Category Archives: electric vehicles

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.


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 20th and early 21st 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 20th 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

 new technology chart

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

EV growth chart

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 – 24th 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  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).




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