Tag Archives: energy technology

Hydrogen and electricity for low carbon heat

Hydrogen and electricity are competing carriers, and there may be a role for both in providing low carbon heat.

There has recently been a lot of interest in the role of hydrogen as a carrier of low carbon energy, because it produces no CO2 on combustion (or oxidation in a fuel cell).  This is the first of three posts looking at hydrogen and how it might compete with electricity to provide low carbon heat.  Hydrogen and electricity may also compete in transport, but that is a large subject in its own right and will need to await further posts.

This first post outlines some of the possibilities and the issues raised.  The next post will compare electricity with hydrogen for heating in buildings.  The third post will look at the ways they may complement each other to supply heat.

There are broadly two main sources of primary energy for low carbon heat:

  • Fossil fuels with CCS, which I’ve assumed in these posts will usually be natural gas.
  • Renewables, likely in practice to be mainly wind and solar.

Each of these primary energy sources can get to the energy consumer in the form of electricity or hydrogen.  Wind and solar can produce low carbon electricity directly, or they can produce hydrogen via electrolysis of water.  Natural gas can be burnt in a CCGT to produce electricity.  It can also be processed to produce hydrogen, most commonly in a steam methane reformer (SMR).  I’ve assumed here that SMRs are used, although many are looking at alternative approaches such as autothermal reforming (ATRs) which may allow for higher efficiencies and capture rates.

If fossil fuels are used CCS is required, as both CCGTs and SMRs produce CO2.  This means they provide low carbon energy, rather than a zero-carbon energy, as a maximum of 90-95% of the CO2 produced is captured.  Any CCS built now or in the future will likely still be in use by 2050, so its capture rate must be judged against 2050 net-zero targets.  In this context, the residual emissions from any large-scale use of CCS for fossil fuels are likely to be significant, and may place limits on the extent of deployment.  SMRs produce different streams of CO2. Some of this is concentrated and so relatively easy to capture, some is more dilute.  Both streams need to be captured for the technology to play an appropriate role in a net-zero carbon economy.

Both CCGTs and SMRs also produce waste heat, which may be used, so improving the overall thermal efficiency, although applications to date have been limited.

Hydrogen can be converted into electricity using a fuel cell or CCGT (with appropriately designed turbines).  This may enable use of hydrogen for electricity storage.

Electricity for building heating is likely to come from heat pumps (likely mainly air source heat pumps) as these greatly improve efficiency.

This gives a variety of routes for primary energy to low carbon end use. These are shown in the diagram below.  In practice several of these may co-exist, and some may not happen at scale.  The pathways shown assume natural gas cannot continue to act as a carrier of energy to individual buildings.  This is because its combustion inevitably produces CO2 and very small-scale CCS for individual buildings is likely to prove impractical, for example because of the very extensive CO2 transport network that would be required.

Both fossil fuels and renewables can deliver energy as electricity or hydrogen …

Which mix of these pathways will provide the best solution? It’s not yet clear.  It will depend on various factors.

Suitability for end use.  Some industrial processes require high temperature heat or a direct flame, which heat pumps cannot provide.  Conversely, hydrogen needs to demonstrate its safety in a domestic context, though this is likely tractable.

Consumer acceptability. This is critical for residential heating, and both hydrogen and heat pumps face potential difficulties.  For example, heat pumps may be perceived as noisy, or require modifications such as installation of larger radiators which people resist.

Costs.  Which route is cheaper depends on a wide range of factors, including :

  • The capital costs of the equipment (e.g. CCGT or SMR, hydrogen boilers, and heat pumps)
  • The costs of reinforcing, creating or repurposing grids, including the extent to which the natural gas gird can be repurposed for hydrogen, and the cost of reinforcing the electricity distribution network to accommodate demand from heat pumps.
  • The cost of the primary energy, for example whether renewable energy is produced at times of low demand so might be available at a low price. If electricity from renewables is available very cheaply then resistance heating without heat pumps may make sense in some cases.
  • The thermal efficiency of the processes, for example the extent to which CCS adds costs by requiring additional energy, and the coefficient of performance (heat out divided by electricity in) for heat pump, especially in winter.
  • The costs of electricity storage via batteries or as hydrogen.
  • Load factor for heat and electricity production.

Many of these variables are uncertain.  They also vary with location and over time. The very large cost falls for renewable electricity demonstrate the need for caution in judging options on present costs.

In my next post I will take a look at how these factors may play out for building heating in the UK, and will consider the policy implications.

Adam Whitmore – 30th September 2019

 

 

The IEA’s solar PV projections are more misleading than ever

The IEA is still grossly underestimating solar PV in its modelling

This post is a quick update of previous analysis.

Back in 2013 I pointed out how far from reality the IEA’s projections of renewables deployment were.  They persistently showed the rates of installation of renewables staying roughly constant over the following 20 years at whatever level they had reached at the time of the projection being made.  In reality, rates of installation were growing strongly, and have continued to do so (see chart).  Rates of installation are now a factor of nearly four times greater than the IEA was projecting back in 2013 – they were projecting installation rates of about 28GW for 2018, where in fact around 100 GW were installed in 2017[1] and an estimated 110GW in 2018.

I have returned to the topic since 2013 (see links at the bottom of this post), as have many others, each time pointing out how divorced from reality the IEA’s projections are.

Unfortunately, the IEA is continuing with its approach, and continuing to grossly understate the prospects for renewables.  Auke Hoestra has recently updated his analysis of the IEA’s solar PV projections to take account of the latest (2018) World Energy Outlook New Policies Scenario (see link below chart – in addition to chart data his post also contains a valuable commentary on the issue).  The analysis continues to show the same pattern of obviously misleading projections, with the IEA showing the rate of solar PV installation declining from today’s rate until 2040.  Of course eventually the market will mature, and rates of installation will stabilise, but this seems a long way off yet.

IEA projections for solar PV in successive World Energy Outlooks compared with outturn

http://zenmo.com/photovoltaic-growth-reality-versus-projections-of-the-international-energy-agency-with-2018-update/

In 2013 I was inclined to give the IEA the benefit of the doubt, suggesting organisational conservatism led to the IEA missing a trend.  This no longer seems tenable – the disconnect between projections and reality has been too stark for too long.  Instead, continuing to present such projections is clearly a deliberate choice.

As Hoekstra notes, explanations for the disconnect have been advanced by the IEA, but they are unsatisfactory.  And as renewables become an ever-larger part of the energy mix the distortions introduced by this persistence in misleading analysis become ever greater.

There is no excuse for the IEA persisting with such projections, and none for policy makers taking them seriously.  This is disappointing when meaningful analysis of the energy transition is ever more necessary.

Adam Whitmore -21st January 2019

https://onclimatechangepolicydotorg.wordpress.com/2013/10/08/why-have-the-ieas-projections-of-renewables-growth-been-so-much-lower-than-the-out-turn/

https://onclimatechangepolicydotorg.wordpress.com/2015/02/27/the-ieas-central-projections-for-renewables-continue-to-look-way-too-low/

https://onclimatechangepolicydotorg.wordpress.com/2015/06/27/the-ieas-bridge-scenario-to-a-low-carbon-world-again-underestimates-the-role-of-renewables/

https://onclimatechangepolicydotorg.wordpress.com/2017/09/26/underestimating-the-contribution-of-solar-pv-risks-damaging-policy-making/

[1] The BP Statistical Review of World Energy shows a total of 87GW installed in 2017 https://www.bp.com/content/dam/bp/business-sites/en/global/corporate/pdfs/energy-economics/statistical-review/bp-stats-review-2018-renewable-energy.pdf

Satellite data can help strengthen policy

Advancing satellite technology can improve monitoring of emissions.  This will in turn help make policies more robust.

There are now around 2000 satellites in earth orbit carrying out a wide range of tasks.  This is about twice as many as only a decade ago[i].   Costs continue to come down, technologies are advancing and more organisations are making use of data, applying new techniques as they do so.   As progress continues, satellite technologies are positioned to make a much larger contribution to monitoring greenhouse gas emissions.

Tracking what’s happening on the ground

Satellites are critical to tracking land use changes that contribute to climate change, notably deforestation.   While satellites have played an important role here for years, the increasing availability of data is enabling organisations to increase the effectiveness of their work.  For example, in recent years Global Forest Watch[ii] has greatly increased the range, timeliness and accessibility of its data on deforestation.  This in turn has enabled more rapid responses.

This is now extending to other monitoring.  For example, progress on construction projects can be tracked over time.  This enabled, for example, monitoring the construction of coal plant in China, which showed that construction of new plants was continuing[iii].

Monitoring operation and emissions

As the frequency with which satellite pictures are taken increases, it becomes possible to monitor not only construction and land use changes, but also operation of individual facilities.  For example, it is now becoming possible to track operation of coal plant, because the steam from cooling towers is visible[iv].  This can in turn allow emissions to be estimated.

More direct monitoring of emissions continues to develop.  Publicly available data at high geographic resolution on NOx, SOx, particulates and in the near future methane[v] are becoming increasingly available[vi].   For example, measuring shipping emissions has traditionally been extremely difficult, but is now becoming tractable, at least for NOx.

Measuring methane is especially important.  Methane is a powerful greenhouse gas with significant emissions from leakage in natural gas systems.  Many of these emissions can easily be avoided at relatively low cost, leading to highly cost-effective emissions reduction.

Monitoring CO2

CO2 is more difficult to measure than other pollutants, in part because it disperses and mixes in the atmosphere so rapidly.  However, some of the latest satellites have sophisticated technology able to measure CO2 concentrations very accurately[vii].  These cover only quite small areas at the moment but are expected to scale up and allow more widespread direct monitoring.  The picture below shows a narrow strip of the emissions from a coal plant in Kansas, based on data from the Orbiting Carbon Observatory 2 (OCO‐2) satellite.  These estimates conform well with reported emissions from the plant.

Figure 1:  Satellite data showing CO2 emissions for a power plant in Kansas

Note: the red arrow shows prevailing wind direction.

Space agencies around the world are now exploring how such monitoring can be taken further.  For example, the EU has now asked the European Space Agency to design a satellite dedicated to monitoring CO2.  It is expected to be operational in the 2020s.[viii]

Work is also underway to improve data analysis, so that quantities of emissions can be attributed to individual plants.  Machine learning holds a good deal of promise here as a way of finding and labelling patterns in the very large amounts of data available.  It is likely soon to be possible to monitor emissions from an individual source as small as a medium size coal plant, taking account of wind speed and direction and so forth.

Implications

These developments will make actions much more transparent and subject to inspection internationally.  Governments, scientists, energy companies, investors, academics and NGOs can monitor what is going on.  Increasingly polluters will not be able to hide their actions – they will be open for all to see.  This is turn will make it easier to bring pressure on polluters to clean up their act, potentially including, for example, holding countries to account for their Nationally Determined Contributions (NDCs) under the Paris Climate Agreement.

Improved transparency and robust data are not in themselves solutions for reducing climate change.  Instead, they play an important role in an effective policy architecture.  And the do so with ever increasing availability and quality.  This gives cause for optimism that policies and their implementation can be made increasingly robust.

Adam Whitmore – 12th September 2018

Thanks to Dave Jones for sharing his knowledge on the topic .

[i] https://www.ucsusa.org/nuclear-weapons/space-weapons/satellite-database#.W5Y-7ZNKhcA, https://allthingsnuclear.org/lgrego/new-update-of-ucs-satellite-database,

[ii] https://www.globalforestwatch.org/about

[iii] See here http://www.climatechangenews.com/2018/08/07/china-restarts-coal-plant-construction-two-year-freeze/ for examples

[iv] https://twitter.com/matthewcgray/status/1032251925515968512

[v] http://www.tropomi.eu/data-products/methane

[vi] https://www.scientificamerican.com/article/meet-the-satellites-that-can-pinpoint-methane-and-carbon-dioxide-leaks/

[vii] https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017GL074702

[viii] https://www.bbc.co.uk/news/science-environment-43926232

 

A limited but important medium term future for CCS

CCS has not yet been implemented on a scale needed to make a substantial difference to climate change.  However it continues to look necessary for the longer term, with more projects necessary to get costs down.

A decade or so ago many people expected rapid development of Carbon Capture and Storage (CCS) as a major contributor to reducing global emissions.  I was one of them – at the time I was working on developing CCS projects.  However, the hoped-for growth has not yet happened on the scale needed to make a material difference to global emissions.

The chart below shows total quantities captured from large CCS projects, including 17 that are already operational and a further 5 under construction.  The quantity of emissions avoided are somewhat lower than the captured volumes shown here due to the CO2 created by the process itself.[i]

Between 2005 and 2020 capture will have grown by only around 25 million tonnes p.a..  This is only 0.07% of annual global CO2 emissions from energy and industry.  In contrast the increase in wind generation in 2017 alone reduced emissions by around 60 million tonnes[ii], so wind power reduce annual emission more from about 5 months’ growth than CCS will from 15 years’ growth – though it took wind power several decades to get to this scale.    

Chart 1: Growth of large CCS projects over time

Source: Analysis based on Global Carbon Capture and Storage Institute database[iii]

The picture gets even less promising looking at the types of projects that have been built.  The chart below shows the proportion of projects, measured by capture volume, in various categories.  The largest component by some distance is natural gas processing – removing the CO2 from natural gas before combustion – which accounts for over 60% of volumes.  This makes sense, as it is often a relatively low cost form of capture, and is often necessary to make  natural gas suitable for use.  However, it will clearly not be a major component of a low carbon energy system.  Much of the rest is chemicals production, including ethanol and fertiliser production.  These are helpful but inevitably small. There are just two moderate size power generation projects and two projects for hydrogen production, which is often considered important for decarbonising heat.

Furthermore, most of the projects separate out CO2 at relatively high concentrations or pressures.  This tends to be easier and cheaper than separating more dilute, lower pressure streams of CO2.  However it will not be typical of most applications if CCS is to become more widespread.

Chart 2:  Large CCS projects by type (including those under construction) 

Source: Analysis based on Global Carbon Capture and Storage Institute database

This slow growth of CCS has been accompanied by at least one spectacular failure, the Kemper County power generation project, which was abandoned after expenditure of several billion dollars.  Neither the circumstances of the development or the technology used on that particular plant were typical.  For example, the Saskpower’s project at Boundary Dam and Petra Nova’s Texas project have both successfully installed post combustion capture at power plants, rather than the gasification technologies used at Kemper County.  Nevertheless, the Kemper project’s failure is likely to act as a further deterrent to wider deployment of CCS in power generation.

There have been several reasons for the slow deployment of CCS.  Costs per tonne abated have remained high for most projects compared with prevailing carbon prices.  These high unit costs have combined with the large scale of projects to make the total costs of projects correspondingly large, with a single project typically having a cost in the billions of dollars.  This has in turn made it difficult to secure from governments the amount of financial support necessary to get more early projects to happen. Meanwhile the costs of other low carbon technologies, notably renewables, have fallen, making CCS appear relatively less attractive, especially in the power sector.

The difficulties of establishing CCS have led many to propose carbon capture and utilisation (CCU) as a way forward.  The idea is that if captured CO2 can be a useful product, this will give it a value and so improve project economics.  Already 80% by volume of CCS is CCU as it includes use of the CO2 for Enhanced Oil Recovery (EOR), with project economics supported by increased oil production.

Various other uses for CO2 have been suggested.  Construction materials are a leading candidate with a number of research projects and start-up ventures in this area.  These are potentially substantial markets.  However the markets for CO2 in construction materials, while large in absolute terms, are small relative to global CO2 emissions, and there will be tough competition from other low carbon materials. For example, one study identified a market potential for CCU of less than two billion tonnes p.a. (excluding synthetic fuels) even on a highly optimistic scenario[iv], or around 5% of total CO2 emissions.  It is therefore difficult to be confident that CCU can make a substantial contribution to reducing global emissions, although it may play some role in getting more early carbon capture projects going, as it has done to date through EOR.

Despite their slow growth, CCS and CCU continue to look likely to have a necessary role in reducing some industrial emissions which are otherwise difficult to eliminate.  The development of CCS and CCU should be encouraged, including through higher carbon prices and dedicated support for early stage technological development.  As part of this it remains important that more projects CCS and CCU projects are built to achieve learning and cost reduction, and so support the beginnings of more rapid growth.  However in view of the lead times involved the scale of CCS looks likely to continue to be modest over the next couple of decades at least.

Adam Whitmore – 25th April 2018

[i] CO2 will generally be produced in making the energy necessary to run the capture process, compression of the CO2 for transport, and the rest of the transport and storage process.  This CO2 will be either emitted, which reduces the net gain from capture, or captured, in which case it is part of the total.  In either case the net savings compared with what would have been emitted to the atmosphere with no CCS are lower than the total captured.

[ii] Wind generation increased by a little over 100 TWh between 2016 and 2017 (Source: Enerdata).  Assuming this displaced fossil capacity with an average emissions intensity of 0.6 t/MWh (roughly half each coal and gas) total avoided emissions would be 60 million tonnes.

[iii] https://www.globalccsinstitute.com/projects/large-scale-ccs-projects

[iv] https://www.frontiersin.org/articles/10.3389/fenrg.2015.00008/full

Prospects for Electric Vehicles look increasingly good

Electric vehicles update

Indicators emerging over the last 18 months increase the likelihood of plug-in vehicles becoming predominant over the next 20 years.  However, continuing strong policy support is necessary to achieve this.

Several indicators have recently emerged for longer term sales of plug-in vehicles (electric vehicles and plug-in hybrids).  These include targets set by governments and projections by analysts and manufacturers.

The chart shows these indicators compared with three scenarios for the growth of plug-in vehicles globally if policy drivers are strong.  (The scenarios are based on those I published around 18 months ago, and have been slightly updated for this post – see the end of this post and previous post for details.) The green lines show the share of sales, and the blue lines show the share of the total vehicle stock.  Other indicators are marked on the chart as diamonds, shown in green as they correspond to the green lines.  I’ve excluded some projections from oil companies as they appear unrealistic.

The scenarios show plug in vehicles sales in 2040 at between just over half and nearly all of new light vehicles.  However the time taken for the vehicle fleet to turn over means that they are a smaller proportion of the fleet, accounting for between a third and about three quarters of the light vehicle fleet by 2040.  The large range of the scenarios reflects the large uncertainties involved, but they all show plug-in vehicles becoming predominant over the next 20 years or so.

The indicators shown are all roughly in line with the scenario range (see detailed notes at the end of this post), giving additional confidence that the scenario range is broadly realistic, although the challenges of achieving growth towards the upper end of the range remain formidable.  Some of the projections by manufacturers and individual jurisdictions are towards the top end of the range, but the global average may be lower.

Chart.  Growth of sales of Plug-in light vehicles

 

The transition will of course need to be accompanied by continuing decarbonisation of the power sector to meet greenhouse gas emissions reduction goals.

Maintaining the growth of electric vehicle sales nevertheless looks likely to require continuing regulatory drivers, at least for the next 15 years or so.  This will include continuing tightening emissions standards on CO2 and NOx and enabling charging infrastructure.  If these things are done then the decarbonisation of a major source of emissions thus now seems well within sight.

Adam Whitmore – 13th October 2017

 

 

Background and notes

This background section gives further information on the data shown on the chart.  In some cases it is unclear from the reports whether projections are for pure electric vehicles only or also include plug-in hybrids.

Developments in regulation

Policy in many countries seems increasingly to favour plug-in vehicles.  Some recent developments are summarised in the table below.   These policy positions for the most part still need to be backed by solid implementation programmes.  Nevertheless they appear to increase the probability that growth will lie within the envelope of the projections shown above, which are intended to correspond to a world of strong policy drivers towards electrification.

Policy developments 

Jurisdiction Policy commitment
UK Prohibit sale of new cars with internal combustion engines by 2040[1]
France Prohibit sale of new cars with internal combustion engines by 2040[2]
Norway All new sales electric by 2025[3]
India All cars electric by 2030 (which appears unrealistic so goal may be modified, for example to new cars)[4]
China Reportedly considering a prohibition on new petrol and diesel.  Date remains to be confirmed, but target is for 20% of the market to be electric by 2025.[5]

 

Sales

The market is currently growing rapidly from a low base.  Total vehicle sales were 0.73 million in 2016, compared with 0.58 million in 2015.  Six countries have reached over 1% electric car market share in 2016: Norway, the Netherlands, Sweden, France, the United Kingdom and China. Norway saw 42% of sales being EVs in June 2017

Manufacturers’ projections

Several manufacturers have issued projections for the share of their sales they expect to be for plug-in vehicles.  Some of these are shown in the table.

Manufacturers’ projections for sales of plug-in vehicles

 

Manufacturer Target/expectation for plug-in vehicles
Volkswagen 20-25% of sales by 2025[6]
Volvo All new models launched from 2019[7]
PSA ( Peugeot and Citroen brands) 80% percent of models electrified by 2023[8]

 

Clearly individual manufacturers’ projections may not be achieved, and to some extent the statements may be designed to reassure shareholders that they are not missing an opportunity.  So far European manufacturers have been slow to develop EVs.  Also these manufacturers may not representative of the market as a whole.  Other companies may progress more slowly.

However others may proceed more quickly.  As has been widely reported, Tesla has taken over 500,000 advanced orders for its Model 3 EV, itself equivalent to almost the entire market for electric vehicles in 2015.  And in line with the Chinese Government’s targets manufacturers in China are expected to increase production rapidly.

Projections by other observers

Projections by other observers are in most cases now in line with the scenairos shown here.

  • Morgan Stanley project 7% of global sales by 2025[9]
  • BNP Paribas project 11% of global sales by 2025, 26% by 2030[10]
  • JP Morgan profject 35% of sales by 2025 and 48% of sales by 2030[11]
  • Last year Bloomberg’s projections showed growth to be slower than with these projections. However they have since updated their analysis, showing 54% of new cars being electric by 2040[12].
  • DNV.GL recently published analysis showing EV’s accounting for half of sales globally by 2033, in line with the mid case in this analysis.

In contrast BP predicts much slower growth in their projections[13].  However BP’s view seems implausibly low in any scenario in which regulatory drivers towards EVs are as strong as they appear to be.  Exxon Mobil gives lower projections still, while OPEC’s are a little above BP’s but still well below the low case shown here.[14].

Notes on changes to projections since May 2016

These projections are updated from my post last year but the differences over the next 15 years are comparatively minor.  The projections are for light vehicles, so exclude trucks and buses.  Note that percentage growth in early years has been faster than shown by the s-curve model – however this is likely to prove a result of the choice of a simple function.  What matters most for emissions reductions is the growth from now and in particular through the 2020s.

Assumption change Rationale
Higher saturation point Continuing advances in batteries reduce the size of the remaining niche for internal combustion engine vehicles
Longer time to saturation The higher saturation point will need additional time to reach.
Somewhat slower growth in total numbers of vehicles Concerns about congestion and changed modes of ownership and use are assumed to lead to lower growth in the total vehicle stock over time.  This tends to make a certain percentage penetrations easier to achieve because the percentage applies to fewer vehicles.

 

 

[1] http://www.bbc.co.uk/news/uk-40723581

[2] http://www.bbc.co.uk/news/world-europe-40518293

[3] http://fortune.com/2016/06/04/norway-banning-gas-cars-2025/

[4] https://electrek.co/2016/03/28/india-electric-cars-2030/

[5] http://www.bbc.co.uk/news/business-41218243

[6] http://www.bbc.co.uk/news/business-36548893

[7] https://www.media.volvocars.com/global/en-gb/media/pressreleases/210058/volvo-cars-to-go-all-electric

[8] http://www.nasdaq.com/video/psa-prepared-for-electric-vehicle-disruption–says-ceo-59b80a969e451049f87653d9

[9] https://www.economist.com/news/business/21717070-carmakers-face-short-term-pain-and-long-term-gain-electric-cars-are-set-arrive-far-more

[10] https://www.economist.com/news/business/21717070-carmakers-face-short-term-pain-and-long-term-gain-electric-cars-are-set-arrive-far-more

[11] https://www.cnbc.com/2017/08/22/jpmorgan-thinks-the-electric-vehicle-revolution-will-create-a-lot-of-losers.html

[12] https://about.bnef.com/electric-vehicle-outlook/

[13] https://www.bp.com/en/global/corporate/energy-economics/energy-outlook.html

[14] https://www.economist.com/news/briefing/21726069-no-need-subsidies-higher-volumes-and-better-chemistry-are-causing-costs-plummet-after

Half way there

The UK has made excellent progress on reducing emissions.  But the hard part is yet to come.

The UK’s Climate Change Act (2008) established a legally binding obligation to reduce UK emissions by at least 80% from 1990 levels by 2050.  This is an ambitious undertaking, a sixty year programme to cut four in every five tonnes of greenhouse gas emissions while simultaneously growing the economy.

The story so far is, broadly, an encouraging one.  2016 emission were 42% below 1990 levels, about half way to the 2050 target[1].  This has been achieved in 26 years, a little under half the time available.  And it has been achieved while population has grown by about 15%[2] and the economy has grown by over 60%.  The reduction in emissions from 1990 to 2015 is shown on the chart below, which also shows the UK’s legislated carbon budgets.   There is of course some uncertainty in the data, especially for non-CO2 gases, but uncertainties in trends are less than the uncertainty in the absolute levels, and emissions of CO2 from energy, which is the largest component of the total, are closely tracked.

The UK is half way towards its 2050 target, in a little under half the available time …

Source: Committee on Climate Change

The chart below shows the sectoral breakdown of how this has been achieved, and this raises some important caveats.

Progress in some sectors has been much more rapid than others …

Source: Committee on Climate Change

The largest source of gains has been the power sector, especially if a further fall of a remarkable in emissions from power generation in 2016 is included (the chart only shows data to 2015).  While renewables have made an important contribution, much of this fall has been due to replacing coal with gas.  This been an economically efficient, low cost way of reducing emissions to date, to which UK carbon price support has been a major contributor.  However coal generation has now fallen to very low levels, so further progress requires replacing gas with low carbon generation – renewables, nuclear and CCS.  This is more challenging, and in some cases is likely to prove more expensive.

The next largest source of gains, roughly a third of the total reduction, is from industry.  However, while detailed data is not available, a large part of this reduction may have been due to broader economic trends, notably globalisation of the world economy leading to heavy industry becoming more concentrated in emerging economies.  This trend may also have had some effect on electricity demand and thus emissions.  The aggregate reduction in global emissions may thus be smaller than indicated by looking at the UK alone.  Reducing global emissions still requires a great deal more progress on industrial emissions, especially in emissions intensive sectors notably iron and steel and cement.

Progress in reduction of emissions from waste, especially methane from landfill, has been a third important contributor.  Again, this has been highly cost-effective reduction.  However about two thirds of emissions have now been eliminated so further measures will necessarily make a smaller contribution, though there is much that can still be done with the remainder such as eliminating organic waste from landfill.

Other sectors have done much less, and will need to do more in the years to come.  Progress on f-gases may be helped by the recent international agreement on HFCs, although more will still need to be done.  Transport emissions have made only slow progress in recent years.  It is essential that electrification is encouraged so that a large change similar to that achieved in the power sector can be achieved in transport.  The buildings stock remains an intractable problem, and the first priority must be to at least make sure that new buildings are built to the highest standards of insulation.

So continuing the trend of falling emissions in future will be difficult and will require new and enhanced policy measures.  But in 1990 the prospects of achieving what has already been achieved doubtless looked daunting, and progress to date should encourage further efforts in future.

Adam Whitmore -25th April 2017

Material in this post draws on a presentation by Owen Bellamy of the Committee on Climate Change at a British Institute of Energy Economics seminar on 5th April 2017.

[1] The UK’s domestic emissions need to go down slightly more rapidly than the headline target would suggest due to the role of international aviation and shipping.  This is shown on the chart.  However the broad message is the same.

[2]https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/articles/overviewoftheukpopulation/mar2017

The constrained role of biomass

The role of biomass in the world energy system looks likely to be constrained, so there will be a need to focus on high value applications where there are few low-carbon alternatives.

This is the second of two posts looking at the role of biomass.  Here I focus on potential resource constraints.

A wide range of possibilities

The amount of biomass available to provide energy depends a lot on the amount of land available to grow energy crops, and how much that land can yield.   Different assumptions on these variables produce quite different estimates of the total resource, and numerous studies over the years have produced a wide range of results.    The amount of waste biomass available also matters, but potential availability from this source is smaller.

A comprehensive review of estimates of the biomass resource was carried out two years ago by researchers at Imperial College[i] (see chart).  It showed a variation in estimates of a factor of around 40, from of the order of 30 EJ to over 1000 EJ (1EJ =1018 J, or a billion GJ, or 278 TWh).  This compares with total world primary energy demand of just under 600 EJ, transport demand of around 100 EJ, and at least 250 EJ to produce present levels of electricity, assuming biomass combustion to remain relatively inefficient[ii].

Estimates of available biomass resource

biomass chart processed

Source: Slade et. al. (2014)

The authors examine reasons for differences in estimates, which I’ve summarised in the table below.  The differences are largely assumption driven, because the small scale of commercial bioenergy at present provides little empirical evidence about the potential for very large scale bioenergy, and future developments in food demand and other factors are inevitably uncertain.

Reasons for variation in estimates of total biomass supply

Range Typical assumptions
Up to 100EJ Limited land available for energy crops, high demand for food, limited productivity gains in food production, and existing trends for meat consumption.  Some degraded or abandoned land is available.
100-300 EJ Increasing crop yields keep pace with population growth and food demand, some good quality agricultural land is made available for energy crop production, along with 100-500Mha of grassland, marginal, degraded and deforested land
300-600EJ Optimistic assumptions on energy crop availability, agricultural productivity outpaces demand, and vegetarian diet
600 EJ + Regarded as extreme scenarios to test limits of theoretical availability

 

Reasons for caution

In practice there seem to me to be grounds for caution about the scale of the available resource, although all of these propositions require testing, including through implementation of early projects.

Land Availability

  • There will rightly be emphasis on protection of primary forest on both carbon management and biodiversity grounds, with some reforestation and rewilding.
  • There is little evidence of a shift away from meat consumption. With the exception of India, less than 10% of people in  most countries are vegetarian despite many years of campaigning on various grounds[iii].   In China meat consumption is associated with rising living standards.
  • Demand for land for solar PV will be significant, although a good deal of this will be on rooftops and in deserts

Yield

  • The nitrogen cycle is already beyond its limit, constraining the role of fertiliser, and water stress is a serious issue in many places (agriculture accounts for 70% of current fresh water use). The UN Food and Agriculture Organisation has projected fairly modest increases in future yields.

Policy support

  • Difficulties in limiting lifecycle emissions from biofuels are likely to lead to caution about widespread deployment.
  • Concerns about food security may limit growth of biofuels.

Small scale to date, despite many years of interest

  • There has been little progress to date compared with other low carbon technologies. Though traditional biofuels remain widely used, modern biofuels account for a very small proportion of demand at present.  World biofuels consumption currently accounts for only 0.2% of world oil consumption[iv] .  Many biofuels programmes have had subsidies cut and there is still limited private sector investment.

In this context some estimates of the potential for biomass to contribute to energy supply seem optimistic.  For example, Shell’s long-term scenarios (Oceans and Mountains) show biomass of 74 EJ and 87 EJ respectively for commercial biomass, 97-133 EJ including traditional biomass by 2060[v].  These totals are towards or above the more cautious estimates for the resource that might ultimately be available (see table above).  A recent review article[vi]  suggested that by 2100 up to 3.3 GtCp.a. (around 12 billion tonnes of CO2) could be being removed, and producing around 170EJ of energy.  However the land requirements for this are very large at about 10% of current agricultural land.  The authors suggest instead a mean value for biomass potential of about a third of that, or 60EJ.

On balance it seems that biomass is likely to account for at most less than 10% of commercial global energy (likely to be around 800-900EJ by mid-century), and potentially much less if land availability and difficulties with lifecycle emissions prove intractable.

It thus seems likely that biomass energy will be relatively scarce, and so potentially of high value.  This in turn suggests it is likely to be mainly used in applications where other low carbon alternatives are unavailable.  These are not likely to be the same everywhere, but they are likely often to include transport applications, especially aviation and likely heavy trucking, and perhaps to meet seasonal heat demand in northern latitudes.  For example, according to Shell’s scenarios aviation (passengers + freight) is expected to account for perhaps 20-25EJ by 2050, and biomass could likely make a useful contribution to decarbonisation in this sector.

None of this implies that biomass is unimportant, or has no role to play.  It does imply that policies focussing on deploying other renewable energy sources at large scale, including production of low carbon electricity for transport, will be essential to meeting decarbonisation targets.  And the optimum use of biomass will require careful monitoring and management.

Adam Whitmore  – 11th April 2016

 

[i] Slade et.al., Global Bioenergy Resources, Nature Climate Change February 2014

[ii] Data on final consumption and electricity production from Shell and IEA data.  35% efficiency for biomass in electricity is assumed, which is likely to be somewhat optimistic, especially if CCS is employed.

[iii] https://en.wikipedia.org/wiki/Vegetarianism_by_country

[iv] BP Statistical Review of World Energy

[v] http://www.shell.com/energy-and-innovation/the-energy-future/shell-scenarios.html  These totals include biofuels, gasified biomass and biomass waste solids, and traditional biomass.

[vi] Smith et. al., Biophysical and economic limits to negative CO2 emissions, Nature Climate Change, January 2016.  The paper estimates land requirement for 170 EJ of 380-700 Mha, around 10% of total agricultural land area in 2000 of 4960Mha.