Bioenergy and carbon capture with storage (BECCS): the prospects and challenges of an emerging climate policy response
There is increasing impetus for large-scale deployment of carbon dioxide removal geoengineering approaches to help keep temperatures to below 2 °C, as provided for under the Paris Agreement. The primary option that has been discussed to date is Bioenergy with carbon capture and storage (BECCS). While BECCS could sequester very large amounts of carbon dioxide, it also poses substantial socio-economic risks to society, as well as threats to biodiversity. This essay suggests that a human rights-based approach can help to protect the interests of those who might be adversely impacted by BECCS deployment.
KeywordsClimate change Bioenergy with Carbon Capture and Storage Climate Geoengineering
The recent announcement by US President Donald Trump of his intention to withdraw the United States from the Paris Agreement could have serious implications for the future viability of the treaty in meeting its objective of “holding the increase in the global average temperature to well below 2 °C above pre-industrial levels …” (UNFCCC Conference of the Parties 2015; Galston et al. 2017). However, beyond this setback, the disconcerting reality is that pledges made by the Parties to the Paris Agreement to date via Intended Nationally Determined Contributions, or INDCs, put the world on track to blow well past the Paris temperature goals. Researchers at MIT project that global greenhouse emissions may rise to 64 gigatons carbon dioxide equivalent by 2050, and 78 gigatons carbon equivalent by 2100, resulting in temperature increases of between 3.1–5.2 °C by 2100 (MIT Joint Program on the Science and Policy of Global Change 2017). Other recent studies peg potential temperature increases by the end of century of between 2.6–3.7 °C by 2100 (Rogelj et al. 2016), with even higher temperatures over the course of several centuries beyond (Clark et al. 2016).
There is growing recognition that major emitting States may lack the political will to effectuate rapid decarbonization of the global economy, as well as face daunting technological challenges in achieving this goal. This has increased focus in the last decade on so-called climate geoengineering options, defined by the UK’s Royal Society as “the deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change.” (The Royal Society 2009). Indeed, as David Victor observes, while the idea of willfully seeking to alter planetary albedo was once derided as “a freak show in the otherwise serious discussions of climate science and policy” (Victor 2008), investigations into geoengineering options are now considered more orthodox, though still relatively niche, areas of inquiry (Pasztor et al. 2017).
Climate geoengineering options are generally divided into two broad categories, solar radiation management (SRM) and carbon dioxide removal (CDR) (Burns 2012). SRM geoengineering approaches focus on reducing the amount of solar radiation absorbed by the Earth (estimated at approximately 235 W m−2 currently) by an amount sufficient to offset some, or all, of the increased trapping of infrared radiation by rising levels of greenhouse gases (MacCracken 2009). Examples of frequently discussed SRM options include the following: sulfur aerosol injection (SAI), which would seek to enhance planetary albedo (surface reflectivity of sun’s radiation) through the injection of a gas, such as sulfur dioxide, into the stratosphere, potentially exerting a potent cooling effect; marine cloud brightening schemes, which contemplate dispersal of seawater droplets approximately 1 μm in size into marine stratiform clouds to increase their albedo; and space-based systems, which involve positioning sun-shields in space to reflect or deflect solar radiation back to space (Burns 2012).
Carbon dioxide removal approaches, by contrast, seek to remove and sequester carbon dioxide from the atmosphere through biological, geochemical, or chemical means (Williamson 2016) to limit the absorption of solar radiation. The most frequently discussed CDR options include ocean iron fertilization, which would entail seeding iron-deficient areas of the world’s oceans to stimulate carbon-sequestering phytoplankton production; enhanced weathering, which uses the dissolution of natural or artificially created minerals to remove carbon dioxide from the atmosphere; direct air capture, a process to extract CO2 from ambient air in a closed-loop industrial process, and bioenergy carbon capture and storage (BECCS) systems that convert biomass to heat, electricity, or liquid or gas fuels, coupled with carbon dioxide (CO2) capture and sequestration (CCS), storing the CO2 terrestrially or in the ocean (Burns 2016a). CDR technologies as a class have typically been characterized as expensive, long-term, slow-acting climate engineering response options, in comparison to the relatively cheap, fast-acting regional or planetary cooling that models suggest through deployment of certain SRM technologies (Olson 2011; Russell et al. 2012). However, it has also been emphasized that CDR approaches could, unlike SRM options, help address the threat of ocean acidification and (Hansen et al. 2017).
Interest in climate geoengineering began to intensify approximately a decade ago, spearheaded by Nobel Prize-winning scientist Paul Crutzen’s 2006 article in Climatic Change (Crutzen 2006). Crutzen’s piece effectively punctured a research community taboo against consideration of solar radiation management climate engineering technologies (Kerr 2006; Robock 2008). The subsequent decade has witnessed a large increase in academic interest in SRM (Scott 2013), as well as growing consideration in the policy arena (USGCRP, Bracmort and Lattanzio 2013; United Kingdom, House of Commons 2010).
Over the past decade, a number of studies have emphasized the potential for SRM technologies to ensure that temperatures do not exceed critical thresholds, or to facilitate rapid cooling of the earth in the event of a so-called climate emergency, such as rapid deterioration of the Greenland ice sheet or massive releases of methane from Arctic permafrost (Klepper and Rickels 2014; Morgan et al. 2010). However, research in recent years has also emphasized that deployment of SRM approaches could pose serious risks to humans and natural systems, including weakening of the hydrological cycle in certain regions, which could, inter alia, radically alter monsoon patterns in some regions, including South Asia depletion of the ozone layer, and extremely large pulses of warming if use of said technologies was suddenly terminated (Niemeier and Tilmes 2017; Lohmann and Gasparini 2017; Burns and Nicholson 2016).
Concerns of this nature have probably encouraged scientists and policymakers to increasingly shift their gaze toward CDR options. Perhaps even greater impetus has come from the conclusions of the Intergovernmental Panel on Climate Change’s Fifth Assessment report. The report included 204 separate scenarios, which in integrated assessment model runs held atmospheric temperature increases to less than 2 °C above pre-industrial averages by 2100. Of those 204 scenarios, 184 contemplated large-scale deployment of one specific CDR option, BECCS (IPCC 2014; Moreira et al. 2016). Across all these scenarios, the median commitment to the use of BECCS in the latter half of this century is 12 gigatons of removal annually, equivalent to a quarter of current emissions (Field and Mach 2017). In the interim, a number of other studies have also concluded that large deployment of carbon dioxide removal approaches may be critical to holding temperature to 2 °C or below (Rockström et al. 2017; Bui et al. 2017).
Moreover, deployment of so-called negative emissions technologies (technologies that could effectuate a permanent net removal of carbon dioxide, as opposed to options that merely reduce emissions to the atmosphere) could afford society the opportunity to recover from “overshooting” carbon dioxide concentration targets later in this century (Lomax et al. 2015; IEA 2011). Additionally, negative emissions from BECCS may compensate for residual emissions in other sectors, such as transportation, in the second half of this century (IPCC 2014). Some commentators have also contended that CDR technologies might be deployed in conjunction with SRM options (as well as mitigation and adaptation responses), with CDR technologies slowly lowering concentrations of greenhouse gases to the point where deployment of SRM options could cease (Long 2017).
A large-scale BECCS program would generate energy by converting vast amounts of biomass into liquid biofuels, or direct burning of biomass at appropriately equipped power stations. Potential sources of bioenergy feedstock include energy derived from woody biomass harvested from forests, including fuel wood, charcoal, and residues; energy crops, such as jatropha and palm; food crops, including corn, sweet sorghum, and annual crops such as switchgrass; and agro-residues (animal manure and crop residues), agro-industrial and municipal solid wastes, and other biological resources (Mirzabaev et al. 2014).
The bioenergy system would then need to be paired with a carbon capture method, so that carbon emissions could be captured at the source of combustion. Finally, the carbon must be converted into a form, probably liquid, for transportation and then injection into the earth for storage, deep in the underground chasms left vacant by removal of oil and gas deposits, in deep saline formations, in unminable coal beds, or in the deep ocean (IPCC 2005; Kornneeff et al. 2012; USEPA 2016). There are also proposals for using carbon dioxide for other purposes, such as enhanced oil recovery, biochemical conversion into biofuels, or for energy storage technologies (Oloman 2009).
At this point, large-scale deployment of BECCS to combat climate change remains largely theoretical, with only 15 pilot plants and 1 commercial plant currently in operation (Gough and Vaughan 2015). One imposing challenge is whether BECCs will prove economically viable absent the imposition of much more robust prices on carbon, or regulatory mandates (Venton 2016; Kemper 2015). Recent studies suggest that a carbon price of as much as $150–165/ton might be necessary to drive large-scale adoption of BECCS (Kemper 2015; Humpenöder et al. 2014).
However, even if BECCS can overcome cost concerns, serious questions may arise in terms of the potential environmental, social justice and livelihood impacts of large-scale utilization. It is particularly important to robustly scrutinize these issues because there has been a tendency by some members of the geoengineering community to portray CDR options as “benign” (Read and Lermit 2005) or “safe,” or relatively risk-free, often in comparison to potential SRM technologies (National Research Council 2015; Zheng and Xu 2014). We believe that it is critical that BECCS be scrutinized in a manner that protects the interests of the very same people that may be disproportionately impacted by the climate change.
“[B]iological versions of CDR may largely transfer environmental risk from the atmosphere to the land (Tavoni and Socolow 2013).” One of the most potentially serious ramifications of large-scale deployment of BECCS could be in the context of food production, and its implications for food security for some of the world’s most vulnerable populations. Delivery of a relatively modest 3 gigatons of carbon dioxide equivalent negative emissions annually from BECCS would require conversion of a land area of approximately 380–700 million hectares in 2100, translating into 7–25% of agriculture land and 25–46% of arable and permanent crop area (Smith et al. 2016; Williamson 2016). The range of land demands would be 2–4 times larger than land areas that have been classified as abandoned or marginal (Smith et al. 2016). This would be in the face of rising demands for food that will require 10–20% more cropland over the course of the next few decades (Creutzig 2017).
Demands on land of this magnitude could substantially raise prices on basic food commodity crops (Barrett 2014). One recent assessment that incorporates strict protection of forest ecosystems projects large-scale BECCS deployment could result in the rise of food price indices of 82% in Africa, 73% in Latin America, and 52% in Asia Pacific (Popp et al. 2011). This could imperil food security for many of the world’s most vulnerable, with many families in developing countries already expending 70–80% of their income on food (De Schutter 2013; US Government Accounting Office 2011). One recent study indicated that even modest increases in bioenergy development could increase the number of malnourished children in sub-Saharan Africa by 3 million, with an 8% decline in calorie availability (Ewing and Msangi 2008). Efforts to develop feedstock for bioenergy can also result in displacement of the poor from land, which can undermine food security, as well as livelihoods, political power, and social identity (Catula et al. 2008; Kartha and Dooley 2016). Some proponents of BECCS have contended that pressures on food production and prices could be substantially ameliorated by using “degraded” or “abandoned” land for expansion of bioenergy feedstock. However, the reality is that hundreds of millions may rely on these lands for income and sustenance (Smolker and Ernsting 2012).
BECCS could imperil the right to water in some regions of the world given its “very large water footprint,” even when implemented at a relatively modest scale of between 1.1 and 3.3 gigatons of carbon dioxide equivalent per year (Smith 2016). By 2100, BECCS feedstock production at scale could require approximately 10% of the current evapotranspiration from all global cropland areas (Smith et al. 2016), or of the same magnitude as all current total agricultural water withdrawals (Bonsch et al. 2016; Chaturvedi et al. 2015). This is at a time that when global water withdrawals are projected to increase by 20% and the number of people experiencing water shortages could grow by billions (Delucchi 2010). Moreover, 800,000 humans currently die annually as a consequence of contaminated drinking water (UN Water 2017). Large deployment of BECCS could exacerbate this threat by further degrading water quality by salinization, and from fertilizer and pesticide runoff associated with production of bioenergy feedstocks (Delucchi 2010).
Many of the most propitious areas for bioenergy development are also characterized by high levels of biodiversity, with a large share of endemic species (Beringer et al. 2011). Recent research indicates that large-scale BECCS deployment could also have profound impacts on biodiversity, primarily due to potential land conversion (Searchinger and Heimlich 2015; Smith and Torn 2013). More specifically, BECCS could “vastly accelerate the loss of primary forest and natural grassland, (Williamson 2016), resulting in the loss of up to one-fifth of natural forests, grasslands and savannahs (Creutzig 2017). This could precipitate habitat loss for many species, and ultimately, “massive” changes in species richness and abundance (Wiltshire and Davies-Barnard 2015). Indeed, Williamson concluded that large-scale deployment of BECCS could result in a greater diminution of terrestrial species than temperature increases of 2.8 °C above pre-industrial levels (Williamson 2016).
Finally, BECCs deployment could require more than doubling fertilizer inputs (Creutzig 2014), exacerbating environmental degradation associated with anthropogenic perturbation of the nitrogen cycle. Current human fixation of atmospheric nitrogen exceeds sustainable levels by 75% (Kartha and Dooley 2016). This results in serious environmental impacts, including large-scale anoxia in oceans, eutrophication of streams and rivers, and changes in nutrient health in forests (Kartha and Dooley 2016; Bernhard 2010). Large-scale deployment of BECCS could require as much as 75% of global annual nitrogen production (Buck 2016), “enhancing the pressure on the planetary boundary for biogeochemical flow” (Boysen et al. 2016).
We wish to emphasize that we are not conceptually opposed to BECCS as a potential climate change response measure. Given the feckless response of the international community to date, and the potentially catastrophic ramifications of unchecked climate change, one would be hard-pressed to take virtually any option off the table at this point. However, we believe that it is important to dispel notions that large-scale deployment of BECCS would necessarily prove “benign.” Rather, we believe that a full-throated assessment of BECCS should be conducted on the axes of technological and economic viability, as well as in the context of social justice, and sustainable development. We also believe that institutional mechanisms should be put in place to seek to ameliorate any potential negative ramifications of BECCS deployment in terms of the environment or human welfare.
[I]f the many reservations increasingly voiced about negative-emission technologies (particularly BECCS) turn out to be valid, the weakening of near-term mitigation and the failure of future negative-emission technologies will be a prelude to rapid temperature rises reminiscent of the 4°C “business as usual” pathway feared before the Paris Agreement.
Engage in robust assessment and certification of the sustainability and equity of BECCS projects. As Erb observes, “policy strategies are needed that succeed in simultaneously optimizing production and consumption systems and considering the many potential conflicting uses of biomass, land and water” (Erb et al. 2012). Critical components of such strategies include comprehensive life-cycle assessments and integrated assessment modeling of the environmental and economic impacts of large-scale adoption of BECCS. Most current assessments are suboptimal in these contexts. For example, Integrated Assessment Models (IAMs) often project minimal indirect land-use effects (conversion to croplands somewhere in the world to compensate for some portion of displaced crops) by assuming that policies are in place to protect forests and restrict bioenergy production to unproductive land. This is despite the fact that this is often not the case (Creutzig 2012). Modeling of BECCS must, in particular, realistically assess the existence of such legal or regulatory protections in States that might provide substantial portions of bioenergy feedstock, including African nations, where such protections may not exist (Amigun et al. 2011). IAMs also often incorporate extremely simplistic representations of markets, such as an assumption of perfect competition and a failure to take into account non-market subsistence farming and non-market uses of other environmental goods and services, including biodiversity. This could have substantial ramifications for future bioenergy markets and their environmental and social consequences (Creutzig 2012). More generally, the large uncertainties attendant to assessing carbon dioxide removal options necessitate investigation by employing robust decision making, portfolio management, and/or Bayesian learning (Creutzig 2014). Similarly, life-cycle assessments (LCAs) of bioenergy often fail to assess critical environmental issues including air pollution, abiotic resource depletion, and perhaps most importantly, potential impacts on biodiversity (UNEP 2014). It should also be incumbent on the world community to develop binding, uniform international sustainability standards for BECCS projects and compulsory certification schemes (UNEP 2014; Buyx and Tait 2011). These standards should include consideration of environmental and social impacts of BECCS deployment, including human rights considerations, such as potential impacts on the right to food and water (Burns 2016b; Buyx and Tait 2011). Guidelines that have been formulated in this context would provide a good starting point for developing such standards. These include those of the Roundtable on Sustainable Biofuels, the biofuels standards of the European Union, Global Bioenergy Partnership, the International Organization for Standardization, and the International Sustainability and Carbon Certification System (Popp et al. 2014; Mclaren 2012; Buyx and Tait 2011). While development of such standards needs to include granular assessments at the national and local levels (Amigun et al. 2011), international governance in this context is particularly important because a number of the countries that may be targeted for BECCS development are characterized as failed states, including several in sub-Saharan Africa, or currently have no sustainability standards for bioenergy production (Erb et al. 2012; Amigun et al. 2011). It should be emphasized that BECCS deployment could provide benefits for many developing countries, including helping to meet energy needs and providing income to farmers (Amigun et al. 2011; Ewing and Msangi 2008). However, optimizing benefits and ameliorating risks of deployment will only occur if sound assessments and effective institutional regulation are effectuated.
Increase dedicated Research, Development and Demonstration (RD&D) funding to further develop the viability of potentially sustainable advanced bio-feedstocks. So-called second generation feedstocks for BECCS could substantially reduce competition for arable land and threats to ecosystems through land conversion (Gough and Vaughan 2015). These options could include lignocellulosic biomass (plant biomass that is composed of cellulose, hemicellulose, and lignin) derived from raw materials such as municipal and industrial wastes, wood, and agricultural residues (UNEP 2014; Limayem and Ricke 2012). Research is also proceeding on “third-generation” biofuels, including algal biofuels, and longer-term options, such as bio-propanol or bio-butanol. (UNEP 2014; Greene et al. 2010). Challenges in this context include effectuating large-scale deployment of conversion technologies to reduce the costs of the value chain, integrating renewable energy options to reduce electricity costs associated with production, and exploration of potential co-product development to help reduce processing costs (Greene et al. 2017; European Biofuels Technology Platform 2015; Balan 2014). Moreover, assessment of these options must also include a close assessment of social-justice and development considerations. For example, heavy use of crop residues may rob crops of critical nutrients, as well as diminish soil porosity and water infiltration and storage (Demirbas 2004). This could result in erosion and reductions in crop yields (Beringer et al. 2011). Similarly, use of microalgae for biomass could require very large amounts of land, as well as unsustainable inputs of water and energy (Searchinger and Heimlich 2015).
Explore options to substantially increase crop yields through creative agricultural policies and processes. Measures to substantially increase crop yields could reduce direct land-use change (displacement of crops, pastures. or forests by bioenergy crops) and indirect land-use change, diminishing, inter alia, the pressures on food prices, water, and biodiversity that might accompany large-scale deployment of BECCS (Kinver 2016; Dale et al. 2010; Edgerton; 2009). Moreover, van Vuuren estimates that increasing yields by 12.5% could increase bioenergy potential by a whopping 50% (van Vuuren et al. 2009). There is an array of potential approaches that could prove fruitful. Agroforestry is an intensive land management system that capitalizes on the biological benefits of wedding trees and shrubs with crop production and/or livestock (Association for Temperate Agroforestry 2017). Agroforestry systems can increase crop yields, reduce threats of deforestation, and provide conservation benefits, such as riparian buffers along streams and erosion control strips (Hoffner 2016; Sileshi et al. 2012). Other methods to increase crop yields include inter-cropping (the practice of growing two or more crops in close proximity), no-till agriculture, and integrated soil fertility management (International Food Policy Research Institute 2014; Sileshi et al. 2012).
Increase research funding for other carbon dioxide removal options.As indicated above, large-scale deployment of carbon dioxide removal technologies may prove to be a critical component of global climate change policy, especially in the second half of this century. However, as also indicated previously, BECCS is not the only CDR option, and other technologies may ultimately prove to pose fewer risks to the environment or society. For example, Jones contends that direct air capture (DAC) could soak up to 650 gigatons of carbon dioxide by 2100, which could limit atmospheric concentrations to 450 ppm (Jones 2009). Sequestering huge amounts of carbon dioxide captured from ambient air terrestrially or in the world’s oceans would prove logistically challenging, and may pose safety risks (Smits et al. 2014). However, this risk is no greater than that posed for sequestering carbon dioxide from BECCS operations. Moreover, DAC would not pose commensurate risks with BECCS in terms of water usage or land conversion (Center for Carbon Dioxide Removal 2017; Smith et al. 2016; Cox and Jeffery 2009). Unfortunately, funding for other carbon dioxide options is currently almost non-existent (Center for Carbon Removal 2016; Krauss 2013). A modest research program for other carbon dioxide removal options could help us in “sorting out the wheat from the chaff in this debate” (Jha 2009). Given how long it will take to deploy any CDR option, and how slowly these technologies would act in terms of drawing down carbon dioxide (Bracmort and Lattanzio 2013; Meadowcraft 2010), research programs should be implemented expeditiously.
In 2018, the Intergovernmental Panel on Climate will release a study on the implications of temperature increases of 1.5 °C above pre-industrial levels (IPCC 2017) The Expert Group’s report will invariably discuss the potential implications of deployment of negative emission technologies to address climate change, including BECCS. As the focus on negative emissions technologies sharpens, it is important that members of the environmental science and studies communities play an active role in the assessment process.
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