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Six problems with BECCS

28 setembro 2018

Six problems with BECCS

Years of inaction have meant that climate scientists are no longer just discussing the need to reduce emissions, they are also talking about having to remove carbon dioxide from the atmosphere. Known as negative emissions, carbon dioxide removals are now at the centre of the climate conversation. Governments are responding by looking for technological fixes, and one of the most often discussed is Bioenergy with Carbon Capture and Storage (BECCS).

What is BECCS? 

Bioenergy with Carbon Capture and Storage (BECCS) is a geo-engineering technique that provides energy and removes carbon dioxide from the atmosphere. Plants such as trees or agricultural crops are planted, removing carbon dioxide as they grow. They can then be cut down and burnt to produce energy (bioenergy), with the carbon dioxide emissions captured and stored in geological formations underground (carbon capture and storage).

The theory is that BECCS can be considered to have negative emissions with trees and plants sequestering CO2 from the atmosphere during the growing phase. However, this is based on the faulty assumption that bioenergy is carbon neutral.

In practice there are no operational BECCS facilities claiming to produce substantial negative emissions anywhere in the world, and many scientists have highlighted feasibility constraints that would make it unlikely to ever work, at least not on the scale foreseen. 

This briefing note outlines six reasons why policy makers planning decarbonization pathways for 2050 or beyond must not rely on BECCS to achieve negative emissions: 

1. BECCS may not deliver large scale carbon dioxide removals 

BECCS is proposed as a solution based on the assumption that bioenergy is carbon neutral. This assumption is flawed, notably because of emissions from land use and forestry. Even in a best-case scenario where bioenergy was made from ‘additional biomass sources’, carbon capture and storage (CCS) only captures emissions released from burning biomass. No mention is made of the indirect and supply chain emissions related to biomass growth, transport, refining, capturing and storing. These could considerably reduce the positive impact of the capture and storage of the combustion emissions. 

2. BECCS has technical barriers and is expensive 

Most of the scenarios for keeping global warming to 1.5 degrees require BECCS to be available and functioning on a gigantic scale from mid-century onwards. There is an implicit assumption that BECCS can be deployed at an extremely rapid pace, but it faces significant questions about feasibility, scale and cost. Costs for BECCS are difficult to estimate as they depend on the price of biomass feedstock, CCS components, infrastructure, operations and the price of electricity. A synthesis of different cost estimates gives BECCS a price of 86-172 € per tonne of carbon dioxide (tCO2). As a comparison, during the first half of 2018, the carbon price in the EU Emissions Trading System was 8-17€/tCO2. 

3. BECCS would require a huge amount of land and push up the price of food 

As the human population increases, more land is needed for food, animal feed and other biomass uses. This is made even more problematic by the increase in meat-eating, as rearing animals takes more land than growing pulses. In addition, climate change and land degradation are reducing the extent of areas suitable for biomass production. BECCS would put pressure on limited natural resources, and thus increase conflict for land, biomass and water.

4. BECCS would harm biodiversity 

The areas considered to have good potential for dedicated bioenergy crops overlap with protected areas, especially in central Europe, the Mediterranean, the United States of America, Central America, South-East Asia and Central Africa. Increasing demand for land for BECCS is therefore an additional threat to biodiversity. When biomass comes from harvesting existing forests, biodiversity is harmed during the harvest and this is even worse if the forest is converted to a monoculture plantation.

5. BECCS would take a huge amount of water and threaten planetary boundaries 

When climate modellers talk about ‘additional biomass’ requirements, it is important to consider the large amounts of water it would require. As well as increasing the price of land, biomass demand is expected to increase the price of water by the end of the century, especially in Asia Pacific (by 330 per cent) and Latin America (by 460 per cent). Irrigation is the leading cause to groundwater depletion globally. Already nearly half of the world’s population live in areas with water scarcity and this is expected to increase to five billion people by 2050.

6. BECCS is a barrier to energy transition 

BECCS is presented as a fossil fuel-free source of energy, but there are various ways in which it encourages continued use of coal and oil in particular.  Bioenergy without CCS is already offering a life-line to coal, as many coal power plants are being converted to allow the co-firing of biomass and coal. BECCS power stations that allow for co-firing of biomass with coal would be no different. Co-firing with coal is envisaged as the way to make BECCS facilities economically and technically more feasible. Demonstration projects in the UK and Norway are already testing the CCS of co-firing biomass with coal. 

Find out what is bioenergy

Categories: Briefing notes, Bioenergy, Forest Restoration

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