Recycle: Bioenergy

GCT Guide to Bioenergy; Waste-to-Energy | Green City Times


Climate change is one of the greatest threats of our era. Over the past decade, energy-related
carbon dioxide (CO2 ) emissions have increased by 1% per year on average. If the historical trends were to continue, energy-related emissions would increase by a compound annual rate of 0.7% per year to 43 gigatonnes (Gt) by 2050 (up from 34 Gt in 2019), resulting in a likely temperature rise of 3°C or more in the second half of this century. Meanwhile, a growing world population is increasing the demand for energy. At the same time, large numbers of people have no access to electricity or are forced to spend a large part of their incomes on energy. Indeed, it is becoming increasingly harder to address the three central issues: security of supply, environmental sustainability and energy justice.

Current Status

Bioenergy makes up a large share of renewable energy use today and plays a key role as a source of energy and as a fuel in the end-use sectors (industry, transport and buildings), as well as in the power sector. Figure 1 shows key indicators of the current contribution of bioenergy to the energy transition. Bioenergy use has been growing and changing in promising ways, thanks to improvements in the technology, growing acceptance and supportive changes in policy environment, such as the global commitment to reaching the Sustainable Development Goals (SDG), in particular SDG7: ensure access to affordable, reliable, sustainable and modern energy for all.

Current bioenergy shares, and liquid biofuel production

Industry sector
The industry sector uses energy for a wide range of purposes, such as for processing and
assembly, steam generation, cogeneration, process heating and cooling, lighting, heating, and air conditioning. However, most of the energy consumed in industry is in the form of heat, especially in the most energy-intensive industrial sectors – iron and steel, chemical and petrochemical, non-metallic minerals, pulp and paper, and the food industry. Current direct renewable energy use in industry is predominantly in the form of biofuels and energy from waste. Biomass could play an expanded role for the decarbonisation of the industry sector, as it offers an established renewable energy option to provide low-, medium- and high temperature heat, as well as a feedstock that can replace fossil fuels. At a regional level, the largest share of biomass in industry’s final energy consumption in 2017 was in Latin America and the Caribbean at 32%, followed by Asia and Sub-Saharan Africa, both at 29%.

Transport sector
Globally, the share of renewable energy in this sector is very small at just 3% in 2017. In road
transport, the use of renewables is dominated by liquid biofuels, mostly bioethanol and biodiesel, which offer an alternative fuel for all types of internal combustion engines in both passenger vehicles and trucks. North America had the largest production of liquid biofuels in 2017, with 64 billion litres, followed by Latin America and the Caribbean with 31 billion litres and the European Union with 25 billion litres.

Buildings sector
There are two different ways of using biomass in the buildings sector: space heating and cooking. Buildings can currently be heated using biomass through town-scale district heating systems or building-scale furnaces, both of which use feedstocks such as wood chips and pellets very efficiently.

Power sector
Biomass and waste fuels in solid, liquid and gaseous forms are currently used to generate
electricity. The feedstocks and technologies range from mature, low-cost options, like the
combustion of agricultural and forestry residues, to less mature and/or expensive options, like
biomass gasification or municipal solid waste generators with stringent emissions controls. However, electricity generation from biomass is most often provided through combined heat and power (CHP) systems. Power production from biomass is relatively flexible, so it can
help to balance output over time on electricity grids with high shares of variable wind and solar power. At a regional level, in 2017 the European Union and Asia had the largest bioenergy capacity installed, a total of 34 GW each.

The technology outlook for bioenergy and bio-based materials

Bioenergy in the Industry Sector

Biomass, due to its versatility, could play significant roles in the industry sector. Biomass can be
used as a feedstock to replace fossil fuels, it can be used to produce low-, medium- and high-temperature heat, and it can be used as a fuel for localised electricity production. The versatility of biomass and its finite supply, however, also result in competition for its use within and between industry sectors, and other sectors of the economy. In IRENA’s analysis, renewable energy (including renewable electricity and district heating) could contribute 63% of industry’s total final energy consumption by 2050 (89 EJ in absolute terms). Of that total energy, 24% would be sourced from biomass (direct, bioelectricity and biomass in district heating) and the remaining 39% from other renewable sources (Figure 2).

Renewable energy contribution to industry final energy consumption in the Transforming Energy

Bioenergy in the Transport Sector

Compared to current levels, energy demand in the transport sector is lower under the
Transforming Energy Scenario due to efficiency improvements and other measures, such as
changes in transport modes and reductions in the need for travel. Fossil fuel consumption (oil,
natural gas) is sharply reduced, and there is a major increase in biofuels, which reach 17 EJ in 2050 (over five times 2017 levels) and provide 20% of total transport final energy demand. Electricity use in transport also grows sharply to 37 EJ (of which 2 EJ is bioelectricity, 29 EJ is from other renewable sources and the remaining 5 EJ is from fossil fuels), representing 43% of total transport final energy demand in 2050 (Figure 3).

Final energy consumption in the transport sector per energy carrier (2017 and 2030- 2050 TES)

Bioenergy in the Buildings Sector

In some cases, fossil fuel-based boilers can be co-fired with solid biomass, such as wood residues, or converted into biomass-only boilers. Biomass can also be used for both electricity and heat production in combined-heat and power (CHP) plants. Using biomass solely for electricity generation is not seen as a good choice because of its low efficiency, at about 30% (Koppejan and van Loo, 2008). However, the overall efficiency of biomass-based CHP plants for industry or district heating can be 70%-90%. As a result, sustainable bioenergy used to provide heat and power can reduce emissions considerably compared to coal, oil and natural gas generated heat and power.

In IRENA’s Transforming Energy Scenario, by 2050 the final energy consumption of modern
biomass (solid, biogas and liquid biomass, bioelectricity and biomass in district heating) grows
more than three-fold from the 2017 level in the buildings sector, from 5EJ in 2017 to 16EJ in 2050. (Figure 5).

Final energy consumption in the buildings sector by energy carrier (2017-2030 and 2050 under
the Transforming Energy Scenario)

Bioenergy in the Power Sector

Under the Transforming Energy Scenario, the power sector would be transformed. The total amount of electricity generated would more than double by 2050 – to over 55 000 TWh (up from around 24 000 TWh today). The share of electricity in total final energy use would increase from just 20% today to 49% by 2050, and 86% of that electricity would be generated by renewable sources, mostly wind (35% of renewable electricity), solar PV (25%) and some hydro (14%) (Figure 6). Biomass would be the fourth largest renewable power source, generating 7% of electricity. To produce that much power, bioenergy installed capacity would increase six-fold from 108 GW in 2017 to 685 GW in 2050. Asia would lead in bioenergy installed capacity, with 318 GW, followed by the European Union with 107 GW and Latin America and the Caribbean with 94 GW. In addition, biomass can be used for co-firing coal
power plants as an intermediate measure to reduce CO2 emissions.

Electricity generation mix in 2017 and in the Transforming Energy Scenario in 2050

Bio-based Materials

Because petrochemicals require hydrocarbon feedstocks, the only ways to produce these
sustainably are by using biomass feedstocks or by using CO2 captured from the air or from biomass combustion. The use of biomass feedstocks for plastics may result in the CO2 being
stored in products for decades and can, therefore, provide either carbon neutrality or negative
carbon emissions, depending the products’ eventual fate.

Carbon management potential of biomass

IRENA’s analysis is centered around the need to accelerate the global energy transformation,
driven by the dual imperatives of limiting climate change and fostering sustainable growth.
Renewable energy (including biomass), electrification and energy efficiency have emerged as key solutions for emissions reductions and achievement of the Paris Agreement goals.

Key drivers for the energy transformation

However, the reduction of carbon emissions is at the heart of IRENA’s analysis, given the urgent need to swiftly reduce the emissions that cause climate change.

Global pathway and the role of bioenergy

Emissions reductions and the role of bioenergy

IRENA’s Transforming Energy Scenario outlines a climate-friendly pathway with energy-related
CO2 emissions reductions of 70% by 2050 compared to current levels. About 9.5 Gt energy-related CO2 emissions would remain by 2050. Of that, just under one-quarter would be emitted in electricity generation, just under another one-quarter in transport, one-third in industry, 5% in buildings and the remaining 15% in other sectors (agriculture and district energy). The Transforming Energy Scenario is focused on energy-related CO2 emissions reductions, which make up around two-thirds of global greenhouse gas emissions. Of the 23.6 Gt of CO2 reductions achieved in 2050 relative to the Planned Energy Scenario, 11% (or 2.6 GtCO2 ) would come from bioenergy. Of that 0.6 GtCO2 is from biomass power generation, 0.7 GtCO2 from displacing liquid fossil fuel with liquid biofuels, 1.1 GtCO2 from solid biofuels and 0.2 GtCO2 from biogas/biomethane use in end-use sectors including district heating.

Energy outlook for biomass
Under current and planned policies in the Planned Energy Scenario, the share of biomass in total primary energy supply (TPES) would remain at similar levels as today, rising slightly from 9.4% in 2017 (4.8% from traditional uses and 4.6% from modern uses) to 10% in 2050, while under the Transforming Energy Scenario, it increases to 23% by 2050.

The global energy supply must become more efficient and more renewable

Barriers to the deployment of biomass for energy and material use

As is the case with other renewable energy and low-carbon technologies, several barriers inhibit the more widespread deployment of bioenergy and prevent this part of the circular carbon economy from reaching its carbon management potential.

Barriers to transitioning from traditional to modern uses of biomass

The inefficient traditional use of biomass leads to significant indoor and outdoor air pollution with severe health consequences along with other negative environmental and social impacts. One of the UN’s Sustainable Development Goals (SDG) is to ensure universal access to clean cooking solutions by 2030, and that goal has stimulated a global effort to reduce or improve the traditional use of biomass. Solutions include the use of fossil-based LPG as well as renewable solutions, such as solar based electricity. More sustainable biomass-based solutions also can provide energy for cooking and heating in developing economies, but there are still barriers to their adoption.

Financial barriers
One major barrier is the higher cost of the improved equipment and fuels which replace what is essentially a “free” resource of wood fuels and other residues (although their collection requires considerable time and effort) (World Bank, 2017). In addition, many potential users are living outside the cash economy and do not have the means to pay for fuels.

Technological barriers
Many proposed cookstove solutions do not have the technical characteristics to meet appropriate efficiency and environmental performance standards and also do not provide culturally acceptable solutions which reflect the needs of consumers, particularly in rural areas.

Comparison of costs of bioenergy and other options

Bioenergy heat costs are strongly influenced by the utilisation rate of the heat producing system, which favours industrial and larger-scale applications such as district heating. The relatively high cost of biomass fuels compared to low-cost coke and coal used in many high-temperature industry applications and in power production is a major impediment to fuel switching. (In the cement industry, low-cost waste fuels are used rather than wood-based fuels for cost reasons.)

Policy barriers The deployment of bioenergy depends on a strong and supportive policy and regulatory regime that provides for investor certainty over the income streams that projects will receive and also clearly establishes the regulatory requirements that projects must satisfy. For example, regulations must specify levels of emissions to air and water that are permitted and what other sustainability criteria must be achieved. Policy certainty is particularly important for bioenergy projects, where project lead times tend to be long, given the needs to plan technical aspects of projects, to negotiate other energy off-take agreements (sometimes for more than one energy product – e.g. heat and power), and to build up the necessary supply chain.

Sustainability of bioenergy
Concerns about the sustainability of bioenergy – the extent to which bioenergy contributes to
GHG emissions reduction targets and whether its widespread development would have positive or negative environmental, social or economic impacts – has made bioenergy a controversial subject, with poor public understanding of its benefits and uncertainty among policy makers. Confidence in the sustainability of bioenergy is an important requirement for its widespread development. Without this confidence, politicians are wary of including bioenergy in national GHG reduction programmes. Policy uncertainty and risks of reputational damage also discourage investment by industry.

Policies to support biomass use in energy

A wide range of policies and regulatory instruments can reduce barriers to bioenergy development and help create a positive enabling environment, ensuring that its development optimises carbon savings and avoids negative environmental, social or economic impacts. Bioenergy can benefit from measures that impact the whole energy economy – for example,
measures that constrain fossil fuel-based energy or increase its costs – or that generally promote renewable energy. Some measures tackle generic issues associated with bioenergy while others can be targeted at issues affecting specific technologies (for example, biogas and biomethane) or specific sectors, such as heat, transport and electricity production. Addressing all of the barriers described earlier requires a portfolio of policy and regulatory measures.

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