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.

New coal plants wouldn’t be clean, and would cost billions in taxpayer subsidies


Frank Jotzo, Australian National University

Following a campaign by the coal industry, Prime Minister Malcolm Turnbull has argued for new coal-fired power stations in Australia. But these plants would be more expensive than renewables and carry a huge liability through the carbon emissions they produce.

Major Australian energy companies have ruled out building new coal plants. The Australian Energy Council sees them as “uninvestable”. Banks and investment funds would not touch them with a barge pole. Only government subsidies could do it.

It may seem absurd to spend large amounts of taxpayers’ money on last century’s technology that will be more costly than renewable power and would lock Australia into a high-carbon trajectory.

But the government is raising the possibility of government funding for new coal plants, with statements by Deputy Prime Minister Barnaby Joyce, Treasurer Scott Morrison and Environment and Energy Minister Josh Frydenberg. The suggestion is to use funding from the Clean Energy Finance Corporation. For this to happen, presumably the CEFC’s investment mandate would need to be changed, or the meaning of “low-emissions technologies” interpreted in a radical way.

It should come to nothing, if minimum standards of sensible policy prevailed.

But an ill wind is blowing in Australia’s energy and climate policy debate. The situation in parliament is difficult, and the Trump presidency is giving the right wing in the Coalition a boost.

Definitely not ‘clean’

Proponents of new coal plants call them “clean coal”. They have appropriated a term that normally means burning coal in power stations with carbon capture and storage, a technology that filters out most of the carbon dioxide. But this is expensive and has made little progress.

Turnbull and others are simply suggesting Australia build the latest generation of conventional coal-burning plants. They are not clean – merely marginally less polluting than the old plants running now.

A new high-efficiency coal plant run on black coal would produce about 80% of the emissions of an equivalent old plant. An ultra-supercritical coal plant running on black coal emits about 0.7 tonnes of CO₂ per megawatt hour of electricity, or about 0.85 tonnes using brown coal. That is anything but clean.

For comparison, typical old “dirty” black coal plants in operation now emit around 0.9 tonnes, so the improvement from replacing them with the latest technology is not large. Gas plants produce between 0.4-0.6 tonnes, much less than the suggested new coal plants. Gas has the added benefit of being able to respond flexibly to demand. A plant with carbon capture and storage might emit around 0.05 tonnes, and renewables zero.

The Australian grid average right now is around 0.8 tonnes and gradually falling. New coal would tend to keep that average higher over the long term.

A single typically sized new coal plant could blow out in the order of 5 million tonnes of CO₂ each year – about 1% of Australia’s current annual emissions – and would have an expected lifetime of 40-60 years. It would also pollute the air locally, as all coal plants do, causing damage to people’s health.

If we wanted to make up for the extra coal emissions by doing more in industry, transport or agriculture, then this would come at a cost in those parts of the economy. In-depth research has shown that decarbonisation of Australia’s economy needs to have zero-carbon electricity supply at its core.

What if we don’t care about the climate?

Building coal power plants is expensive. The average lifetime cost of producing power with ultra-super critical plants in Australia is estimated at around A$80 per megawatt-hour. This assumes financing is available at standard interest rates and that the plant runs at high capacity.

Given the risk that the plants will be liable under stricter carbon limits in the future, the financing costs are bound to be higher, probably north of A$100 – and may be as much as A$160. If the plant is not fully utilised, as is already the case for existing coal plants, average costs will be even higher.

By comparison, wind farms now get built at an average cost of A$75 per megawatt-hour, and solar parks at around A$110. Both are expected to come down to perhaps A$50 by 2025. New coal plants take many years to prepare and build, so 2025 is the relevant comparison.

In fact, the overall comparison costs for renewables are even lower. This is because wind and solar built in 2025 would be replaced in the 2050s with even cheaper systems.

There are extra costs associated with wind and solar – for instance, through pumped-hydro storage or more gas-fired power plants to balance supply. But these costs are far less than the underlying cost of renewables.

So renewables including system integration costs will be cheaper than new coal plants, perhaps by quite a margin. Let’s say, very conservatively, that renewables are A$20 per megawatt-hour cheaper. For the coal plant that’d be an extra cost of A$150 million per year, or A$6 billion over 40 years. The extra cost could be much higher if the plant was retired before the 2060s or not run at full capacity.

The subsidy required would be potentially billions of dollars for each plant. That’s billions of dollars from the taxpayer or electricity user, in order to supply power with high carbon emissions that are then locked in for half a century. It should not happen in a country that prides itself on rational economic policy.

Instead, government should set its sights on the long-term economic opportunities for Australia in a low-carbon world, and chart a path for the transition of the energy system.

Turnbull referred to Australia’s position as a coal exporter. But a revolution is under way in energy technologies. While coal will continue to be used in existing plants, the times of growing coal use are over. Already more than 70% of the world’s annual power sector investment goes to renewables.

Australia is lucky in that there are no limits to the amount of renewable energy that could be produced. New industries can be built around it. We should invest in the industries of the future, not sink more money into the technologies of last century.

The Conversation

Frank Jotzo, Director, Centre for Climate Economics and Policy, Australian National University

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

Is ‘clean coal’ power the answer to Australia’s emissions targets?


Lynette Molyneaux, The University of Queensland

As Australia’s energy debate heats up, some politicians are calling for cleaner and more efficient coal power stations to reduce greenhouse gas emissions.

Energy Minister Josh Frydenberg told ABC radio on Tuesday that “ultra-supercritical coal-fired power plants actually drive down the carbon footprint by up to 40%”.

And last week Resources Minister Matt Canavan referenced a report, as yet not released by the Department of Industry, Innovation and Science, which claims that Australia can meet its carbon emission targets by replacing existing coal generators with ultra-supercritical coal generation.

So, is this a reasonable strategy to reduce Australia’s emissions?

Cleaner coal

Australia’s coal generation fleet is ageing and needs replacing. Two-thirds of the 25 gigawatts in operation (after Victoria’s Hazelwood power station is retired this year) is more than 30 years old, according to ACIL Allen’s generator report. By 2025 a further 18% of the fleet will be more than 30 years old.

That means that in 2025 a mere 4GW of our existing coal power will still be considered adequately efficient. This is important because efficient generation affects not only how much generators are paying for fuel, but also carbon dioxide (CO₂) emissions.

Modern coal power plants feed pulverised coal into a boiler to combust. Tubes in the boiler walls then absorb the heat and the steam generated in these boiler tubes turns the steam turbine and generates electricity.

The difference between subcritical, supercritical and ultra-supercritical boilers is in the steam conditions created in the boiler. Supercritical and ultra-supercritical boilers are often referred to as high-efficiency, low-emissions technologies.

Ultra-supercritical power stations are designed to operate at higher steam temperature and pressure. This improves efficiency, and has been made possible by new materials that can cope with higher temperatures.

Ultra-supercritical coal power stations operate under steam conditions above 593-621℃ and 28.4 million pascals (a measure of pressure). You can find further detail in this report.

Using higher temperatures means greater efficiency, producing more electricity using less coal. Australia’s most efficient coal power station, Kogan Creek, is able to convert 37.5% of the gross energy, or calorific value, of coal into electricity. Hazelwood converts only 22%. The remaining energy is lost as heat.

By comparison, ultra-supercritical coal stations are able to convert up to 45% of the gross energy of coal to electricity.

Advanced ultra-supercritical coal generation is expected to convert over 50% of the gross energy of coal to electricity, but the expensive alloys required to accommodate the very high temperature requirements make the plants very expensive. Before advanced ultra-supercritical coal plants can be deployed, new design changes like this will first need to be tested and evaluated in pilot implementations.

Reducing fuel use reduces emissions. Hazelwood’s reported CO₂ emission intensity from 2014-15 was 1,400kg of greenhouse gas for every megawatt-hour of electricity it produced. Kogan Creek emitted 831kg per megawatt-hour.

The greater efficiency of ultra-supercritical generators can reduce emissions intensity to 760kg per megawatt-hour for black coal. Advanced ultra-supercritical generators can reduce emissions even further. Upgrading or replacing Victoria’s brown coal generators to ultra-supercritical would reduce emissions intensity to 928kg per megawatt-hour.

So greenhouse gas emissions can be reduced if ultra-supercritical generators replaced Australia’s old, inefficient coal generators.

But is it enough?

The problem is just how much CO₂ emissions can be reduced. Emissions from coal power are the largest contributors to Australia’s total emissions.

In 2013-4, coal generators emitted 151 million tonnes of greenhouse gas, generating 154 million kilowatt-hours of electricity. Details can be found here. This is 29% of Australia’s total emissions in 2013-14 of around 523 million tonnes. (Transport contributed around 18% to total emissions.)

Let’s assume the current fleet of power stations is operating at 80% capacity, considered to be an economic optimum for coal power. This would generate 176 gigawatt-hours of electricity and 165 million tonnes of emissions. This allows for a 14% increase in consumption of electricity by 2030, which is likely given projections of population and economic growth.

If we then replace the entire 25GW, both black and brown, with ultra-supercritical generation, according to the assumptions included in the Australian Power Generation Technology Report, emissions would total 139 million tonnes. This would represent a 16% reduction in coal emissions, but a mere 5% reduction in Australia’s total emissions in 2013-4.

And then we would have those ultra-supercritical power stations for the next 30-40 years, incapable of reducing our emissions further as global targets tighten.

If Australia were to wait until advanced ultra-supercritical coal power is tested and trialled, then we could speculate that emissions from coal generation could reduce by a further 10% to 124 million tonnes. This would be a more promising 25% reduction in coal emissions, but still only a 7.7% reduction in Australia’s total emissions.

Understanding Australia’s emission reduction target

Australia’s emission reduction target for 2030 is 26-28% below 2005 levels.

Emissions in 2005 were 594 million tonnes. Australia’s climate target would require emissions to reach around 434 million tonnes in 2030, a reduction of 160 million tonnes.

If coal power stations were to reduce emissions by 26-40 million tonnes through a shift to ultra-supercritical generators, then Australia would still be a very long way from meeting its committed targets.

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The only way shifting to ultra-supercritical coal power could meet Australia’s 26-28% climate target is if carbon capture and storage (CCS) were applied.

Ultra-supercritical coal plants are expected to generate electricity at A$80 per megawatt-hour, according to the Australian Power Generation Technology Report. This is 45% more expensive than the average wholesale cost of electricity for 2015-16. If CCS is added, then the projected cost swells to A$155 per megawatt-hour, nearly three times last year’s wholesale cost of electricity.

These costs eventually get passed on to electricity bills, and it’s unlikely that consumers will be willing to see electricity prices rise that much.

Until we see more detail underpinning the current enthusiasm for “clean coal”, we’ll have to speculate on the assumptions of the report referenced by minister Canavan.

The Conversation

Lynette Molyneaux, Researcher, Energy Economics and Management Group, Global Change Institute, The University of Queensland

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