Saturday, 3 November 2012

And now...liquid ammonia???

Researchers at Texas Tech University believe they have found a new solution to storing surplus energy from renewable sources - liquid ammonia!

It is claimed that by using a new kind of transformer the researchers expect to produce hydrogen at almost half the cost of traditional electrolysis methods. The hydrogen is then pumped into a compression chamber causing it to heat up to around 400°C. It is then vented into a second chamber compartment where an iron oxide catalyst starts the conversion to ammonia, using nitrogen from the air. The ammonia and leftover hydrogen is then allowed to cool down and decompress in a third chamber. Some of the decompression energy drives a piston that helps in the compression part, reducing the overall electric consumption. The ammonia must then be cooled to -75°C and pumped into a tank for use.

It is claimed that many modern cars can use ammonia as a petrol additive without modification (up to 10%) and flex-fuel cars could be modified to use ammonia in conjunction with ethanol, allowing for a mixture of 85% ammonia. The TTU team are variously reported as saying the fuel could end up costing as little as between 75c and US$1 a (US) gallon as the raw materials are essentially free. It's not clear if this includes any amortisation of the plant needed to make and store the liquid ammonia.

The overall process is offered as a way of creating a liquid energy store from intermittent renewable energy sources, such as wind or PV.

I'm dubious about the TTU process. My knowledge of chemistry is a little ancient, but I never recall ammonia being touted as a possible fuel, especially if it has to be cooled to -75°C to liquefy: it does have a reasonable energy density (about half that of petrol) but is a nasty, caustic and poisonous substance. (Not that different from some other fuels, I guess, and easier to handle than liquid hydrogen!) And although there are many ways of creating a hydrocarbon (or similar) from air and water (usually using CO2 rather than N2 as the air component) but they almost all fall down on the overall system efficient. Sure, in the context of a way of storing surplus renewable energy from wind or solar to drive the electrolysis and compression/cooling cycles it doesn't have to be quite as efficient as if it were part of a fossil fuel storage cycle, but I'd still be surprised if the system efficiency came anywhere near some of the other storage mechanisms. On the plus side, water and air are pretty widespread raw materials, and liquid fuels for cars may be easier to market than electric vehicles. The idea of using bioethanol as the base in a flex fuel vehicle is also intriguing, and if it reduced the land take for biofuels by five-sixths, would surely be welcome.

Thursday, 18 October 2012

Cheap energy is not always best

It's disappointing that David Cameron has jumped onto the bandwagon and committed the Government to forcing energy utility companies to move customers onto their lowest price tariff. During Prime Minister's Questions on Wednesday, Mr Cameron made a surprise announcement promising to legislate "so that energy companies have to give the lowest tariff to their customers". Although this might sound like a no-brainer at first, by focusing just on price and not on the need to incentivise companies to invest in truly green (renewable) supplies, the Government is sending the wrong signal.

One side effect of a move to force consumers onto a single (lowest price) tariff is that the fledgling green tariffs, whether those offered by the Big 6 under Ofgem's Green Energy Supply Certification Scheme1 or ones from independent suppliers will become less attractive to consumers. In particular those who have signed up to certified Green tariffs from the Big 6 will find they are moved back onto a brown tariff periodically, and will have to take positive action to reconfirm their greenness - and it's likely that simple inertia will stop many from doing so.

Moreover, I'm not totally convinced that profits in the sector are actually excessive, given the need to de-carbonise the UK's electricity supply (not to mention the Rest of the World...). Cheap electricity may be available today from gas - whether imported from Russia or obtained by environmentally dubious fracking techniques from shale - but this is not low-carbon, unless compared to coal. And if the US fracks all their shale, then global CO2 emissions are most unlikely to start falling in the near future. Of course, the consequences of this are hard to sure about, but as an inherently cautious observer, I would like to see proof that the US droughts this summer were not caused by the jet stream being further South than normal, and that in turn this was not caused by higher than normal melt water from a rapidly warming Arctic Ocean.

But to come back to the UK, politically motivated pressure on prices (from all parties, not just the Conservatives) will lead to short-termism and poor investment decisions about cleaner (and more secure) energy resources. And the Prime Minister's statement was opportunistic as neither the Energy Secretary nor Ofgem, who are about to issue the latest version of their Retail Market Review into how the consumer energy markets work, appear to have known anything about it. The last thing that the UK (and the environment) needs is an energy policy made up on the hoof in order to get a favourable sound-bite and the approval of the Daily Mail.

1 Disclosure of interest I am professionally connected with this Scheme

Wednesday, 26 September 2012

Total won't drill in the Arctic...because a spill may damage its image!

In an interview with the Financial Times, the French energy company Total is reported as saying
Energy companies should not drill for crude in Arctic waters, marking the first time an oil major has publicly spoken out against offshore oil exploration in the region. Christophe de Margerie, Total’s chief executive, told the Financial Times the risk of an oil spill in such an environmentally sensitive area was simply too high. “Oil on Greenland would be a disaster,” he said in an interview. “A leak would do too much damage to the image of the company”.

Call me a cynic, but I am not impressed by this apparent volte-face. Mr de Margerie does not seem to be concerned about the environmental damage per se, but about what it might do to the image of Total. Don't worry about the polar bears or the near pristine environment, just think about poor old Total...

Of course it's worse than than that. A Macondo-style spill might kill some wildlife, or pollute a few ice floes, but successful drilling could be even worse for the environment. If there really are billions of barrels of oil locked away under the Arctic Ocean or the Barents Sea, releasing it to the market would add many more millions of tonnes of carbon dioxide. And in turn that could lead to catastrophic climate change that could affect wildlife across the globe, not just around Total's rig.

Am I being too harsh on Total? Probably not, although the other big oil companies are equally culpable. True Shell has suspended drilling for this year due to environmental concerns and it did seem slightly less concerned about its image, but not before it has spent a reported US$4.5 billion: I suspect that they won't abandon the Arctic after making that investment in it.

A Total Hydrogen refuelling station in Berlin (c) Ian Byrne

So is there an alternative? Well, conservation - energy efficiency and investment in better public transport - has to be the starting point for reducing demand, with alternative fuels still worthy of consideration. There have been some interesting developments in algae-based biofuels recently, and I may blog on those in the near future. Or we could look instead at trying to capture solar energy to generate electricity, which can drive land vehicles directly, or through creating hydrogen from electrolysis of water. And here Total may get a small plaudit from me, as they have at least one public hydrogen refuelling station in Berlin, in partnership with Norway's Statoil.

Friday, 3 August 2012

CO2 emissions from cycling

The Environmental Transport Association (ETA) Trust (always an interesting website) reports that the European Cyclists Federation (ECF) have compared the CO2 produced by cycling with other modes of transport.

According to the report cycling is responsible for CO2 emissions of 21g per km. The calculations included emissions associated with production, maintenance and fuel. The figures were based on a heavy 19kg European-style town bike built using 14.6kg of aluminium, 3.7kg of steel and 1.6kg of rubber and the cost of producing the extra calories consumed by a cyclist rather than a motorist. The report calculated that an average car produced 271g and a bus 101g.

It concludes that Europe could reduce its overall emissions by one quarter if its population cycled as regularly as the Danes. In Denmark the average person cycles almost 600 miles each year – far more than the EU average of almost 120 miles per person per year and a total of 46 miles in Britain. ETA comment that this is largely due to better facilities in Denmark, as the climate and generally flat urban areas are similar in both.

Figures like this are always fun, but a little misleading. Although it’s right to consider the embodied emissions in the bike itself, an even more favourable comparison would be to look purely at the marginal emissions for those who already own a bike (and that’s most of us) – mainly tyre wear for a bike (plus a teeny bit of oil, brake blocks and wear & tear on other components).

When I cycle to work (2.5 miles each way, not very flat) I usually reward myself with a bun or a few biscuits, but the calorific value consumed (and net carbon emissions) are lower than the marginal energy that I exert compared to the wet days when I drive. In other words I’m eating into my fat resources on cycling days, and adding to them on other days. So there’s not too many extra CO2 emissions from that. I have attempted to use a more direct carbon conversion from, say, the footprint on some packets of crisps but it’s very hard to know exactly how much energy I use cycling (and I do know I use less energy now that am I fitter than when I first started regularly cycling to the office 6 years ago).

Finally, there’s one thing to avoid – that tempting shower on arrival at the office. If heated by electricity, the emissions from an extra shower are likely to undo all the good work cycling. A 3 minute shower using an average 8.5kW (based on electric ones advertised in the UK) and Defra grid average emissions would use 0.425kWh, equivalent to about 223g of CO2 (see the NEF's Carbon Calculator for an easy converter). Longer showers - baths - only add to the net emissions.

Wednesday, 9 May 2012

Sayonara, nuclear power?

Japan has - temporarily at least - closed its final nuclear power station, for testing and maintenance, in the continuing aftermath of last year's disaster at Fukushima. Some pundits are suggestion that this may simply be a Japanese way of ending nuclear power in the country for good, with pro-nuclear commentators claiming that they have ducked taking the tough decision to keep nuclear operational, instead creating the risk of summer power cuts as air-conditioners are switched in in Japan's humid weather.

However it may be that the right decision is to admit that relying heavily on nuclear power in an area noted for its seismic activity wasn't such a good idea after all. If fracking is leading to a global fall in gas prices (albeit unevenly distributed), then maybe LNG is a safer prospect (in both senses of the word safe). And a nation that is collectively as keen on high-tech solutions as Japan will likely find more cost effective ways of storing energy from renewables, if they know that they have not got the base load of nuclear on which to fall back. Moreover, Japan is also a world beater in finding ways of cutting energy demand without damaging industrial competitiveness, and is socially cohesive enough that a call for citizens to show restraint in cooling their homes or offices in summer in order to conserve energy is likely to succeed. So it may be a smart decision to go for the short sharp shock and end nuclear power in the country now.

Ironically, this may then make nuclear a better option in the UK, as if LNG is being swallowed up by Asia, the cost of delivering to Milford Haven shoots up. And that makes our CCGT generation look less attractive. Of course, we can always wait for the Japanese to solve the energy storage issue...

Friday, 30 March 2012

Have Eon/RWE killed nuclear power in the UK?

The two large German-owned UK energy suppliers Eon and RWE Npower have announced that they are abandoning their plans to build two new nuclear power stations through their Horizon joint venture. If they are unable to find a buyer for Horizon, it is unlikely that new nuclear power stations will be built at Wylfa, on Anglesey, or Hinkley Point in Gloucestershire. So is this an early warning sign for the end of the Government's plans to revitalise the UK nuclear power sector?

This view is to some extent supported by Npower's chief executive, who is quoted as saying that "the payback is too long compared with conventional and renewable sources of power". However it may be too early to write off nuclear power completely, as both partners in Horizon have German parent companies, and are being forced to close nuclear power stations in their home market and to invest heavily in new conventional sources. Investors in the other six sites earmarked by the UK Government for new nuclear plants may be able to take a longer investment view, even though it is likely to be 2022 before any new power stations come on stream.

Nuclear power is still an important part of the UK energy mix, providing around a quarter of all electricity. On the same day that Horizon announced its withdrawal from building new nuclear power stations, the Government announced that emissions of carbon dioxide, the main gas contributing to global climate change, had fallen to their lowest levels for 40 years in 2011. While there are several factors, including a milder winter and reduction in manufacturing, the largest single factor was that output of nuclear power rose 11% in the year.

So what does all this mean for UK consumers? Firstly, it shows that that the cost of renewable electricity is already competitive with (or lower than) new nuclear power, so creating demand for more green energy will encourage companies to invest in it. But it also shows that the UK still has a long way to go if it wants to limit both carbon dioxide emissions and the use of nuclear power. Although UK renewables output rose by nearly 10% in the year (mainly due to large - often offshore - wind), it is still only a tint fraction of the overall total.

And finally, it should remind us that reducing demand, usually by encouraging greater energy efficiency, is still most important, especially if we are to rely on a greater proportion of renewable energy sources rather than building more giant nuclear power plants. The time lag in building any plants also means that we may have to (again) extend the life of existing plant if we are to avoid the danger of damaging power cuts towards the end of this decade.