This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

[IOP] A community website from IOP Publishing

environmentalresearchweb blog

UK Carbon plan – a three way split

By Dave Elliott

The UK government’s new Carbon Plan, produced as required under the Climate Change act, looks at a core strategy based on a mix of renewables (45GW), Carbon Capture and Storage (28GW) and nuclear (33GW) by 2050, but also includes three alternative possible scenarios. In one, if CCS does not take off (just reaching 2GW) and renewables are restricted to 22GW, up to 75GW of nuclear is built by 2050. In the second, with CCS moving up to 40GW, nuclear is then at 20GW and renewables 36GW. However, in the third, renewables move up to 106GW, with nuclear at 16GW and CCS at 13GW by 2050. All three future scenarios are at http://2050-calculator-tool.decc.gov.uk.

Some might say having three main options spreads the risks. Certainly there are risks and problems with each and it could be argued that some of these are sufficiently serious that the options should be reconsidered.

Nuclear balance
We are used to hearing about the short-term economic, safety and security risks of nuclear, but there are also longer term issues- and beyond the usual one of waste disposal. In a report on ‘Energy balance of Nuclear Power Generation’ the Austrian Institute of Ecology and the Austrian Energy Agency have had another look at the issue of the full lifecycle energy requirements for providing the fuel for nuclear power plants. They looked at all the previous studies and concluded that, assuming the low growth scenario of the World Nuclear Association (WNA) and the IAEA data on uranium resources from currently operated uranium mines, reserves will be sufficient until 2055. If mines which are currently being developed are also taken into account, the uranium reserves would last until around 2075 in the low WNA growth scenario. However emissions from the increased use of lower grade uranium ore will rise, since uranium fuel production will get much more energy intensive.

With ore grades between 0.1-2%, the energy expenditure for generating one kWh of final energy is put at between 2-4%. With ore grade of 0.01% and 0.02% the energy expenditure rises to 14-54% and the resulting CO2 emission amount to 82-210 g/kWh. By contrast, CO2 emissions for renewabales are put at 3 – 60 g/ kWh.
The study notes that one third of currently operated uranium mines have an ore grade below 0.03%, but if we push ahead with more nuclear, then we reach the point when continuing become increasingly pointless in energy/carbon terms.

You might of course still continue with nuclear despite that, but below about 0.008 to 0.012 % ore grade, the report notes, ‘the energy expenditure for the uranium mining is so high, that the overall energy balance turns negative… From this ore grade on, the operation of nuclear power plants does not generate any energy surplus.’

The only option then, if for some reason you wanted to continue to use nuclear, would be to use renewables to provide the energy for uranium mining and processing. It’s just conceivable that uranium mines in Namibian might use solar PV power and those in Kazakhstan wind power, and that uranium ore processing plants will also use renewable sources, but surely it would not make sense to use renewable so wastefully. See www.ecology.at/lca_nuklearindustrie.htm.

CCS delayed or dead?
The demise of the proposed coal-fired Carbon Capture and Storage pilot project at Longannet in Scotland, due to the high investment cost, led some to say CCS was dead as an option in the UK. One key issue for CCS evidently is the need to cover the risk of accidental sudden large scale CO2 release at some future point. Hard to quantify!

For a spirited demolition of CCS see Eurosolar president Prof Peter Droege’s review: www.europeanenergyreview.eu/site/pagina.php?id=3251.

He notes that the IEA roadmap envisions that by 2050 3,000 CCS projects will capture and store 10 billion tonnes of CO2 annually, about a third of current global carbon emissions. He says that’s ‘a tall order, in view of the fact that not a single utility-scale CCS plant is currently operating on the planet’. He reports that ‘American Electric Power, cancelled plans to deploy CCS at one of its big facilities – even though the U.S. government offered to pick up half the tab.’ At best he says ‘most observers peg 2020 or 2025 as the earliest date by which enough large-scale CCS plants are on-line and returning evidence to prove technical viability’ However ‘renewables are set to achieve grid-parity over the same period. This means that there will be risk that CCS becomes economically obsolete just as the returns come in.’

He concludes ‘Funds can be far better spent on stimulating demand reduction and energy efficiency, improving renewable energy storage and two-way energy grids to balance intermittent generation, and – last, not least – to bank on ‘carbon storage’ that works: namely the active bio-sequestration of greenhouse gases in wetlands, moors, humus rich agricultural soil and in growing new forests.’

Nevertheless, CCS enthusiasts argue that it could be competitive with renewables and avoid their grid balancing issues. Some small pilot projects exists around the world and the UK government is still keen to press ahead with its £1bn CCS competition, if it can find a new candidate. In addition, there are it seems still 6 industrial consortia keen to compete for maybe 4 UK ‘slots’ in the EU subsidised (NER-300) CCS demo programme. The UK’s proposed new CfD support system should also offer support for CCS, cheaper gas-fired plants included.

The Longannet coal project was to involve post-combustion capture and access to offshore storage via a 170 mile long pipeline. Some say a better first option would gas fired pre-combustion capture schemes, possible even using bio-methane in existing CCGTs. Many environmentalists are unhappy with CCS, not least since they say it will deflect support from renewables. But biomass-fed CCS would be carbon negative, assuming the biomass is fully replaced, so some see fossil-fed CCS as just a preliminary stage and as a bridge to a much more sustainable approach.

For an overview of EU CCS prospects, see http://www.europeanenergyreview.eu/site/pagina.php?id_mailing=223&toegang=115f89503138416a242f40fb7d7f338e&id=3361]%28http://europeanenergyreview.eu/site/pagina.php?id_mailing=223&toegang=115f89503138416a242fb7d7f338e&id=3361.

Renewables
Renewables certainly have their problems, not least, for some of them, intermittency, although that can be overstated. It’s a relatively minor operational issue when the renewable input is below around 20%, and can be dealt with without leading to significant extra emissions using standard approaches, including the new breed of flexible, but high efficiency, combined cycle gas turbines, like the FlexEfficiency 50, developed by GE: www.ge-flexibility.com.

As more renewables come on line, we may need more energy storage capacity, and there are some clever new ideas emerging in the hydrogen field. The electrolysis of water is sometimes seen as inefficient, especially with variable electricity inputs, but RE Hydrogen say that their novel materials electrolyser can handle intermittent electricity inputs, usually a bugbear for wind or PV powered hydrogen generation: www.rehydrogen.com/id1.html.

More radically, there’s a new idea for thermal dissociation of water at high efficiency using high temperatures and solid acid materials: www.sciencedirect.com/science/article/pii/S0360319911010007.

Meanwhile, Airproducts has developed a cryogenic system for storing energy as liquid air. It claims that overall energy conversion efficiencies of 75-85% are possible with up to 100MW storage for 12 hours: www.airproducts.com/industries/Energy/Power/Power-Technologies/product-list.aspx?itemId=%7B7D677622-F274-40B1-8EC9-F6D33CC19C5E%7D.

Innovations like this, and also upgrades to the basic renewable generation technologies, are moving ahead rapidly around the world, with costs falling rapidly. And if you want to spread risks, well there are dozens of different types of renewables- real diversity. I know where I’d put my money!

This entry was posted in Renew your energy and tagged , , . Bookmark the permalink.
View all posts by this author 

Leave a comment

Your e-mail address will not be published.

Guidelines

  • Comments should be relevant to the article and not be used to promote your own work, products or services.
  • Please keep your comments brief (we recommend a maximum of 250 words).
  • We reserve the right to remove excessively long, inappropriate or offensive entries.

Show/hide formatting guidelines

Tag Description Example Output
<a> Hyperlink <a href="http://www.google.com">google</a> google
<abbr> Abbreviation <abbr title="World Health Organisation" >WHO</abbr> WHO
<acronym> Acronym <acronym title="as soon as possible">ASAP</acronym> ASAP
<b> Bold <b>Some text</b> Some text
<blockquote> Quoted from another source <blockquote cite="http://iop.org/">IOP</blockquote>
IOP
<cite> Cite <cite>Diagram 1</cite> Diagram 1
<del> Deleted text From this line<del datetime="2012-12-17"> this text was deleted</del> From this line this text was deleted
<em> Emphasized text In this line<em> this text was emphasised</em> In this line this text was emphasised
<i> Italic <i>Some text</i> Some text
<q> Quotation WWF goal is to build a future <q cite="http://www.worldwildlife.org/who/index.html">
where people live in harmony with nature and animals</q>
WWF goal is to build a future
where people live in harmony with nature and animals
<strike> Strike text <strike>Some text</strike> Some text
<strong> Stronger emphasis of text <strong>Some text</strong> Some text