Friday, September 18, 2015

5 Undeniable Advantages of Anaerobic Digestion the Industry Has Failed to Publicize

The UK anaerobic digestion industry has done very well in recent years, with a huge growth in the number of AD Plants, but are new UK government policies are about to reverse all this against a background of media distaste for anything to do with anything mucky, and public apathy?

That there has been great progress is clear from the following quote taken from a recent article published in Resource by Charlotte Morton, Chief Executive of the Anaerobic Digestion & Bioresources Association (ADBA), in which she explains that:

"The [UK] anaerobic digestion (AD) industry recently celebrated the passing of a huge industry milestone, with the announcement that over 400 biogas plants are now in operation as a result of over 600 per cent growth outside the water sector over the past five years.* In total, the AD industry now delivers a combined electrical equivalent capacity (electricity and biomethane) of over 514 megawatts - equivalent to the remaining capacity of one of the UK's nuclear power plants, Wylfa, which is being decommissioned this year.
With almost 100 plants expected to be commissioned by the end of this year, mirroring last year's growth surge in which AD's electrical capacity grew by 40 per cent, the industry's prospects should look encouraging for developers, operators and investors alike. Sadly, however, quite the opposite is true as the government's spending axe has fallen sharply on vital support for renewables."

Read the full article here.

Clearly, the UK government either does not understand the real benefits which AD offers, or is willfully pandering to the whims of the entirely discredited "climate change deniers" which remain within the Conservative party.

The leading trade association within the UK anaerobic digestion says that the industry is working to demonstrate the excellent return on investment, which anaerobic digestion (biogas) plants provides. This advantages are, is in our opinion, not only advantageous for its owners, but also for the government, and society as a whole.

That the message is failing to be made effectively is against common sense, is illogical, and will set back the UK, and the UK's previously benign influence on global decarbonisation by many years.
The media frequently talks constantly about wind, tide, and solar power, but almost never about anaerobic digestion. Within the BBC, the only programme which fairly regularly talks about AD is Countryfile. Elsewhere, heaven forbid that they mention anything as distasteful as waste food, or "sludge". Do they think that nice people would rather not be reminded of their wasteful habits?

And, yet the advantages of anaerobic digestion are real, and substantial, and here are some that seldom get aired, but everyone who knows about AD should be singing these 5 benefits from the rooftops:

1. AD is Cost Effective and Low Risk

The case for AD needs no help from any unfashionable "green" notions, although it has many advantages in this area. AD technology improvements mean that the energy it provides will be cheaper than nuclear by the time England's only new nuclear plant actively in development comes online.

AD provides localised generation without all the inherent risks of huge power station project developments which the government dictates must be implemented without direct government investment. Lack of government investment means lack of control over commercial nuclear plant programmes. The Hinkley Point C Nuclear Facility planned for Somerset, is already 6 years late before building even starts.

At the same time AD is reducing the UK's carbon emissions by four per cent, a huge number for a single technology. It also remains highly questionable how much nuclear saves on carbon emissions when decommissioning energy use and storage for thousands of years is truly factored-in.

2. Benefits to the Local Economy, Improved Agricultural Productivity and Improved UK Global Competitiveness

AD provides benefits to the local economy from employment which employs more people per megawatt than nuclear ever will. It is, according to ADBA already employing 4,500 people, and if the government does not crush the current upward trend, the industry will soon potentially employ over 30,000 more people. These jobs will be in construction, transport, waste collection, manufacturing and engineering.

Who could pretend this potential is not worth protecting? But also, on-site AD is a win-win for the way it boosts the economic and environmental sustainability of farming and enables food production with less imported fertilizer.

But it doesn't stop there. By developing a core of AD businesses with world-class expertise in biogas production and all its uses, the value of the very large export markets that is just starting create for the UK biogas market sector can help massively to re-balance the UK economy toward exports worth billions. The US alone is planning for over 10,000 AD plants within the next 5 years, and that's just one market.

3. Security of Gas Production and Provision of 24/7 Available Electricity

The government has to plan for providing the nation with secure energy sources, sources which can be relied upon in a world of increasing political turmoil. The pressing need for the availability of home-produced gas supplies, is partly why the current UK government is willing to weather the inevitable protests from its core voting supporters from pushing forward with the development of fracking. Why must we frack when we can make biogas?

There is an obvious economic benefit in balancing the intermittency of other renewable, because unless sufficient power is available at all times the nation will suffer hugely costly power cuts. The "baseload" electrical output that AD supplies is capable of doing this, and is much more valuable to the power industry than the unpredictable energy produced by wind and solar. That's proven by the way that the power industry is prepared to pay for it.

So, why build nuclear until all AD feed materials have been used up, when rather than the money being paid to overseas investors it goes back into the pockets of local people through a myriad of agricultural AD plants?

The UK AD industry according to ABDA, if fully developed, can deliver a massive 30% of the UK's domestic gas demand.

AD by generating power locally and reducing the need to ship massive amounts of energy around the country reduces the need to reinforce the national power grid, and ADBA estimates this to be worth about £30 per megawatt hour (MWh).

Don't forget either, that power generated and consumed locally does not end-up unavoidably heating up the wires it flows through. When most of the power comes from no more than a dozen or so regional power stations, as it does now, this energy never reaches the homes and factories it was destined for and is completely wasted. Distributed power of the sort AD provides could reduce these power losses by 30% according to some experts. That means that with AD the UK could scrap 3 power stations, and not replace them!

4.  EU Recycling Target Failure Without AD

AD is the best treatment option for food waste, by the UK government's own declaration. Without AD and large scale separate food waste collections, there is no way that the UK/ England can meet the government's own recycling targets. The public when asked, wants "zero waste" or 100% recycling, so any government which subjects the nation to a failure so undeniable that the nation has to pay EU fines, had better watch out for a major backlash from public opinion.

5. AD is Made for Decarbonising Transport and CHP Heat

Electric cars sound like a great idea, but achieve nothing more than reducing roadside emissions many of which are caused by earlier government policies which encouraged the adoption diesel fuelled cars, is futile if the electricity is made from fossil fuels.

AD plants are increasingly being upgraded to produce a very pure "natural gas" substitute known as biomethane, and new membrane technologies are helping to bring this to many more AD plants. Biomethane from the crude biogas made by AD provides renewable energy in the form of gas. This high energy gas can do much more to help with decarbonising (reducing the carbon emissions of) heavy goods vehicles (HGVs), buses and this gas also happens to be ideal for supplying CHP heat networks otherwise using fossil fuel derived natural gas.


This has been a long article, but the length is also a testimony to the amazing benefits of the AD process, and the skill in recent years of a young AD industry to innovate and develop the technology rapidly.

With all the benefits of AD it is hard to explain them quickly. Will all this be lost to apathy, and a press increasingly incapable of delivering more than a 30 second soundbite?

The message speaks for itself. Do more to spread the word!

We hope that those that have read this article to its fullest, will now be inspired to persuade others, at all potential opportunities of the folly of the present UK governments policies toward AD which, if continued, are most likely to throw another winning UK technology onto the scrapheap like so many other leading UK technologies throughout recent history.

Friday, July 31, 2015

Do Anaerobic Digestion Plants Smell?

Anaerobic digestion plant smell is a very highly debated subject, and whenever most new AD (biogas) plants are proposed (and a planning application is submitted) it is a topic of great concern to every local resident. With that in mind, I expected to see any number of articles on this topic when I looked on the web. So, I looked, and I didn't find them.

To my surprise I found that there are numerous website pages written by AD Plant objectors about specific planning applications, and by journalists reporting on what those same AD plant objectors were saying for local papers. But, nowhere did I see an attempt at presenting a rational view on this vexing question. It is an important subject, so I thought that I would write this piece in an attempt to present a "balanced" view on whether anaerobic digestion plants really do smell.

First of all. Let's be perfectly honest, these plants handle organic materials and at times these will already be starting to decompose as soon as they reach the AD Plant site. Once on-site the anaerobic digestion process itself is inherently smelly. Nobody could truly say that there is not a potential odour problem for all biogas plants. Decomposition (rotting) of organic matter produces some of the most offensive odours known to man, and decomposition is what the anaerobic digestion process is all about.

So, anaerobic digestion smells? Well to put a finer point to it, the materials which are fed into a biogas reactor can smell unpleasantly, and the output which is known as "digestate" (simply meaning the liquid and fibre which is left-over after the biogas gas-making reaction has occurred) invariably has a nasty odour, when it is first exposed to the air.

But, that categorically does not mean that an anaerobic digestion PLANT will smell, nor that anaerobic digestion plants are smelly. They can and should be operated responsibly, and with adequate design provisions for covered and air-sealed spaces, where the odour producing activities will take place. The great majority produce less odour than an average Dairy or intensive Chicken rearing farm.

As in all walks of life, some people do fail to run their biogas facilities in a responsible manner, and there are regulations against causing odour nuisance which will always need to be policed alongside other environmental protection legislation. Commercial scale AD Plants in the UK, and in most other jurisdictions too, are subject to permitting requirements, and if these are not met, bodies like the UK Environment Agency have powers to close down the AD facility if an odour-nuisance persists.

Odour that is produced by the AD process, can and must be contained and the ventilated air is filtered to remove any odour, before it is blown out through the ventilation system. The technology is routinely available for this, and when correctly applied, the view of many people is that anaerobic digestion plants don't smell. In truth, they routinely create less odour than the farmyard next door.

For any resident who is concerned about a new AD plant planning application being approved, due to their concerns about smells, we would suggest that they conduct some fairly simple research. Find out where there are already biogas plants in your area, and make a visit. Go, get out of your car for a minute, draw a deep breath, and stand on the public roadside, and draw in the air, and smell for yourself.

In my area there are already 4 anaerobic digestion plants within a mile and a half, of where I live and they are all two or more years old, but I have never smelled them outside of the property where each is located. When I have been detected a suspicious odour I have found that the offending odour was in fact the result of general farming activities and not the AD plant.


The anaerobic digestion process has a bad smell, but as long as it is kept sealed in by good practices in the operation of the leachate plant, or other waste disposal method, provided at sanitary landfills, there is no reason for the AD Facility to produce an unpleasant odour.

Monday, July 06, 2015

55% Growth in Anaerobic Digestion Capacity in the UK in 2013/14 Announced

The official Anaerobic Digestion UK figures are out, and confirms that there was an amazing 55% Growth in Anaerobic Digestion Capacity in the UK over the 12 months 2013/14. This massive over 50% growth, is described simply as being "significant growth", by WRAP (the compiler of these figures - See the EAEM Press Release, which is copied in full below).

In any other sector this rate of growth would be considered to be huge, and the national press would be full of the achievement. So, why is this latest ASORI report announcement being treated in such a luke-warm manner?

We suggest that the reason for this is that the officials are embarrassed to have missed their own target by a large margin, as follows (see the extract from below). The achievement of 117 operational biogas sites in the UK at the end of 2014, showed even then, that they were not going to get anywhere near the government's 2011 target of 1,000 operational AD Plants for 2015, and they could not therefore declare it for the success that it undoubtedly has been.

To help convey how far the projections fall short of the target, we have included below part of an article by Energy and Environmental Management (EAEM) Magazine. This explains that the current operational AD Plant number has been growing a lot more rapidly since that time, with the pace of plant commissioning accelerating. Currently, there are 400 Anaerobic Digestion plants now in use according to EAEM Magazine. 

At this rate the magic figure of 1,000 AD Plants in operation in the UK, will finally only be reached some time in 2017.

AD Sees Significant Growth Says Latest Sector Survey

Anaerobic digestion (AD) has grown significantly in the UK, according to the latest sector survey (ASORI), published today by WRAP.
WRAP’s comprehensive study of the AD sector (which complements the Scottish survey of the organics reprocessing industry – also published today, by Zero Waste Scotland*), for the calendar year 2013, shows that:
  • the number of operational sites increased by 34% (up from 87 to 117);
  • operating capacity is up by 55% (from 2.07mt to 3.20mt);
  • 51% more organic material is being processed (from 1.69mt to 2.55mt); and,
  • employment in the sector has increased by 36% (with 482 full-time equivalent jobs compared to 354 in 2012).
In addition, there has been an increase in all the types of feedstocks processed - separated solid food, liquids, manures and crops. However, food and drink waste continues to be the largest proportion of the material processed - with separated solid food accounting for 38% of the feedstocks reported in the survey and liquids 30%.
Food manufacturers and processors provide the biggest proportion of the feedstock, however the volume of material sourced from local authority collections, has increased by more than a third**.
Over a million tonnes of digestate (the product of AD) was applied to agricultural land in 2013 – that’s 98% of total digestate use – demonstrating the benefits of readily available nutrients as well as potentially reducing the reliance on inorganic fertilisers.
Ian Wardle, Head of Organics and Energy at WRAP, said: “It’s fantastic to see such positive results from this survey. The industry is turning a wide variety of wastes into valuable renewable energy and digestate that can be used by farmers as a fertiliser.
“Each year we are seeing the sector grow and this year’s data shows the AD industry is starting to make a marked contribution to the UK economy. Industry has always supported this survey and this year’s excellent response is testament to that.”
The report was commissioned by WRAP, working in partnership with the Renewable Energy Association’s Organics Recycling Group (REAORG), Anaerobic Digestion and Bioresources Association (ADBA), and the Environmental Services Association (ESA). It is widely recognised as the most definitive picture of the organics recycling industry.
The full ASORI report - A survey of the UK Anaerobic Digestion Industry in 2013 - can be found here
Notes to editors
*The Scottish report - A Survey of the Organics Reprocessing Industry in Scotland 2013 - was managed and delivered by WRAP on behalf of the Scottish Government having been initiated in 2013/14. The survey of Scottish AD sites was part of the UK ASORI project, however the Scottish Government also funded a survey of the composting sector.
**Of the feedstock for which sources were stated, it increased by around 35% from 170,000t to 230,000t.
  1. ASORI – Annual survey of the UK organics recycling industry.
  2. WRAP’s vision is a world without waste, where resources are used sustainably. Working in partnership to help businesses, individuals and communities improve resource efficiency.
  3. Established as a not-for-profit company in 2000
  4. More information on all of WRAP's programmes can be found on

Recent UK Anaerobic Digestion Developments and Future Projections
"The growth of anaerobic digestion in the UK has not met Defra’s strategy target of 2011, when 1,000 new digesters were to be built by 2015. In fact less than half that figure was achieved, nevertheless the industry has been growing rapidly in real terms in the UK. Considering, the difficult economic circumstances, and reticence […] The post Recent UK Anaerobic Digestion Developments and Future Projections appeared first on Rinobs Renewables. "

Anaerobic digestion steps on the gas - Energy and Environmental Management (EAEM) Magazine

"Energy and Environmental Management (EAEM) Magazine. Commissioning of the UK's 400th anaerobic digestion (AD) plant by food waste management company Biogen in South Wales marks a milestone for the industry, in a year which has seen 102 new plants open. The announcement was made at the UK AD ...AD feedstock guidelines get industry backingMaterials Recycling World500% jump in volume of recycled UK food wasteEat Out Magazineall 3 news articles »"


A massive 50% rise in Anaerobic digestion plant numbers (and UK capacity in use) to 117, was recorded in 2013 (the latest year for which data is available).

But, the achievement has been played down by the UK government. We think that the reason for that is, that a target of 1,000 biogas plants was set for 2015, but even now (mid-2015), only 400 have been commissioned, with the knock-on effect that by the end of 2015 there will still be less than half of those 1,000 plants, operating in the country.

The UK/ European biogas industry has been, and still is, growing rapidly and the momentum is growing. We would like to point out that this growth is being achieved, by project promoters, despite uncertainties caused by changes which have been made to the subsidies on offer by the UK government.

More reading: BioCycle Magazine has an article about AD Capacity Expansion here.

Friday, June 12, 2015

10 Easy Biomethane Lessons

Lesson 1. The Real Biomethane Definition

The definition of biomethane is quite a difficult one, because there are competing definitions. According to the general dictionaries dotted around the web, the term "biomethane" is interchangeable with the word "biogas".

However, in technical use among energy professionals and commentators, this is not correct. Biomethane is really a particular pure form of biogas, which is only produced after high quality further purification of raw biogas. This purification is usually referred to as "biogas upgrading", and this is performed in an "upgrader".

Lesson 2.  What is a Biogas Upgrader?

A biogas upgrader is a particular type of gas treatment unit that is used to concentrate the methane in biogas to natural gas standards (those being the high purity levels of "natural gas" as produced by capturing fossil fuel reserves). These upgrading treatment systems remove carbon dioxide, hydrogen sulphide, water, and other contaminants found in tiny (trace) quantities, from the biogas, to meet standards for "natural gas" quality, as issued by the gas grid distribution companies.

One technique for doing this utilizes what is known as amine gas treating, to purify biogas to become biomethane.

To put it simply, it can be used interchangeably with natural gas in gas distribution grids.

Amine treating is not the only way to produce biomethane from biogas, and recently membranes have been developed which perform this function very efficiently.

Lesson 3. Cutting Through the Confusion which Surrounds Biomethane Use in Transport

At this point I can hear my readers saying: "Haven't I also read about biomethane buses as well as biogas powered engines, so what's the difference". To understand the nuances of meaning in the different uses of these words, a distinction must be drawn between basic treatment of raw biogas, which is needed, for example for use in a biogas combined-heat-and-power (CHP) plant to run a gas-engine, and the more technologically advanced treatment needed to produce natural gas quality (biomethane).

Lesson 4. How Corrosion Problems Affect Raw Biogas Use

Suitably corrosion resistant gas-engines can be powered by untreated raw biogas, but put that biogas through a normal vehicle engine, and the life of the engine will suffer, hence both biogas and biomethane is used to fuel transport vehicles. But, the degree of ruggedisation needed for raw biogas use as a transport fuel is greater (and the engines are more costly), than the use of biomethane which is equivalent to using compressed natural gas CNG.

It is both environmentally preferable and economically justifiable to distribute this CNG made from biogas. Rather than using the term of CNG though, the energy industry is starting to use the term bio SNG, for biogas Synthetic Natural Gas. Bio SNG is best distributed together with natural gas in the existing gas grid.

Lesson 5. Injection of Accredited Quality Biomethane into Gas Grids

The production of renewable gas, at accredited biomethane quality, is injected into the nearest gas main, and paid for by the local gas supplier company. The biomethane price paid will vary according to the market and any green subsidies available locally. The large scale production of renewable biomethane now coming on-stream, is produced through anaerobic digestion (biogas), followed by methanation to create bio SNG, or by gasification.

Lesson 6. Biogas Treatment for Grid Injection

Biogas has, most of the time until now, been used directly in biogas cogeneration plants. This already requires desulphurisation and de-humidifying in order to avoid corrosion in the CHP.

However, to be able to feed biogas into the natural gas network, or use it as a transport fuel a more comprehensive method of treatment is necessary. Added to the need for drying and desulfurization, the carbon dioxide must be removed, and chemical conditioning undertaken to obtain gas quality properties which meet the specifications for natural gas.

This biomethane is more and more, being injected into the natural gas network, and converted to electricity and heat through a CHP unit. Efficiency of heat production is best served when the gas is burnt at a place close to where the thermal energy can be used. A good use would be, for example, in heating a swimming pool, as these have an almost constant year-round, and large, heat demand.

Lesson 7. Technological Advances in Gasification (A Competing technology for Gas Grid Injection)

We mentioned gasification technologies earlier and these are well established for conventional feedstocks for example, as coal and crude oil. The technology used in these processes has been advancing rapidly in recent years, producing a second generation of gasification technologies. These include gasification of, waste wood, forest and agricultural residues, energy crops and may also extend to black liquor.

Lesson 8. Syngas from Gasification

When gasification takes place the output is normally known as "syngas". Syngas undergoes further synthesis to create biomethane. This for example can take the form of, Fischer Tropsch products including the possible conversion of biomethane into diesel fuel, biomethanol, BioDME (dimethyl ether), or gasoline using catalytic conversion of dimethyl ether, or biomethane (Synthetic Natural Gas) (SNG). Syngas can also be used for heat production, and it is increasingly being used for generation of mechanical and electrical power using gas motors or gas turbines.

Lesson 9. Biomethane in America

We provide news here from NGVAmerica, which is a US national organization dedicated to:
… the development of a growing, profitable, and sustainable market for vehicles powered by natural gas or biomethane. NGVAmerica represents more than 200 companies, environmental groups, and government organizations interested in the promotion and use of natural gas and biomethane as transportation fuels. Our member companies are those that produce, distribute, and market natural gas and biomethane across the country; manufacture and service natural gas vehicles, engines, and equipment; and operate fleets powered by clean burning gaseous fuels."

Lesson 10. Biomethane in the UK

The UK has subsidies which are currently being been made available for biomethane upgrading under the (Renewable Heat Incentive RHI) and/ or for the "Renewable Heat Incentive" scheme, which has been on-sale since March 2011.

The UK government has just announced that the initial part is solely for non-domestic applications.
The key aspects are that:

"… the owner of the installation, or the producers of the biomethane for injection, are the people to whom the payments claimed are paid to, and payments will be made over a 20 year period".


By reading this article, and our 10 Lessons, you will have learnt a lot about "biomethane". We think that this will be a very useful knowledge for you to have, because biomethane production, with injection into the local natural gas supply grid, is here to stay. 

After-all how many other businesses create a product for which there is unlimited demand, and once connected into the gas grid needs no selling! Simply read the meter of the flow into the gas grid and charge the gas supply company!

Monday, May 25, 2015

6 High Demand Anaerobic Digestion and Biogas Plant Products

In this article we have identified 6 popular anaerobic digestion and biogas plant products, which with the rising rate of biogas plant installation, has meant that these products are in high demand to ensure the proper running of an ever increasing number of anaerobic digestion plants.

(If you have suggestions for products that you think we should add, just add them to this page via our commenting facility below.)

1. pH/Redox measurement by Hach Lange

It is important to measure pH and Redox potential is all anaerobic digestion plant fermenters, other than perhaps some of the most basic un-mixed plastic membrane covered anaerobic digestion lagoons which are used in hot countries, and are not optimized or controlled. 

For all other plants this measurement is essential, and also needs to be reliable, and very accurate even if not re-calibrated over long periods. That's because the pH and redox information the device provides is used to adjust the operation of the fermenter. Get that wrong and the production of biogas can cease!

Keeping a biogas plant running at close to its full design gas yield, is done mostly through adjusting the feed material type and quantity day by day, and also at times, to decide on how much of any dosing chemicals must be supplied to bring the pH or Redox back within the optimum operating range. These adjustments are used to ensure that the micro-organisms in the digester are maintained in the chemical conditions in which they will thrive and produce the most biogas, at a high methane quality.

One company that has a pH/Redox monitoring instrument which is in high demand, and is designed for the extreme conditions found in biogas plant reactors is Hach Lange.

It is best to provide their technical details to describe this pH robe system. They state the following in their downloadable pdf file:

“The digital pHD electrode used to measure pH and redox is fully encapsulated so that it does not come into contact with the fluid being measured. A special, soil resistant salt bridge forms the direct contact to the fluid to enable the measurements to be made."

"In contrast to conventional membrane based electrodes, this electrode can be used for very long periods even in fluids with a high particulate content, e.g. digester water. The intervals between cleaning are especially long. Electrode poisoning, e.g. by any H2S that may be present, is prevented and dilution of the electrolytes is avoided.”

There is more information about this popular product at:

2. pH Test Strips

pH test strips have been around for many years, but nowadays the technology behind the best of these strips enables the user to assess the pH value, and not just whether the liquid tested is acid or alkaline. They are still not as accurate as using a good quality pH probe, however, they can be very useful when an immediate assessment of approximate pH value is needed, and when there is no probe, such as the Hach Lange pH/Redox probe discussed in 1., above.

For that reason we have included pH Test Strips in this list of our "in demand" anaerobic digestion products.

Probably the best known test strips are those made by Merck in their Millipore range. They offer a large number of products for pH measurements with various methods of operation. These include pH indicator papers, and MColorpHast™ pH test strips, and pH indicator solution, however it is the simple test strips that are most used and can be an essential tool, especially when carrying out process troubleshooting site checks on anaerobic digestion plants.

For anyone that wishes to find out more about pH test strips by Merck we suggest the following link as a starting point:

3. NPL Biogas Analysis

NPL, once the UK's National Physical Laboratory is a private company which specialises in carrying out trace-level impurity analyses for gases, especially for biogas. Knowing what may be present in biogas as trace-level impurities is critical for the design of the gas-engine for power generation, and also increasingly for upgrading biogas to biomethane by removing these impurities.

The concentrations of both the trace-level impurities which cause corrosion and those that cause the build-up of hard silica materials on valves, and combustion cylinders, are assessed by using these tests. Also, very sticky tar-like substances within a gas-engine used for electrical power generation, can build-up, and trace-level gas impurity tests will when used skilfully by an expert, allow the need for pre-treatment of the biogas before it enters gas engines to be investigated, thus avoiding the risk of very expensive remedial maintenance on the power generation and biomethane upgrading system later.

Traceable gas standards containing each of the following components are available, from NPL as follows:

• Siloxanes (multi-component mixtures of the siloxanes most commonly found in biogas)
• Hydrogen sulphide
• Ammonia.

Further information on this in-demand service can be obtained from:

4. Prosonic Flow B 200 Ultrasonic Flowmeter

Almost all anaerobic digestion systems require the monitoring of flow, and it is particularly important to measure the flow and volume of the substrate feed continuously and accurately, so that the calorific value feed that is added is known, and can be controlled. The Prosonic Flow B 200 by Endress and Hauser Ltd is a well-known example of such a flowmeter.

An inexperienced biogas plant designer might think that a cheaper, vane type flowmeter would be satisfactory, but due to the presence of fibrous materials in the flow, these get caught around the vane of a cheap flowmeter and cause malfunction of the device. As a "non-intrusive" flowmeter the ultrasonic types are very well suited to biogas applications, and ATEX rated explosion proof versions are also available to avoid explosion risks where these occur.

Further details are available at:

5. Biogas Plant Mixer Systems

Biogas plant mixing systems have traditionally been under-specified for completely stirred mixed reactor type biogas plants. With inadequate stirring, their performance can be far below what would be achieved if well designed, good quality mixing, was installed and operated.

Anaerobic digestion operators can experience problems with the build-up of a hard cap of biomass floating on the surface. It can impede the circulation of biogas through this "hard crust", and as the crust can contain a large proportion of the organic material in the reactor, the rate of biogas production can be significantly reduced.

The installed mixers may be incapable of breaking up the "hard crust" and opening the top of a reactor to physically smash up a floating crust, means significant plant down-time, and loss of biogas production.

The Landia GasMix has not been around for even 18 months (time of writing is May 2015), and yet it is a biogas plant reactor mixing system that is in high-demand. Users report that once installed, and using the cleverly designed combination of biogas and substrate purging, hard crust accumulations can be broken up and re-submerged in not much more than half an hour of operation using this system. Once initial crust break-up and re-suspension has been achieved, the system is run on an automatic setting and runs for only short periods daily, to prevent any further significant build-up of floating material.

Further information of the Landia GasMix is available here:

6. Biogas Storage Covers and Vessels

If there is one thing that all biogas plants have in common is that they produce gas which must be stored, until needed. Suppliers of biogas storage covers and vessels, have been in increasing demand for their products, as the rate of anaerobic digestion plant construction has accelerated.

VERGAS Ltd is a leading company in biogas storage systems, and specialises in the design, manufacture and installation of high quality flexible membrane biogas management equipment, worldwide.

The following is a link to VERGAS Ltd's website where further information on biogas storage covers and vessels is available:


We hope that this article has been useful. If it has, or even if it has not and you have suggestions on improvement you would like us to make, please provide us with feedback via the "commenting" facility below, or via our contact page.

Saturday, May 02, 2015

At Last EU Biofuels Cap Agreed and Should Now Allow Biogas from Waste to Thrive

"Waste Fed Biogas Plants" Should Now as Time Goes On, be Able to Throw Off the Critics Who Confuse them with Food Crop Based "Biofuel Biogas Plants"

The EU has at last agreed 7% cap on 'harmful' biofuels, and although many would say that this cap should have been set much lower, it is an important step away from one aspect of the use of anaerobic digestion, which has caused much damage, to the concept of gaining renewable energy from biogas plants, in the eyes of the public.

A example of an anti-biofuels campaign poster recently available on Twitter
About 15 years ago, when oil price rises had been inexorably rising for as long as anyone could remember, and the supply sources of oil looked increasingly insecure, governments began the renaissance of anaerobic digestion by subsidizing so called "biofuel" biogas plants.

The idea of biofuel is focused mainly on the production of diesel fuel, and the organic feedstock was almost entirely food crops.

It was seen as being "green", at first, but when in-depth and "whole-life" assessments were conducted on the balance of net energy produced by the crop use processes, and the fact that food prices have been rising as population demand raises consumption, the idea quickly began to look like nothing other than "greenwash".

The big hope that gave rise to the whole "biofuels" movement, was that the carbon emissions reduction benefits from it would be large, and would justify the use of food to make energy. But, sadly these gains have never materialised.

Worse still, in countries like the UK where biofuel subsidies were introduced late, and were lower than in Europe generally, waste material fed anaerobic digestion plants have often been mistakenly also tarred by the same brush, and perceived cynically as just another deceptive "green" lable.

Even today, objectors protest about proposed organic-waste-fed biogas plants, in the false belief that they will turn-out to be just the opposite! This is entirely due to studies conducted on biofuel production, and planning consents are being held-up, and even rejected, due to negative publicity related in fact to crop-fed biofuel plants, by hostile media and the public.

On this blog we have always been at pains to make the distinction between the very positive environmental (carbon emission reduction potential) of waste fed biogas production, as opposed to the poor record of crop-fed biogas production when used to make biofuels (mostly bio-diesel).

The main countries which did adopt biofuel production in a big way were, Germany and other central Eurpoean States, the US, and some South American countries. Most of these have been progressively reducing their subsidies for biofuels for some time. In fact, steep subsidy reductions in Germany have led close to stagnation, in the numbers of their biogas plants in recent years.

The 7% cap on 'harmful' biofuels will go hand-in-hand with further reduction in biofuel production subsidies, as governments seek to cut-back their national biofuel production, and to meet the new low target.

Hopefully, existing Agricultural Biogas Plants built for the creation of biogas for further processing into biofuel will, in the most part, be able to convert their operations to accept agricultural waste and continue in profitable operation as a result.

For those interested in reading more about the fall from grace of "biofuels", we suggest a visit to the following web pages for further reading:

EU agrees to burst biofuels bubble after 2020

After more than 10 years of debate, the European Parliament has today (28 April) agreed new laws to limit the use of crop-based biofuels across the continent.

The new rules effectively limit the use of biofuels in the transport sector at 7%, which count towards the 10% renewable energy target in transport by 2020.

The decision will prevent up to 320 million tonnes of CO2 - equal to Poland's total carbon emissions in 2012 - from entering the atmosphere. It has dually been welcomed by green groups and industry bodies alike.

Friends of the Earth Europe's biofuels campaigner Robbie Blake said: "Let no-one be in doubt, the biofuels bubble has burst.

EU agrees 7% cap on 'harmful' biofuels

Pietro Caloprisco, senior policy officer at Transport & Environment, said: "After years of industry and member state lobbying, this agreement is far weaker than the Commission's original proposal. Nevertheless, it sends a clear signal that land-based biofuels have no future role to play in Europe."

'Shun food crops'

European representatives of the Green party were rather more scathing, calling the deal a "major missed opportunity".

Green climate spokesperson Bas Eickhout said: "Feeding crops into cars has fuelled rising food prices and rainforest destruction and the EU should not be further exacerbating these trends by promoting the use of agricultural land for fuel.

"We should be shunning the use of food crops for fuel altogether but a 7% 'cap' is clearly too high and will allow for further increasing the large share of climate-damaging biofuels in our fuel mix."

What do you think? Please comment below...