This group brings together the best thinkers on energy and climate. Join us for smart, insightful posts and conversations about where the energy industry is and where it is going.

Roger Pielke, Jr.'s picture
Center for Science and Technology Policy Research at the University of Colorado at Boulder

Roger Pielke Jr. is a professor of environmental studies at the Center for Science and Technology Policy Research at the University of Colorado at Boulder. He also holds appointments as a...

  • Member since 2018
  • 38 items added with 28,223 views


Emissions: Can the British Decarbonize?

Britain Carbon Pollution

If the United Kingdom is going to hit its short-term targets for the emissions of carbon dioxide, then it is going to have to accelerate its rates of decarbonization observed since the passage of its 2008 Climate Change Act by a factor of four. Since the passage of that Act the rate of decarbonization in the UK has slowed dramatically from the rate observed during the pervious decade. The enormous magnitude of the task called for in the Act has been overshadowed by a debate of the setting of targets for the decarbonization of energy supply, targets which are already implied by the 2008 legislation and thus unnecessary.

Earlier this month the UK parliament debated an amendment to an energy bill which would establish quantitative targets for the decarbonization of the nation’s energy sector by 2030. The amendment was defeated in a close vote, prompting strong reactions. Tim Yeo, the Conservative chair of the Energy and Climate Change Select Committee who introduced the amendment, said that the “failure to introduce a clean energy target now could make it harder for the UK to meet its long-term carbon reduction targets.”  Caroline Flint, Labor’s shadow minister for energy and climate change called the vote “a humiliating failure.”

However, lost in the debate before and after the vote is that the UK has already committed itself to the decarbonization of its energy supply. This commitment results from the combination of an expectation of future economic growth and the passage 2008 Climate Change Act that mandates targets and timetables for emissions reductions. Growth in GDP coupled with reduced emissions is decarbonization.

Consequently, adopting formal legislation for decarbonization would be largely redundant. The UK government estimated that in 2012, 40 percent of emission came from the power supply sector.  If the Climate Change Act is to succeed in its goal of achieving a 34 percent from 1990 emissions by 2022, then a substantial decarbonization of the power sector must occur.

The rate of decarbonization of the power sector implied by the targets and timetables of the Climate Change Act could be a bit more or less than the overall decarbonization rate. In the following discussion I assume that the rate of decarbonization of the power sector occurs at the overall implied rate and explore what that would imply. 

Before jumping into the numbers it will be useful to precisely explain what “decarbonization” actually means. In discussing policies related to carbon it can be very useful to start with an appreciation for the Kaya Identity, which posits that carbon dioxide emissions are a function of economic activity and technologies of energy production and consumption. It looks like this:

carbon emissions = GDP * energy intensity * carbon intensity

Or more precisely:

carbon emissions = GDP * energy consumption/GDP * carbon/energy consumption

The decarbonization of energy supply refers to the final term in that equation, that is, a reduction in the amount of carbon emitted per unit of energy consumption, called carbon intensity. (Note that the second term, energy consumption/GDP, refers to energy intensity — very important and distinct.)  Historically, decarbonization of energy supply has been the result of the substitution of less carbon intensive sources of energy for more carbon intense sources — such as when gas replaces coal, or solar, wind or nuclear replace any type fossil fuel. 

How fast would the decarbonization of energy supply have to occur to meet the targets of the 2008 Climate Change Act?

We can answer this precisely using the Kaya Identity. First, let’s move GDP to the other side of the equation:

carbon emissions/GDP = energy intensity * carbon intensity

In this exercise I have equated the rate of decarbonization of economic activity (carbon emissions/GDP) with the implied rate of decarbonization of energy supply. Different assumptions can of course be made, but the conclusions reached below are not particularly sensitive to these assumptions. 

While the level of emissions in 2022 is established in the legislation at a level 34 percent below 1990 emissions, the rate of future GDP growth is unknowable, though policy makers would clearly like it to be higher rather than lower. In the exercise below I consider three annual rates of UK GDP growth to 2022, 1 percent, 2 percent, and 3 percent. It could of course turn out to be higher or lower.

If the UK is to hit its 2022 emissions target, then assuming a 2 percent annual GDP growth implies a rate of decarbonization of the economy of 4.4 percent per year over the next 9 years (for 1 percent annual GDP growth it is 3.3 percent and for 3 percent GDP growth it is 5.4 percent). Since the Climate Change Act was passed in 2008 the UK economy has actually decarbonized at a rate of 1.1 percent per year (data on GDP is here and emissions here), reflecting almost no change in emissions and a small amount of economic growth. The implication is thus that at a modest rate of economic growth to 2020 the rate of decarbonization will have to quadruple from that observed over the past 3 years.  Over the decade prior to the passage of the act the UK economy decarbonized at a rate of 2.6 percent annually.

What would a 4.4 percent rate of decarbonization mean in terms of more readily understandable concepts of energy supply? 

To achieve a 34 percent reduction in carbon dioxide emissions by 2022 implies a reduction of some 90 million metric tonnes (MMT) of carbon dioxide emission from 2012 levels. In 2012 according to the UK government, “There was a 31 per cent decrease in gas use for generation, alongside a 31 per cent increase in the use of coal. Together, these changes resulted in an increase of around 8 per cent in emissions from electricity generation.”

That substitution implies an increase of about 11.6 MMT of carbon dioxide and further implies that replacing all coal with gas would lead to a reduction of about 45 MMT of carbon dioxide (calculated as approximately 4 * 11.6). That means that if energy supply is responsible for half of the required emissions reductions to 2022 (with energy efficiency accounting for the reminder), then all coal would have to be replaced by gas in order to achieve the implied decarbonization target, roughly reflecting a tripling of gas consumption.  Similar exercises could be calculated with other technologies such as wind or nuclear.

No matter what units of technological substitution are used, the scale of the decarbonization challenge implied under the UK Climate Change Act is huge. The additional experience gained since the Act was passed indicates that the magnitude of that challenge has increased as progress is not being made at a rate necessary to hit the targets. Slow, even negative, economic growth in recent years has masked the lack of progress.

Of course it is possible that targets could be met via creative strategies such as the use of offsets or the counting of emissions reductions in gases other than carbon dioxide. However, such strategies, irrespective of their inherent merits, would only postpone the decarbonization needed in the power sector if deep emissions reductions proposed to 2050 are to be met. Of course, the main consequence of adopting a decarbonization target for 2030 might be to simply move the goal posts further into the future to reset the emissions challenge, as it appears that the shorter-term targets are likely to be missed.

The UK government is planning to revisit its commitment to carbon targets next year. Such a review will be far more effective with a commitment to understanding what the government has already committed to and its actual performance with respect to those ambitions, even if the resulting data is inconvenient or uncomfortable.

Photo Credit: Britain and Carbon Pollution/shutterstock

Roger Pielke, Jr.'s picture
Thank Roger for the Post!
Energy Central contributors share their experience and insights for the benefit of other Members (like you). Please show them your appreciation by leaving a comment, 'liking' this post, or following this Member.
More posts from this member


Spell checking: Press the CTRL or COMMAND key then click on the underlined misspelled word.
Robert Bernal's picture
Robert Bernal on Jul 4, 2013

“Failure to introduce a clean energy target now could make it harder for the UK to meet its long-term carbon reduction targets”.

Clean energy is the ultimate objective, however, at the rate we’re going, (the world) it will be too little too late. However, there are other options that must be considered due to their lower price and (relative) ease of global implementation. One is to “paint everything white” but that does not address the problem, and worst yet, could actually have a negative effect on reducing ocean acidification.

Sequestration is usually thought of as putting the CO2 directly underground. Worst concept ever! Putting nuclear wastes underground is a FAR better option because, eventually (from molten fuels reactors, that is), they decay into a non concern in just a few hundred years. Not so with CO2. It will eventually leak or mix unfavorably. Also, the shear mass of the CO2 is many orders of magnitude greater than any nuclear headaches.

However, there is a form of sequestration called mineral decarbonization. Simply duplicate nature (and speed things up) by mining and crushing olivine rocks and spread about for nature to do the rest. It sounds almost to good to be true but is cheaper than every other option (including geological sequestration) and therefore, may actually be deemed acceptable by the world’s nations as a real and doable solution to their decarbonization obligations.

Of course, developing machine made wind, solar and batteries, as well as molten fuels reactors is a must, however, the olivine solution is already an order of magnitude cheaper, which must be used now, while we’re waiting for the FF companies to invest in clean…

Robert Bernal's picture
Robert Bernal on Jul 4, 2013

Update, I found that this is more energy intense, being only about 70% efficient (due to its CO2 emission during grinding down to 1 micrometer dust particals) and that it would have to scale to the coal industry to work.

Nathan Wilson's picture
Nathan Wilson on Jul 5, 2013

Robert, the transition to sustainable energy essentially means that all jobs related to the coal industry and all towns dependent on coal must disappear.  That is a pretty serious change that will harm a lot of people, and we should not expect it to happen quickly.

I’m no particular fan of carbon sequestration, but I accept that it might be necessary is some places in order to win political support for reducing carbon emissions.

Nathan Wilson's picture
Nathan Wilson on Jul 5, 2013

Replace existing nuclear plants with new ones and implement modular nuclear plants “

This IEA data and  IEA graph shows that as of 2009, the UK’s electric contribution from nuclear was only 18% (9.2% of total primary energy), which is way too low for a developed nation, especially given that it was making 28% of electricity from coal.  The developed nations (including the US) should grow our nuclear deployments to over 50% of the grid, to reduce emissions and to protect our children and grandchildren from the high cost of renewables with energy storage.  In many cases, lifetime extensions of existing nuclear plants can safely be used to greatly reduce the cost of nuclear power, and ease the transition.

The ongoing growth in the use of natural gas for electricity production is short-term thinking.  Natural gas is the second best transportation fuel (after oil); in the longer term we must reduce its use for electricity and increase its use for transportation for energy security.

This is also a development model that we can export to developing nations which will benefit them too, and won’t produce the massive habitat destruction and CO2-emitting deforestation of biofuels and other renewables.

Alistair Newbould's picture
Alistair Newbould on Jul 6, 2013

But sequestered as carbonate not CO2

Robert Bernal's picture
Robert Bernal on Jul 6, 2013

If mineral sequestration is 70% efficient, and a cap on carbon is enacted, isn’t it still competative with other sources? I understand that a lot of jobs are on the line but as we move on to other sources, I believe there would be new jobs. Infact, doesn’t the coal industry have fewer jobs per unit than nuclear?

And definately, the “little” bit of solar and wind creates “too many” jobs.

Geological co2 storage will eventually leak. Mineral sequestration is like turning the excess into rock!

Paul O's picture
Paul O on Jul 6, 2013

Just a thoughtful question, and if already answered kindly direct me to where.


1) If we have 100yrs of Natural gas, is this estimate  for Electricity production, or does it include heating in homes as well.

2) How will the widespread use of Nat Gas in power generation affect/impact the price of the product for home heating consumer use.

3) Some states are resisting Fracking, does the 100 yr estimate account for this fact?

4) Natan mentioned oil for power generation, how is US domestic supply of this grade of Oil?

5)  Since not every country has Nat Gas, those that don’t will continue to use Coal, and those that do have Nat Gas will use it almost exclusively. Also more and more countries are discovering the joys of Fracking. Will this not plateau the drive toward FF reduction/elimination? Is WideSpread us of Nat Gas for electricity not simply delaying the inevitable, and should we not simultaneously focus on Nuclear, and or CSP?

Get Published - Build a Following

The Energy Central Power Industry Network is based on one core idea - power industry professionals helping each other and advancing the industry by sharing and learning from each other.

If you have an experience or insight to share or have learned something from a conference or seminar, your peers and colleagues on Energy Central want to hear about it. It's also easy to share a link to an article you've liked or an industry resource that you think would be helpful.

                 Learn more about posting on Energy Central »