity and hydrogen production are the revenues generated from negative emissions, rather than from energy production. However, in REMIND modern bioenergy is predominantly used to produce low-carbon fuels, since the transport sector has significantly fewer low-carbon alternatives to biofuels than the power sector. Since negative emissions increase the amount of permissible emissions from fossil fuels, given a climate target, bioenergy acts as a complement to fossils rather than a substitute. This makes the short-term and long-term deployment of fossil fuels dependent on the long-term availability of BECCS.

A multi-model assessment of the co-benefits of climate mitigation for global air quality

The 2015 Paris Agreement calls for countries to pursue efforts to limit global-mean temperature rise to 1.5 °C. The transition pathways that can meet such a target have not, however, been extensively explored. Here we describe scenarios that limit end-of-century radiative forcing to 1.9 W m−2, and consequently restrict median warming in the year 2100 to below 1.5 °C. We use six integrated assessment models and a simple climate model, under different socio-economic, technological and resource assumptions from five Shared Socio-economic Pathways (SSPs). Some, but not all, SSPs are amenable to pathways to 1.5 °C. Successful 1.9 W m−2 scenarios are characterized by a rapid shift away from traditional fossil-fuel use towards large-scale low-carbon energy supplies, reduced energy use, and carbon-dioxide removal. However, 1.9 W m−2 scenarios could not be achieved in several models under SSPs with strong inequalities, high baseline fossil-fuel use, or scattered short-term climate policy. Further research can help policy-makers to understand the real-world implications of these scenarios.Scenarios that constrain end-of-century radiative forcing to 1.9 W m–2, and thus global mean temperature increases to below 1.5 °C, are explored. Effective scenarios reduce energy use, deploy CO2 removal measures, and shift to non-emitting energy sources.

Pathways limiting warming to 1.5°C: a tale of turning around in no time?

This document describes the REMIND model in its version 1.5. REMIND is an integrated assessment model of the energy-economy-climate system. REMIND stands for “Regional Model of Investments and Development.”

Techno-Economic Review of Direct Air Capture Systems for Large Scale Mitigation of Atmospheric CO2

We present a model comparison study that combines multiple integrated assessment models with a reduced-form global air quality model to assess the potential co-benefits of global climate mitigation policies in relation to the World Health Organization (WHO) goals on air quality and health. We include in our assessment, a range of alternative assumptions on the implementation of current and planned pollution control policies. The resulting air pollution emission ranges significantly extend those in the Representative Concentration Pathways. Climate mitigation policies complement current efforts on air pollution control through technology and fuel transformations in the energy system. A combination of stringent policies on air pollution control and climate change mitigation results in 40% of the global population exposed to PM levels below the WHO air quality guideline; with the largest improvements estimated for India, China, and Middle East. Our results stress the importance of integrated multisector policy approaches to achieve the Sustainable Development Goals.

Global energy sector emission reductions and bioenergy use: overview of the bioenergy demand phase of the EMF-33 model comparison

We explore the feasibility of limiting global warming to 1.5°C without overshoot and without the deployment of carbon dioxide removal (CDR) technologies. For this purpose, we perform a sensitivity analysis of four generic emissions reduction measures to identify a lower bound on future CO2 emissions from fossil fuel combustion and industrial processes. Final energy demand reductions and electrification of energy end uses as well as decarbonization of electricity and non-electric energy supply are all considered. We find the lower bound of cumulative fossil fuel and industry CO2 emissions to be 570 GtCO2 for the period 2016–2100, around 250 GtCO2 lower than the lower end of available 1.5°C mitigation pathways generated with integrated assessment models. Estimates of 1.5°C-consistent CO2 budgets are highly uncertain and range between 100 and 900 GtCO2 from 2016 onwards. Based on our sensitivity analysis, limiting warming to 1.5°C will require CDR or terrestrial net carbon uptake if 1.5°C-consistent budgets are smaller than 650 GtCO2. The earlier CDR is deployed, the more it neutralizes post-2020 emissions rather than producing net negative emissions. Nevertheless, if the 1.5°C budget is smaller than 550 GtCO2, temporary overshoot of the 1.5°C limit becomes unavoidable if CDR cannot be ramped up faster than to 4 GtCO2 in 2040 and 10 GtCO2 in 2050. This article is part of the theme issue ‘The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels’.

The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview

We review energy and economic requirements, available technologies, and limiting factors for direct air capture systems.As the concentration of carbon dioxide in the Earths atmosphere continues to increase, discussion about various methods to bring this gas under control intensify. Current data from the US National Oceanic and Atmospheric Administrations Earth System Research Laboratory: Global Monitoring Division (NOAA/ESRL) shows atmospheric carbon dioxide concentrations teasing the 400 ppm by volume threshold in 2015 (Dlugokencky & Tans, 2015). The climate goal noted in the Copenhagen Accord, and discussed internationally since, is “to hold the increase in global temperature below 2 degrees Celsius” (UNFCCC, 2010, p. 5, 2015). To obtain this goal, various pathways have been suggested by the IPCC which incorporate different scenarios utilizing varying combinations of methods and technologies (IPCC, 2014). While ideally atmospheric carbon dioxide would be reduced through a decrease in consumption and introduction of new technologies that eliminate emissions, reduce emissions, or capture emissions at their source, removing atmospheric carbon dioxide after release into the atmosphere for sequestration is also an option. Direct air capture (DAC) is one of several proposed technologies intended to remove carbon dioxide directly from the atmosphere, regardless of its source. Since the atmosphere effectively disperses CO2 emissions from both large and small sources quickly and evenly, a continuous supply of CO2 laden air would naturally be delivered to any DAC site, with no local buildup of CO2 depleted air likely (Goeppert, Czaun, Surya Prakash, & Olah, 2012, p. 7837). Debate about the efficiency and practicality of this technology has been heated, but as atmospheric carbon continues to rise the pathways necessary to achieve the 2 degree goal become increasingly dependent on achieving negative carbon emissions by the second half of this century (IPCC, 2014, p. 490). The success of technologies such as DAC become ever more important.

Future air pollution in the Shared Socio-economic Pathways

We present an overview of results from 11 integrated assessment models (IAMs) that participated in the 33rd study of the Stanford Energy Modeling Forum (EMF-33) on the viability of large-scale deployment of bioenergy for achieving long-run climate goals. The study explores future bioenergy use across models under harmonized scenarios for future climate policies, availability of bioenergy technologies, and constraints on biomass supply. This paper provides a more transparent description of IAMs that span a broad range of assumptions regarding model structures, energy sectors, and bioenergy conversion chains. Without emission constraints, we find vastly different CO2 emission and bioenergy deployment patterns across models due to differences in competition with fossil fuels, the possibility to produce large-scale bio-liquids, and the flexibility of energy systems. Imposing increasingly stringent carbon budgets mostly increases bioenergy use. A diverse set of available bioenergy technology portfolios provides flexibility to allocate bioenergy to supply different final energy as well as remove carbon dioxide from the atmosphere by combining bioenergy with carbon capture and sequestration (BECCS). Sector and regional bioenergy allocation varies dramatically across models mainly due to bioenergy technology availability and costs, final energy patterns, and availability of alternative decarbonization options. Although much bioenergy is used in combination with CCS, BECCS is not necessarily the driver of bioenergy use. We find that the flexibility to use biomass feedstocks in different energy sub-sectors makes large-scale bioenergy deployment a robust strategy in mitigation scenarios that is surprisingly insensitive with respect to reduced technology availability. However, the achievability of stringent carbon budgets and associated carbon prices is sensitive. Constraints on biomass feedstock supply increase the carbon price less significantly than excluding BECCS because carbon removals are still realized and valued. Incremental sensitivity tests find that delayed readiness of bioenergy technologies until 2050 is more important than potentially higher investment costs.