Tag Archives: bioenergy

Seven Years On

The last seven year have seen too little progress on solving the climate change problem, despite some welcome developments.  Much more rapid progress is now needed.

It is now seven years since I started this blog – my first post was on 3rd March 2013.  It seems a good time to take a look at what has gone well and what has gone badly over that period in efforts to reduce climate change.  So here are seven ways in which things have gone badly, and seven ways in which they have gone well.

Things that have gone badly over the last seven years

  1. Annual CO2 emissions from energy and industry have increased over the last seven years, continuing the long-term trend, when they need to be decreasing rapidly.

Chart 1: Emissions of CO2 from energy and industry (excluding land use)

Source: EDGAR  https://edgar.jrc.ec.europa.eu/booklet2019/Fossil_CO2andGHG_emissions_of_all_world_countries_booklet_2019report.pdf

  1. Deforestation has not fallen – if anything it’s increased.

This not only bad for the climate, it’s bad for biodiversity and the wider stability of ecosystems.

Chart 2: Tropical primary forest loss (million hectares)

See:  https://www.bbc.co.uk/news/science-environment-48104037

  1. Over 15% of the remaining carbon budget has been used since 2013, even on the most optimistic view[i].

In 2013 the remaining carbon budget (that is, total cumulative CO2 emissions that remain possible while limiting global mean surface temperature rises to 2 degrees) was around 1900Gt CO2.  It is now around 1600Gt CO2.The remainder is getting used up ever more quickly as emissions continue to rise.

  1. Large amounts of high carbon infrastructure are still being built.

This includes large amounts of new coal-fuelled power generation. This risks lock-in of emissions for decades.

  1. There is a lack of progress with developing and implementing low carbon technologies in many sectors

Most emissions intensive industries, notably steel, have made little progress in changing their processes to reduce emissions.  One of the main technologies likely to be needed for decarbonising industrial emissions, CCS, has seen very little deployment, with only about an additional 10 mtpa[ii] stored from projects coming on line since 2013.  The largest contributor to the increase has been the Gorgan project, which is natural gas production, so not likely to be part of a net zero emissions world.  10 mtpa is only about 0.02% of global emissions.  CCS is also likely to be essential for achieving negative emissions from Bioenergy with CCS (BECCS), among other things.  There has also been only very limited progress to date on deploying low carbon hydrogen.

  1. China appears to be making emissions reduction less of a priority.

Among other factors, recently slowing economic growth seems to have focussed attention in China towards economic stability and energy security rather than the threats from climate change.

  1. Most countries have targets that are far too weak

Existing pledges under the Paris Agreement imply a continuing increase in global emissions rather than the rapid decrease that is needed[iii].

This is a daunting list of problems.  However, there is also some good news, although in all cases it would be even better if positive trends were happening faster.

Good news from the last seven years

  1. Costs of low carbon technologies have fallen rapidly, and continue to fall.

Wind and solar electricity are in many cases now competitive with, and often cheaper than, electricity from new fossil fuel generation.  Falling battery costs will enable to the electrification of surface transport and help balance the grid.

This seems to me to be by far the greatest cause for optimism.  Low carbon options will simply become the default choice for new investment in many cases, and policies to reduce emissions will increasingly be working to support a trend that is driven by economic as well as environment imperatives.

  1. Some countries have put binding targets in place for net zero emissions.

The UK already has such a target for 2050, seeking to end the UK’s contribution to climate change.  The EU seems likely to formalise a similar target very soon.

  1. Some countries have cut emissions significantly, showing what can be done.

The UK has cut its annual emissions by nearly 20% since 2013[iv], with the largest component of this being a reduction in coal use in the power sector, a change readily replicable elsewhere.

  1. Public concern about climate change has risen while scepticism about the science has largely disappeared, at least outside the USA and a few other countries.

85% of UK voters are now concerned about climate change[v] with over a quarter ranking it among their top three issues[vi].  This was reflected during the recent general election campaign[vii] in all parties offering policies to reduce emissions to net zero .  Over time this should create the political space for some of the more challenging policies that will be needed to reduce emissions to close to zero.

  1. Additional policies are being put in place, and carbon pricing is increasingly widespread.

For example, almost all major economies now have renewables targets, and there are over 50 carbon pricing systems in place around the world.

  1. Governments increasingly see economic opportunities in decarbonisation rather than costs.

The opportunities created by new industries are increasingly recognised as part of wider industrial policy.

  1. The Paris Agreement has been signed.

Almost all countries have now committed to limit temperature rises to below 2 degrees and to make a contribution to reaching that target, recognising different national circumstances.  Some may consider this is the main piece of good news over the past seven years.  However its effectiveness remains to be proven, and its success looks likely to depend on some of the other trends I’ve highlighted, notably falling costs for low carbon technologies.

Looking at these trends together, I am both less optimistic and more optimistic than I was in 2013.  I am less optimistic because seven years of rising emissions and continuing investment in high carbon infrastructure have made the challenge of limiting climate change even greater than it was.  But I am more optimistic because there is greater recognition and acceptance of the problem, more is now being done (though still nowhere near enough) and, above all, because low carbon energy is rapidly becoming cheaper than high carbon energy.  As a result it looks likely that emissions from the energy sector will eventually be greatly reduced and even halted entirely.  This may make it easier to focus on reducing other emissions as well, especially those from deforestation.

But eventually will be too late.  Much damage is already being done to our world.  More will inevitably follow. This will include the loss of irreplaceable parts of the natural world.  Given rising emissions, and how much of the carbon budget has been used up, it now looks practically impossible to keep temperature rises to 1.5 degrees, and difficult, though still possible, even to limit them to 2 degrees.

However it could still get much worse.  The task now is to avoid the worst of the risks by keeping emissions and accompanying temperature rises as low as possible, including keeping global temperature rises to below 2 degrees.  With a lot of effort and a little luck there is still time (just) to achieve this.  But the task has never been greater or more urgent.

Adam Whitmore – 9th March 2020

[i] For a 50% chance of remaining below 2 degrees, based on cumulative CO2 emissions.  See https://onclimatechangepolicydotorg.wordpress.com/2018/10/

[ii] https://www.globalccsinstitute.com/resources/global-status-report/

[iii] https://climateactiontracker.org/global/cat-emissions-gaps/

[iv] https://www.theccc.org.uk/publication/reducing-uk-emissions-2019-progress-report-to-parliament/

[v] https://www.ipsos.com/ipsos-mori/en-uk/concern-about-climate-change-reaches-record-levels-half-now-very-concerned

[vi] https://www.bbc.co.uk/news/science-environment-50307304

[vii] https://onclimatechangepolicydotorg.wordpress.com/2019/11/25/the-uks-political-consensus-on-climate-change/

 

Hydrogen and heat pumps may both play a role in UK building heating

Low carbon hydrogen and electricity via heat pumps may both play a large role in decarbonising building heating in the UK.  Ways forward are needed that maintain optionality around solutions while more is learnt about the right mix.

This is the second of three posts looking at the potential role of hydrogen in residential heating in the UK.

Decarbonising building heating in the UK poses a range of challenges.  First, the required transition is very large scale.  There are around 27 million households in the UK, with many more commercial buildings, small and large.  This implies around a million or more premises a year on average need to be converted to low carbon heat between now and 2050.

Along with scale, there is cost.  Replacing the UK’s heating system is expensive both on in total and by household, even if the existing natural gas network can be used for hydrogen.   This challenge is made more difficult by the high seasonality of heating demand (Chart 1).  Building natural gas supply chains, reformers to produce hydrogen from natural gas, CCS, low carbon electricity and heat pumps all involve major capital investment.  Running this for only part of the year – the colder months – increases unit costs substantially. The chart below shows daily gas and electricity demand from non-daily metered (i.e. small) customers.  Demand for energy from gas, the major source of building heating at present, is about two or three times electricity demand during winter, and is much more seasonal.

Chart 1: Heating demand is highly seasonal …

Source: BEIS (2018) ‘Clean Growth – Transforming Heating’ https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/766109/decarbonising-heating.pdf

Furthermore, the transition to low carbon heat needs to be made largely with the UK’s existing building stock, which is mainly old and often badly insulated.  Improved insulation is a priority in any programme, but there are practical and cost constraints on what can be done with existing buildings.  (Buildings also need to be able to cope with the increased prevalence of heat waves as the climate warms, but that is a separate topic.)

Finally, building heating directly affects people’s day to day lives, so consumers’ acceptance is critical.  On the whole the present system, based mainly on natural gas boilers, works quite well except for its emissions.  Any new system should preferably work as well or better.

The leading candidates for low carbon heating in buildings are electricity, almost certainly using heat pumps to increase efficiency, and low carbon hydrogen.  Biomass seems unlikely to be available either at the scale or cost that would be needed for it to be a major contributor to low carbon heating, though it may find a niche.  District heating networks require low carbon heat and this must draw on the same ultimate set of sources of heat.  Waste heat from nuclear, once discussed as a possibility, no longer seems likely to be either practical or cost effective.

Recently the Committee on Climate Change (CCC) analysed the costs of decarbonising heat in 2050 using different approaches.  They looked at electricity, hydrogen, and combinations of the two.  The analysis concluded that a 50% increase over current costs was likely (Chart 2).  The remarkable thing about the analysis is that this cost was similar for all of the options considered.  Any differences were well within the uncertainty of the estimates.

Chart 2: Costs of different modes for decarbonising building heating …

Source:  Committee on Climate Change

With no large cost difference leading to one or the other option being preferred there is a need to test each option out to see which works better in practice.  Mixed solutions may be appropriate in many cases.  For example, hydrogen may be useful in providing top-up heat even if heat pumps are providing the baseload, or may be the only solution for some poorly insulated properties for which heat pumps don’t run at high enough temperatures.

The CCC’s analysis includes expected cost savings.  The transition to low carbon heat will clearly be more acceptable if this cost can be reduced further.  In particular there seem likely to be both technical advances and large economies of scale in heat pump manufacture and installation, and the costs of low carbon power may fall by more than assumed by the CCC.  As the analysis stands, a 50% increase is clearly politically difficult, especially when there do not seem to be advantages for the customer, and potentially some drawbacks.  However, this is less than a 2% p.a. compound increase in real terms over a 30 year period, which might be politically feasible if introduced gradually spread across all consumers.

With such large changes in demand between summer and winter, seasonal storage is a major issue for reasons of both cost and practicality.  This is an under-researched area, and needs further work.  There are various possibilities – storage of hydrogen itself in salt caverns, storage of hydrogen as ammonia or storage of heat in ground sinks, but each has its problems and the scale involved is very large.

A final uncertainty is the form which hydrogen production will take.  At the moment methane in reformers predominates and, with the addition of CCS, may continue to do so.  However both the costs of low carbon electricity and of the electrolysis are decreasing rapidly.  Over the long term this may become the main pathway for hydrogen production.

These uncertainties imply that building heating poses a particularly difficult set of choices for policy.  It is not clear what route, or mix of routes is the right one.  The transition needs to be quite rapid relative to the lifetimes and scale of existing infrastructure, and it involves the need for consumer acceptance.  There are also potentially strong network and lock in issues.

The best approach is likely to be to develop several types of solution in parallel, maintaining optionality while learning, and being prepared for some approaches to be dead ends.  The implications of this include the need for roll out of low carbon heat sources in some districts now to get an idea of how they will work at scale.

Some of this is happening, much more is needed.

Adam Whitmore -29th October 2019.

 

Comparison of cost estimates with previous analysis by this blog.

Around four and a half years ago I looked at the costs of decarbonising domestic heating in the UK in winter using low carbon electricity.  I concluded that switching to low carbon heat would add 75% or more to domestic heating bills, with some drawbacks for consumers (I also looked at higher cost case, but this case no longer seems likely due to the fall in the costs of low carbon electricity, especially offshore wind, since the analysis was done.)  I suggested that this meant that the transition would be difficult and that reductions in capital costs were necessary.

This analysis is broadly consistent with the CCC analysis quoted here, which suggests a 50% increase on current costs.  The estimates are roughly similar given the large uncertainties involved , the inevitable differences is assumptions, and different basis of the estimates.  In particular the CCC analysis factors in reductions in costs of low carbon heating likely by 2050, whereas my previous analysis was based on current costs to make the point that cost reductions are necessary,  Consequently it would be expected that the CCC analysis would show a smaller cost increase relative to current costs.  Also, the CCC’s analysis may exclude some costs – estimates such as these have a tendency to go up when you look at them more closely.  Equally it may understate the cost reductions possible over decades.

 

 

Deploying CCS on fossil fuel plant is more of a priority than implementing negative emissions technologies

The potential for biomass with CCS and direct air capture of CO2 should not distract from deployment of CCS on fossil fuel plants over the next few decades.  Among other things, learning from CCS on fossil fuels will help make eventual deployment of CCS on biomass cheaper and more effective.

There appears to be increasing likelihood that atmospheric concentrations of greenhouse gases will grow to exceed levels consistent with the target specified in the recent UNFCCC Paris agreement of limiting temperature rises to “well below” two degrees.  Such an outcome would require CO2 to be removed from the atmosphere faster than natural sinks allow, in order to restore concentrations to safe levels.  Near zero net emissions in the latter part of this century will also be needed to stabilise concentrations.

Many models of future emissions pathways now show negative emissions technologies (technologies that result in a net decrease in CO2 in the atmosphere) needing to play a major role for in meeting climate goals. They have the potential to remove carbon dioxide from the atmosphere in the event of “overshoot” of target atmospheric concentrations, and to balance remaining emissions from sectors where abatement is difficult with a view to achieving net total emissions of close to zero.  But the application of such technologies should not be considered in isolation.

Bio Energy with CCS (BECCS)

Bio energy with CCS (BECCS ) is the most widely discussed approach to negative emissions.  BECCS is not a single technology but a combination of two major types of CO2 removal.  Bioenergy from burning biomass to generate electricity or heat emits a substantial amount of CO2  on combustion – around as much as a coal plant.  However much of this can be captured using CCS.  More carbon dioxide is reabsorbed over time by the regrowth of the plants, trees – or perhaps algae – that have been harvested to produce the bioenergy.  Together, the capture of the CO2 from the flue gas and the subsequent absorption of CO2 from the atmosphere by regrowth of biomass can lead to net removal of CO2 from the atmosphere, although this takes time.  (The net amount of CO2, that is emitted on a lifecycle basis from burning biomass without CCS depends on the type of biomass and is subject to considerable variation and uncertainty – a controversial topic that would need another post to review.)

However at an energy system level, where the CO2 is captured – biomass plant or fossil fuel plant – is less relevant than the total amount that’s captured.  Broadly speaking, if there is a biomass plant and fossil fuel plant both running unabated the same benefit can be achieved by capturing a tonne of CO2 from either.

Indeed there may be advantages to putting CCS on a conventional plant rather than biomass plant.  It may be technically more tractable.  Furthermore, CCS require a lot of energy to capture the CO2 and then to compress and pump it for permanent storage.  Biomass is likely to be supply constrained (again, this is an issue that requires a post in itself), so using biomass rather than fossil fuels to provide this energy may limit other applications.  Only when there are no fossil fuel plants from which to capture CO2 does biomass plant become unambiguously a priority for CCS.  This is clearly some way off.

Furthermore biomass with CCS for electricity generation may not be the best use of bioenergy.  Converting sunlight to bioenergy then turning that into electricity is a very inefficient process.  Typically only 1-2% of the sunlight falling on an area of cropland ends up as useful chemical energy in the form of biofuels.  There are various reasons for this, not least of which is that photosynthesis is a highly inefficient process.  Burning biomass to make electricity adds a further layer of inefficiency, with only perhaps a third or less of the energy in the biomass turned into electricity.  Sunlight therefore gets converted to electricity with an efficiency of perhaps 0.5%.  This compares with around 15- 20% for solar cells, implying that scarce land is often likely to be best used for solar PV.  (The calculation is closer if solar PV is used to create storable energy e.g. in the form of hydrogen).   For similar reasons the use of biofuels rather than electricity in transport is inefficient, in part because internal combustion engines are less efficient than electric motors.

Limited available biomass may be better used for those applications where it is the only available lower carbon energy source, notably in aviation and (likely) heavy trucks, or for other applications such as district heating with CCS, where the ability to store energy seasonally is especially valuable.

At the very least, detailed system modelling will be required to determine the optimal use of biomass.  Suggesting that BECCS should have a major role to play simply because in isolation it has negative emissions may lead to suboptimal choices.

Direct Air Capture (DAC)

Direct Air Capture (DAC), where carbon dioxide is chemically absorbed from the atmosphere and permanently sequestered, can also reduce the stock of CO2 in the atmosphere.  However the typical concentration of CO2 in a flue gas of a power plant or industrial plant is several percent, about a hundred times as great as the concentration of 0.04% (400 ppm) found in the atmosphere.  This makes the capture much easier.  Furthermore, millions of tonnes can be captured and piped from a single compact site using CCS, generating economies of scale on transport and storage.  In contrast DAC technology tends to be more diffuse.  These considerations imply that CCS from power plants and industrial facilities is always likely to be preferable to direct air capture until almost all the opportunities for CCS have been implemented, which again is a very long way off.

Uncertainties and optionality

There are many uncertainties around negative emissions technologies, including the availability of biomass, cost, and the feasibility of reducing emissions in other sectors.  For these reasons developing optionality remains valuable, and research to continue to develop these options, including early trial deployment, is needed, as others have argued[i].

One of the best ways of developing optionality is to deploy CCS at scale on fossil fuel plants.  This will reduce the costs and enable the development of improved technologies through learning on projects.  It will also help build infrastructure which can in turn benefit  BECCS.  This needs to run in parallel with ensuring that the lifecycle emissions from the bioenergy production chain are reduced and biodiversity is safeguarded.

Negative emissions technologies may well have a role to play in the latter part of the century.  But they seem likely to make more sense when the economy is already largely decarbonised.  In the meantime deployment of CCS, whether on industrial facilities or power plants, needs to be a much greater priority.

Adam Whitmore – 21st March 2016

[i] Investing in negative emissions, Guy Lomax,  Timothy M. Lenton,  Adepeju Adeosun and Mark Workman, Nature Climate Change 5, 498–500 (2015)  http://www.nature.com/nclimate/journal/v5/n6/full/nclimate2627.html?WT.ec_id=NCLIMATE-201506