Energy crisis? We’ve been here before

Around 400 years ago, Britain faced another problem of dwindling energy resources: ‘peak wood’.

Colin McInnes


Through the production of cheap energy, the British Isles had seen swathes of its natural environment blighted and was running short of easily accessible carbon-rich fuel. In response, the state attempted to constrain resource-use through law, and energy-efficiency measures were actively encouraged. Progressives advocated a way forward by gearing up the production and exploitation of a potent new energy-dense fuel. However, some environmental thinkers viewed the impending transition to the new low-carbon technology as quite simply an affront to nature. This was a very real national energy crisis. It took place some 400 years ago.

The lessons of the Elizabethan energy crisis (which peaked between 1570 and 1630) are relevant today as we contemplate the prospect of ‘peak oil’, ‘peak gas’, ‘peak uranium’ or whatever other bottleneck peak-energy catastrophists can muster. The most important lesson of all is that the Elizabethan energy crisis was overcome, paving the way for the Industrial Revolution to deliver a more enlightened and prosperous society than many Elizabethans could possibly have imagined.

The energy crisis which struck the British Isles was ‘peak wood’. The idea of peak wood may seem absurd from our vantage point in human history, but be assured it was taken seriously by the Elizabethans. Indeed, peak wood is no more absurd than the observation that wars were once fought over salt when it was an important preservative, instrumental in international trade, rather than the mere table condiment it is now. Technologies such as electrification or refrigeration can dramatically change our view of the value of resources that we now regard as mundane.

Wood was a hugely important resource for the Elizabethans in construction and domestic heating and as the source of charcoal for iron smelting. Of particular importance was the availability of high-quality oak for naval construction yards to ensure maritime supremacy. Indeed, resource conservation laws forbidding the felling of trees made exemption for forests within a few miles off the coast due to their strategic naval importance. Aside from a shortage of fuel for heat and material for homes and warships, the felling of trees laid waste to wide areas of the countryside. It is reported that in the hinterlands of population centres barely a single tree could be found standing. Due to its poor energy density, wood requires vast areas of forest to be felled for energy production and demonstrates the strong relationship between the environment and energy production from diffuse sources.

This relationship can be seen again today in the recent expansion of wind farms to exploit diffuse renewable energy. The growth of wind farms appears to go against a 400-year trend of increasing energy density and a continuous decoupling of energy production from the environment. Such wind farms could become a blight on our landscape if we go too far, just as the felling of trees ravaged the countryside in the past.

Fortunately for the Elizabethans, there was an alternative fuel at hand which, although known for many years, had never been seriously exploited. Coal was energy dense, transportable by sea and could generate tremendous heat for industrial processes. Although it is perhaps hard to believe, the substitution of coal for wood was the first transition to a low-carbon economy. In comparison to wood, coal is a low-carbon fuel. In wood, there are typically 10 carbon atoms for every hydrogen atom, compared to one or two hydrogen atoms per carbon atom in coal. So coal has a far better hydrogen-to-carbon ratio. That matters, because when carbon is burned, it produces carbon dioxide, widely regarded as the most important greenhouse gas in the theory of man-made climate change. When hydrogen is burned, it produces water. So, the more a fuel is made up of hydrogen rather than carbon, the ‘cleaner’ it is.

This decarbonising of energy production has continued through further transitions from coal to oil, gas (four hydrogen atoms per carbon atom) and now nuclear fission, which does not rely on burning a carbon-based fuel at all. Each new fuel has a higher energy density and lower carbon content, particularly so for carbon-free fission.

These continuous improvements in energy density have led to greater energy utility, and so greater energy use. This is human progress. The growth in the use of coal during and after the Elizabethan era, for example, led to innovations in materials to deal with the potent heat produced, while stone-built homes with glass windows produced in coal furnaces became prevalent. Efficient fired-brick chimneys were deployed to remove fumes and improve indoor air quality. While the developed world has enjoyed the overwhelmingly civilising and liberating effects of cheap energy from coal, many in the developing world are still in the wood-burning Elizabethan era, cooking indoors over open fires with appalling consequences for their health.

The similarities between the Elizabethan energy crisis and the present day are quite remarkable. As wood became scarce near population centres, there was a strong motivation to shift energy supply to energy-dense, low-carbon coal. This is the same transition that many advocate today by displacing coal from energy production using ultra-energy dense, carbon-free uranium and thorium.

Not only is the technological shift required similar – in that we will soon need to move to alternative fuels, but those fuels are already available – but there are parallels between the reaction to technological change 400 years ago and the reaction today. While the improved energy density of coal was clear to Elizabethans, there was resistance to its widespread use. Coal was seen as dirty and polluting, a fuel of last resort, while deep mining was long seen as a form of robbery from the Earth until the early sixteenth century, echoing current environmental sentiment. While wood remained plentiful, there was little incentive to mine coal. However, as practical resource limits were approached, coal became accepted. The improved energy density of coal and its ease of transport by water would lead to the marvels of the Industrial Revolution, ultimately raising standards of living and providing an escape for many from subsistence agriculture.

One of the key observations of the Elizabethan energy crisis is that the scarcity of wood precipitated a new, low-carbon energy infrastructure which delivered greater availability of cheap and ultimately cleaner energy. Present-day greens who advocate a transition to a low-carbon energy infrastructure should therefore be careful what they wish for. Global deployment of new generation-III nuclear reactors, macro-scale renewables projects, ultra-low cost solar power and (some day) fusion will certainly reduce carbon emissions, but will almost certainly increase total energy production, reduce real energy costs and lead to greater energy use in the long term. Again, this is human progress, even if it is not what many greens may hope for.

Yet another observation is that the Elizabethans did not start with a blank sheet of paper in finding an alternative to wood. They geared up an existing energy supply from a minor role in energy production to the dominant source of fuel. In turn, it is nuclear power and possibly shale gas – a fuel source that has only recently become exploitable – that are in a similar position to displace coal and oil over the coming decades. Compressed natural gas is also an excellent substitute for oil since it can be used with existing internal combustion engines; all that is required is to fit a pressurised tank to an existing car, something that is already quite commonly done. Alternatively, battery energy density will eventually approach that of hydrocarbons, allowing effective transportation through the use of clean electricity. We are not short of options when it comes to a new stage in our energy usage.

Peak energy catastrophists can always find a new stumbling block on the path to new energy sources. For example, many argue that there is only sufficient high-grade uranium to fuel a new fleet of generation-III reactors for a few decades. However, increased demand for uranium will lead to a resumption of uranium prospecting, improvements in energy-efficient fuel fabrication from lower-grade ores, spent fuel re-processing and ultra-efficient reactor designs. During the transition from wood to coal some 400 years ago, agricultural writer Arthur Standish bemoaned ‘there is no assurance how long they [coals] will last’. Much later, in 1865, economist Stanley Jevons noted that the great improvements in engine efficiency from the steam power pioneer Thomas Newcomen to the industrial innovator James Watt paradoxically led to a greater demand for coal. Again, present-day greens should be careful in calling for energy efficiency measures. They have a rather poor track record of actually reducing long-term energy use. The only effective means of reducing energy use is through socially regressive measures to engineer artificial scarcity, such as subsidies for inefficient modes of energy production. Why would we take such a backward step?

For nuclear power, the current generation of once-through light water reactors were never seen as an end point for nuclear energy, but only a beginning. We are currently using the inefficient Newcomen engines of the nuclear age, but have yet to deploy the greatly improved equivalent of the Watt engine. The Watt engines of the nuclear age will likely be generation-IV fast reactors, possibly accelerator-driven machines or even fusion-fission hybrids, each of which can improve fuel burn from less than one per cent to greater than 99 per cent, while incinerating the spent fuel (wrongly classified as waste) from our current fleet of reactors. This will create yet more energy and extend the useful life of uranium deposits into the far future. Even more important for the future will be the use of thorium as a fertile and abundant fuel which will enable nuclear energy to be generated in copious quantities for quite literally thousands of years to come.

Let’s be clear: there is no shortage of high-grade energy, only a shortage of ambition in some quarters and a retreat from the idea of human progress through technical innovation. That doesn’t mean there are no technical problems to overcome – for example, there are serious engineering challenges in building really big nuclear plants – but there are some startling ideas now being discussed about how these problems could be solved.

Whatever technologies are ultimately devised and deployed, our goal must be to generate yet more clean, low-cost energy. We will need this energy to power the developing world, deliver rapid transportation, process and store information, light our growing cities, explore new intellectual horizons in science and recycle strategic materials in ways undreamt of by today’s greens.

New sources of energy can not only replace resources that may dwindle with time, but can also provide new starting points for innovation, with many unforeseen benefits. Just as the Elizabethan switch from burning trees to burning coal helped to fire the Industrial Revolution, so an ambitious approach to energy supply could help to revolutionise society in the future.

Colin McInnes is professor of engineering science at the University of Strathclyde.