Bioenergy carbon capture: climate snake oil or the 1.5-degree panacea?



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Bioenergy Carbon Capture and Sequestration, known as BECCS, is one of the technologies we may need to limit warming to 1.5 degrees.
from http://www.shutterstock.com, CC BY-ND

Paul Behrens, Leiden University

With the release of the latest special report by the Intergovernmental Panel on Climate Change, it’s time we talk frankly about Bioenergy Carbon Capture and Sequestration, known as BECCS. It is one of the key technologies many models say we will need to limit warming to 1.5℃.




Read more:
The UN’s 1.5°C special climate report at a glance


BECCS involves growing plants which remove carbon dioxide as they grow and are then burned in power stations to produce electricity. The resulting carbon dioxide from this combustion is captured and stored underground. The result is carbon dioxide removal from the atmosphere.

It is the not-so-high-tech wonder many are waiting for, but it comes at a high price. It also risks delaying policies that actually reduce emissions in the first place.

Mapping the future, now

According to models, BECCS is the technology we are banking on to fix our climate disruption and safeguard our future. The models have doubled down on BECCS, but it is an unproven solution on a large scale – and one that has significant and damaging side effects.

There are three choices on the table (we will likely see a mix of at least two):

  • Equitable sustainability Massive amounts of low-carbon energy (solar, wind, batteries, electric vehicles), huge improvements in energy efficiency, a revolution of the food systems and a transition of society towards lower growth, both in population and economy.

  • Hypothetical backstop Continue down the road we are on, and hope to “overcorrect” the problem in the future by sucking carbon dioxide out of the atmosphere. A lack of political will and intense lobbying has meant what was once a fairly manageable problem has become an exercise in inventing heroic backstops.

  • Cowboy optimism Engineer the planet (even further) to ease the impacts of climate disruption, but not the underlying causes themselves.

The first choice means we change ourselves and alter the way we do things. The second means we continue polluting as we do now, and hope to clean up later. This option is a bit like the plastic clean-up trial currently underway in the Pacific.

Choice three means we simply paper over the cracks, perhaps saving some aspects of human civilisation but pushing large parts of nature to extinction.

It’s worth noting that in any scenario, massive investment by richer countries on behalf of poorer countries will be necessary. This is already a significant problem).

Given the delay, the majority of 1.5℃ and 2℃ scenarios run by models have doubled down on the second choice. But this lessens the need for unprecedented changes today.




Read more:
New UN report outlines ‘urgent, transformational’ change needed to hold global warming to 1.5°C


The reliance is so heavy that, on average, current models for meeting 2℃ suggest we will be using BECCS and afforestation to mop up total, annual global emissions by around 2070 (or 2055 for 1.5℃). This results in a massive growth in BECCS power plants through this period, from three today to 700 by 2030, and 16,000 by 2060.

Bonfire of the BECCS

But large-scale BECCS is a monumentally tricky idea. BECCS aims to fix one thing – climate disruption – but makes many other things worse.

BECCS on an industrial scale needs many resources. Plants need land, water and fertilisers (sometimes) to grow, and infrastructure to get low-density plant matter from one place to another. We already struggle to do this sustainably.

Related to this, it is reasonable to think that BECCS will increase food prices. We have to produce 70% extra food by 2050 to just keep up with population and food demand increases. Can we do this while using vast tracts of land for BECCS production? Perhaps only if we have a big change in dietary habits which frees up land?

While BECCS will provide some electricity, you don’t get much bang for your buck – it has the lowest power density of any other type of energy.

BECCS make use of thermal power plants so inherit many problems related to running them. Power plants are heat engines and need water for cooling.
We already have problems with water cooling, and it is getting worse with climate change.

Finally, BECCS power plants will produce ash, which is a “better” version than the ash from coal plants (it doesn’t take much), but will still need attention.

The role of Integrated Assessment Models

The origin story for BECCS has been told elsewhere, but how did we end up in a situation where the large majority of models point to this one problematic solution? These models are called Integrated Assessment Models, and come in two main varieties: simple and complex.

The complex ones are mostly used for investigating technology choices. The simple ones are often used to explore what the cost of carbon could be. This year’s Nobel Prize winner in economics, Bill Nordhaus, works with these simple models.

The overall weaknesses of these models have been covered in compelling and entertaining ways. Given the depth of the complex models, it is difficult to be sure why BECCS dominates. Most would agree that there are three likely possibilities.

First, these models discount future benefits and costs to a large extent. That is, they assume that future benefits and costs are much less in the future than they are today. The default rate at which models discount is 5% per year, meaning that to avoid $100 of climate damage in 2100 is only worth $3 to us today. Many have argued that this is much too high, ethically inappropriate, and misleading.

I know of only one study which performs a sensitivity analysis using so-called discount rates. It finds that carbon dioxide removal is significantly reduced with lower discount rates.

Second, these models are very sensitive to prices and since a very low price for BECCS is assumed, this is the technology that dominates. The problem is that we don’t actually know what these prices might be, especially on a large scale.

Third, these models have a difficult job estimating the damage from climate change. The risk from emitting now and paying later is fat-tailed – there is a non-negligible increased risk of catastrophe even if we do manage to implement choice two at a large scale.

Taking off the BECCS blinders

Are there technologies other than BECCS? If we must hypothesise backstop technologies, then direct air capture is a possibility. As the name implies, it sucks carbon directly from the air.

Although it doesn’t generate energy in the process (in fact it uses large amounts of energy), it doesn’t have as many of the problems faced by BECCS. A possible future consists of solar-powered direct air capture in the Middle Eastern desert pulling carbon dioxide from the atmosphere and pumping it underground into reservoirs from which oil was once pumped. This is speculative though, comes with it’s own big problems, and as yet doesn’t feature much in modelling efforts due to its high cost (though they are coming down quickly though).




Read more:
The science is clear: we have to start creating our low-carbon future today


Fortunately, there are an increasing number of studies which take a non-backstop approach. These still use integrated assessment modelling, but investigate other options, like very low-energy demand scenarios and large-scale behaviour change (for example to plant-based diets) which reduce other, non-CO₂ gases quickly.

There is nothing to be lost by committing to the first choice as fast as possible. In fact, many of the important solutions are better for our health too (such as using bikes instead of cars, plant-based diets, and insulating houses). And if we end up needing BECCS, then so be it, but the earlier we start moving to low-carbon economies, the more potential catastrophes we avoid.The Conversation

Paul Behrens, Assistant Professor of Energy and Environmental Change, Leiden University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The ‘clean coal’ row shouldn’t distract us from using carbon capture for other industries



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Has carbon capture and storage been tarnished by its association with the coal industry?
Peabody Energy/Wikimedia Commons, CC BY-SA

Alfonso Martínez Arranz, Monash University

Since the February blackouts in South Australia, the Australian government has increased its interest in carbon dioxide capture and storage (CCS). However, in Australia and elsewhere, CCS is closely associated to so-called “clean coal” technologies. The media sometimes treats them as one and the same thing. The Conversation

Given the negativity with which the general public, and expert commentators view “clean coal”, this confusion is distracting attention from other sectors where CCS can make a unique and substantial contribution.

CCS is vital for “clean coal”. Even the most efficient coal-fired power plants emit huge amounts of carbon dioxide. Unless these emissions are captured and stored in rock formations thanks to CCS, meeting climate targets with coal power is impossible.

But here’s the thing: carbon dioxide can be captured from any large-scale source. This means that CCS has a valuable role to play in other industrial sectors – as long as clean coal’s bad reputation doesn’t drag CCS down with it.

Other industries

About half of the global potential for CCS by 2050 has been estimated to lie in industry. Some sectors like synthetic fuels and hydrogen production may not grow as predicted. But others such as cement, steel and ammonia, are here to stay.

Several recent UK reports on industrial decarbonisation argue that CCS brings emissions reductions beyond the 50% needed by 2050 required in most sectors and countries.

For cement in the UK, the report argues, efficiency and other measures could deliver a roughly 20% emissions reduction by 2050. But adding CCS could bring this figure to 54%.

Meanwhile, the British steel industry could cut emission reductions by 60% compared to 34% without CCS. For UK chemical manufacturers, these figures are 78.8% versus 34%. These processes often produce a high-purity stream of carbon dioxide that avoids the costly capture methods used for power applications.

So why aren’t industries like these the stars of carbon capture and storage right now?

Money and hype

Unlike the power sector, which is under pressure to reduce emissions, other high-carbon industries currently have little incentive to pay the estimated cost of US$50-150 per tonne of carbon dioxide captured. Carbon pricing has been hard to introduce even far below such levels.

However, if CCS is to be deployed by mid-century, concept demonstration and confirmation of suitable storage sites needs to start now, and on a wide enough scale to deliver useful emissions cuts. Other strategies may be needed to incentivise it.

CCS was first mooted in 1976, but it only caught world leaders’ attention in the mid-2000s. However, over the past decade its popularity seems to have waned, perhaps because of the “clean coal” issue.

In 2005, WWF joined Europe’s CCS platform, and the following year the environmentalist George Monbiot described the technology as crucial.

But over the ensuing ten years, as a “hype process” around CCS for clean coal developed, industrial CCS was largely ignored. At its peak in 2007, proponents announced some 39 CCS power projects, most of them coal-fired, aiming to capture an average per project of 2.2 million tonnes (Mt) of carbon dioxide per year.

Yet by early 2017, only two large-scale power projects have been completed around the world: Boundary Dam, capturing 1Mt per year, and Petra Nova, capturing 1.4Mt per year.

Number of carbon capture and storage projects by type since first concept. Mature refers to projects in sectors in which capture is routinely commercial, such as in natural gas processing. Immature refers to projects in sectors where capture is not the norm, including power generation, steelmaking, and certain chemicals. The share of power generation projects among immature is highlighted.

Cynicism around the technology has grown, with the Australia-founded Global CCS Institute recently being described as a “coal lobby group”. Unfortunately for CCS, the focus has been mostly on the gap between announced and successful “clean coal” projects, rather than on its contribution to industrial emissions reduction.

Last year, Emirates Steel Industries completed its steelmaking CCS project, which now captures 0.8Mt of CO₂ per year.

Australia will soon be host to the world’s largest CCS development, at the Gorgon LNG Project, which will store 4Mt a year from 2018.

Steel, gas-produced ammonia and other industrial products will be fixtures of the 21st century, whereas coal-fired electricity has no such certainty. Economies that aspire to 100% renewable energy will have no room at all for coal, “clean” or otherwise.

Even if our electricity and transport were to become 100% renewables-based, there will be parts of the economy where greenhouse emissions are hard to eliminate. It is important that the unpopularity of “clean coal” does not distract from the importance of CCS in decarbonising other industries.

Alfonso Martínez Arranz, Lecturer, Monash University

This article was originally published on The Conversation. Read the original article.

Carbon capture and storage is unlikely to save coal in the long run


Gary Ellem, University of Newcastle

As the world moves to combat climate change, it’s increasingly doubtful that coal will continue to be a viable energy source, because of its high greenhouse gas emissions. But coal played a vital role in the Industrial Revolution and continues to fuel some of the world’s largest economies. This series looks at coal’s past, present and uncertain future.

Coal is the greatest contributor to climate change of all our energy sources. This means that if the world acts to limit global warming to well below 2℃, coal will likely be constrained – unless its greenhouse gas emissions can be removed.

One of the great hopes of the industry is carbon capture and storage (CCS), a way to burn coal, remove the carbon dioxide (CO₂) emissions and store it safely away from the atmosphere. While there have been several breakthroughs, the technology remains expensive.

Advances in energy technologies mean that adding CCS doesn’t just need to work; it needs to work at a lower cost than its growing legion of competitors. And while the alternatives are good news for avoiding dangerous climate change, it’s a substantial challenge for the coal industry.

Capturing carbon

The current range of CCS technologies can be grouped into “pre-combustion” and “post-combustion” methods.

Pre-combustion methods typically react the carbon in the fuel with high-pressure steam to make hydrogen CO₂. The CO₂ is then separated (captured) from the hydrogen before the hydrogen is burned in the power station to make energy, with the only emissions being water vapour.

Post-combustion technologies try to capture the carbon after it has been burned and becomes CO₂. If the fuel is burned in air, then the CO₂ needs to be separated from the exhaust gas stream which, like air, is mostly composed of nitrogen gas. This is usually done by passing the gas stream through a liquid that dissolves the CO₂ but not the nitrogen.

Another technique, called “oxyfuelling”, separates oxygen out of the air and then uses it to burn the fuel in an atmosphere of oxygen and recycled CO₂. The exhaust gas stream from this process is close enough to pure CO₂ that it can be sent directly to the storage process.

Several options have been explored for storing the carbon. These include the deep ocean, depleted oil and gas wells, deep saline aquifers, as manufactured mineralised carbonate rock, or as naturally mineralised carbonate by injection into basalt reservoirs.

Regardless of the technique, the outcomes for coal combustion are similar. The amount of emissions is reduced by 80-100%, while the cost of coal-fired electricity generation increases by at least the same amount.

These costs come from building the capture plant, CO₂ transport pipelines and the sequestration plant. More than double the amount of coal must be burned to make up for the energy cost of the CCS process itself.

When CCS was first considered as an emissions solution, competition from renewables, such as solar and wind, was weak. Costs were high and production volumes were negligible.

How cheap?

In the 1990s, many believed that renewables (other than existing hydro, geothermal and biomass for heating) might never be able to replace coal cheaply. The future of energy was going to be a centralised grid, rather than the distributed power models being discussed today, and there were only two widely backed horses in the technology race: CCS and nuclear.

But the early part of this century has seen an energy revolution in both renewables and fossil fuels. Among renewables, solar and wind have both taken enormous strides in reducing production costs and building manufacturing scale.

For fossil fuels, the expansion in gas pipeline infrastructure, the development of liquefied natural gas (LNG) shipping and the growth of both conventional and unconventional gas production have encouraged fuel switching from coal in European and US markets in particular.

Trying to compare the costs of different types of electricity can be tricky. Power stations require capital to build and have heavy financing, operational and decommissioning costs. Nuclear and fossil fuel power stations also have to buy fuel.

Analysts use the term “levelised cost of electricity (LCOE)” to aggregate and describe this combination of factors for different methods of electricity generation.

A significant challenge for coal and CCS is that the LCOE for wind and solar at a comparable scale is already competitive with coal generation in many places. This is because the cost of manufacturing has fallen as production has increased.

While this seems not to bode well for coal and CCS, there’s a caveat: a coal with CCS power station makes power when the sun doesn’t shine and the wind doesn’t blow.

It’s easier for wind and solar to compete when traditional fossil fuel power stations are there to back them up, but not so easy when renewables become dominant generators and the cost of storage needs to be taken into account to ensure a consistent supply.

A game changer?

That was until batteries came along and offered the ability to store renewable energy for when the sun doesn’t shine. There is considerable hype around the entry of the Tesla Powerwall into the home electricity market.

But that is only one of numerous home battery solutions from the likes of Samsung, LG, Bosch, Panasonic, Enphase and others. All are designed to store excess solar power for use at night.

The emerging breakthrough of these products is the price, which is bringing batteries into the realm of competition with centralised electricity generation.

While a battery won’t take your family entirely off-grid at first, such batteries mean most suburban households can become largely energy-independent. They need only top up from the grid now and then when a run of cloudy days comes along during the shorter days of winter.

In the longer term, there’s a clear pathway for most homes to disconnect completely from the grid, should battery prices continue to fall.

Why are batteries a threat?

The reason that batteries can compete with centralised generation is because the cost of transmission and distribution from a coal-fired power station to your home is considerable.

These costs are not normally considered in the LCOE calculations, because it is assumed that all power generators have access to the same, centralised electricity grid.

But a battery in your home means that these costs are largely avoided. That makes home energy generation and storage much more competitive with traditional power generation in the longer term.

For developing nations without a strong centralised grid it also means that energy systems can be built incrementally, without large investments in infrastructure.

This is an ill wind for the competitive future of CCS, which depends on the centralised generation model and a lack of low-cost competitors to stay viable.

That doesn’t mean the coal industry should give up on CCS. Having a range of options for a low-emission future is a good thing. Affordable energy is at the heart of our modern civilisation and standards of living.

CCS may also lay the foundations for Bioenergy with Carbon Capture and Storage (BECCS), one of the few (albeit expensive) technologies with the potential to recoup significant amounts of CO₂ from the atmosphere. But this points to a renewable biomass future, not a coal future.

The odds that CCS will keep coal alive as an industry into the future are getting longer each year.

What we are seeing is the start of the great transition from fossil fuel mining to manufacturing as the basis for our energy systems. It’s not dominant yet, but you would be starting to get very nervous if you were betting against it.

The Conversation

Gary Ellem, Conjoint Academic in Sustainability, University of Newcastle

This article was originally published on The Conversation. Read the original article.