Prospects for Anaerobic Digestion Remain Positive Despite Failure of Copenhagen Climate Summit

A recent article in the New Civil Engineer magazine, the magazine of the UK’s Institution of Civil Engineers, discusses how now after the failure of the Copenhagen Climate Summit it will be possible to rise to the challenge of complying with UK carbon reduction pledges.

You only have to read the following paragraphs from the above NCE article to realise the enormity of the task ahead even for just the water industry:

The UK government has pledged that emissions of greenhouse gases will be cut by 80% C02 equivalent - measured against 1990 levels - within the next 40 years.

Yet over the same time Britain's population is expected to grow by anywhere from 15% to 30%, per capita water use is rising and it is likely the [water] industry will be required to meet higher quality and environmental standards - all driving up energy consumption. How are companies going to square the circle?

As readers of my Anaerobic Digestion blog, I am sure that you will not want me to dwell upon the negatives, such as the fact that so far almost all we have seen so far has been rhetoric, while UK carbon emissions have continued to rise.

This is despite that fact that we have exported so much of our emissions as our manufacturing industry has declined, in favour of imports. Even the water industry admits to a 10% rise in carbon emissions since 2000.

So, where will we find the huge cuts needed? We will clearly have to go far beyond efficiency savings which might optimistically, for example, within the water industry provide 30% to 45% savings given the right (high) levels of investment needed.

Opportunities to cut carbon further do undoubtedly exist, and to quote the 14 January 2010 NCE article, for the UK Water Industry example, these might comprise:

• demand reduction
• improved design
• adoption of new technologies
• operational improvements
• better management of catchments and drainage systems and
• wider use of renewable energy.

Now those that have experience of Anaerobic Digestion will know that with present technology the potential for the AD industry to provide renewable energy is large enough to be worthwhile, but not that big. Even with a very high rate of adoption AD will not provide enough power to meet the demand as a major contributor to the 80% reduction target. To do that would need a technical revolution.

But, again quoting from the NCE article, Ofwat’s head of Climate Change Policy Mike Keil has said that:

“Looking at the next five to ten years you can say with some certainty there won't be a technical revolution. Certainly there will be innovation contributing to carbon reductions, but not a huge step change".

Beyond 2020 it is possible there will be breakthroughs as research and development bears fruit and new technologies come to maturity.

So, based on current technologies, an 80% reduction looks extremely difficult, if not verging on impossible, to achieve. The lack of hard commitments from the Copenhagen Summit contributes to a feeling that the political commitment to “pledges” far outweighs the ability to deliver, given the enormity of the task ahead.

Nevertheless, it is important that Engineers do push forward where this can be done on the basis of economically justifiable results. That is where the prospects for UK Anaerobic Digestion do look very good indeed.

Again, referring to the Water Industry; In the next investment period the UK water companies will be making the most of the opportunities offered by enhanced sewage sludge digestion technologies to generate high calorific biogas and reduce the final volume of biosolids as waste for disposal. Adding hydrolysis up front before the digester will help to greatly increase the amount of conversion of the total biomass in sludge to methane, for example.

Another development to continue will be that:

"By using biogas to drive combined heat and power engines, enhanced biodigestion offers potential to make sewage treatment works energy self-sufficient," 

says Mott MacDonald head of water regulation Andrew Heather [again quoted here from the NCE article].

Some companies, we are told, are also planning to clean-up biogas so that it can be used as a vehicle fuel or sold into the national gas grid. It will be interesting to report on that in this blog in due course.

In addition to the digestion of their own sewage works sludge some Water Companies are also, we are told, looking to increase energy from biodigestion by supplementing sewage sludge with food and industrial waste.

So, the prospects for Anaerobic Digestion are good, but the big question mark, which continues to become more urgent to answer remains.

Where will the rest of these carbon savings come from, which are so badly needed to plug the huge gap between current reality and an 80% saving?

Answers to Recent Questions About Anaerobic Digestion from the Public

Why Would a Farmer Choose Anaerobic Digestion?

Waste biomass from farming and food-industries, such as slurries and the organic waste from food processing can present a considerable waste disposal problem. Release of large quantities of organic wastes into local water courses or seepage into ground water results in pollution of water courses and water supply. To prevent this occurring, the biomass needs to be treated and suitably stored and Anaerobic Digestion is a great way to achieve this.

Biogas is produced by the natural microbial degradation under anaerobic conditions. This technique has been applied to agricultural wastes world-wide on a small scale. Treating the waste by AD gives some environmental benefits, and in addition to AD also results in energy, in the form of biogas. Biogas is an inflammable gas, which can easily be used to generate electricity and heat. The potential benefits are many from on-farm and local use of fossil fuels and provision of energy within rural communities.

Some commentators have said that in addition to energy production, there is considerable potential for Anaerobic Digestion to assist in centrally managing the distribution of plant nutrients in manures, together with minimising biosecurity risks (ie pathogen kill).

Where is Anaerobic Digestion Most Popular?

In countries such as Denmark, Sweden, Germany, Austria and Switzerland there are many examples of co-digestion of farm manure with other suitable organic wastes in prefabricated digestors. There is a large interest in this option in these countries and in other countries both inside and outside the EU.

The most successful digesters utilize all energy produced. The most efficient use of biogas is direct heating. If biogas is burned in an electric generator, the heat produced by the engine must be harnessed and used in order to achieve optimum efficiency. The electricity produced can be used on site or sold into the power grid.

What Happens to the Sludge After the AD Process?

Once the digestion process is complete, the digested manure, or effluent, is released from the digester and stored until it is land applied. The digestion process breaks down many of the solids contained in the manure. As a result, the effluent causes less stress on pumps and agitation equipment than manure does. Also, effluent is homogeneous and may not require agitation prior to land application.

Many agri-food AD systems are located on farms. Farm-based AD systems work well with liquid manure. AD systems provide a valuable manure treatment option, since most other economically effective manure treatment systems (such as composting) require solid materials with dry matter greater than 30%.

What are the Most Popular AD Types of Plants?

Biogas from biomass has historically been used in Asia as a fuel for household uses such as cooking. Denmark and Germany have many modern digesters operating on farms and in central locations using materials such as manure, energy crops, and food-based products and byproducts. These systems typically use biogas to produce electricity and heat.

Anaerobic digestion (AD) plants can be on-farm units, designed to deal with manures and other organic materials produced at farm level. Alternatively, AD plants can be designed as centralised units to deal with products from a number of farms, along with co-digestion of organic materials from other industries.

AD plants can include mechanical separation of fibrous solids from the digestate that, after further processing, can give a value added product, such as compost or pellets (fertiliser or combustible fuel).

How Would I recognise an Anaerobic Digestion Plant if I Saw One?

Anaerobic Digesters themselves are completely sealed vessels which are covered and sealed. Most are insulated and heated, and the digester is an immediatelely recognisable feature at most large biogas plants as a large tall, usually vertical sided, circular tank, with an access ladder and a number of pipes leading to the top where there is also usually a pedestrian access way and handrail.

Biogas plant digesters of this type can usually be spotted very easily when you see them by the characteristic pairing of the digester with the biogas storage tank which acts like a traditional town gas ‘gasometer’, and is usually elegantly curved or “globe” shaped. Many visibly expand and contract to accommodate the volume of biogas present, the result is that most of them become significant landmark features.

Anaerobic Digestion Technologies to Get Help Through Feed-in-Tariffs

The following has been posted in MRW, and is great news for the future of UK AD.

Financial support for anaerobic digestion
Liz Gyekye, 02 Feb 2010

The Government has announced ambitious plans to provide financial support for anaerobic digestion technologies through feed-in-tariffs (FITs) and the “world’s first” renewable heat incentive scheme.

The schemes are designed to bring about a significant increase in the amount of locally produced green energy and help the UK meet its renewable energy targets.

FITs is a financial support system that will incentivise small scale low-carbon electricity generation by providing “clean energy cashback” for householders, communities and businesses. It will work alongside the Renewables Obligation, which will remain the primary mechanism to incentivise deployment of large-scale renewable electricity generation.

The FITs scheme will start from April 1 and will support new AD plants with a five megawatts limit capacity. The scheme will also support the first 30,000 combined heat and power installations with an electrical capacity of two kilowatts or less, as a pilot programme.

Under the FITs scheme AD operators will be paid for every kilowatt hour of electricity generated and metered by a generator. Farm scale AD operators, producing less than 500kW a year will get 11.5 pence/kWh per year over a 20 year period. AD operators producing more than 500KW will get 9p/kWh.

Speaking at the launch of the FITs scheme in London [February 1], Energy Minister Lord Hunt told MRW that he thought the FITs would encourage more AD plants to be built. He said: “I think that we have made an adjustment in order to make small scale AD more attractive. I think that the farming community will be very welcoming of this news. I very much hope that we will see a big market growing for AD.”

Energy and Climate Change Secretary Ed Miliband added: “Where there is muck there is brass!
“The FIT will change the way householders and communities think about their future energy needs, making the payback for investment far shorter than in the past.”

The Government also launched its consultation on the RHI scheme [February 1].

The RHI scheme is a financial support mechanism for individuals, communities and businesses that aims to incentivise low carbon heating and will be introduced in April 2011.

Under the RHI scheme, the proposed tariff for solid biomass technology operators will be 9p/kWh, biogas on-site combustion plants will get 5.5p/kWh and biomethane injection technology will get 4p/kWh.

Solid biomass can include municipal wastes and biogas can be upgraded to biomethane, which has similar thermal characteristics to natural gas and can be injected into the grid.
Where a plant can generate heat from both renewable and non-renewable fuels, the RHI tariff will only reward the renewable component of the mixed fuel load. The RHI consultation stated that this will usually involve combined heat and power using energy-from-waste.

Anaerobic Digestion and Biogas Association chair Lord Redesdale said that he was disappointed at the Government’s announcements on FIT and RHI. He said the Government had “horlicked” the whole thing. He explained: “It is unfortunate that the tariff has come in at nine pence which shows a distinct lack of enthusiasm. We thought it was going to be more than this and were hoping for 13p.

“To meet our climate change and renewable energy targets we need as much AD as we can possibly muster. Both the RHI and FITS have not met expectations from industry.

“The purpose of the tariff is to encourage entry in the market place but this is not going to be the case because the tariffs are too low. How many plants will be built out of this next year on this basis? If there is not enough plant going to be built you question whether the whole thing has been a success or not.”

Lord Redesdale also said that the AD industry was concerned with the issue of “grandfathering” of Renewable Obligation Certificates (see MRW story).Government is likely to alter tariffs for new levels for new projects from time to time to respond to changes in technology costs. However, once installation of a project has been completed, investors will consider it important that its support levels are not changed. Such a guarantee not to change support for existing projects is known as grandfathering.

At the moment biomass technologies, such as AD, are not protected through grandfathering.

However, the RHI consultation states: “We are nevertheless inclined to provide the RHI tariffs as grandfathered tariffs.” More...

US Climate Bill Setback and Clean Development Rethink on Renewable Energy Developments

All those interested in Anaerobic digestion and how demand for the technology might increase over the next few years have no doubt been watching the news on the post Copenhagen Summit devlopments, keenly.

Clearly, the way the US acts now will be important for the prospects of continuation after 2012 of Carbon Credit schemes under the "Clean Development Mechanism", such as the EU ETS. The growth of Anaerobic Digestion based technology utilisation is assured in many developed nations, but I would also would expect to see a surge of advanced technology based AD Plant development in the industrializing nations once the post 2012 Climate Emission Reductions (CERs) become tradable.

The following is a 22 January Reuters post, which provides an update on the US scene:

LONDON (Reuters) - Still reeling from disappointing UN climate talks in Copenhagen in December, clean energy project developers were dealt another blow this week when U.S. Democrats lost their Senate supermajority, potentially killing a federal cap-and-trade scheme for years to come.

Although the passage of a U.S. bill to cap greenhouse gas emissions in 2010 was far from certain, the election of a Republican in Massachusetts to the Senate on Tuesday derailed any momentum President Obama had following his healthcare push toward introducing a cap-and-trade scheme this year.

This, coupled with a disappointing UN climate summit in the Danish capital last month where leaders from over 190 countries failed to agree a legally-binding pact to succeed the Kyoto Protocol, is causing concern for some clean energy project developers and forcing them to reassess their game plan.

"I'm not as bullish as I was a year ago," said Sascha Lafeld, an executive board member at First Climate AG. "The U.S. pre-compliance market is cautiously developing, so our strategy is also one of caution ... We're on hold, we'll keep our two U.S. offices open but we're not expanding this year."

Frankfurt-based First Climate has a global project portfolio of some 250 projects, including around 20 projects in the U.S., that generate carbon offsets by cutting carbon dioxide.

Observers say the spotlight in the U.S. now shifts back to state and regional schemes launched by a handful of states during George W. Bush's presidency, when the prospect of a federal U.S. carbon market was a distant mirage.

"It's not ideal but we welcome this as a fallback solution," said Alexander Sarac of JP Morgan-owned EcoSecurities, one of the world's biggest aggregators of carbon offsets.

For the full article visit:

http://uk.reuters.com/article/idUKTRE60L4DE20100122