Oxo degradable plastics

plastic bottle greenhouse at CATThere was a letter in today’s Guardian about oxo degradable plastics.  I’d never heard of the term before and decided to do a bit of research.  Conventional wisdom is that plastics do not degrade.  Or at least only on a geological timescale.  Conventional wisdom is largely right.  Polyvinylchloride (PVC) is degraded by heat and light and releases hydrochloric acid, which isn’t great.  Polypropylene is pretty much regarded as non biodegradable.  Most plastics do break down into small nano-particles.  Then progress stops.  Research this week has found these are present almost everywhere in supposedly pristine environments.  Other research has found that they are in the food chain and therefore in us.  The longterm biological effects of this are unknown.  They are unlikely to be too serious for the plastic itself, which is as alluded to above is biologically inert.  The problem is the effects of the plasticisers.  These are chemicals that give the same plastic different physical properties.   These plasticisers mimic hormones in the body.  Large pieces of plastic of course have detrimental effects on wildlife.

A number of solutions have been proposed to this problem.  The first has been so called bioplastics.  These are polymers largely made from natural polymers (e.g cellulose) using renewable feedstocks.  These are mostly, but not totally biodegradable.  Broadly speaking compounds are biodegradable when bacteria or fungi have seen them in evolution before and therefore possess enzymes capable of degrading them.  This is not the case for oil based plastics.  We outlined the problems with bioplastics in our book.  Basically in replacing our massive plastic use we need a lot of plant based feedstock.  This is not possible to do totally.  But these materials will have a place in a post oil world.  Another issue is that bioplastics do not have either the durability or entire range of properties of oil based plastics.

The next solution to the problem is the circular economy.  Recycle and reuse what we have in new products.  Some progress is being made on this.  One problem is that plastics do degrade when reused.  Not enough to destroy them but enough to make them unusable.  This is a particular problem in mixed recycling.  So this is not a total solution either.  Chemical methods of destruction using heat are being developed.  These would allow the resulting material to be reused perhaps de novo.

The next solution is to find bacteria or fungi that can breakdown conventional plastics.  Again some progress is is being made.  This is probably of more interest in bioreactors as a means of disposing what we produce at some point in the future.  But for what’s out there now it won’t work.  Bacteria and Fungi will degrade compounds that are simpler, easier nad more abundant first.

Of course we mustn’t forget the solution of using less in the first place.  Under public pressure companies are starting to alter the way that packaging is used.  Walkers Crisps and Guinness (this week) are too examples.  But the reader will know progress on this front is slow.

Finally this brings us to oxo degradable plastics.  These are plastics that contain small amounts of salt or metals.  These act as a catalyst and allow oxygen to break the plastic down to short chain molecules such as ketones or organic acids.  These bacteria will readily use.  It sounds to good to be true.  And to some people it is.  The EU don’t believe it works.  Other countries such as some in the middle east think it does and require its use.  Even if it does work its not a total solution.  Potentially it solves the litter in the environment bit. But not the use of non-renewable resources problem.

There is not one solution to the plastics issue.  All of the above are required.  We have become addicted to these highly convenient materials.  We need to reduce our use of plastics and look for alternatives, fast.


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Global energy transformation

The International Renewable Energy Agency has produced a report called “Global Energy Transformation”.  There are number of headlines being pulled out of this report, but the main one is that renewable capacity will make up most generation capacity by 2050 with wind and solar providing most of that.  There would 8.5TWp of solar capacity and 6TWp of wind capacity.  This would provide 50% of global electricity.  The report covers the areas that are going well and going badly for the Global Energy Transformation, with very interesting and clear graphics.  As you can see from the one below there is much to be cheerful about.


progress so far in the global energy transformation

However other graphics make plain there is still much progress still to make.  Energy efficiency gains need to be over 3% a year, not 2% as they are now. Share of electricity in final energy consumption i.e. electrification of the economy is off track, as is annual wind additions, use of heat pumps, use of liquid biofuels, energy consumption per capita, reduction in fossil fuel demand (there isn’t any -apart from coal)and energy related emissions.

On track are;

Renewable energy share in power generation, solar capacity, (surprisingly) electric car use, use of solar thermal collectors, solar energy costs and use of smart meters.

There is much in the above and other parts of the report I don’t agree with.  There is too much support and reliance on biofuels and only a tiny reference to competition with growing food. “Bioenergy must be produced in ways that are environmentally, socially and economically sustainable. There is a very large potential to produce bioenergy cost-effectively on existing farmland and grassland, without encroaching upon rainforests, and in addition to growing food requirements.”  I disagree.  I think the use of agricultural wastes will provide limited amounts of biofuel for transport.  I also regard the use of hydrogen as a waste of space.  However there is much that is good in the report and its well worth a look at.


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One thing we have learnt this week – transparent wood

B and W birch trunkThis week we learnt of a remarkable new material transparent wood. Two groups at the University of Maryland and the KTH institute of Technology in Sweden have developed a see through wood.  Not only that but it can store and release heat.  The researchers have achieved this by removing the lignin.  This absorbs visible light and is achieved by boiling the wood in a mixture of sodium hydroxide and sodium sulphite for some hours.  Adding hydrogen peroxide completes the process.  Than an epoxy compound is added to occupy the space liberated by the lignin.  Finally by adding glycol you can give its insulating heat storage capabilities.   When the now transparent wood warms the glycol warms absorbing the energy.  When it cools the glycol freezes again, liberating the heat energy.  Different glycols melt at different temperatures so you can easily adapt the material to a particular application.  Its also stronger than plastic.  There is talk of electronic applications and even producing solar cells.

The advantages are that by using it you are trying up carbon in structures that may be used for many years, acting as a much needed carbon store.   The material also reduces our oil dependency.  The disadvantage is that the process is still oil dependent unless the chemicals can be made by bio-refining.  In addition 100g absorbs as much heat as a 1W bulb uses in one hour.  So we are not talking about huge amounts here of energy storage in my view.  Nevertheless this is a fascinating idea that could find widespread application.


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Ryanair pollutes as much as coal fired power stations

Ryanair pollutes as much as coal fired power stations.  The data comes from the EU emissions trading scheme registry.   Ryanair’s flights in Europe are in the top 10 emitters.  The 9 above are coal fired power stations.  Ryanair pollutes more than other short haul airlines, its rival are further down the list.  It could be because they use newer more fuel efficient aircraft, or it could be because Ryanair flies more.  There are two countervailing things going on here.  At the moment airline emissions make up only 3% of the EU’s greenhouse gas emissions.  However before we all book our next flight the output from this source is rising fast.  Some estimates say there could be a 700% increase by 2050.  That to me is a very surprising figure since it sort of implies an over 700% increase in flights (aircraft are getting more fuel efficient).  I’m not sure where you would all these aircraft.  Anyway leaving that aside…EU ET data 2019 top 10Conversely coal power is falling fast (at least in the EU).  Could it be that airline emissions take over from coal power as the biggest EU emitters (at least those who have to buy permits)?  At the moment airlines are exempted from fuel taxes and VAT on the fuel.  They do have to buy permits under the trading scheme.  This costs the whole lot of them 800million Euros a year i.e. nothing.  Its reckoned that if they had to pay the above taxes then the costs would be an astounding 27 billion Euros.  You can guess what’s going to happen, nothing.  But until it does the airlines will have a free ride, whilst other sectors make sacrifices.


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One thing we have learnt this week- pollinator losses

honey bee in oregano 2018A paper has come out this week on UK pollinator losses.  This paper does not directly look at numbers, but instead looks at range an habitat.  The study was based on the work of volunteers between 1980 to 2013.  The implication of the study is that there has been a catastrophic loss of species from the sites studied over this time.  353 different types of insects have disappeared from these sites with just 10% expanding their range.  This does not mean the insects concerned are extinct yet.  It does mean that they are in retreat.  The reasons are quite clear, climate change and the use of pesticides.  The danger from all this is 75% of all our crops are pollinated by insects.  Even some kinds of self fertile crops do better with pollination.  Unfortunately the pollinator losses study does chime with what I saw in the garden last year.  The weather was particularly strange last spring but there was a noticeably lower number of insects last summer.  The only increase I saw was in honey bees visiting my oregano.  We had lower numbers of some of the more unusual types of parasitic insects and wasps.

One solution as I have seen it and I hope its still correct is to use gardens as places protected from pesticide use.  Hopefully these reservoirs would protect numbers.  I would encourage all readers to not use pesticides to any great extent and to plant insect friendly plants.


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Coal power is on its way out

Rugely_Power_Station_from_Pipe_Ridware_-_geograph.org.uk_-_1192162Coal power is on its way out.  Not due to any renewable subsidies but because its now more expensive.  And this is the US.  A report there says that currently 75% of coal fired electricity production is more expensive than wind and solar.  By 2025 all will be more expensive than wind and solar.  The question is what is Trump going to do?  To reverse the situation will require subsiding coal in the same way that renewables have been subsidised.  Of course most fossil fuels get some kind of subsidy still and I suspect this is the same with US coal power.  However, even if it does, this is clearly not enough as things stand.

Coal power is on its way out in the UK as well and so far we have not missed it with nearly 40% of electricity coming from renewable sources.  The figure is 17% in the US.  Clearly the grid can cope and its vital for tackling climate change and other pollution to phase out coal power.  This clearly means that global coal demand will fall.  What happens in the US happens elsewhere generally, good or bad.  All this begs the question, why is the UK opening its first deep coal mine in decades?


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Grass fed artificial meat

2015-11-25 11.22.09I heard an article on the news about grass fed artificial meat this morning.  This was from a group from a University in the South of England trying a new approach.  The artificial meat cells were grass fed but in culture.  The big problem with experiments in growing meat in culture up until now is the problem over the protein source.  All cells need a protein source or at least a source of amino-acids.  What normally happens is that any proteins provided are then broken down to their constituent amino-acids.  These are then used to make new proteins by the cells.  Having worked in animal cell lines I personally don’t fancy eating cells grown on animal serum. The issue is two fold. The cells still require the use of animals to grow animal serum.  This to me defeats the purpose.  The second problem is the viruses that might be present in the serum. This is to be fair is a potential problem in many vaccines, where the viruses are cultured in mammalian cell lines.  It doesn’t seem to be problem with vaccines since hundreds of millions of people are vaccinated every year without a problem. However, there is a difference between the way vaccines are produced and cultured meat cell would be produced.  Vaccines are freeze dried before use.  That is the vaccine material is cooled under a vacuum, then the vials are sealed aseptically.  This promotes “viral kill”, (although technically viruses aren’t alive). The reader will be aware that every time you’re vaccinated the nurse or doctor has to reconstitute the lyophilsed material with sterile water. As part of the development of the vaccine, virus models are used to determine that the virues have been removed.  I’ve been involved in some of this work in the past. The point is meat grown in culture will not be freeze dried, but merely recovered and processed in some way. The alternative is to use serum free media.  In this amino-acids are added individually not formed as proteins.

The work described on the radio was merely changing the carbon source of the cells grown as artificial meat.  All cells require this as well as amino-acids and vitamins/minerals.  The researchers are not literally adding grass but breaking the grass down to glucose.  Does this really help though?  The grass has to come from somewhere? So do the proteins or amino-acids.  The people concerned reckoned their artificial meat had carbon emissions are less than a cow in a field. But really supplying all the nutrients etc. takes energy.  Its a little bit to believe any industrial process is more efficient than an animal in a field.


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Diet for the planet

homegrown saladWe have just spent a week following the EAT commission’s “diet for the planet” based on a healthy diet that the planet could produce sustainably for a population of 10bn (see here).  Its got lots of nuts, legumes and vegtables and modest amounts of dairy (250g… but that’s only a small glass of milk), chicken (29g), fish (28g), and very little eggs (13g) or red meat (14g) per day. But when you add those up over the week it makes for a decent portion of meat, fish or eggs every other day.

It was a pleasant surprise to find out little we needed to change our normal diet… with the exception of snacks where we had to swap biscuits for fruit, nuts, and homous and carrots. Fruit juice was off the menu as a small glass would have constituted the daily fruit allowance. But these “sacrifices” were not hard and we ate very well. H ere is our menu:

Monday: Miso ramen with beef, mushrooms and pak choi
Tuesday: nut roast wellington
Wednesday: chicken curry and rice
Thursday: (We’d planned to eat lentil and sweet potato bake but there was plenty of left over chicken
Friday: fishfingers and chips (keeping the 4yr old on board !)
Saturday: vegetable tagine
Sunday: cheese, egg and spinach pie with pinenuts.
Lunches: leftovers, sardines or vegetable and legume soup
Breakfast: toast an marmalade or cereal with oat milk
Treats : banana bread, pumpkin pie, chocolate cake, dark chocolate (does cocoa count as a legume, nut or vegetable?)

Whilst far from vegan, we have been gradually cutting down on foods we know to be high in carbon emissions.  We generally eat very little red meat and swapped from cow milk to oat milk last year.  Having followed the diet for the planet I think we should cut down a bit more on our fish and eggs, but not by much.  We were probably cheating a bit on fruit as we use dried fruit as bribery to get my daughter to keep cycling.
If it was a long term diet, we’d request to swap our allocation of cow pasture for an oat field (we went slightly over on carbs when we included the oatmilk, but we were well under on dairy).

It was good to know that, if the rich nations cut down on meat and dairy a bit, everyone on the planet could eat well and sustainably. But that remains a very big “IF”.

A spreadsheet of the menu is available diet for the planet menu here in excel format and diet for the planet menu here in libreoffice calc format.


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last subsistance lunchLent has crept up on us all this year perhaps since it is so early (can we please have a fixed date for Easter).  My lent guide book started talking about food.  Its a little known fact that the medieval church tried to limit meat consumption, not just in lent but all the year round.  In feudal Europe the church attempted to direct both when and what people could eat.  Consumption of meat was forbidden for about at least a third of the year for one reason or another.  Meat free days were to remember various saints or the virgin Mary (all Saturdays).  There were also periods of fasting throughout the year, 4 days at the start of each season than advent and lent.   Some people say a particularly devout person would have spent 8 months of the year being vegetarian.  Fish was not completely banned and this led to those with money fish farming.  Fish farming perhaps is not the right word but the local lords of the manor in the town where my parents lived got permission from the King to dam streams in the royal hunting ground and they stocked these pools with fish.  These rules also seemed not apply to the monastic system at one monastery near London in the late middle ages historians have worked out the calorie intake was 5000kcal/day (recommended intake 2000kcal/day).  Much of this was meat.

What does this teach us?  It easy to sacrifice something or give something up for the wrong reasons.  You do wonder whether the church did ban meat entirely due to religion.  Providing enough meat for everyone would have been a challenge for medieval farming.  However the medieval peasant diet was very low in protein (the rich probably ignored the rules).  For us giving up something for lent can have mixed motives but still can be useful.  What is more useful is if that change carries on beyond lent.   To help you this blog has a No oil in the lamp lent guide.


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Energy use and stuff

Energy use and stuff, what’s the correlation?  Quite a lot as we put in our book.  Our editor didn’t like the use of the word “stuff”.  He thought it was not descriptive enough.  The problem is  we all know what we mean by stuff.  If you are reading this in the west then you probably only need to look around your room.  The problem is all this “stuff” takes a lot of energy to make.  There are two problems here.  First the world is using more energy.  Renewable energy has increased vastly in scope and scale.  But global energy demand is going up faster.  This is leading to climate change.  A lot of this energy demand is due to making stuff.  The second problem is resource depletion.  All this stuff takes a lot of other resources such as metals and oil/gas to make.  The classic that is in the news at the moment all the time is plastic, especially single use plastics.  Whilst plastic is in almost everything (including until recently teabags) we are using metals and other materials up at a rate of knots as well.

As we enter lent maybe this is a good time to think about reducing our consumption of energy use and stuff.  What practical ways could we do this?  One way would be to build in exceptional reliability so that products lasted decades.  A classic example is the Queen Mothers fridge which is supposed to be still working after at least 50 years.  The second is to design in recycling or repair.  This means something can be reused (or bits of it can) more easily.  The last thing to do is either buy less or buy second hand stuff.  One thing we have done as a church homegroup is to have bring and swap evenings.  These latter ideas  are things we can all do as well as seek out products that are made with recycling and reuse in mind.


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