Biomass

From ScienceForSustainability
Jump to: navigation, search


Biomass (Wikipedia) is the oldest form of energy harnessed by humans in the form of wood burning, which still represents the major source of energy for the poorest people in developing countries (with attendant detriment to human health through smoke inhalation, and contribution to global warming through production of Albedo-altering aerosols).

Biological material (usually plant based but also including animal manures) can be burned directly as Biomass or chemically or biologically processed to make Biofuels (such as ethanol or biodiesel).

Solar Biomass David MacKay; SEWTHA Chapter D - more

Relevance to AGW mitigation

According to the IPCC's AR5 synthesis report on Mitigation and Adaptation (Section 4.3): Bioenergy can play a critical role for mitigation, but there are issues to consider, such as the sustainability of practices and the efficiency of bioenergy systems (robust evidence, medium agreement). Evidence suggests that bioenergy options with low lifecycle emissions, some already available, can reduce GHG emissions; outcomes are site‐specific and rely on efficient integrated ‘biomass‐to‐bioenergy systems’, and sustainable land use management and governance. Barriers to large‐scale deployment of bioenergy include concerns about GHG emissions from land, food security, water resources, biodiversity conservation and livelihoods.

Anaerobic Digestion

Anaerobic digestion Wikipedia

Biogas Wikpedia

Farm-Scale Anaerobic Digestion Plant Efficiency Lucy Hopwood; NNFCC; Mar 2011

The Coalition Agreement, published in May 2010, stated ‘We will introduce measures to promote a huge increase in energy from waste through AD’ with the focus therefore on maximising the efficient use of available waste.
While on-farm AD plants can theoretically operate using only manures and slurries, stakeholders have informed DECC that, in order to operate efficiently and cost-effectively, a certain amount of ‘energy crop’ is required. This project seeks to determine how much, if any, energy crop is required to ensure that on-farm AD plants using slurry or manure as the primary feedstock are able to operate effectively and the amount required, where necessary, to make the plant cost-effective.
The operations and economics of farm-based AD projects vary dependent on the existing farmingsystem, availability and seasonality of feedstocks, labour and capital, and the output requirements of the operator.
A number of scenarios have been modelled in this project to illustrate the impact on costs and returns of including energy crop material in a dairy slurry-based AD system. Three ‘typical’ farm sizes, combined with a range of slurry to crop ratios and three crop types were modelled.
The crops most appropriate for production in the UK as a supplementary feedstock for AD are maize silage, grass silage and wholecrop cereals. Grass silage is the most productive, with annual yields around 45 fresh tonnes per hectare, compared with 40t/ha for maize and 28t/ha for wholecrop wheat. Production systems are quite different; maize and wheat are annuals that are harvested only once in their lifetime and therefore require more intensive labour input to cultivate and sow the crop each year but minimal input at harvest; grass on the other hand is a perennial with a lifetime of 7 – 10 years, requiring less frequent cultivation and sowing but will be harvested up to three times per year.
Figure 2: Biogas yield data for a range of potential feedstocks
168 m^3 per fresh tonne for grass silage
Table 3: Methane yield ranges for a number of possible crop feedstocks (m^3 per t volatile solids)
Grass 298 - 467
Clover grass 290 - 390
Sudan grass 213 - 303
Reed Canary Grass 340 - 430
Ryegrass 390 - 410
Grass typically yields around 45 tonnes of fresh material per hectare per year. The first cut will be the most productive with subsequent cuts achieving lower yields.
The land areas required for feeding the digester are not insignificant; on an average dairy farm over 70% of the land area is already committed to providing grazing and forage for the cattle, leaving relatively small areas to produce other products and to supply crops for the AD plant. At all scales the likelihood is that supplementary feed, either for the plant or the dairy herd, will have to be bought in from local suppliers or neighbouring farms.

Biogas from Energy Crop Digestion Rudolf BRAUN, Peter WEILAND, Arthur WELLINGER; IEA Bioenergy; Jan 2015?

Currently some 80% of the world‘s overall energy supply of about 400 EJ per year is derived from fossil fuels. Nevertheless roughly 10–15% of this demand is covered by biomass resources, making biomass by far the most important renewable energy source used to date. On average, in the industrialised countries biomass contributes by some 3 –13% to the total energy supplies, but in developing countries this proportion is much higher. In quite a number of countries biomass covers even over 50 to 90% of the total energy demand.
Biomass combustion is responsible for over 90% of the current production of secondary energy carriers from biomass. Liquid biofuels cover only a small part and the most used are ethanol and biodiesel. Ethanol is produced from sugar- or starch crops, while biodiesel is derived from vegetable oils or animal fats.
Currently biogas plays a smaller, but steadily growing role. Traditionally applied for sewage sludge treatmentand stabilisation purposes, energy recovery from biogas was a welcome by-product. However, biogas has become a well established energy resource, especially through the use of renewable biomass i.e. “energy crops”. Since about 1950, biogas production from manure and /or energy crops, continued to develop as an important new farm enterprise.

The Potential for Biogas Production from Grass Jehad K. Abu-Dahrieh, Angela Orozco, Mohammad Ahmad, David Rooney; Jordan International Energy Conference; 2011

Abstract: Grass is generally considered as one of the major agricultural products and covers over 90% of Irish agricultural land. While useful as an animal feedstock it can also be used for energy production. Here batch mesophilic anaerobic digestion of grass silage was studied. The methane concentration in the biogas clearly showed that grass silage has a high affinity to produce a high quality methane steam between 70-80%. Investigation of the effect of inoculum to substrate ratio on methane yield from grass silage using BMP (batch) anaerobic digester under mesophilic conditions, showed that the optimum I/S ratio is approximately 1 with a maximum methane yield of 0.385 m3 kg-1COD

Feedstocks The Official Information Portal on Anaerobic Digestion

m^3 / t
Grass silage 160-200 (28% DM)
Grass 298-467

Power density

Hopwood:

  • 168 m^3 per fresh tonne for grass silage
  • Grass typically yields around 45 tonnes of fresh material per hectare per year.
  • 1 hectare = 10,000 m^2

This gives (168 * 45 / 10,000) = 0.756 m^3 gas per m^2 land per year

National Grid gives:

  • Calorific Value of natural gas = 37.5 - 43.0 -- say 40 -- MJ/m^3
  • 3.6MJ = 1 kWh so 1 m^3 gas ~= 40/3.6 = 11.1 kWh

Thus power density of grass silage -> AD -> NG = (0.756 * 11.1 / 365 * 24) = 0.96 kW / m^2 ??? can't be right

Ecotricity

Campaign For Green Gas Green Gas: The Opportunity for Britain

We knew that our Green Gas Mills were going to be a revolution in gas, but we wanted to see just how much potential they really had. So we commissioned a study to look into this.
The results were better than we could have imagined. The report found that green gas made from grass could potentially power 97% of Britain’s homes, employ 75,000 people and inject £7.5 billion into the rural economy every year.
Green gas will cut carbon emissions, help Britain to become energy independent, support food production by improving soils, create wildlife habitats, and support farmers who will lose EU subsidies as a result of Brexit.
And these are long term targets – in the short term, green gas can play a key role in helping to meet our 2020 renewable heat target by delivering 12% of heating demand.

Green Gas report pdf Green Gas summary pdf

Ecotricity’s Green Gas Mill at Sparsholt College gets go-ahead 13 Oct 2016

Located at Sparsholt College in Hampshire and fuelled by locally sourced grass, the Green Gas Mill will inject £60 million into the local economy, create new jobs, and produce enough clean gas to heat over 4,000 homes every year. As part of the unique partnership, Ecotricity will finance and build the Green Gas Mill with an investment of £10 million, and also help fund the development of a Renewable Energy Demonstration Centre. The College has agreed funding of £1.2m in grant funding from the Local Enterprise Partnership (M3 LEP) to go towards the development of the College’s Renewable Energy Demonstration Centre. The Renewable Energy Demonstration Centre will also be the first of its kind – a place to train the next generation of green energy engineers in Britain. Ecotricity introduced the concept of making green gas from grass in Britain early last year, and after today’s planning permission from Winchester City Council, it will be full speed ahead to complete the necessary preparation before construction can begin.

Biomass

University of East Anglia abandons ambitious biomass scheme

Sources say £10.5m plant intended to burn woodchip to power much of the university has never worked
A UEA spokesman said that the unit had provided energy, but using gas rather than woodchip.

Feeding Biogas Reactors at Longer Intervals Produces More Biogas Tek-Think; 18 Mar 2016

Biogas production has long been a valuable technology, as the constant feed of organic raw materials such as energy crops, manure, sewage sludge, catch crops and plant residues helps produce energy around the clock. The ability to produce energy at a constant rate is a clear advantage over other renewable energy sources such as wind or solar energy, which depend on the wind or sun for production. As a result of this ability, Germany currently has around 8,000 biogas plants installed, with a total electricity output of approximately 4,500 megawatts. Around seven percent of the electricity generated in Germany now comes from biomass. It is hoped that even more electricity will be produced from this source in the future. Scientists from the UFZ, the University of Aarhus (Denmark) and the DBFZ succeeded in increasing the production of methane, the most valuable component of biogas, by up to 14 percent under laboratory conditions when the scientists added the substrate to the fermentation tank at intervals of between one and two days compared to the conventional interval of every two hours feeding.

small scale

Household air pollution and health World Health Organisation Fact sheet N°292; Feb 2016

  • Around 3 billion people cook and heat their homes using open fires and simple stoves burning biomass (wood, animal dung and crop waste) and coal.
  • Over 4 million people die prematurely from illness attributable to the household air pollution from cooking with solid fuels.
  • More than 50% of premature deaths due to pneumonia among children under 5 are caused by the particulate matter (soot) inhaled from household air pollution.
  • 3.8 million premature deaths annually from noncommunicable diseases including stroke, ischaemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer are attributed to exposure to household air pollution.

Woodsmoke health effects: a review Naeher LP, Brauer M, Lipsett M, Zelikoff JT, Simpson CD, Koenig JQ, Smith KR; Inhalation Toxicology; Jan 2007 (T&Fonline)

The sentiment that woodsmoke, being a natural substance, must be benign to humans is still sometimes heard. It is now well established, however, that wood-burning stoves and fireplaces as well as wildland and agricultural fires emit significant quantities of known health-damaging pollutants, including several carcinogenic compounds. Two of the principal gaseous pollutants in woodsmoke, CO and NOx, add to the atmospheric levels of these regulated gases emitted by other combustion sources. Health impacts of exposures to these gases and some of the other woodsmoke constituents (e.g., benzene) are well characterized in thousands of publications. As these gases are indistinguishable no matter where they come from, there is no urgent need to examine their particular health implications in woodsmoke. With this as the backdrop, this review approaches the issue of why woodsmoke may be a special case requiring separate health evaluation through two questions. The first question we address is whether woodsmoke should be regulated and/or managed separately, even though some of its separate constituents are already regulated in many jurisdictions. The second question we address is whether woodsmoke particles pose different levels of risk than other ambient particles of similar size. To address these two key questions, we examine several topics: the chemical and physical nature of woodsmoke; the exposures and epidemiology of smoke from wildland fires and agricultural burning, and related controlled human laboratory exposures to biomass smoke; the epidemiology of outdoor and indoor woodsmoke exposures from residential woodburning in developed countries; and the toxicology of woodsmoke, based on animal exposures and laboratory tests. In addition, a short summary of the exposures and health effects of biomass smoke in developing countries is provided as an additional line of evidence. In the concluding section, we return to the two key issues above to summarize (1) what is currently known about the health effects of inhaled woodsmoke at exposure levels experienced in developed countries, and (2) whether there exists sufficient reason to believe that woodsmoke particles are sufficiently different to warrant separate treatment from other regulated particles. In addition, we provide recommendations for additional woodsmoke research.

Global Alliance for Clean Cookstoves

Sustainability / Emissions

Europe’s green energy policy is a disaster for the environment Michael Le Page; New Scientist; 2 Dec 2016

The European Union’s proposals for revising its renewable energy policies are greenwashing and don’t solve the serious flaws, say environmental groups.
The EU gets 65 per cent of its renewable energy from biofuels – mainly wood – but it is failing to ensure this bioenergy comes from sustainable sources, and results in less emissions than burning fossil fuels. Its policies in some cases are leading to deforestation, biodiversity loss and putting more carbon dioxide in the atmosphere than burning coal.

New EU Wood Energy Rules Threaten Climate, Forests John Upton; Climate Central; 19 Dec 2016

As American foresters ramp up logging to meet the growing demand for wood pellets by power plants on the other side of the Atlantic Ocean, a new European wood energy proposal would allow the power plants to continue claiming their operations are green for at least 13 more years, despite releasing more heat-trapping pollution than coal.
Most of the wood fueling converted coal plants in England, Denmark and other European countries is coming from North American forests. Each month, about 1 million tons of tree trunks and branches from southern U.S. pine plantations and natural forests is being turned into pellets and shipped to European power plants, mostly to Drax power station in the U.K.
The growing transatlantic trade is being financed with billions of dollars in European climate subsidies because of a regulatory loophole that allows wood energy to count as if it’s as clean as solar or wind energy, when in reality it’s often worse for the climate than burning coal. Only the pollution released when wood pellets are produced and transported is counted on climate ledgers. Actual pollution from the smokestack — by far the greatest source of carbon pollution from wood energy — is overlooked.

UK burning wood from U.S. forests to meet EU renewables targets

Not everyone is delighted over countries using wood pellets to meet "renewable" energy targets, and they are speaking up about the issue. A consortium of NGO's published a paper on September 6, 2015, arguing that the EU should exclude wood from its renewable energy targets.
The group's argument is worth consideration because they claim that hardwood wetland forests are being cut down in the Southeastern U.S., and in effect this is causing a greater lack of biodiversity and adding to the increase in carbon emissions.
When you add to the cutting down of the trees the cost of using transportation to bring the wood to a seaport for shipment across the Atlantic, it is questionable where the sustainability is supposed to be in this practice. You could argue that the forest will regrow, but in the meantime, there is a loss of wildlife habitat, and the soil doesn't store as much biomass as it would if left undisturbed.
It should also be noted that a UK study published in July 2014 showed that energy produced from regenerated forests produced a carbon intensity that was five-times higher than coal.

The EU is emitting way more greenhouse gases than it says

'Wood-pellet fuel emits more carbon than coal': U.S. watchdog to probe shock claims on power giant Drax's 'green' supplier David Rose; This Is Money (Daily Mail?); 12 Mar 2016

How Europe’s climate policies led to more U.S. trees being cut down Joby Warrick; Washington Post; 2 Jun 2015

For the sake of a greener Europe, thousands of American trees are falling each month in the forests outside this cotton-country town. ... Each day, dozens of trucks haul freshly cut oaks and poplars to a nearby factory where the wood is converted into small pellets, to be used as fuel in European power plants. Soaring demand for this woody fuel has led to the construction of more than two dozen pellet factories in the Southeast in the past decade, along with special port facilities in Virginia and Georgia where mountains of pellets are loaded onto Europe-bound freighters. European officials promote the trade as part of the fight against climate change. Burning “biomass” from trees instead of coal, they say, means fewer greenhouse gases in the atmosphere. But that claim is increasingly coming under challenge. A number of independent experts and scientific studies ... are casting doubt on a key argument used to justify the cutting of Southern forests to make fuel. In reality, these scientists say, Europe’s appetite for wood pellets could lead to more carbon pollution for decades to come, while also putting some of the East Coast’s most productive wildlife habitats at risk.

Carbon Emission Estimates for Drax biomass powerplants in the UK sourcing from Enviva Pellet Mills in U.S. Southeastern Hardwoods using the BEAC model Dr. Thomas Buchholz, Dr. John Gunn; Spatial Informatics Group; 27 May 2015

Looking for reduced greenhouse gas emissions from the electricity sector, governments across the globe promote biomass as a feedstock to this end. However, GHG emissions from biomass are challenging to calculate based on carbon stock changes on the landscape as well as emissions along the production, transportation, and conversion chain. The UK government has released a model to calculate emissions associated with biomass sourced in the US. This study analyzes emission profiles for the utility company Drax that operates wood pellet-fired power plants in the UK. This feedstock is to a large extent derived from three Enviva operated pellet mills in the Southeastern US, namely Ahoskie and Northampton in North Carolina and Southampton in Virginia. Using publicly available data on biomass consumption and origin for the three Enviva plants, we created customized emission profiles using default model outputs from the UK’s Department of Energy and Climate Change’s (DECC) BEAC (Biomass Emissions And Counterfactual) Model. According to the BEAC model, electricity derived from biomass sourced through additional hardwood harvests in the southeastern US is associated with emissions exceeding the UK’s emission standard for coal stations converted to biomass of 285 kg CO2e/MWh by over eleven times. Based on BEAC model outputs, customized feedstock mixes for the Enviva plants exceed this standard by at least five to nine times. In order to meet the standard of 285 kg CO2e/MWh, a maximum of 8% of biomass from additional hardwood harvests could be contained in the feedstock mix, assuming i) a minimum analytical timeframe of 40 years and ii) that the remainder of the feedstock mix is derived from low-emission saw mill residues only.

Europe's 'renewable' energy plan is actually destroying US forests Rebecca Harrington; Tech Insider; 23 Dec 2015

Europe imported more than 4 million tons of wood pellets from US forests last year and wrote it all off as renewable energy. A new report from Climate Central exposes how 4.4 million tons of wood pellets were cut from American forests last year, and 98% of it was shipped to Europe to be burnt for energy. Because of a loophole, the European Union classifies this wood-generated electricity as "carbon neutral," though research actually indicates it's more environmentally dangerous in the short term.

UK’s renewable energy targets drive increases in U.S. wood pellet exports US Energy Information Administration; 22 Apr 2015

Enviva Wood Pellets Enviva

THE USE OF WHOLE TREES IN WOOD PELLET MANUFACTURING / EVIDENCE OF THE USE OF WHOLE TREES BY TOP WOOD PELLET EXPORTERS FROM THE US SOUTH TO EUROPE Dogwood Alliance; 13 Nov 2012

Forests in southern states are disappearing to supply Europe with energy Adam Macon; Salon; 18 Oct 2016

In the past 60 years, we’ve lost 33 million acres of natural forests in the southern U.S. Many of them are coastal wetlands forests, which act as life jackets against hurricanes for coastal communities. These forests would have helped to save homes and lives in eastern North Carolina from the ongoing impacts from Hurricane Matthew—if they were still standing. The intense European demand for wood pellets has put at risk 15 million acres of unprotected southern forests (about the size of West Virginia), and more than 600 imperiled, threatened or endangered species. It’s become abundantly clear: Now is the time to act to protect southern forests. In 2009 the European Union, in an admirable and necessary effort to increase renewable energy and reduce carbon emissions, passed a new energy policy. This policy considered any and all biomass material as “renewable energy.” It created a major loophole for energy companies, allowing them to now burn forest wood from industrial timber operations in power stations—and receive government incentives to do it. It raised a critical question: Where would Europe get all this wood to feed a growing demand? Energy companies quickly turned to one of the world’s largest wood-producing regions: the southern United States. In just a few years, the southern U.S. has become the world’s largest exporter of wood pellets, the prefered form of biomass for industrial use. Last year alone, over 5 million tons of wood pellets were exported from the South directly to markets in Europe. This arrangement has had serious impacts on the climate, communities and forests of the region.

Burning Wood May Do More Harm Than Good Sami Grover; TreeHugger; 27 Sep 2010

Biomass – a burning issue Nick Grant, Alan Clarke; Association of Environmentally Conscious Builders

In this short discussion paper from September 2010, Nick Grant and Alan Clarke consider whether it is right — or helpful — to define biomass fuel as zero carbon
The use of biomass as a 'low or zero carbon fuel' is increasingly being adopted as the default solution to meet emission targets for new buildings. This approach is fundamentally misguided and is leading to increased UK carbon emissions1. This paper demonstrates that there is a crucial distinction between viewing biomass as a renewable fuel - in that plant matter can be self- renewing - and as a low carbon fuel. This is because the amount of plant matter that can renew itself each year is finite, and plant matter burnt for heat reduces the amount available for other sequestered uses, for example as a building structural material or insulant.

The huge flaw in how Congress is approaching burning wood for energy Chelsea Harvey; Washington Post; 16 Jun 2016

some potential new legislation, which critics claim relies on scientifically questionable assumptions, has scientists and environmentalists worried about taking a step backward when it comes to climate goals. The controversy centers on a specific provision in the House appropriations bill for fiscal year 2017 regarding the burning of biomass (typically wood and other plant material) for energy. The bill proposes that the Environmental Protection Agency treat biomass energy as carbon neutral —that is, the agency would assume the practice does not contribute any extra greenhouse gas emissions to the atmosphere — under certain conditions.

Woody Biomass for Power and Heat: Impacts on the Global Climate Duncan Brack; Chatham House; 23 Feb 2017

Current biomass policy frameworks are not fit for purpose and require substantial changes to ensure they contribute to mitigating climate change rather than exacerbating it.

Most wood energy schemes are a 'disaster' for climate change By Matt McGrath; BBC; 23 Feb 2017

Using wood pellets to generate low-carbon electricity is a flawed policy that is speeding up not slowing down climate warming.
That's according to a new study which says wood is not carbon neutral and emissions from pellets are higher than coal.
Subsidies for biomass should be immediately reviewed, the author says.

Belgium

GE to build world’s largest commercial biomass-fired power plant (GE; Biomass magazine; 25 Feb 2016)

Belgian plant powered by woodchip & agro residues, 215MW, 60% efficiency in cogeneration mode, 110MW district heating, GE Steam Power Systems

Denmark

Dong is upgrading Denmark's largest power plant to use wood pellets Sun and Wind Energy; 6 Oct 2016

Denmark is making good progress with its efforts to phase out conventional energy. The energy company Dong Energy has now announced that Denmark's largest power plant in Avedøre will be completely transitioned to wood pellets by 2016, making it the largest biomass power plant in the country. All remaining units for district heating at the Avedøreværket power plant, which is located 10 km south of Copenhagen, will be completely converted to firing wood pellets. The power plant has an electrical capacity of 793 MW and a thermal capacity of 918 MW. Avedøreværket supplies approximately 200,000 households with district heating in the Copenhagen area. The power plant consists of two units: Avedøre 1 and Avedøre 2. Together they have a generation capacity of 825 MW. The Avedøre 1 block was built in 1990 and is mainly coal-fired. Avedøre 2 was built in 2001 and already utilises pellets as fuel in addition to both gas and oil. Dong Energy will now upgrade the entire Avedøreværket power plant to biomass fuel by 2016, making it possible to increasingly use wood pellets instead of coal and gas.
Commenting on the increased use of wood pellets, Dong stressed in a press release that only biomass from sustainable forestry will be fired at Avedøreværket. For this purpose, the company has designed a system of certificates and audits together with international partners. In order to ensure uniform sustainability criteria for the procurement of biomass, the company is also participating in the 'Sustainable Biomass Partnership' (SBP) initiative. European energy suppliers, pellet producers and testing organisations have teamed up in the initiative. The suppliers have made a commitment to fulfil the highest EU requirements. The wood for Avedøre comes from by-products of industrial timber processing as well as sustainable forest management, and 60% of it comes from the Baltic States. The second largest supplier is Portugal with 22%, followed by Russia in third place with 11%. Even when the processing and transportation of the wood pellets is taken into consideration, emissions are still reduced by approximately 90% compared to the coal and gas that was used previously, according to Dong Energy. During the past nine years, the company has been able to reduce the use of coal by 65%. CO2 emissions have been reduced by 41% since 2006.

Australia - bagasse

Bagasse and cane trash Biomass Producer (Au)

Australia’s sugar industry has used bagasse to meet its electricity and heat requirements for over 100 years. Today, bagasse is a major contributor in the bioenergy sector – accounting for over 60 per cent of Australia’s dedicated bioenergy capacity (Clean Energy Council). There are projects also working towards using bagasse as a biomass for ethanol production.
Australian sugar mills burn bagasse on site to generate heat and electricity.

Canada

Ontario Spent 170 million to Convert a Coal Power Plant to burn Norwegian Wood Pellets Sunshine Hours; 4 Apr 2016

Ontario has shut down its coal power plants. One of those coal power plants was Atikokan. What OPG decided to do (because they needed dispatchable power) was to convert the plant to biomass. And that biomass was wood pellets. Not just any wood pellets. It was “Advanced Biomass”. Advanced biomass has been treated to withstand exposure to rain, and has handling and storage properties similar to those of coal. It is still in the early stages of development, which is why OPG purchases advanced biomass fuel from Norway.

Biofuels

BiofuelWatch

Well-to-wheels energy use and greenhouse gas emissions of ethanol from corn, sugarcane and cellulosic biomass for US use Michael Wang, Jeongwoo Han, Jennifer B Dunn, Hao Cai, Amgad Elgowainy; Environmental Research Letters, Volume 7, Number 4; 13 Dec 2012 pdf

Globally, bioethanol is the largest volume biofuel used in the transportation sector, with corn-based ethanol production occurring mostly in the US and sugarcane-based ethanol production occurring mostly in Brazil. Advances in technology and the resulting improved productivity in corn and sugarcane farming and ethanol conversion, together with biofuel policies, have contributed to the significant expansion of ethanol production in the past 20 years. These improvements have increased the energy and greenhouse gas (GHG) benefits of using bioethanol as opposed to using petroleum gasoline. This article presents results from our most recently updated simulations of energy use and GHG emissions that result from using bioethanol made from several feedstocks. The results were generated with the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model. In particular, based on a consistent and systematic model platform, we estimate life-cycle energy consumption and GHG emissions from using ethanol produced from five feedstocks: corn, sugarcane, corn stover, switchgrass and miscanthus. We quantitatively address the impacts of a few critical factors that affect life-cycle GHG emissions from bioethanol. Even when the highly debated land use change GHG emissions are included, changing from corn to sugarcane and then to cellulosic biomass helps to significantly increase the reductions in energy use and GHG emissions from using bioethanol. Relative to petroleum gasoline, ethanol from corn, sugarcane, corn stover, switchgrass and miscanthus can reduce life-cycle GHG emissions by 19–48%, 40–62%, 90–103%, 77–97% and 101–115%, respectively. Similar trends have been found with regard to fossil energy benefits for the five bioethanol pathways.

EU

EU green transport target 'may have increased greenhouse gas emissions' Guardian; 14 Mar 2016

Renewable transport goal has encouraged biofuels including those from palm oil and soybean, which are found to be worse than diesel oil for emissions

Biofuels cause four times more carbon emissions Louise Gray; Telegraph; 22 Apr 2010

The European Union, including the UK, has set a goal of obtaining 10 per cent of its road fuels from renewable sources by 2020. But a new report commissioned in Brussels found some biofuels can lead to four times more carbon dioxide polluting the atmosphere than equivalent fossil fuels. Biofuels have already been criticised for causing food shortages in countries where land for rice or wheat has been displaced by fields of soy beans or sugarcane for fuel. Environmental campaigners say the latest report proves the renewable energy source is also bad for climate change, since carbon dioxide is a greenhouse gas that causes global warming. The report for the European Commission, released under Freedom of Information rules, looked into the "indirect emissions" from biofuels caused by land use change. The worse example is soy beans in America. Because the land that used to grow soy beans for animal feed is now being used for biofuels, it means that more soy beans must be grown in the rainforests of Brazil to make up for the loss in the domestic market. Soybeans grown in America therefore have an indirect carbon footprint of 340kg of CO2 per gigajoule, compared to just 85kg for conventional diesel or gasoline. Biodiesel from European rapeseed has an indirect carbon footprint of 150kg of CO2 per gigajoule, while bioethanol from European sugar beet is calculated at 100kg – both much higher than conventional diesel because of indirect use of land in other countries to replace the food crops that are no longer grown in Europe. By contrast, imports of bioethanol from Latin American sugar cane and palm oil from southeast Asia have relatively low indirect emissions at 82kg and 73kg per gigajoule respectively. But these biofuels have high direct emissions because although no land for food is being displaced, rainforest it being cut down to grow the crops in the first place.

DeCicco

Biofuels worse for climate change than gas, U-M study says Keith Matheny; Detroit Free Press; 25 Aug 2016

Despite their purported advantages, biofuels — created from crops such as corn or soybeans — cause more emissions of climate change-causing carbon dioxide than gasoline, according to the study from U-M Energy Institute research professor John DeCicco.

Study: Biofuels increase, rather than decrease, heat-trapping carbon dioxide emissions Jim Erickson; U of Michigan News; 25 Aug 2016

A new study from University of Michigan researchers challenges the widely held assumption that biofuels such as ethanol and biodiesel are inherently carbon neutral. Contrary to popular belief, the heat-trapping carbon dioxide gas emitted when biofuels are burned is not fully balanced by the CO2 uptake that occurs as the plants grow, according to a study by research professor John DeCicco and co-authors at the U-M Energy Institute. The study, based on U.S. Department of Agriculture crop-production data, shows that during the period when U.S. biofuel production rapidly ramped up, the increased carbon dioxide uptake by the crops was only enough to offset 37 percent of the CO2 emissions due to biofuel combustion.

Biofuels increase, rather than decrease, heat-trapping carbon dioxide emissions: study PHYS.org; 25 Aug 2016

Carbon balance effects of U.S. biofuel production and use John M. DeCicco, Danielle Yuqiao Liu, Joonghyeok Heo, Rashmi Krishnan, Angelika Kurthen, Louise Wang; Climatic Change; 25 Aug 2016

The use of liquid biofuels has expanded over the past decade in response to policies such as the U.S. Renewable Fuel Standard (RFS) that promote their use for transportation. One rationale is the belief that biofuels are inherently carbon neutral, meaning that only production-related greenhouse gas (GHG) emissions need to be tallied when comparing them to fossil fuels. This assumption is embedded in the lifecycle analysis (LCA) modeling used to justify and administer such policies. LCA studies have often found that crop-based biofuels such as corn ethanol and biodiesel offer at least modest net GHG reductions relative to petroleum fuels. Data over the period of RFS expansion enable empirical assessment of net CO2 emission effects. This analysis evaluates the direct carbon exchanges (both emissions and uptake) between the atmosphere and the U.S. vehicle-fuel system (motor vehicles and the physical supply chain for motor fuels) over 2005–2013. While U.S. biofuel use rose from 0.37 to 1.34 EJ/yr over this period, additional carbon uptake on cropland was enough to offset only 37 % of the biofuel-related biogenic CO2 emissions. This result falsifies the assumption of a full offset made by LCA and other GHG accounting methods that assume biofuel carbon neutrality. Once estimates from the literature for process emissions and displacement effects including land-use change are considered, the conclusion is that U.S. biofuel use to date is associated with a net increase rather than a net decrease in CO2 emissions.

RESPONSE TO “CARBON BALANCE EFFECTS OF U.S. BIOFUEL PRODUCTION AND USE” BY PROF. JOHN DECICCO ET AL. Renewable Fuels Association; 25 Aug 2016

Stats

Area of Crops Grown For Bioenergy in England and the UK: 2008 - 2014 DEFRA; 10 Dec 2015

Key Messages
  • 122 thousand hectares of agricultural land was used for bioenergy in the UK in 2014.
  • The area of crops grown for bioenergy equated to 2% of all arable land in the UK in 2014.
  • Just over 68% of land used for bioenergy in 2014 was for biofuel for the UK road transport market.
  • 1.2 million tonnes of UK crops were produced for the UK road transport market in 2014/15.
  • Maize grown for use in anaerobic digestion accounted for 19% of the total maize area in England in 2015 and 0.7% of England’s total arable area.
  • Figures relating to biofuel used for road transport in 2014/15 are provisional based on data currently available. This shows that, of the total volume of renewable fuel supplied in 2014/15, 99.6% (1,665 million litres) has so far been demonstrated to meet the sustainability requirements