The right to repair

The right to repair has been on the news to today.  Coincidentally I earlier passed the Edinburgh Remakery on my way to get some lime for my wall.  The news reporter visited the same type of organisation in Leicester.  There is increasing pressure for the right to repair since so many products seem to be made with built in obsolescence in mind.  The EU is passing a law which would this make it easier (what Brexit will mean for this is anybodies guess).  There are essentially two related issues which the news covered.  The first is whether the product is designed with repair in mind.  The second is whether the product manufacturer will allow third party repairers access to information that will allow them to repair the product.  In some cases consumers don’t have the right to repair the product without invalidating the warranty.

The Remakery and other places that work on the same principle offer tools, space and advice for a fee. They also do surgeries where you bring along products.  Volunteers will repair your product for a donation.  Examples given on a programme include irons where the only problem is the lead is damaged at the iron end (had this).  By replacing the lead the iron is as good as new.

There have been bills passed in various US states giving consumers more rights to repair but there has been pushback by manufacturers.  When I was young you could get anything repaired.  There was a culture of repair which has vanished.  Its this that needs to be rediscovered especially as we need to move to a circular economy.


Posted in brexit, Practical low carbon living, recycling, Uncategorized | Tagged | Leave a comment

One thing we have learnt this week – shipping emissions

Shipping emissions account for about 2% of global carbon.  This is the same as flying.  Most ships now are powered by vast diesel engines and the particulate emissions are high, which is a problem in ports.  Under the Paris climate agreement shipping emissions were left to the International maritime organisation.  They have just made a pledge to cut shipping emissions by 50% by 2050.  This is a large but a relatively lax pledge compared to other sectors.  The question is how?  There are number of surprising low tech or easy ways to cut down.  Looking at low hanging fruit for existing ships first of all.

  • Steaming more slowly.  Maersk found you cut emissions by cutting speed by 30%.  This is not totally surprising when you consider driving speeds.
  • Fitting ships with a bulbous bit of metal below the water line.  2-7%.  Who would have thought of it?
  • Even more weird.  Pump a blanket of air bubbles around the ship.  3%.  Works by reducing drag (friction).  Makes some sense when you think about it.
  • Following on this friction idea.  Paint the ship with low friction paint.
  • Rotate the propellers in opposite directions (both going forwards).  This cuts a surprising 8-15% by cutting slipstream effects.
  • Lastly it occurs to me what goes on on the deck itself could also help.  Wind resistance will surely add to fuel consumption.

So all this looks like a 50%ish cut in shipping emissions.  One could be very cynical and say this is no coincidence.

More significant cuts depend on complete ship redesign.  Again there are number of ideas around.

  • Build slimmer ships.  This apparently cuts up to 25% at speeds and about half at low speeds.  Presumably this cuts drag (see above).
  • Switch to LNG.   A partial solution.  Use biofuels? not really sustainable.
  •  Go back to sail.  We are not talking about sailors singing shanties and pulling on ropes here (only if things get really bad).  These are high tech ships possibly combining sails with solar panels.  A 70% cut.  Would still need some kind of backup power.

There is no doubt that cutting shipping emissions is easier than cutting aircraft emissions.  However to get the really deep cuts new ships are needed which the agreement does not force until 2030.  In 2008 there was a lot of thought about this but the drop in oil prices put it on a back burner.  Its difficult as things stand to see international trade at the same levels with out oil.


Posted in climate change, Practical low carbon living, Transport, Uncategorized | Leave a comment

Is the weather getting worse?

module power losses over timeIs the weather getting worse?!  This is the question I have pondering for somewhile.  What I mean by this is it getting duller.  I have had two PV systems on my roof for some years and the output is dropping year on year.  There are 3 possible reasons I have come up for this.

The first is that there is something wrong with the PV’s.  PV efficiency does indeed fall very slowly and the modules have a 20-25 year guarantee against power loss.  This is very low even after 25 years and in fact studies have shown the actual declines in efficiency are much lower than the module’s guarantee.  I know its not this since this February one system had a record output for that month (even higher than the computer prediction).  Most years I get such months for either system.

My favourite theory until recently was my neighbours tree (and to be fair one of mine).  My neighbours tree is a birch bought from a supermarket for £2.50.  Over 20 years it has grown from a few cm to 6 stories.  Its much too big for the garden blocks her and our light and she has said she will have it taken down.  My Scots Pine (far older) which it yomped past is about 4 stories high, this also blocks our light (I probably would not be allowed to take it down).  Again I still get record output now and again and in summer when the sun is high in the sky so the problem from either is not that great when there is max power output.  PV output is greatly impacted by trees and buildings and is difficult to predict.

The last theory is that raised by this blog is the weather getting worse?  By that I mean is getting more cloudy?  Its very hard to be sure since this data if its kept at all is kept by the met office.  There is some logic to this though.  We know that climate change is heating the atmosphere.  This pushes more water vapour into it.  These form clouds and make the weather more dull as well as causing many more torrential downpours (interestingly I think we are getting less of these). As well as this the gulf stream is weakening this will make UK weather different with colder winters and hotter summers.  I want to test this theory using a paired test but I have odd numbers of data.  Missing one year out would introduce bias so I will will wait till the end of the year to see if the rate of fall is significant.

The implications of this are that predicted PV output might be lower than thought.  Is is balanced by higher efficiency modules (this is constantly creeping up).  The techno solution might be to use modules that work cross spectrum, on a bright cloudy day they work as well as a sunny one.


Posted in climate change, other, Renewables, Uncategorized | Leave a comment

Digital energy

Blockchain-ProcessIn this blog we are going to have a quick look at digital energy.  One of the biggest problems with rising energy prices is that that many in the West on low incomes struggle to afford them.  Since 2008 energy prices have risen in all countries and despite the plunge in oil prices have yet to fall to any significant extent.  There are a number of reasons for this, excess profit taking by energy companies, rising gas prices due to a fall in the amount of easily extractable gases, a switch to renewables etc.  In the future its impossible to predict with any certainty where prices are going to go.  There are two competing trends.  Renewable costs are falling fast and are soon going to be cheaper than conventional fuels.  Conversely there is need to electrify the whole economy.  This requires not only a huge amount of new generating capacity but also massive grid reinforcement.  This could raise prices.

So the fuel poverty could get better or worse.  Those of us who have been thinking about this have proposed a number of solutions covered in other blogs on this site.  These include the idea of a carbon ration to fairly share out energy resources or direct subsidy through bills by those who can pay to those who cannot.  This happens already to an extent in the UK.  The last idea is to directly pay someone’s bills or part of it.  This is made safer by digital energy.

Most people have heard of bitcoin.  Bitcoin relies on a technology called blockchain.  Despite this link attempting to explain it in a way that 5 year old’s can understand its still difficult to get your head around.   But basically its a decentralised digital ledger that does not go through banks.  Every-time you buy something your purchase is verified its added in a block of transactions to the end of the file (hence the name).  You get this enormous file spread over masses of computers.   Its supposed to be unhackable.  The idea of digital energy is that it fits in very well with a decentralised grid.  So if I want to sell my excess solar power to someone else I can do.  I can also give it to someone.  I also found a site that is allowing you to donate “energy” to those without it in the developing world also using blockchain.  This is quite a big story as you can see here and here.

There a variety of issues to overcome before this becomes a practical reality.  First the technology as we have covered before uses a lot of energy although one of the proponents has modified the technology to get around this (or so they claim).  Second the receivers have to be on the internet and tech savvy.  Last it has to be safe to use.  Its not a total solution to the idea of fuel poverty since it relies on voluntarism but it has great potential to change how we and the grid manage our energy.


Posted in Lifestyle, Uncategorized | Leave a comment

One thing we have learnt this week – plastic breakdown

You can hardly move at the moment for news of plastic and its role in the environment.  As we have learnt plastic breakdown is a really huge problem.  Could a group of researchers discovered a way of breaking down one very commonly used plastics?  Poly(ethylene terephthalate) (PET) is a very common plastic used to make drink bottles and other materials such as clothes.   Its structure is shown below.  Its a polymer with thousands of the repeating units.

petA group in Japan discovered a new bacterium in waste recycling centre that could use PET as its main energy and carbon source.  Bacteria need both of these and they do not have to be the same thing.  Simple sugars such as glucose provide both in one molecule but sometimes the energy source (which is basically electrons) can be provided by inorganic molecules.  It makes it simpler that the organism uses PET as both.  The bacteria breaks the PET down to the several components of its monomer units.

The group had to do a number of thing identify the enzyme(s) concerned and then sequence the protein(s) and then determine their 3D structure.  An enzyme is a protein (there are exceptions to this rule) that speeds up a chemical process but is unchanged by it.  Enzymes are highly efficient catalysts.  Sequencing the protein is easy but determining its 3D structure is much more difficult.  There are 3 ways but the preferred way is to fire x-rays at a protein crystal.  X-rays have wavelengths of the order of atomic bonds.  They are diffracted by the crystal atoms giving a complex pattern on a detector which must be interpreted by powerful computers.  The 3D structure is important because it gives you information on the enzyme family it belongs to in more detail.  Also it gives you the mechanism by which it works and may allow modifications and improvements.  The group made some modified versions which worked better by mistake!  They are now modifying it further to speed up PET breakdown.

So far so encouraging.  It looks like bacteria are evolving to break down some kinds of plastic.  However this does raise some issues.  First bacteria will prefer to break down simpler molecules if these are available.  If you were to engineer the bacterium so it only could use PET as its carbon source (the obvious solution) then it still may revert to suing simpler carbon sources of which there are many in seawater.  In addition its illegal to let GM bacteria loose into the environment at present.  Another issue is that plastic ties up carbon that would otherwise be released into the atmosphere.  The bacterium will produce CO2, water and biomass from the PET.  This in one thing in a controlled recycling environment but different if let loose in the sea.   Its important that the biomass is maximised and this then falls to the ocean floor where its carbon is tied up for the long term.

These dilemmas are the product of our use of plastic.  We have some very hard decisions to make fast.  But short of going and capturing nano particles of plastic without capturing plankton (impossible at present) which would use a lot of energy anyway, this looks like the best solution to dealing with it so far.


Posted in materials, One thing we have learnt this week, plastic waste, Uncategorized | Leave a comment

BP energy outlook – another look

china emissions by sourceAnother look at the BP energy outlook.  One thing that used to be said by climate sceptics was there was no point in doing anything about climate change since China was producing so much more pollution.  Its an argument I have not heard made for some time perhaps for a variety of reasons.  Here is the data plotted that I pulled out of the BP energy outlook 2018.  The graph shows emissions from coal, gas and oil for this country.  As you can see two of the three are going to peak and start falling according to BP one of them soon in the case of coal (or it may already have peaked).  This is hardly the actions of a country that is doing nothing.  As we have covered on this site before there are a variety of reasons for China’s actions including old fashioned air pollution.

The graph below shows the historical and projected growth rates in different types of generation.  As you see the idea that we should do nothing since China is opening a new coal fired power station every week is a little out of date.

china energy changeThere are many things I do not like about the current Chinese government, but their action on climate change is to commended.  Their contribution is also vital to meet the Paris targets and this criticism of them is out of date.


Posted in climate change, Uncategorized | Leave a comment

One thing we have learnt this week – Renewable heat

Southampton_District_Energy_SchemeRenewable heat is one of the biggest problems facing the environmentally sustainable economy.  That’s why governments worldwide have concentrated on switching to renewable electricity.  There are plenty of options which in this latter area that work well and as we have seen the costs have plummeted.   Renewable heat by contrast is as we covered in our book is a highly disruptive technology with less options and common underlying drawbacks.  This week I have learnt of a partial solution to this issue.

There is a lot more detail in our book which I would highly recommend for a look at this issue but in brief here is a summary of each technology and its pros and cons.

Air source heat pumps.  Heat pumps work on the same principle as a fridge.  Think of the hot air you get out of the back as the inside is chilled.  As the name implies these extract heat from the air.  There are number of problems with this technology the main ones being they are noisy, use lots of electricity and work less and less effectively when you want the most heat.  I have a friend who bought one and said it was rubbish, they are however very much used in Norway.  Presumably the Norwegians switch them on in Autumn and leave them on till the spring.  The thermal mass of their well insulated buildings would keep them warm and their hydroelectricity is cheap.  The advantage is they are easy to retro-fit.

Ground source heat pumps.  Cousin of the above and work on the same principle this time extracting heat from the ground or water.  Much more efficient (particularly using water) you could be much more confident your house would be warm.  The main problem is they are very disruptive to fit and use a lot of electricity (requiring grid reinforcement).  You either bury a tube all over your (very large) garden or sink two very deep boreholes.  A form of solar geothermal heat.

Solar collectors.  See below.

Wood.  There is not enough of this to go around, it might have a possible niche use in some district heating systems (see below) or an individual basis

Inter-seasonal heat transfer.  Basically you capture the renewable heat in summer (I’m thinking from conservatories rather than solar panels), store it in some way and use throughout the winter.  There are chemical methods but the easiest is to use a large tank of water.  This up until now is my personal future favourite (more for a lack of  better alternatives).  The disadvantages are disruptive retro fit and poor summers (would have to be combined with electric backups).

Gas.  There is possibility of using anaerobic digestion to make about 25% of our (UK) gas needs.  This is tantalisingly high but relies on a steady stream of food waste.  The gas needs to also have the same calorific value as natural gas (so would fracked or imported gas).  There is a little of this gas going onto the grid at the moment.  The huge advantage is that there is no retrofit issue hence would be the cheapest of the above.  To make it go around we would need to use a lot less each.  Perhaps this is a partial solution.

All the above have one common drawback.  They are all low temperature systems that use low temperature systems either special radiators or underfloor heating and require very well insulated buildings.

District heating.  Very common in Scandinavia and growing slowly here.  However what technology is the heat to come from above?  A mix?  This week I heard of an idea.  This is to use heat from abandoned coal mines.  There are literally thousands of these scattered over the UK.  Many surprisingly near or even under major cities.  If you think about it mines are always hot with geothermal heat.  They also tend to flood.  This renewable heat and we are talking about near Glasgow in this study 12°C can be extracted using very highly efficient heat exchangers and pumped to houses.   There is a scheme in Southampton that uses hot rocks but the principle is the same and coal mines are probably easier to access.  There are two potential huge drawbacks.  The first is would work better as a low energy system the second is that is going to be disruptive and therefore expensive to fit. We would have to build a network of pipes.  One reason the Edinburgh tram scheme may have run over price was the problem of lost (orphan) pipes and wires still in use.  This could be seen as an advantage though we could sort the whole lot out and make maintenance easier in the long term with out having to dig roads up all the time…


Posted in climate change, Community energy, One thing we have learnt this week, peak gas, Practical low carbon living, Renewable heat, Renewables | Tagged , | Leave a comment

Sustainable energy update – part 2

Nissan_Leaf_002Last week I blogged on a sustainable energy update on  the book”Sustainable Energy — without the hot air” by the late Professor David JC MacKay.  The blog post became too long so I’ve split it in two.  Here continues another look at the book in the light of events…

Aircraft.  Who would have thought it that short haul electric aircraft are under development.  Professor MacKay does talk about electric aircraft and describes the energy use of one which is exactly the same as a normal aircraft.  He not unreasonably asks if we do have such aircraft are under development then where is the energy going to come from?  The only change as I have mentioned before is in battery technology.

Cars.  There has been surprisingly little change here on the face of it.  Professor MacKay suggests ranges that are not exceeded today and there are not that many electric cars on the road (although its reached the stage that its not that uncommon to see one).  The main changes are in the political and manufacturing drive towards them becoming commonplace.  Also the battery technology is undergoing regular incremental improvement and the costs have plummeted and continue to do so.  When the book was written with the ranges suggested by Professor MacKay there would have been little room for any passengers or luggage!  As we looked at in the last post the multiplier effect of so many items is important and even small improvements in battery technology will make the overall energy use lower.

There is one more point that Professor MacKay talks about.  That is the use of car batteries to store energy as grid backup.  This was in vogue at one point then went out of vogue with the government and now seems to back in.  The main problem as we wrote in our book is getting people to sacrifice their car use.  What has changed is the cost of batteries has made home storage for people with renewable energy systems a practical possibility.  Huge battery systems are also being built as grid storage.

Wind Turbines.  Two things have changed since book was written in the UK.  Onshore wind has pretty much been banned to appease nimbys.  The second is that offshore wind prices have plunged and electricity is now cheaper than nuclear (one thing he definitely did not foresee although neither did many other people).  The reason for this is the size of turbines has increased dramatically.  When the book was written most turbines being installed out at sea were probably 2-3MWh peak output.  Now we are approaching 15MWh per turbine with 20 being talked about.  The question is do these large turbines offer any advantages in terms of space?  Turbines upwind interfere with those downwind and put stress on them and lower their power output.  In the E-version of the book Professor MacKay does not show his calculations.  He comes up with huge areas required.  This question has been impossible for me to determine definitively.  If people have the figures they are not letting on.  An anti-wind site in the US says the answer is that the larger the turbine they need to be spaced relatively further apart.  However the academic links given don’t reveal this.  I think it must be true- its logical.  Therefore bigger size does not mean more capacity for a given area, just much lower costs.   Predicting a given number of turbines per unit area is a mugs game anyway.  This site gave two offshore wind farms which used the same turbine (I looked this up) and the areas were very different, presumably due to the sea bed?

There are things that Professor MacKay did not see.  One of which is surprising that he did not is that wind turbines are being put in deeper and deeper water.  This makes his area availability calculations wrong.  As does the use of floating turbines which are also coming along fast.  The last thing to say is the load factor (fraction of time turbines operate at full output) for UK offhore wind is almost 40%.

No book is perfect and making predictions is never easy (we know).  Professor MacKay future proofed some of his predictions but not others.  Overall today we can produce more power from less for less money and increasingly store it.  The overall conclusion that we cannot switch wholesale to renewables and maintain our current lifestyles is still correct though.  We can however get closer than Professor MacKay thought for less money.


Posted in Book, climate change, Practical low carbon living, Renewables, Uncategorized | Tagged , , , | Leave a comment

One thing we have learnt this week – average driving speed

average traffic speedThe average driving speed (in England but I’m sure the story is the same on other nations) is falling according to Department for Transport figures.  I’ve downloaded the data and plotted it out (shown above).  The point is that with the average driving speed falling will it soon be quicker to cycle?  The average speed has fallen from about 20mph to under 18mph in 4 years.  Its easy to see from the trend line I’ve fitted to the data that the trend in the data that has a very regular pattern to it and that within another 8 years the average driving speed will be about 12mph.  The average cycling speed is about 14mph for men and 12mph for women.  So it does look like on the current trend in England it will soon be quicker to cycle than to drive.

There are two very different conclusions you could draw from this data.  The first is to build more roads and build your way out of the problem.  History suggests this won’t work.  Besides in urban areas the scope for building more or wider roads is very limited.

The second conclusion is that to reduce congestion you need to encourage the alternatives like walking, cycling and public transport.   The advantages of this are obvious, better health, less pollution and a more pleasant cityscape.

As you can see there are up and down spikes in the speed.  These are higher during the summer holidays and fall again in November.  Presumably as the weather worsens people start driving again and also snow can reduce speeds.   This fact must have lessons to get people out their cars.  You have to make as easy, cheap and pleasant as possible.
Thanks to Make Wealth History for alerting me to this story.


Posted in cars, One thing we have learnt this week, Transport, travel | Leave a comment

Sustainable energy update

1024px-PVeff(rev171030)A sustainable energy update.  I have been thinking about “Sustainable Energy — without the hot air” by the late Professor David JC MacKay.  I had another look at the PV data a few months ago on this site. I’ve ben thinking about some of his conclusions and how they still stack up.  The book was published in 2009.

There has been no major unforeseen new technology (nor will there be), but there have been both incremental and even major changes in some areas.  I’ll consider a number of these briefly and draw some conclusions in this sustainable energy update in the next post.

First re-reading the PV section I had a look at what module efficiency he had used.  Interestingly he used 2 figures.  He used 20% for domestic installations and 10% for stuff in fields.  He used the lower figure since he thought they could be massed produced and used in fields if they were low efficiency and hence cheaper.  This is the first thing that he got wrong (wrong is too stronger a statement but the PV world has changed dramatically in a way no could have seen) in less than 10 years.  Module prices have collapsed.  PV electricity is almost competitive with that on the grid and an unsubsidised solar farm has opened.   Most PV capacity (of which there is a lot) in the UK is in fields.  Domestic PV cell efficiency has not generally reached 20% but is generally in the 17% range.  There are however modules you can buy that are 22% efficient and I doubt if those on solar farms are of a lower efficiency than domestic ones (they are same modules).  There is one remaining prediction that McKay is looking to get wrong on module efficiency.  He doubted if modules could be made more than 30% efficient and be massed produced.  The data shows that modules in the lab are at almost 50%*.  It seems likely that the 30% figure will be breached at some point its only a case of when.  Why is this important?  Obviously you can pack more energy output into a given area.  With as I blogged on previously PV capacity in the UK have barely scratched the surface this means McKay’s figures are too low even looking only at optimal sites.

Energy efficiency is something that Professor McKay considered very important.  For what its worth so do I and the next part of the sustainable energy update will consider this.  Running a renewable energy economy is much much easier if we radically reduce our energy use.  One way of doing this is to use more energy efficient lighting.  Professor McKay was writing about LED’s which were in their infancy then and very expensive.  Since then the “ban the bulb” has forced the technology to come on leaps and bounds.  The quality of light is indistinguishable from incandescent bulbs and the cost has plummeted.   Use of this technology allows  a big potential saving on lighting energy use which Professor McKay estimates as 2.7kwh per person.  He kind of foresaw this though saying in a few years LED’s would be the way to go.  One major disagreement I had with the book was over devices on standby.  He said switch them off but it makes little difference compared to our overall energy use.  I can sort of see where he is coming from.  Apart from the first argument there is the person that says I don’t leave anything on standby so I can fly.  I always thought Professor McKay lived in a house with not many devices plugged in and charging.  Its the shear number per house multiplied by 22 million (UK).  Again the situation has changed and EU directive has limited such things as  phone chargers to 0.1W I believe and all other electrical stuff you buy has become more energy efficient.  But consider 22 million houses with 2 chargers left on all the time per year this is 52MW a year.  Still not much but consider all the other stuff left on all the time in your house….  As a last thought there is one thing Professor McKay mentions that uses more energy than in 2009.  That is the broadband router.  We have had to have another one recently.  It uses exactly double the amount that the old one used which was anyway more than was listed in the book.

The next part of the sustainable energy update will consider planes, cars and wind turbines…


*please note thermodynamic limits are about 60%

Posted in Renewables, Uncategorized | Leave a comment