How well is the UK on track for zero emissions by 2050?

By 2020 the UK will have very nearly halved its emissions over 30 years.  Reducing emissions by the same amount over the next 30 years will get the UK very close to zero.  However this will be very much more difficult.

A robust net zero target has been recommended for the UK …

A recent report by the UK’s Committee on Climate Change (CCC), the Government’s official advisory body, recommends that the UK adopts a legally binding target of net zero emissions of greenhouse gases by 2050[i], that is remaining emissions must be balanced by removal from the atmosphere.  If the Government agrees, this will be implemented by amending the reduction mandated by the Climate Change Act, from an 80% reduction from 1990 to a 100% reduction.

The target has several features that make it particularly ambitious.  It:

• sets a target of net zero emissions covering all greenhouse gases;
• includes international aviation and shipping;
• allows no use of international offsets; and
• is legally binding.

This is intended to end the UK’s contribution global warming.  It has no precedents elsewhere, although in France a bill with comparable provisions is under consideration[ii].

Progress to date has been good …

The UK has made good progress so far in reducing emissions since 1990.  Emissions in 2018 were around 45% below 1990 levels, having reduced at an average rate of about 12.5 million tonnes p.a. over the period.  On current trends, over the thirty years from 1990 to 2020 emissions will be reduced to about 420 million tonnes p.a., 47% below their 1990 levels.  Emissions will thus have nearly halved over the 30 years 1990 to 2020, half the period from 1990 to the target date of 2050.

Chart 1 shows how the UK’s progress compares with a linear track to the current target of an 80% reduction, to a 95% reduction and to a 100% reduction.  (For simplicity I’m ignoring international aviation and shipping).  The UK is currently on a linear track towards a 95% reduction by 2050.

Chart 1: Actual UK emissions compared with straight line progress towards different 2050 targets

 

Source: My analysis based on data from the Committee on Climate Change and UK Government.  Data for 2018 is provisional[iii]

The largest contributor to the total reduction so far has been the power sector.  Analysis by Carbon Brief[iv] showed that the fall in power sector emissions has been due to a combination deploying renewables, which made up about of third of generation in 2018, reducing coal use by switching to natural gas, and limiting electricity demand growth.

Industrial emissions have also fallen significantly.  However some of this likely represents heavy industry now being concentrated elsewhere in the world, so likely does not represent a fall in global emissions.  Emissions from waste have also fallen, due to better management.

Reducing emissions will be relatively easy in some sectors …

There are also reasons for optimism about continuing emissions reductions.  Many technologies are now there at scale and at competitive prices, which they were not in previous decades.  For example, falling renewables costs and better grid management, including cheaper storage, will help further decarbonisation of the power sector.  Electrification of surface transport now appears not only feasible, but likely to be strongly driven (at least for cars and vans) by economic factors alone as the cost of batteries continues to fall.

But huge challenges remain …

Nevertheless important difficulties remain for complete decarbonisation.

CCS is identified by the report as an essential technology.  However, as I have noted previously, it has made very little progress in recent years in the UK or elsewhere[v].  CCS is especially important for decarbonising industry.  This includes a major role for low carbon hydrogen, which is assumed to be produced from natural gas using CCS – although another possibility is that it comes from electrolysis using very cheap renewables power, e.g. at times of surplus.  CCS also looks to be necessary because of its use with bioenergy (BECCS), to give some negative emissions, though the lifecycle emissions from this will require careful attention

Decarbonising building heating, especially in the residential sector, continues to be a challenge.  The report envisages a mix of heat pumps and hydrogen, perhaps in the form of hybrid designs, with heat pumps providing the baseload being topped-up up by burning of hydrogen in winter.  I have previously written about the difficulties of widespread use of heat pumps[vi], and low carbon hydrogen from natural gas with CCS is also capital intensive to produce and therefore expensive to run for the winter only.  The scale of any programme and consumer acceptance remain major challenges, and the difficulties encountered by the UK’s smart meter installation programme – by comparison a very simple change – are not an encouraging precedent.

Emissions from agriculture are difficult to eliminate completely, and no technologies are likely to be available by 2050 that enable aviation emissions to be completely eliminated.  This will require some negative emissions to balance remaining emissions from these sectors.

Policy needs to be greatly strengthened …

Crucially several of the necessary transformations are very large scale, and need long lead times, and investment over decades.  There is an urgent need to make progress on these, and policy needs to recognise this.  This includes plans for significant absorption from reforestation, as trees need to be planted early enough that they can grow to be absorbing substantial amounts by 2050.

The UK’s progress on emissions reduction so far has been good, having made greater reductions than any other major economy[vii].  And technological advances in some areas are likely to enable substantial further progress.  However much more is needed.  In particular policy needs to look now at some of the difficult areas where substantial long-term investment will be needed

Adam Whitmore – 22^nd May 2019

 

 

[i] https://www.theccc.org.uk/2019/05/02/phase-out-greenhouse-gas-emissions-by-2050-to-end-uk-contribution-to-global-warming/

 

[ii] The CCC report notes that Norway, Sweden and Denmark have net zero targets, but they allow use of international offsets (up to 15% in the case of Sweden).  France has published a target similar to the UK’s in a bill.  The European Commission has proposed something similar for the EU as a whole, but this is a long way from being adopted. California has non-legally binding targets to achieve net zero by 2045.  Two smaller jurisdictions (Costa Rica, Bhutan) have established net zero targets but these are expected to be achieved mainly by land use changes.  New Zealand has a draft bill to establish a target, but eliminating all GHGs will be difficult because of the role of agriculture in the New Zealand economy.

 

[iii] https://www.gov.uk/government/statistics/provisional-uk-greenhouse-gas-emissions-national-statistics-2018  The change from 2017 to 2018 is applied to the data series from 1990 produced by the CCC (the two data series differ very slightly in their absolute levels).

 

[iv] https://www.carbonbrief.org/analysis-uk-electricity-generation-2018-falls-to-lowest-since-1994

 

[v] https://onclimatechangepolicydotorg.wordpress.com/2018/04/25/a-limited-but-important-medium-term-future-for-ccs/

 

[vi] https://onclimatechangepolicydotorg.wordpress.com/2015/05/18/reducing-the-costs-of-decarbonising-winter-heating-needs-to-be-a-priority/

 

[vii] https://onclimatechangepolicydotorg.wordpress.com/2017/05/09/uk-emissions-reductions-offer-lessons-for-others/

 

How fast could the market for electric vehicles grow?

Various policy driven scenarios show electric vehicles gaining market share over the next few decades but with the turnover of the vehicle stock taking longer.

I recently argued that BP’s projections showing almost no take-up of plug-in vehicles[1] by 2035 was unrealistic in view of several convergent trends.  There is increasing pressure to reduce CO₂ emissions, there is large and growing concern about urban air quality,  and electric vehicles are likely to prove attractive to consumers in many respects.  In line with these drivers, sales are growing very quickly and many new models are coming on line, while battery technology is improving rapidly, with costs falling sharply and energy density rising.

However while these factors suggest that electric vehicles will gain substantial market share it does not say how much how soon[2].  So how fast might the market for plug-in vehicles grow if policy drivers are strong and matched by favourable economics?  Here I consider how quickly electric vehicles could gain market share on that sort of optimistic view.

Market share gains for new technologies

The transition to electric vehicles is in its early stages, so extrapolating historical trends offers only limited guidance.  Similarly, highly detailed modelling may not offer robust insights, because too many assumptions are required.  Instead it seems appropriate to look at some broad indicators.

A good starting point is to look at adoption other new technologies.  The chart below shows the rates of penetration of new technologies in the USA over the 20^th and early 21^st centuries.  It shows variants on a characteristic s-curve shape, with most technologies reaching eventual penetrations of 80-100%.  The typical time to reach about 80% penetration following the first 1% or so of deployment (about where plug-in vehicles are now) is around 20-30 years, although some modern highly scalable technologies have become nearly ubiquitous faster than this, and other technologies have taken as long as fifty years or so to reach high penetration.

For example, cars themselves experienced rapid growth between around 1910 and 1930, reaching 60% of households, before experiencing hiatus and decline during the Great Depression and Second
World War, before growing steadily again through the to the second half of the 20^th Century.

However these timings are for the USA, and, even in increasingly homogenous, world global adoption may take a little longer.

Chart:  Transitions of major technologies

 

The chart mainly shows technologies that fulfil a new function, rather than those that replace existing technologies, as plug-in vehicles do.  However replacement technologies can also gain market share quickly.  Digital cameras replacing film almost completely over a period of around 15-20 years, and DVDs replaced VHS in less than 10 years.  In these cases the new technology brought clear advantages.  For plug in vehicles a combination of some advantages plus regulatory drivers could play a similar role.

Modelling the transition

EVs are rather different from many of these cases in that there is a large existing capital stock which is expensive to replace – a new car is much more costly than a new camera.  This limits the rate of change of the stock.   I have therefore applied the sorts of timescales shown above to a rough and ready model representing the potential rate of gain market share of new vehicles, rather than changes to the stock.  The model uses a standard s-curve (logistic function).  Changes in the stock are then calculated considering stock turnover.

I have developed three scenarios representing respectively strong policy drivers, more moderate policy drivers, and a delayed transition representing either weaker policy or greater practical or economic obstacles.  The strong policy case fits better with the historic data, but this may not be a reliable marker as the history is so short and there are a number of particular circumstances at work.

I have assumed plug-in vehicles will eventually account for 80%-90% of the market for light vehicles, with markets for internal combustion vehicles likely to remain where consumers seek low capital costs or they need long range with poor infrastructure.  There will doubtless also be small niches for car enthusiasts seeking experience of the internal combustion engine, just as there are for taking photographs on film.  However these are likely to play only a small role.

The rate at which the stock of vehicles is replaced depends on how long vehicles last.  I have assumed this to be 15 years, although there is obviously a distribution around this.  If this were to lengthen further it would slow the change in the stock, or could be shortened by incentives to scrap older vehicles.  The life of new electric vehicles is unproven (although battery guarantees of typically around 8 years are available), but in any case I have assumed buyers replace their battery packs, or replace their EVs with other EVs rather than returning to internal combustion engines.

Growth of the vehicle fleet leads to a faster proportional changeover of the stock, assuming plug in vehicles gain the same share of the larger market, because current sales are a greater proportion of the historic stock.  I’ve here assumed a 2.5% p.a. global growth rate for car sales[3].

The results of this analysis are shown in the chart.  Annual sales of EVs reach 20-60% of the market by 2030, expected to be over 100 million vehicles p.a. by then.  They by then account for around 7-22% of the vehicle stock, or around 100-330 million vehicles.  By 2050 electric vehicles account for a majority of light vehicles on the roads in all the scenarios.

Global market share of plug in light vehicles

So do  these projections make sense, and what might stop them?

Cost competitiveness.  Analysis by a variety of commentators show EVs becoming economically competitive in the early to mid-2020s, varying between geographies depending on factors such as driving patterns and petrol prices.  This timing corresponds with the period when vehicles begin to gain market share much more rapidly in the above model, especially in the first two cases, which appears consistent.

China.  A large proportion of vehicle sales in the coming years will be in developing countries, especially China.  Concerns around urban air quality, development of the indigenous automotive industry, infrastructure development, and oil imports look likely to tend to favour EVs in China.  Driving patterns based around lots of shorter distance urban driving are also compatible with EVs.  For these reasons government policy in China strongly favours EVs.  Again this seems consistent.

Growth rate.  The compound annual growth rate for annual sales over the period to 2030 ranges from 25% to 33%, both well below current growth rates of around 60% p.a.

Scale-up.  The need to produce tens of millions of additional EVs by 2030 is a formidable challenge.  However the international car industry increased production by about 35 million units p.a. over the two decades between the 1990s and 2015, and added 20 million units p.a. in the last decade alone[4].  Replacing models with electric equivalents at this scale does not seem like an insuperable barrier, at least in the lower two scenarios.  However the challenges of achieving this for the stronger policy scenario are formidable, and policy drivers would need to be correspondingly strong to overcome these barriers.

Battery production would also need to be scaled up by orders of magnitude.  There don’t appear to be any fundamental barriers to supply of the vast quantities of lithium that would be needed, but it may take time to develop the infrastructure.

The need to ramp up production of both new models and batteries may act to slow growth, at least for a while and especially in the strong policy case, but do not seem likely to act as a fundamental longer term constraint.

Grid constraints.  EVs are likely to require reinforcement of grids, but again this does not look like a major barrier given the timescales involved.

Other projections

These projections show much faster growth than analysis by BNEF, which suggests 35% market share by 2045[5].  However the reasons that BNEF sees growth being so restricted are unclear, and there appear to be few examples where the penetration of a new technology has been so slow.  It seems a more likely estimate for a share of the stock by that date, though even then looks to be towards the low end of the range.

Goldman Sachs estimates 22% of the market being EVs by 2025[6].  This includes conventional hybrids, with the share of plug-in vehicles being only about a third of this, closer to the moderate case.  However it would not seem to require a fundamental change to the market’s development for a greater share of hybrids to be plug-in, so Goldman’s analysis seems at least potentially consistent with the strong regulation case shown here.

Other scenarios show something close to the moderate case shown here.  The IEA 450 scenario and Statoil’s reform scenario both show EV sales reaching around 30% of the market by 2030[7].

Outturn will doubtless differ from these projections.  But they do highlight the extent to which policy might succeed in stimulating a major transition in car markets in the next two or three decades.

Adam Whitmore – 24^th May 2016

 

[1] All estimates here refer to pure electric vehicles and plug in hybrids, which get much or all of their energy from externally generated electricity.  Depending on driving patterns, a PHEV may typically get 70% of its energy from external electricity.  I exclude conventional hybrids, which are essentially a variant of internal combustion engines with increased efficiency, in that still get all their energy from petrol.

 

[2] Some have made  the case that on pure resource cost grounds internal combustion engine vehicles will continue to predominate.  See  http://www.energypost.eu/can-battery-electrics-disrupt-internal-combustion-engine-part-1/  This is potentially true in the absence of any policy drivers due to emissions or other factors, but this seems unrealistic.

[3] For comparison, BP assume a doubling of the vehicle fleet by 2035, about a 3.5% p.a. growth rate (see there 2035 outlook).

[4] http://www.statista.com/statistics/200002/international-car-sales-since-1990/

[5] http://www.bloomberg.com/features/2016-ev-oil-crisis/

[6] http://www.goldmansachs.com/our-thinking/pages/new-energy-landscape-folder/report-the-low-carbon-economy/report.pdf

[7] See Lost in transition, Carbon tracker p. 102 for plots of these projections

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

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  – 11^th 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.