In the previous section, I discussed Peak oil and what its implications are for society. In this section I will discuss the likely solutions to peak oil. Of course this is as complex a topic as peak oil itself… Hence, I’ll be spliting this second phase of the discussion into three sections.
In this section I’ll discuss and critique many of the proposed solutions to peak oil that involve the use of the various “unconventional oil” options mentioned earlier. I’ll then discuss in more detail natural gas, as well as shale gas and then coal. Also, its important we don’t forget about climate change, so I’ll be putting the impact such options will have on our efforts to mitigate dangerous climate change, in context.
Finally I’ll look at nuclear power and our options here (or lack thereof!). In part 3 I’ll tackle the various renewable options. In part 4 we’ll address the options regarding energy efficiency. Again, we’ll be tackling this in a Q&A style, but this time it will be more A&R (answers and rebuttals) as I go through many of the proposed answers to global warming and peak oil and explain how some of them might work, won’t work or will be subject to various limiting factors.
Question 2.1 – Surely these vast reserves of unconventional oil reserves like the Tar sands can offset everything? Question 2.2 – Have you heard of Shale gas? Question 2.3 – What about coal? Shouldn’t we just forget about global warming and start digging more of that? Question 2.4 – Clearly nuclear power is the answer! Question 2.5 – Ah! Yes, but you see, all we have to do is hang on till fusion power arrives!Question 2.1 – Surely these vast reserves of unconventional oil reserves like the Tar sands can be tapped at a greater rate and that can offset everything?
I summarise my criticisms of the Tar sands project here along with links to many other articles (in newspapers and journals). But in brief, the EROEI ratios for the Tar sands are poor, ranging from 9 to 0.7 (with ratios in the range of 7-3 being probably a more credible estimate), substantially worse than any existing oil fields. This means we’ll need to divert ever increasing quantities of energy to the Tar Sands in order to power this production process. Also, as I pointed out, the maximum production output (5.1 m bbl/day, around 6% of current demand) is on a scale such that its not going to make much difference as far as global demand goes. It could only offset depletion for a few years (after taking 30 years to develop!) if you follow what was said earlier about deletion rates (1.6-5.7m bbl/day). Obviously we cannot build a new Tar sands project or similar every other year or so.
Figure 2.1 – Oil Sands Extraction process [Credit: Greenauto.com]
To say the Athabasca tar sands project has its critics is a bit like saying that climbing Everest on a pogo stick with a Elephant on your back would be a little bit difficult (especially for the Elephant, he’ll get very cold!). Environmentalists decry the wholesale destruction of an area of forest the size of France, not to mention the enormous pollution that results (released into the middle of one of the world’s largest remaining pristine wilderness areas), there are questions as to whether there’s enough water resources in the region to sustain output, not to mention the pollution of those water resources with run off from tailings ponds and “recycled” process water. Its described by the Independent Newspaper as “the worse environmental crime in history”.
Figure 2.2 – The post tar sands extraction mess
Then there’s the huge quantities of natural gas required to power the whole operation, and indeed its questionably if there is sufficient quantities of gas (or coal) to spare within the whole of North America – a fear that seems justified given recent talk about bringing in nuclear reactors to meet demand. While nuclear power would reduce the net carbon output from the Tar sands we are still looking at a situation where they will produced much more greenhouse gases, both from disturbance to the eco system as well as from the oil itself and the refining and processing of it, than existing oilfields.
Finally there are the costs, obviously all this “stuff” needed to run the Tar Sands is going to cost alot of money to build and operate and ultimately the person who pays is us at the petrol pump. The Tar sands, or any other unconventional oil resources, are only economically viable so long as oil prices remain high. There is obviously a limit to how much we are willing to pay, and can afford to pay for oil. And these “costs” don’t just include money, but also the environmental costs and political costs as well. In order to finance the Tar Sands operations the Alberta government has had to invite in some rather unsavoury characters, including the giant Chinese oil companies. Indeed many Albertians now complain that the corporations are more in the driving seat over the Tar Sands than the Alberta or Canadian government.
As noted, the other unconventional sources come with similar “excess baggage” and while yes, they can certainly help and indeed they should help to cushion the blow of peak oil, they are no silver bullet solution and exploiting them is going to create one awfully big mess, and is incompatible with efforts to mitigate dangerous climate change.
Question 2.2 – Have you heard of Shale gas? The people behind it say that they can supply 40% of the world’s energy for several centuries with Shale gas and other unconventional forms of natural gas!
When oil starts going into its depletion phase the instinct will be to use other fossil fuel sources, notably yes natural gas, particularly by the transport industry as our crutch – however we could find it’s a rapidly diminishing crutch.
Already many cities in North America use natural gas powered buses, while CNG and LNG/LPG powered vehicles are becoming quite popular in Asia with much of Thailand’s vehicle fleet for example, already running on natural gas. But we can’t run everything off of gas (planes for example) and gas powered vehicles have a number of limitations compared to petrol powered ones.
Figure 2.3 – Natural Gas powered vehicle
Ultimately, there just isn’t the gas capacity to cope in the long term. Demand is already arguably outstripping supply, so suddenly bringing online a whole new set of users for natural gas will take away supplies from other areas such as power generation and home/industrial heating. The annual gas consumption worldwide in 2009 was around 3.1 Trillion Cubic Metres/yr rate (equivalent to 27.3 trillion kWh/yr or 2,180 mtoe/yr) with a current rate of increase in Gas production at around +130 billion Cubic Metres/yr (+1.1 trillion kWh/yr) which currently already lags substantially behind existing demand for gas, although there has been a decline in gas demand recently due to the continuing global recession. This rate of production increase would struggle to cope with the 1 to 1.5 Trillion kWh/yr we will need post peak oil to offset depletion, and this is assuming a low to median depletion rate and that we can divert nearly all new gas capacity to offsetting peak oil (which we can’t! We need most of that new gas capacity for other things). Note that all stat’s above were taken from Key world Energy Statistics Report 2010.
Also, the “conventional” reserves of natural gas are not that much bigger than our oil reserves. Sometime within 10-30 years of passing peak oil, we will begin to hit peak gas. Of course, there are rather large deposits of “unconventional” natural gas, most notably Shale Gas deposits or coal bed methane, but as with the unconventional oil there are limits to what we can do with these resources. It is doubtful whether these sources can be extracted at a sufficient rate to cope with our greatly accelerated demand. Again, its not the quantity in reserves that’s important, its rate of extraction and the cost of production that is the key point.
The EROEI ratios for Shale gas are not terribly good (though not as bad as the tar sands) and it’s becoming clear that Shale Gas has quite a number of environmental problems associated with it, as the recent film “Gasland” highlighted. Part of the problem with this is that in order to drill for Shale Gas you need the co-operation of local landowners who (thanks to this film), are now more aware of these problems, and may be reluctant to allow drilling (to a farmer clean water and air for his lifestock are far more valuable than anything the gas companies could offer him…short of buying his farm!)…as well as willing to hire lawyers and sue if they’re neighbour allows drilling.
Figure 2.4 – Problems with Hydraulic Fracturing, emission paths and risk to water sources [Credit Gasland website FAQ’s http://www.gaslandthemovie.com/whats-fracking ]
Also, Shale gas results in potentially high release rates of methane (which is basically the chemists name for natural gas) into the atmosphere. Given that methane is a potent greenhouse gas, 25-20 times the global warming potential of carbon dioxide, its entirely possible that Shale gas and indeed many other “unconventional” sources of gas could prove to be as polluting a source of energy as coal and oil…or indeed even worse!).
Although the full impact of shale gas drilling is still a matter of dispute (I discuss this more fully here). Either way these methane leaks could well limit or even curtail use of such unconventional gas resources, once action is undertaken to cope with climate change.
Furthermore the estimates from the DoE are a maximum shale gas output in the US (which has some of the largest reserves in the world) of 4.4 Trillion cfg by 2020 (this link gives 12B cfg/day x365 = 4,400B cfg/yr), that’s roughly 79.6 mtoe. Current US primary energy consumption is hovering around 2,200 mtoe. so shale gas can, at most, meet 3.6% of total US energy needs…..where does the other 96.4% coming from?
Figure 2.6 – Shale Gas Basins within the continental United States [Credit: What is Fracking? Based on USGS estimates]
And that’s just in the US alone, we’ve not considered the global demand, converting the figure above to metric (0.12 tcm/yr) and assuming we can get five times the amount globally than can be extracted from within the US (0.6 tcm/yr a pretty broad and unsupported assumption I admit) we can, at best, meet roughly 18% of current global gas demand, or about 2.5% of total current energy demand. Again, note these last few figures reflect current demand against 2020 output, but of course we know that 2020 demand could well be much higher.
So in short, Shale Gas is great news if you have shares in these companies (or if you’re a lawyer specialising in environmental pollution cases!), but it cannot solve the peak oil crisis. There’s just not nearly enough to offset peak oil depletion and still allow the economic growth we are used to. And of course sustaining current gas production levels once “peak gas” is exceeded (i.e our conventional gas reserves begin to give out in a manner much as described previously for oil).
It is also worth noting, as recently reported by The Oil Drum, the decline rate for Shale gas wells is extremely steep (figure 2.7). In orther words you get good gas flows early in such projects but then it tends to tail off dramatically. Consequently one has to doubt whether even the optimistic projections just stated will be achieved.
Figure 2.7 – Declines in Shale Gas Prospects [Credit: The Oildrum.com and Arc Financial Research]
Thus, a decade or two after we hit peak oil we will likely find the world hitting “peak gas”, indeed if there is a rapid swap over from oil to gas, and with continued increases in energy consumption, this could be hastened all the more. Also it’s important to note that any “peak” in gas will be more regional than global due to the peculiarities of the gas industry.
It’s been argued for example that Gas production has already peaked in North America. This is not necessarily due to a lack of gas (at least at the moment anyway!) as there’s plenty left in conventional reserves, not to mention those unconventional sources mentioned above, as well as large reserves “marooned” in isolated parts of the continent (such as up in Alaska). No, the current problem in the US seems to be a matter of pipeline capacity.
Even if this is overcome of course, eventually the actual supplies will peak, though this could also be mitigated by importing LNG from the Middle East, though eventually of course even these sources will peak too, and it would involve in the interim being even more dependent on politics in the Middle East (as if getting 60% of our oil from there wasn’t bad enough!).
Figure 2.8 – Breakdown of World Gas consumption (other includes agriculture, services, building heating and electricity production), [Credit: IEA 2010]
An important consideration with peak gas is that for some industries, notably the non-energy using consumers, continued reliance on gas (in an absence of oil) will be essential. Currently 16.2% of the worlds oil production is used by the non-energy consumers (IEA 2011) and they also take up 10.8% of the worlds gas (stats in figure 2.8 from the IEA 2010). Industrial processes also consume a further 9% of global oil supplies and 35% of the natural gas (the “other” in figure 2.8 includes such things as home heating, hence the difference in figures).
These industrial/non-energy consumers include many pharmaceutical companies, chemical producers, plastic manufactures and makers of pesticides and fertilisers. They will feel the end of the age of oil more than anyone. Indeed their needs may well be so great that they may well drive the price of oil, and increasingly thereafter natural gas, so high as to make it increasingly uneconomical as an energy source.
Failing that governments may opt to give critical industries priority access to gas and oil supplies due to the essential nature of their products. This would apply most particularly to the production of fertilisers and pesticides, both essential if current levels of food output are to be maintained.
While the end of the age oil may well herald the end of the 3,000 mile Caesar salad or the short haul flight for £1, or the Hummer H2, the end of the age of gas could well be a lot more serious – the peak of global food production! That is unless priority is given where necessary.
So there are limits to what we can do with natural gas and there are many good sound economic and environmental reasons to leave most of that shale gas where it is. Top of the list, global warming. Indeed if we do tap such resources it might be prudent to give most of the output to the industrial and non-energy related users, as opposed to using it for transport fuel or for electricity generation.
Question 2.3 – What about coal? Shouldn’t we just forget about global warming and start digging more of that? They say there’s a thousand year supply of coal in the world.
One is often told that there is enough coal to last us 250 years, or 1,000 years or some other huge figure. However much like another thing we were told that would last a thousand years (by a rather crazy Austrian!) this promise is as equally unlikely to be fulfilled. If we assume business as usual type scenarios (i.e continued growth) then, according to the author Dr D. Mckay, we will exhaust current coal supplies by between 2072-2096.
This is roughly in line I might add with a number of Club of Rome projections putting “peak coal” sometime around the 2040’s to 2050’s. Which is also roughly on par with current projections of coal production set to peak in North America around the 2030’s, China at roughly the same time and Australia around the 2050’s (article on this here).
If production is increased further to offset the oil peak and/or the gas peak, this will take place all the sooner. Of course the US (or China) can offset their peak by importing from other countries, the Australians have substantial sources of “brown coal” (not included in the above figures as its rather polluting), but this would eliminate one of the primary benefits of coal – that it’s an indigenous source of energy.
And of course coal production and mining consumes energy in the process, in particular oil itself. Post-peak oil this will make mining coal all that more expensive and difficult. All in all, it’s entirely possible that coal production will remain static, or even fall post peak oil. This is particularly worrying as we are assuming we can increase production of coal, though on the plus side any fall will significantly mitigate global warming and stretch out the time coal supplies last.
Even if we assume that using Carbon capture and storage the contribution of fossil fuels (gas and coal) to global warming can be mitigated, coal production and use will still result in a considerable environmental footprint.
The mining itself is very environmentally damaging, literally involving the tearing down of whole mountains (puts NIMBY protests about wind farms in prospective!). This process of mining also realises methane (a potent greenhouse gas) so even with CCS in place there will still be a considerable carbon footprint attached to coal mines.
Figure 2.9 – Coal Mine, Mountain top removal
So in short, coal (and natural gas) can only buy us time and no more than that. Expanding coal use substantially post peak oil, while not impossible, will be limited in scale and only offer a temporary reprieve. There are also many practical, environmental and political obstacles to an expansion in coal production, not least the fact that coal is of little use to a world running on oil (unless anyone is suggesting we bring back steam engines or develop steam powered cars, etc.!). Using the F-T process (figure 2.10) to turn coal into synthetic crude would further diminish the associated EROEI ratios, increase costs, and cause more pollution.
Figure 2.10 – Schematic of the Fischer-Tropsch process [Credit: Blog.cafefoundation.org]
It’s also worth noting the issue of poltics. For example, the UK didn’t stop using coal in the 80’s because they ran out of the stuff. No, the mines were closed because the Tory government was scared of the increasing power of the mining unions. I don’t see many of the critics of climate change (often fairly right-wing) calling to bring back the all powerful mining unions. In a post peak oil world such unions would wield enormous political power. If not coal how else do they suppose we meet future energy needs?
Question 2.4 – Clearly nuclear power is the answer!
Of course many will point to Nuclear as the answer. According to the IEA nuclear currently supplies just 4.9% of the world’s energy some 2.7 Trillion kWh/yr from an installed capacity of 372 GW’s, against a world final energy demand of 55.8 Trillion kWh/yr (and 150 Trillion kWh/yr of energy inputs). Nearly all nuclear power is of utilised for electricity generation (some 2.7 Trillion kWh/yr) representing 14.8% of global electricity supplies.
However growth of nuclear power is practically zero, indeed the industry’s own figures show a slight overall drop year on year for roughly the last decade. While new plants are being built worldwide, they are barely keeping pace with the legacy needs – replacing the 420 or so existing reactors worldwide (average age: 24 years). While some countries are expanding capacity, others are scaling it back or even abandoning nuclear power altogether.
But assuming the advocates of nuclear energy are right, suppose there that in the near future there is a “nuclear renaissance” what can we hope for it to achieve? The maximum nuclear reactor building peaked in the 1970’s at a rate of about 30 GW per year.
Figure 2.11 – An Interesting chart that illustrates the problems faced by the nuclear energy industry, not the 70% growth in Renewables against the 5% decline in nuclear [Credit AOL Energy & Worldwatch Institute]
Assuming we deduct 10% of our production capacity for nuclear to account for the legacy issue (strictly speaking we should deduct closer to 30%, but we’ll give the nuclear advocates the benefit of the doubt) and we assume a capacity factor of 90% this gives us a figure of 230 Billion kWh/yr of capacity added each year. A the graph above implies, and as I will show later, this is a little more than half what we are currently adding via renewable each year, and just over 15% of the peak oil depletion rate of 2.4m bbl/day (or 1.5 Trillion kWh/yr) we assumed earlier.
So even our maximum build rate of nuclear reactors would be woefully inadequate in terms of coping with peak oil depletion (or climate change). This incidentally, is why the IEA future projections constantly shows the output from nuclear energy worldwide remaining flat or even falling slightly. Also, in 2011 an important Rubicon was crossed for nuclear, Renewable energy output in the US, overtook nuclear (of course globally, renewable energy output, once you include biomass and biofuels, has generally been twice that of nuclear for many years now, see my article on global energy use for more on that).
But, for the record, could we sustain such a level (30 GW’s per year) of new nuclear reactor construction?
Probably not, back in the 70’s nuclear reactors were lavishly funded affairs that were considered top national priority. Important issues such as the costs or economics of nuclear power were largely ignored as were other issues such as the final dismantling of reactors and the disposal of waste. The safety issue was also either ignored or not entirely understood. Also any public opposition was also disregarded. This conspired to create a perfect storm in which rising worries about all these issues post-Chernobyl led to an effective halt on further nuclear construction, at least in any country with a free press and a market economy. Now modern reactors are far more complex (which on the plus side should improve safety). With so many nuclear engineers busy dismantling older plants, or working on the final waste disposal issue output may be constrained. Economic factors can no longer be ignored nor can we simply railroad over public opposition.
The issue of costs is key (I discuss the cost issue in more detail here). The nuclear industry will often quote figures comparable to natural gas powered stations, however the critics of nuclear energy say that its true costs (i.e. today, nevermind in the future) will be much higher, as much as 3 times higher according to the NEF, making a “nuclear renaissance” unlikely. Figures from Citigroup bank present an equally bleak picture.
Figure 2.12 – An illustration of the cost of Nuclear energy compared to various sources [Credit: Financial Times, based on IEA data]. Note the large level of ambiguity in the graph for nuclear. The reasons for this are discussed further in the text and linked documents
A US government study similarly found that Nuclear energy was substantially more expensive than fossil fuels, even if you factor in future price hikes and climate change mitigation. The current omens aren’t good, the first of the new EPR’s in Finland is years behind schedule and considerably over budget. Its currently likely final cost will come in at 6.4 Billion Euros, or about £3,250 per installed kW, v’s the BWEA estimates for wind of around £1,300-1,600 per kW or about £1900-2100 with intermittency backup.
While one can blame first build factors for these cost overruns (humorous, but informative video of those problems can be found here), the 2nd of the ERA reactors, being built in Flamenville France is being hit by similar delays and cost overruns, with an anticipated cost now of the order of 5 Billion Euros. Overall, it seems likely the installation costs (and presumably decommissioning costs) of Nuclear will likely prove to be much higher than the alternatives.
Figure 2.13 – Illustration from the Independent Newspaper of some of the problems that have dogged the Olkiluoto reactor Project [Credit: the Independent]
And there’s the issue of the long term supplies of nuclear fuel. Figures from the WNA (Nuclear Energy Agency) suggest 80 years of reserves (5.4 Mt) with current consumption rates (68,000 Tons/yr) and extraction techniques if a cost of $80-130kg is tolerated. Obviously by trying to double the production rate of nuclear energy we’ll run down this supply in half the time. Trying to completely replace all fossil fuel resources, assuming no overall increase in energy demand, would involve exhausting our reserves in around 2.8 years!. I’ve previously discussed the issue of reprocessing of fuel and its limitations here.
Challenged on this and their claims of “no problems with fuel supplies”, the nuclear industry would of course point to failed white elephants like “fast” reactors, the most recently built Monju, which has already suffered 2 coolant leaks and fires, cost a staggering $ 5.9 Billion and took 10 years to complete, despite its tiny 280 MW output (that’s about $21,000 per kW! 3 times the cost of PV at the time of its installation!). I recently did a review of many other proposed future nuclear reactor designs. Unfortunately, my conclusion is that while some do offer improvements on the safety side, or reduced nuclear waste flow. On the critical issues of costs, pace of roll out and maximum theoretical output from nuclear, they offer only modest gains, indeed in many cases they will cost more and have much slower build rates!
There are one or two possibilities involving alternative fuel cycles such as those using Thorium or natural Uranium. But both these options would require a whole new generation of nuclear power stations (eating into our assumed building capacity) as our current fleet of Light Water Reactors are not designed to use such fuels. As I mentioned above many of the reactors that can utilize these fuel sources are actually more expensive than existing plants. Even the pro-nuclear National Nuclear Laboratories pour cold water over the idea of Thorium.
Figure 2.14 – Typically daily electricity demand variation for the UK
Then there’s the practical issues. Nuclear power plants like to be on all the time, but the grid demand varies considerably. Once nuclear output goes above 40% of a nation’s electricity demand (about 10-20% of total energy use) you start to get problems with load balance, i.e. the grid suddenly demands power the nuclear reactors can’t add power quickly enough to cope.
Also, as noted earlier, the bulk of global energy demand, roughly 80% of it, is devoted towards things other than electricity, typically heating/cooling and transport fuels. These are the very areas we need to tackle post-peak oil and in offsetting climate change. However, nuclear reactors encounter the same handicaps as renewables here in that one cannot run, say, a car off of a nuclear reactor. No, you need to transform the energy into some form of storage medium (a battery or converting it to hydrogen), accepting the appropriate conversion inefficiencies in the process, after transmitting it across long distances (presumably using hydrogen pipelines or HVDC lines), and storing it (bunkering to use the industry term) to account for seasonal variations in demand. Of course the principle stumbling block to a 100% renewables world is the need for such support infrastructure too. But once we go beyond trying to provide baseload electricity, nuclear power needs this infrastructure also. I will discuss the practicalities of this in Part 3 in relation to renewables, but such a discussion would be applicable to nuclear also…just at a higher cost!
Finally there is this safety issue. The public will only support new nuclear projects so long as there are no accidents and costs are reasonable. If there is another accident, which is probably more likely to occur now in either the reprocessing, decommissioning or experimental reactor industries rather than commercial operation (another reason to abandon reprocessing and fast reactors), it will be like 1986 again with mass public opposition, likely leading to another generation of cancelled plants and expensive holes in the ground. We’re already seeing elements of that post Fukushima.
In summary, any ideas we have about significantly expanding our nuclear capacity (i.e. trying to say completely replace coal with nuclear) and sustaining it for another century or so are probably unrealistic. A probable build rate is no greater than at best 15 GW/year of new capacity or about 117 Billion kWh/yr (the rest of the building capacity gets eaten up by replacing worn out reactors and decommissioning) is the best we can hope for. And, as we shall see, it is but a fifth of the current roll out rate from renewables! And even this 15 GW/yr assumes no major accidents (and we’ve already had Fukushima so we’re already breaking that condition!) and that the costs proposed by the nuclear industry are accurate, or failing that, at least not overly excessive and manageable (i.e. even if wind is cheaper, the reliability offered by that 90% online capacity still makes them useful for grid balancing purposes).
This 15 GW/yr figure amounts to just 12% of the capacity we will loose each year post peak oil (in our median case scenario of 3% depletion per year…where does the other 88% of the lost capacity come from!), assuming we neglect cycle efficiencies (if we include them nuclear fares even worse!). It is also unsure whether we could increase the final energy output level of nuclear power much beyond the existing 2.7 trillion kWh/yr due to fuel supply constraints. Doubling or tripling this figure is a possibility, but not much beyond that, and we’d eventually have to replace this capacity once the Uranium/Thorium runs out, and the quicker we burn the quicker it gets used up.
So overall anyone suggesting we can get any more that 6-10% of our energy from nuclear isn’t really being realistic. And even this is not a sensible option for any country that lacks reliable access to some substantial reserves of nuclear fuels.
Question 2.5 – Ah! Yes, but you see, all we have to do is hang on till fusion power arrives!
Whenever you back a nuclear power advocate into a corner with the limitations of nuclear energy (or increasingly anyone on the energy issue), they inevitably grasp for this hand hold above. Unfortunately the joke goes that they’ve been saying fusion is 30 years away for 60 years! I summarise the main criticism of Fusion (as a practical means of mass power generation) here and here.
Until we have an actual functioning reactor design it would be foolish to invest all our hopes in something that may simply never arrive. Recent news from ITER is not positive , its now not due to go online till 2026, which would imply a completion of experiments in 2046. And it will take sometime beyond that before we wind up with a viable working commercial fusion reactor. As I speculate (here), it would likely be the latter half of this century (or the beginning of the next one) before we start to see Fusion play any sort of major role in mass global power generation. Also the first generation of Fusion reactors will be dependent on supplies of Lithium for fuel, of which there is only a limited global supply available, something that limits the amount of energy which can ultimately be generated from Fusion reactors, probably to between 8-20% of global energy use depending on whose figures you believe. Where does the other 92-80% come from?
And of course we have to contemplate the possibility that commercial Fusion energy never arrives. While speaking personally, I still have confidence that the necessary breakthroughs will be achieved according to a reasonable timetable, it would be foolish to blindly assume that they will. To build any nations energy strategy on the forlorn hope that fusion power will arrive on the scene by a certain date, makes about as much sense as selling your house and all your worldly goods because some preacher told you the world was going to end on a particular date.
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