An integrated energy and security plan for Australia

Where to start? The lack of systems thinking from from our leaders is mind-boggling. 

Ok, let's start with the submarines.  Nuclear submarines, I mean - really?

The whole point of nuclear submarines is that they carry nuclear weapons, can travel anywhere in the world without refuelling, and can stay submerged for months at a time. So your enemy never  knows where they are, and hence isn't willing to risk a direct confrontation. Our brand new AUKUS (awkwas?) nuclear subs won't have a nuclear weapon deterrent, and as a medium sized regional power I don't see the strategic usefulness of the long range capability. Also, nuclear subs are not particularly stealthy - pumps need to run at all times to keep the reactor core cool, and they leave a waste heat signature in their wake. Then there's the fact that we don't have a nuclear industry - we have neither the expertise nor the systems in place to be able to operate, maintain or refuel these things. 

A much better option would be to develop smaller and more numerous home-grown subs to take out enemy shipping and submarines. Powered by hydrogen fuel cells. Those things have no moving parts and are completely silent. Hydrogen and oxygen would be carried onboard, possibly as liquids, allowing extended operation underwater. A very effective deterrent in our region.

As a medium sized regional power, we are not the lion on the Serengeti. Our strategy should be that of the porcupine - not trying to throw our weight around, but make ourselves a really unattractive prospect  for larger powers. 

The core of a hydrogen industry

This constitutes a way to jump start large scale hydrogen production in Australia.

The need to decarbonise the energy sector is urgent, but global warming is by no means the whole story. At least as serious, and certainly more urgent, is fossil fuel depletion. Especially crude oil which when refined fuels effectively all of our transport and military (including our current submarines).

We are horribly exposed on this. Australia  imports about 2/3 of its transport fuel and now has only two domestic refineries remaining. Our "strategic" petroleum reserve is only 21 days worth of consumption, far less than the minimum of 90 days recommended by the International Energy Agency. Not only that, but a large part of our reserve is held on our behalf in the US where it won't be of much use in the event of something like a disruption to shipping. It's no exaggeration to say that if anything were to happen to international trade in crude oil, Australia would be in serious trouble (martial law, rationing) within a few weeks.

Not that a hydrogen industry is going to fix this, it's needed for other reasons:

• to power the submarine fleet
• liquefied (or possibly stored as ammonia) as a large scale energy storage for the grid. See for example this post on the need for storage in the grid. 
• as an export (liquid or as ammonia)

Electrolysis of water and storage of the hydrogen and oxygen as liquids is a good way to soak up the vast quantities of excess renewable energy that we'll have during summer months. And a good way of keeping submarine fuel on hand.

What about transport then?

This is an urgent problem, and should be a pressing national security concern. The critical thing in the short term is to be able to continue to power the transport fleet to ship goods (especially food) around the country.

Short term - start building up the rail network. Dual rail lines all the way between the capital cities and regional centres. Not high speed rail, just normal speed, with dual lines (and maybe even passing bays!) would be nice. Build infrastructure to ship liquefied natural gas from the west to the east. Convert diesel locos to run on LNG, and some of the long distance trucking fleet to run on either LNG or CNG (compressed natural gas). There's no down side to this - it'll be cheaper than diesel, cleaner both in greenhouse emissions and in sulfur, and reduces risk from international supply chains.

Medium term - electrify the whole rail network and start converting locomotives to run as hybrids with liquid hydrogen (or ammonia). It might make sense to build synthetic fuel plants to convert gas to methanol and then dimethyl ether as a diesel substitute for smaller trucks and cars, or to synthetic gasoline for cars (most importantly for emergency service vehicles).

Longer term - battery electric trucking for short distances to and from the rail head to warehouses and retailing.

A few words about nuclear power

In my view this is unwise, for the following reasons:

• We don't have a nuclear industry and we would have to build one almost from scratch, including developing expertise and setting up the training capabilities in universities. The same is true for hydrogen liquefaction and storage, although it's less technically challenging and we already have some of the skills needed. Investing in developing a nuclear industry represents a big opportunity cost to develop a more durable alternative though.
• We have other choices. Australia has shedloads of every energy source except crude oil. We might be much better placed exporting our uranium to other countries that have already made the decision to go down the nuclear path. As a source of export income and also a source of soft political power.
• Despite the required investment, it's not really a long term prospect. There's actually not that much uranium available globally. If everyone in the world were to try to generate their electricity using current nuclear technology, the global supply of U235 would last about 10 years. Yes, breeder reactors and yes, molten salt thorium reactors, but the former hasn't yet been made commercially viable and the latter is not much more than a research prospect. Decades away, at best. We can't wait that long, for something that might not work out.
• Spent nuclear fuel disposal. We (humans) have been generating power from uranium for 70 years, and we still haven't implemented permanent storage for the spent nuclear fuel.  The Onkalo repository is the  first in the world. They applied for a license to start storing waste from 2024. All of the spent nuclear fuel ever produced is sitting around on the surface and requires active systems (laws, management regimes, fences, surveillance, men with guns) to keep it secure. Now ask yourself this: what happens to all of that spent fuel that isn't safely disposed of, when those active management systems go away? It doesn't even have to be as dramatic as social collapse: war would be enough. 
• Inability to adequately model risk. Chernobyl was caused by a combination of bad design and human stupidity. Fukushima was a combination of poor design choices and failure to anticipate an earthquake and tsunami of that magnitude. The point is, that neither of those scenarios were part of the risk analysis that was done in setting those plants up. Far from being one-in-a-million events, we have a lived history of two catastrophic failures in seventy years of nuclear power. We really don't have a good way of modelling these very low probability but very high consequence events. The clean-up at Chernobyl and Fukushima is ongoing, with no end in sight and at  probably unknowable cost. 

Not impossible, but doesn't seem like the best option to me. Solar and wind are much more known and knowable quantities, and have the potential to be truly long term solutions. The difficulty there is the need for large amounts of storage to offset their inherent variability. 

Unfortunately, we are now out of good options.

Electricity supply part 3 - balancing storage capacity with generation capacity

This is part 3 of a short series of posts thinking about energy storage needs for a renewable electricity grid in NSW Australia.

In part 1, we saw that electricity demand and renewable electricity generation both fluctuate over time. To generate enough renewable power on average for the first week of April 2022, we need about 4.7 times the currently installed renewable generation. There's a big problem though, because the electricity grid must be balanced at all times, not just on average. At 5:30am on 5th April 2022 the sun hadn't yet risen and there was almost no wind blowing in the state. We would have needed more than 120 times the currently installed wind farms to avoid a blackout!

Clearly, there is a need for energy storage to avoid over-building renewable generation equipment to the point where most of it is doing nothing, most of the time. We had a look at this in part 2, where we worked out the minimum amount of storage required for that first week in April - assuming that we had just exactly enough renewables to meet the average demand. We needed a minimium 96,000 MWh, or about 14 hours at average state power consumption. 

There's still an obvious problem here though - we don't necessarily need so much storage if we're happy to waste  (not generate) some of the renewable electricity. So far we've only considered two extreme cases - no storage and massive over generation (in part 1) and maximal storage with no over generation (in part 2). Both of these extremes will be very expensive. Likely a cheaper solution will be to have some level of over generation - which would require less storage to avoid a blackout. The right balance would be the combination with the lowest overall cost.

Working out storage needs with some over-generation

We're going to need a slightly different approach than what we used previously. As in part 2, we'll start the storage number at zero, at the start of the week. When we withdraw energy from storage it goes down, and when we store electricity it goes up. However, when the storage reaches the full state, any additional generation has nowhere to go and gets wasted ("spilled" - which in  practice means not generated in the first place, although it could have been if there was somewhere for it to go).

Then, we once again adjust the generation high enough such that the energy storage ends the week at about the same place it started - "zero". We end up with a pair of numbers - a required energy storage value in MWh, and an energy generation value - some of which is used and some of which is spilled. 

Let's further suppose that "zero" on the energy storage graph corresponds to half full (this isn't quite right but probably minimises the error in guessing how much energy we might have remaining on any given midnight in April).

Figure 1 below shows what happens with the storage level. Storage fills from sunrise on day 1, reaching the maximum level shown as 30,000 MWh on the chart. The storage minimum of -45,912 MWh occurs in that early morning of the 5th of April.

Figure 1 - Electricity storage level for NSW in the first week of April 2021, with 7 times currently installed renewable power generation (solar and wind). Renewable generation is curtailed when the storage is full, which happens in the middle of each day. Total storage required to avoid a blackout is the  maximum storage level minus the minimum (30,000MWh - -45,912MWh = 75,912MWh)

This has resulted in 31% of renewable generation being curtailed, mainly solar power in the middle of the day that has nowhere to go because the storage is full and generation exceeds demand. 

As we generate more renewable energy, we expect a smaller required storage. Although we see that here, the effect is not very strong because of that night of 4th - 5th of April when there was not much wind generation. The size of the storage, just looking at this week, is that required to get the state through that particular night.

Widen the lens to a whole year of data

One week looks nice on a graph. Although we've captured an interesting event on the 5th of April, we don't know much about those other types of variability. Let's consider how this looks for the whole year of 2021, applying exactly the same ideas but probably without the graphs now because they'll look like cat fur.

I've had trouble locating the data for rooftop PV, so I'll leave that out for now (that actually helps a bit because it  means we have  proportionally less solar and more wind, which helps us get through the nights). I'll repeat the analysis at the end if I can  find the data again.

Figure 2, below, shows how this looks for the whole of 2021, now showing "End of Month" on the abscissa, instead of "End of Day". I've scaled up the generation up enough to just meet demand over the year (7.05 times the currently installed wind and utility solar plant). There's no energy spill, but we need at least 4.88 million MWh of energy storage (equivalent to meeting the state's entire energy demand for a 29 days running with no generation). We'll get to costing that out in a future post.

Figure 2 - 100% renewable power, no excess generation over the year (no spill) - requiring 4.88 million MWh of energy storage. That's 4,880 GWh, or 29 days of storage at state average power consumption.

You can see the problem here. Most of the draw down happens in winter from the end of April to the end of July. Most of the storage capacity is only used once per year, for that big winter dip. Figure 3 shows how the situation looks if we go to 20 times currently installed solar and wind. Now we waste 65% of the renewable energy we could potentially generate, but we only need 162,000 MWh of storage (equating to about 1 day of energy storage, instead of about a month).

Figure 3 - 20x current renewable generation. Only 162,000 MWh of storage are needed, and the storage is charged and discharged more frequently (that's good). However, we waste about 65% of the renewable energy that we could potentially have generated because there isn't anywhere to use it.

Figure 4 shows how the required storage varies as a function of overgeneration. The left hand side corresponds to just barely enough generation (no wastage) but large amounts of storage required, with just over 7 times currently installed renewable generation. The right hand side corresponds to 20 times currently installed renewables, 65% of which is wasted (curtailed, or spilled), but much less storage is needed.

Figure 4 - Storage requirement vs overgeneration (presented as % of generation which is wasted). High levels of overgeneration are wasteful in terms of renewable generation infrastructure, but efficient in terms of storage infrastructure, and vice-versa.

A trade-off is required

Hopefully this makes it clear that a trade-off is required. Efficient use of renewable generation infrastructure requires excessive and inefficient storage. Minimising the amount of required storage requires over-building of renewable infrastructure and wasting of the potential to generate energy, particularly during the summer.

The best trade-off is the one that minimises overall system cost - probably at between 20 and 40% energy wastage,  going from the shape of the curve in Figure 4, but we'll try to put some dollar figures on that next time.

Electricity supply part 2 - how much storage for 100% renewables?

 Let's "spill" that excess renewable generation into storage

This is part 2 of a short series of posts thinking about energy storage needs for a renewable electricity grid. We'll develop the ideas first, then explore what happens when we change various things, making the results more realistic at the end.

In Part 1, we saw that, for the first week of April 2022 in NSW Australia, once we expand renewable generation much more than about 5 times current generation, there are times we would be generating more electricity than is required by the state. In order to not cause a grid failure, we have to switch off some renewable generation at those times.

There was another time, just before dawn with no solar yet available, when there was very little wind  power being generated across the entire state.

It seems clear that we need to store that energy when it's available in excess, in order to use at times when the sun isn't shining and the wind isn't blowing. 

I'm going to redraw the graphs we had previously, to show what's going on more clearly as we start thinking about storage. Figure 1 shows just two data series, not stacked. The orange is the demand level, and the green is the total renewable generation. This is the same data as shown in Figure 1 of part 1, except we are just showing the renewables total, not the breakdown by type.

Figure 1 - total electricity demand and total renewable (total of solar and wind) generation in NSW Australia for the first week of April, 2022. The difference between the two curves is currently met by fossil fuel generation, but would need to be withdrawn from energy storage in a fully renewable scenario.

Suppose for simplicity that we just keep the current proportions of solar and wind the same, but multiply the renewable output by 4. We can see in Figure 2 below that supply exceeds demand in the middle of the day, and falls below at night. Whenever the green generation curve is higher than the orange demand one we are charging our energy storage system (instead of spilling the electricity), and when the green curve is below the orange curve, we need to discharge from storage to keep the  lights on.

Figure 2 - First week of April, imagining that we've scaled up renewable generation by a factor of four. When the green generation curve is above the orange demand curve we send excess energy to storage, when it is below the renewable generation is not enough to satisfy demand and needs to be withdrawn from storage.

How much storage is needed?

First, lets work out the power flows needed to and from storage, by subtracting the demand curve from the supply curve. If this is positive, it's a measure of the excess power from renewable generation. If it's negative, power is being withdrawn from storage to support the grid. I've shown this in Figure 3, with the area shaded to make it obvious when it's above or below zero.

Figure 3 - storage power required to balance renewables at 4 times the current generation rate in NSW, for the first week of April, 2022

Remember that energy is power multiplied by time is energy. So although the height on the graph represents power (in MW), the shaded area represents energy in MWh. It looks to me like the total energy withdrawn from the storage (area of the blue shading below the zero mark) might be a bit larger than the energy stored (area of blue shading above zero), but we can't be sure just eyeballing the graph.

What we need to do is add all those areas together - to integrate that storage curve to show how much energy we've accumulated since the beginning of the week. Setting the beginning of the week at zero arbitrarily, we can see the energy storage deficit in MWh below in Figure 4. You can see that the energy stored keeps dropping because renewable generation is not keeping up with demand. 

Figure 4 - Cumulative energy storage in NSW for the first week of April 2022, with four-fold increase of renewable energy supposed. Four-fold is clearly not enough to keep up with demand over this week, as the storage level continues to deplete through the week. Compare to Figure 3 - during the day when renewable generation exceeds  energy demand, the storage level increases, during the night it decreases.

This is easily fixed by building more renewables, If we assume a five-fold increase in renewable generation instead of four-fold then the energy stored accumulates over time. If we go with a 4.7 fold increase in renewable generation then we get the result shown in Figure 5, where we end the week with about the same level of stored energy as we started with ("zero"). This means that we have just enough generation such that the average generation over the week matches the average demand over the week, with sufficient storage allowing us to soak up the variability in both.

Figure 5 - Cumulative energy storage in NSW for the first week of April 2022, with 4.7-fold increase of renewable energy supposed. The storage ends the week at the same storage level at the beginning, indicating that, averaged over the week, 100% of demand was met by renewables. The difference between the highest and lowest stored energy states tells us the absolute minimum size for the energy storage - 96,000 MWh, equivalent to about 14 hours of power stored, at state average power consumption.

Where are we at?

So we're getting a picture of what's needed for a fully renewable grid:

• About 4.7 times the renewable generation infrastructure that we currently have installed, so that we generate enough power over the week (Figure 5)
• At least 96,000 MWh of energy storage - able to power the whole state, by itself, for 14 hours (difference between  highest and lowest values on Figure 5)
• Energy storage able to handle discharge rates of 9,000 MW (highest point on Figure 3)

But there are a few problems with what we've done here:

• This analysis is only for the first week of April 2022. I don't expect that week to be special or unusual in any way, but special and unusual times do occur regularly and the grid needs to be able to deal with them. It also needs to deal with seasonal variations that don't show up in a single week.
• We've just scaled the renewable generation all together, we  might be able to do much better if we build proportionally more wind and less solar, for example
• We've assumed that the storage should be able to absorb all of the renewable energy we throw at it, and that the renewable generation should be enough to meet 100% of demand. This might be an expensive solution. It might be cheaper, for example, to over-build the generation by 20% (which means we waste 20% of what's generated) so that we can make do with a smaller amount of storage.

Next time, we'll develop the analysis to answer these questions and get some more nuanced results.

Electricity supply, part 1 - the need for storage

Keeping the lights on isn't easy

Electricity can't really be stored, as such.

It can also be quite dangerous, and so our electricity delivery systems have been designed with a lot of safety features to prevent electrocution, fires and equipment damage. These things do happen from time to time of course, but mostly, the safety features activate to shut down the affected circuits before any damage is done. This is critical to recovery, as preventing equipment damage means that faults can be corrected and service restored in  minutes or hours rather than the days, weeks or months it would take to replace damaged equipment.

To keep the system safe and the lights on, the delivery sytstem - "the grid" - needs to stay within quite tight tolerances for frequency and voltage (50Hz and 240V in Australia). If things get too far out of whack, or stay out of whack for too long then the safety systems start to activate and shut down parts of the grid to prevent damage. Managing the grid and keeping things from failing is actually a fantastically complex task. A great illustration of the sorts of things that can go wrong are the story of the 2003 blackout in the northeastern US, and the Texas power grid failure of 2021.

This means that supply and demand must be exactly balanced at all times. In the National Electricty Market (NEM) for Australia, which covers the eastern states and South Australia, the market operator (AEMO) operates a planning and bidding process every 5 minutes to ensure this balance is maintained on a minute by minute basis. 

This delicate balance between supply and demand has historically been achieved by letting people use electricity when they want it, and then the market operator AEMO organises the dispatch of supply to meet whatever that demand happens to be at that point in time. This means that total demand varies according to the time of day with our wake / sleep cycle, and also with the weather as we turn heaters and air conditioners on or off, use more or less lighting, watch TV in the evening or go for a walk in the park.

Figure 1, below, shows the total NSW demand for the first week of April 2022. All the data used in this series of posts are freely available to the public via the Australian Energy Market Operator (AEMO) although they are not particularly accessible or in a user friendly format. The NEMOSIS software is free and open source window onto that data that improves accessibility considerably, but I used the commercial package NEMsight, which makes things even easier. The OpenNEM project is the easiest of all, but unfortunately has only the most recent week of data available.

Figure 1 Electricity demand in NSW from 00:01 Friday 1st April to 23:59 Thursday 7th April. Total demand is highest during the day, and lowest in the wee small hours of the morning. Average for the state is about 7,000 MW (megawatts), which is about the same as having around 3 million electric kettles, or 3 thousand electric trains running simultaneously.

The demand shown here includes that which is met through rooftop solar panels "behind the meter" so is closer to the the electricity being used, than to the demand which is "seen" by the market operator (anything that happens behind the electricity meter is essentially invisible to AEMO).

Renewable energy sources don't make it any easier

We have some needs to move away from fossil fuel use for electricity production. Yes climate change, but also fossil fuel depletion. We aren't making any new coal, ever. The rate that we're making new oil and natural gas is so slow as to be zero for all intents and purposes. So for both of these reasons and more, we would really like to stop relying on fossil fuels for electricity generation in the grid.

This causes a real problem because as noted above, supply and demand is balanced by letting people use what they like, and then dispatching the supply to meet that. Fossil fuels are dispatchable, in the sense that you can  (more or less) turn them on or off, up or down, in order to meet the electricity demand and keep the whole grid stable.

Renewable energy generation isn't like that. It relies on energy flows in the environment, like the wind and sun. You can't dispatch those sources to the grid if the natural flow isn't available at that point in time, and so there is no guarantee that they will be available to help generate the electricity demanded. The only thing you can do with renewable sources is to "spill" them - turn them down or off when they are not needed, forgoing electricity generation in order to maintain the required balance.

Figure 2 shows how this renewable generation worked in the first week of April. The graph shows electricity supply from different sources. You can see that solar generators, both domestic rooftop units and utility scale commercial plants, only generate during the day and even then that depends on the season and the weather. Wind power can make electricity at night, but is not consistent over the week. Note that on the 5th April there was almost no wind power generated anywhere within the state of NSW.

Figure 2 - Electricity generation over the same period as Figure 1. "Other" generation is mostly fossil fuels, used to fill in the gaps between the total demand, and the generation from these renewable sources.

Let's go to 100% renewable generation

Figure 1 shows us the instantaneous power requirement for NSW in the period 1 - 7th April 2022. Power multiplied by time (the total area of blue shading in the graph) represents the energy requirement for that week - 1.23 million megawatt-hours, with a wholesale value of about $270 million. Of that energy, about 21% was generated from either solar or wind, the remaining 79% mostly from fossil fuels  (74%) and hydro (5%).

We can do some experiments with the data to test what might happen as we build more renewable generation. Perhaps we can even get to the goal of 100%. For example, suppose that we go on a massive program of wind farm building, so that we have 5 times as much wind farm capacity installed as we currently have in NSW. What would that first week of April have looked like? See Figure 3 below.

Figure 3 - Electricity generation over the same period with a five-fold increase in wind power capacity. The vertical red line is 5:30 AM on 5th April. The sun is still below the horizon and almost no wind power is being produced across the state. To meet demand at this time using wind, we would have to expand the NSW wind generation capacity by more than 120 times what's already installed!

Now we are up to 57% renewable generation but if you look closely, you can see a couple of occasions on the third day, and on the 6th and 7th evenings,  when we had to spill some renewable generation because the total exceeded the demand. This electricity has to be wasted because there is nowhere it can go. If it stays on the grid the voltage will start to rise and then the safety systems will start blacking out parts of the network. So we have to turn off some wind turbines before that happens.

In the scenario shown in figure 3, we have to spill about 3000 MWh of electricity, worth perhaps half a million dollars.

We get a similar situation with the solar - expanding commercial solar farms by a factor of 5 also gets us close to spilling electricity (shown in Figure 4).

Figure 4 - Electricity generation with a five-fold increase in commercial solar farms. No spill, but only 39% of energy generated renewably.

This shows why a renewable electricity grid needs to be able to store energy somehow. There are periods (such as 5:30 AM on the 5th April - see the vertical red line in Figure 3) when none of the renewable resources are available. We will need to be able to draw from hydro, from batteries, or from some other form of storage at those times. 

But exactly how much storage do we need? That's a question we'll explore next time.

P.S. I've made quite a few simplifcations here, in the interests of not obscuring the big picture. We'll address some of those in future posts.

Sustainability, ethics, and the needs of future generations

When people speak of sustainability or sustainable development, they almost always use the Brundtland definition of sustainable development, being human development which

"meets the needs of the present without compromising the ability of future generations to meet their own needs"

Leaving aside the question of what is meant by development and whether such a thing can ever be sustainable, long term, a couple of things occurred to me in reading through the latest batch of assignments from my final year chemical engineering students.

One of the central concerns in sustainability is that our behaviour affects others: in different geographical areas, but also in time. Recognising that it's appropriate to consider the interests of these others in choosing our own behaviour, is recognising that sustainability questions are fundamentally questions of ethics.

Now ethics can be tricky, but one of the really important principles in doing the right thing is the idea of informed consent. Make sure that the others who will be affected by your choices are sufficiently aware of what's at stake to understand where their own interests lie, and then listen to their views before deciding what to do.

The big problem with considering the interests of future generations is that they don't exist yet, so we can't have this conversation with them. We are left with the much less satisfactory alternative of imagining what it would be like to be the future generations and making the choices on the basis of a set of assumptions about them. What makes this especially problematic is that we don't know who these people are and what their needs are; and the further we look into the future the more of a problem this becomes.

Let me give you some examples of what I mean.

What if the future features unlimited technological growth?

The 20th Century saw remarkable human progress on many measures. It is easy to think (and indeed many people think) that this progress will continue. Cancer will soon be cured, we'll all have flying cars and there will be a colony on mars. After that, who knows? Probably an interstellar society linked by spacecraft with warp drive propulsion or something even cooler than that! Things we can't even imagine now!

What will the needs of these future people be? What should we do today, if we feel a need to be fair in balancing their needs with ours? This is a very difficult question. Technology can seem like magic, making essentially anything possible. With unlimited technological progress, it looks like we don't need to worry about future generations meeting their pysiological needs. Possibly we should preserve parts of our ecosystems and some of our old infrastructure for sentimental / cultural / historical reasons. The future generations might like to visit the cradle of their species from time to time, which will help meet their need for a sense of identity and history.

What if the future is only a bit more advanced than now?

With some understanding of physics and biology we come to understand that some things are not possible and will never be possible. The warp drive will never happen. The colony on mars looks unlikely - technologically possible (maybe), but very, very expensive and not a pleasant place to live. We might suppose that progress will continue, perhaps at a slower pace than now (as a worst case scenario). We understand that technological solutions to problems are expensive, and that more difficult problems entail more expensive solutions.

How do we balance our needs with those of these future generations? They will have a more advanced society than ours, with clean energy, low levels of pollution, recycling and re-using all of their materials - a "circular economy". To look after their interests, we should be careful to not damage the natural environment too much, so as to not burden them with too much in the way of clean-up or adaptation measures. We should not make valuable resources difficult or impossible to recover.

For example, helium has very particular technological uses (mainly cryogenic cooling - nothing else can cool things down to 4.2 Kelvins like helium can). Future generations might need this ability for their technologies, so we shouldn't carelessly allow this non-renewable resource to escape into the atmosphere. When we do, it quite quickly floats to the top of the atmosphere and escapes into space where it is gone forever. Similar story for phosphorus. It's essential for life, not renewable, and not substitutable by anything else. It can be recycled (and is recycled naturally - very slowly) but if we keep flushing it into the ocean, that makes things more difficult for the future generations because it becomes extremely dilute (read: expensive to recover).

With a future like this we can probably delay immediate action on some of our trickier problems because they may become easier to deal with in future. For example, almost none of the spent nuclear fuel we have produced over the last 70 years of nuclear power generation has been secured in long term storage. It is mostly held short term (years) in special cooling pools or in intermediate term (decades) dry cask storage, both of which require active technical and security management. This is probably reasonable because the future generations will have better disposal technology than ours, but also because this waste product might be a resource in this future. Breeder reactors, for instance, might be made safe and economical, allowing future generations to burn up and make safe our waste, generating a large amount of energy in the process.

What if the future is less advanced than now?

This can be hard to imagine. It's quite literally an article of faith for most that technology only ever improves, or at worst, remains static. That society "improves" with time - education standards go up, as does wealth and life expectancy with improved medical technology, more enlightened public policy and decreasing inequality and violence - is taken by many as a given. That's been the experience of most over our lifetimes, the lifetimes of our parents and grandparents.

That's been our recent experience, but there is no law of nature that makes it so.

Historically there are plenty of periods where all of these things go the other way. Technology is lost, literacy becomes uncommon, the economy contracts along with the population, often along with a rising spiral of political violence. 

It's called social collapse.

It happens to almost all societies, every 200 to 400 years or so. It happened to the ancient Greeks, the ancient Romans, the ancient Egyptians, the Harappans, the Mayans, the Greenland Norse, the Chinese (multiple times), Vietnamese (multiple times), Easter Islanders - it's a really long list. It generally happens when complex societies grow up against resource limits. They become complex in order to use resources efficiently, but it requires a lot of effort. The burden of the effort falls primarily on the lower social classes, for whom life becomes more difficult as real wages fall. This leads to enrichment of the elite social classes, but loss of tax revenue for the state. The state becomes unable to enforce peace between increasingly combative elite factions. Internal conflict and a weakened state make the civilisation vulnerable to disturbances like natural disasters, external aggressors, climate change, etc. Any number of events can be the final push over the edge that starts decline, but the internal social dynamics put the civilisation in a weak and vulnerable position in the first place.

If you're the type that takes notice of these things, you'll have been seeing the warning lights for these things blink on one by one as our modern society walks into the same situation that all the complex societies before ours did. We are hitting resource limits. The economy has stopped growing. We have stagnant wages, falling birth rates, falling tax revenue, economic (GFC) and political (Brexit, Trump) instability. Climate change. Increased political violence. Check, check, check, check, check.

This isn't the point yet, but we're getting there.

Suppose that social collapse happens to us, at some point. Based on the evidence, it's very unlikely that there will be a global industrial society anything like ours, 100 years from now. Even for the next 50 years, it's looking pretty iffy.

Now we're at the point: future generations maybe only 100 years from now are quite likely, the way things are going, to have less technological capability than we do, not more. This is not to imply that our great-great grandchildren will be living in caves and hitting each other over the head with rocks. What we will probably have are societies less globalised, with fewer people than now, using simpler technologies that are easier to sustain. 

They won't have a use for spent nuclear fuel, but they will certainly be harmed by it if we don't make it safe in deep long term storage while we're still able to. 

It's also likely that they won't have any use for helium, so as a sustainability issue we can probably stop worrying about that  one. Only advanced technological societies need helium.

What they will need is a functional ecosystem they can grow food in, free from poisons that will cause unnecessary suffering. 

What we imagine in the future, affects our ethics in the present

So, what we imagine things will be like in the future, affects our ethical calculus in the present quite a lot. The technological views of the future seems to explain quite a bit about the things that people worry about on behalf of future generations. The high levels of concern on preserving pockets of ecosystem beauty, and the rather lower levels of concern for broad ecosystem function. The high profile of space research including searching for Planet B and the limited work on cleaning up the messes we've already made (and continue to make) on Planet A.

To be ethically competent we need to think about a range of realistic probabilities for the world that future generations will live in, and what their needs and capabilities might be. Not just accept without question the narrative than mankind is destined to ever greater achievement. That can give us a dangerously distorted view of what future generations' needs might be.

25:5 Diet - a log, and some comments on frequency

Herewith, an update on intermittent fasting, with examples!

MONDAY

72.5kg, 14.7% fat.

Breakfast.
A glass of water with psyllium husk. Large soy latte, so far it's a usual day except I've cut out the coconut oil that I usually add to my coffee.

Lunchtime (skipped)
Drinking green tea. Not hungry yet, but having trouble concentrating. I've been eating carbs for the few days prior to fast - possibly this makes the transition to fasting a bit harder to deal with. Might check that next time.

Teatime.
8pm - konjac noodles and ratatouille. Konjac noodles have virtually no calories but plenty of fibre to feed my gut bacteria. Eggplant, capsicum, onion, zucchini and tomato in ratatouille - all very ow calorie, main contribution from olive oil. I'd say not more than 400-500 Cal today. Adding a multivitamin and mineral supplement to help avoid possibilities for deficiencies.
9:30pm feeling mentally tired.

TUESDAY

71.3kg, 14.1% fat.

Breakfast.
 A glass of water with psyllium husk. Large soy latte. Feeling quite fine, not really hungry. 11am getting pretty hungry now. Green tea helps suppress it. Feeling mentally pretty sharp.

Lunch (skipped). Green tea.

Didn't check ketones yesterday, but fairly deeply into ketosis this afternoon.

Dinner - same as yesterday, plus the multivitamin and a few scrapes of romano cheese. Some thawed mixed berries for desert.

WEDNESDAY

70.7kg, 13.7% fat. Starting to feel cold easily.

Breakfast.
Water and psyllium husk. Large soy latte.

Lunch. (2pm) - starting to get noticeably weak now. Dinner is going to be a bit tricky this evening due to kids activities and hunger is getting a bit distracting so I'll eat now. Ratatoille and konjac noodles again (one pack, rather than 2). Plus a spoon of tzatziki dip for some variation in flavour.

Dinner (8pm) - a bit more ratatouille (all gone now!) - no noodles. 125g blueberries, and a passionfruit. Not really feeling hungry much now. Ketones are 4 mmol/L in my urine, I'm talking a lot (usually happens to me in ketosis).

THURSDAY

70.2kg, 13.5% fat.

Had a bit of a rough night last night. Just wasn't sleepy at all, didn't fall asleep for what seemed like several hours. This tends to happen near the end of the fast, I put it down to higher levels of ketones. Feeling enthusiastic this morning, not hungry at all.

Breakfast: Psyllium husk and water, large soy latte.

Lunch: skipped, green tea. Not hungry.

5:30pm Urine ketones up to 8 mmol/L, feeling a bit spaced out. Getting hungry again, had some more psyllium husk.

Dinner: 100g of cooked white rice (~130 Cal), stir fried green veg, cauliflower. An orange, some blueberries. No sure of calorie count but vegetables are mostly not very significant. Fat from the stir fry might be a couple of hundred Cal (maybe 10-20g maximum). Almost certainly around 500 Cal for the day.

FRIDAY

69.7kg, 13.1% fat. Woohoo! Eating tonight! I remark upon this every time I fast, but by the time I get to the last 2 days I have effectively stopped feeling hungry and could quite easily continue (which could quickly become dangerous). Food starts to taste really, really good. Plain white rice: delicious! Some flakes of plain, raw, rolled oats? Wow, so tasty who would have thought?

Breakfast: usual psyllium husk and water, a large soy latte

Lunch: skipped, green tea all afternoon

4pm 69.4kg 13.0% fat

Afternoon tea - fast broken! Sourdough toast with lashings of peanut butter and avocado... ahhh....

GENERAL COMMENTS

The original research work was 5 days over a 4 week period, but it's hard to know what is optimal.
If I stretch this to more-or-less 6 weeks, then ending the five day fast can be made to line up with druid holy days: the solstices, equinoxes and those in-between dates that mark transitions to or from periods of rapid change in day length.

I might have to rename it to my "40:5" diet  :-)

The 25:5 diet - second pass

Well, I've completed the second fasting cycle and now I have some data to share. I weighed myself each morning using a digital scale that uses bioelectrical impedance analysis to measure body fat. The method is not very accurate, but is very consistent - so changes probably mean more than absolute fat percentage. 

As a reminder, the diet is a variation on the now popular 5:2 diet, or periodic calorie restriction. The difference is that this one restricts both calories and protein for 5 days in a row, with the remainder of the month eating "ad libitum" - whatever you like. Details and a summary of the original research are given in my previous post. The study showed substantial benefits across a range of different health measures.

The time series starts at the beginning of the previous feed period. I've multiplied total weight by fat percentage to give fat mass (lower series, right hand axis) and (100 - fat percentage) by total mass to give lean mass (upper series, left hand axis). The blue and green data are during the feeding period, pink data are during the fasting (or fasting-mimicking) period.

The first thing to notice is that there is a rapid and sustained loss of both fat and lean tissue during the fasting period - from the data, perhaps 300g per day of each. Assuming that lean tissue loss has about the same calorific value as lean meat, about 100 Cal per 100g, that means I'm deriving perhaps 300 Cal per day by catabolising lean tissue. Fat has around 900 Cal per 100g, so I'm getting about 2700 Cal per day by burning fat stores. If I have the food intake about right, there is another 700 Cal from food each day. This works out 3700 Cal per day, somewhat higher than the average adult male energy requirement (2400 Cal per day), so either I'm missing something, or I have a higher than average energy requirement. This might have something to do with having a relatively high surface area, small volume (I'm tall and lightly built) and it being a bit cold (late winter). ie, I'm using a lot of food calories just to stay warm. Another possible reason is that the scale is over-estimating my body fat percentage and the fat mass reduction is not as large as indicated.

A commenter asked about lean muscle loss last time - and we can see lean mass loss in the graph. The mice in the study linked had a loss of organ weight during fasting, notably kidneys, liver and heart, but not brain, spleen or lungs. It would seem likely that at least part of the mass loss in the graph above is due to this. Part is probably lean muscle tissue.

The next thing to notice is the recovery phase preceding the fast. I least-squares fit a simple model to the fat and the lean mass data for the feeding period only. Expecting that change would be most rapid at the start and tail off towards an equilibrium at the end, I fit an exponential decay curve like

where m is mass (either fat, or lean), a, b and c are constants and t is time (day number).

The values of the parameters probably aren't interesting, but you can see from the graph that the lean mass recovers much, much faster than fat mass. Lean tissue recovery seems to be complete within a week, whereas fat mass is still rising when the next fasting cycle hits. This makes intuitive sense, as lean tissue would be the main priority for our bodies, fat is to a large extent energy storage and perhaps a second priority. It wouldn't make sense to store fat in preference to repairing muscle and internal organs that have been stressed by starvation. This observations could also explain the trend to visceral fat reduction that didn't quite reach significance in the research study after three diet cycles: from the above, it looks like we force a large reduction in fat during the fasting cycle, which the body isn't quite able to make up for during the feed cycle that follows (on the other hand, the same appears not to be true for lean tissue). So we might expect to see an overall reduction in body fat (hopefully, mainly visceral fat) over a number of feed / fast cycles. In addition to the other benefits (lower levels of IGF-1 etc.) which are a bit harder to measure at home!

Anyhow, we shall see. Stay tuned for more data and analysis as they come in.