Importance Of Bioenergy Should Not Be Underestimated

2013-06-17T15:00:31Z

Over the next decade millions of tonnes of biomass will burn in power stations across Europe. But if we are not careful many of the benefits of using biomass could also go up in smoke. This has polarised opinion and caused criticism from NGO’s. Dr. Matthew Aylott from Bioeconomy Consultants NNFCC argues that, while concerns shouldn’t be ignored, they do not reflect the reality.

The abundance of biomass makes it one of the world's most important sources of renewable energy. But this resource is not evenly spread. The UK for example produces relatively small volumes of biomass but growing demand is resulting in a sharp increase in wood imports from countries like the US and Canada. In fact the UK is now one of the world’s largest importers of biomass. The meteroic growth of the UK biomass industry has been made possible by the public subsidies available to bioenergy generators. This has understandably led to intense scrutiny of biomass to ensure it not only delivers greenhouse gas savings but does so in a way that offers taxpayers value for money.

And this scrutiny is unlikely to diminish if predictions on the future use of biomass are correct. According to research funded by the Department of Energy and Climate Change (DECC) we are only at the tip of the iceberg. DECC claim that bioenergy could deliver up to 11 per cent of the UK's primary energy demand by 2020 (1) and will continue to play an important role in energy production until at least 2050 (2).

The use of biomass in energy production is, however, faced with three key criticisms. Firstly, it is expensive compared to other forms of low carbon energy. Secondly, it drives up the cost of wood used in other markets, like manufacturing and construction. And finally, it does not deliver greenhouse gas savings over meaningful timescales relevant to climate change targets.

If we take a worst case scenario then one or more of these statements may be true but when managed sustainably, biomass is an essential part of the portfolio of renewable energy technologies; delivering low cost, low carbon heat and power that can help reverse the decline in the global forestry sector.

The true cost of biomass

A study by ARUP for the UK Government in 2011 (3) – which NNFCC contributed evidence to – found that co-firing biomass in coal-fired power stations is among the cheapest forms of renewable energy. At scales, greater than 20MW biomass co-firing was found to cost around £167,000/MW with an operating cost of £30,000/MW/yr.

This makes co-firing biomass far cheaper than many other forms of renewable energy, such as wind and solar. For example, a 5MW wind turbine has a capital cost of around £1,524,000/MW and an operating cost of £57,000/MW/yr.

Incentives for bio-energy production are also likely to have wider economic benefits, such as investment and jobs in the UK. NNFCC estimates suggest that the biomass heat and power sector (excluding the manufacture of new equipment) could employ 50,000 people in the UK by 2020 (4).

The UK has already seen significant new investment in biomass handling facilities at major ports. In March 2013, Associated British Ports announced it was investing £100 million in new wood pellet handling facilities at the Ports of Immingham, Hull and Goole to support the conversion of Drax – the UK's largest power station – to run off 50 per cent biomass. The project will create over 200 new jobs.

However, if subsidies for bio-energy production were to increase the cost of wood and push other industries out of the UK, we could see a net loss in jobs. The panel industry-led 'Stop Burning Our Trees' campaign quotes unpublished research from consultants Pöyry, stating that energy production creates 2 man-hours of work per tonne of timber used, while making panels, joinery products and paper creates 178 man-hours of work per tonne of timber (5).

This, however, assumes that we are limited by the amount of low quality wood available and that the two industries cannot exist simultaneously. In contrast, evidence shows that both markets are still growing and forest production is increasing to meet this demand (6).

Impact on wood prices

If heat and power generators are incentivised to use biomass then this could artificially drive up the price of wood for other industries. This could have a negative impact on manufacturers and consumers.

The UK Wood Panel Industries Federation states that “the high price that energy companies are able to pay for UK trees may eventually mean it's uneconomic to make things with wood in this country. The factories that produce kitchens, windows, wardrobes, chipboards, building panels and many other useful things may have to move abroad, to places where costs are lower.”

There is also the concern that in cost-competitive markets, wood may be substituted for cheaper alternatives like plastic (7) and further research is needed on the environmental impact of substituting wood for other materials in manufacturing.

But it remains unclear what impact, if any, bioenergy is having on the price of wood used in other industries. It is certainly true that the price of wood in general has risen above inflation over the last decade and this has coincided with the growth of bioenergy in the developed world. However, it is very difficult and potentially misleading to link the two.

In regions where bioenergy generation is subsidised, like Europe, the price generators can pay for wood remains lower than that the average price payable in other industrial roundwood markets (8). Bioenergy generators cannot afford the high quality wood demanded by other industries, like furniture or construction industries. In many cases without a bioenergy industry there would not be demand for the low quality feedstocks, such as diseased or damaged wood.

However, in supply-limited markets that require lower quality wood there may be greater competition with bioenergy generators, which could influence price. This again works on the assumption that we are limited by the amount of wood available.

Worldwide demand for industrial roundwood – i.e. non-fuel wood – is predicted to increase from 1668 million m3 in 2005 to 2165 million m3 by 2020 (6). The FAO predict that this increased demand will be met by increased production in areas like Europe and East Asia – where production is estimated to grow by 2 to 3 per cent per year up to 2020. And large bioenergy markets, like Europe and North America, are expected to remain net exporters of industrial roundwood up to 2020 and beyond.

In fact, industrial roundwood markets could benefit from the growing bioenergy sector, both economically and from a carbon sequestration viewpoint. Bringing neglected woodland back into management and actively managing forests to produce both useful timber products and biomass for heat and power production can increase carbon stocks and make forests more economically productive (9).

Greenhouse gas emissions from biomass

Biomass is not as carbon dense as fuel made from fossilised plant material (i.e. coal or gas) - so you need more of it to produce the same amount of power. For every megawatt-hour of electricity generated, biomass will initially release up to twice as much carbon dioxide as coal and up to four times as much as gas. But unlike coal or gas, we can re-absorb this carbon dioxide in just a few years by replacing the trees we cut down or thinning forests to make them more productive.

The time it takes for a new plant to absorb the same amount of carbon dioxide that was released during the harvest, transport and combustion of the felled plant is called the 'carbon payback' rate. This is important when considering the environmental benefits of using biomass.

Calculating this rate requires a life cycle assessment which takes into account all of the contributing factors to carbon dioxide emissions across the entire biomass supply chain. The rate varies according to the type of biomass being used.

Biomass that has come to the end of its life, such as inedible food residues, will rot if left to decompose naturally and release methane and carbon dioxide – both greenhouse gases. Similarly, forests tend to decline after a number of years and start producing more deadwood. This deadwood will decompose on the forest floor, again releasing methane and carbon dioxide.

If we manage forests by taking out thinnings and deadwood, we can improve productivity, prevent the release of greenhouse gases and create a feedstock for bioenergy generation. But there will also be emissions associated with the harvest and transportation of the wood, which must be paid off. Research tells us that the carbon payback from forest thinnings used in energy production can be as little as four years (10; 11; 12; 13). However, we are limited by the accessibility and availability of forest thinnings.

As we start producing bioenergy on a larger scale some NGO’s believe that the use of whole trees will increase. They argue that this will result in longer and less palatable carbon payback periods from bioenergy. Research (10; 14) suggests that it may take 40 years or more to payback the carbon released when using whole trees in electricity generation.

But what is an acceptable carbon payback period? This is a crucial political question. Europe has 2020 and 2050 emissions targets to meet and if we don’t see an emissions reduction from substituting coal or gas with biomass until after 2050 some will argue we shouldn't be using whole trees to generate electricity and should instead stick to using 'cleaner' alternatives. However, this oversimplifies a more complex picture.

A typical wind turbine can take around three months (15) to payback the carbon used or disturbed in its construction, while a solar photovoltaic panel has a carbon payback period of up to two and a half years (16). On the face of it wind and solar would seem to have an environmental advantage over biomass. However, wind and solar are intermittent and can't be used to meet peak or base-load power demands, unlike biomass.

Hydro-electric can be used in peak and base-load power production, while nuclear can also deliver base-load power, but each of these technologies faces considerable planning and cost barriers that are likely to stunt their future growth.

Without biomass our only alternative would be to use more coal, oil and gas to meet peak and base-load power demands; dwindling sources of energy whose carbon payback rates are not measured in decades but are instead measured in millennia.

The importance of bioenergy simply cannot be underestimated. We need to move away from single issue politics and look at the bigger picture, by considering the broader benefits and implications of utilising a diverse portfolio of renewable energy sources, including biomass.

Opinions voiced by Global Minds do not necessarily reflect the opinions of The Global Journal.

Photo © DR

References

(1) DECC. 2012. UK Bioenergy Strategy. Download at: www.decc.gov.uk/assets/decc/11/meeting-energy-demand/bio-energy/5142-bioenergy-strategy-.pdf

(2) DECC. 2010. 2050 Pathways Analysis. Download at: www.decc.gov.uk/assets/decc/What%20we%20do/A%20low%20carbon%20UK/2050/216-2050-pathways-analysis-report.pdf

(3) ARUP. 2011. Review of the generation costs and deployment potential of renewable electricity technologies in the UK. Download at: www.gov.uk/government/uploads/system/uploads/attachment_data/file/147863/3237-cons-ro-banding-arup-report.pdf

(4) NNFCC. 2012. UK jobs in the bioenergy sectors by 2020, NNFCC 11-025. Download at: www.nnfcc.co.uk/tools/uk-jobs-in-the-bioenergy-sectors-by-2020-nnfcc-11-025

(5) Pöyry. Download at: www.stopburningourtrees.org/why_its_wrong.html

(6) FAO. 2009. State of the World's Forests. Download at: http://ftp.fao.org/docrep/fao/011/i0350e/i0350e.pdf

(7) The Royal Society for the Protection of Birds (RSPB), Friends of the Earth and Greenpeace. 2012. Dirtier than coal? Why Government plans to subsidise burning trees are bad for the planet. 2012. Download at: www.rspb.org.uk/Images/biomass_report_tcm9-326672.pdf

(8) FAOStat. 2012. Forestry Production and Trade. Download at: http://faostat.fao.org

(9) Sedjo R and Tian X. 2012. Does Wood Bioenergy Increase Carbon Stocks in Forests? Journal of Forestry, Vol. 110, pp. 304-311. Download at: www.ingentaconnect.com/content/saf/jof/2012/00000110/00000006/art00005

(10) McKechnie J, et al. 2011. Forest Bioenergy or Forest Carbon? Assessing Trade-Offs in Greenhouse Gas Mitigation with Wood-Based Fuels.Environ, Sci. Technol., Vol. 45, pp. 789-795. Download at: www.pfpi.net/wp-content/uploads/2011/05/McKechnie-et-al-EST-2010.pdf

(11) Manomet. 2010. Biomass Sustainability and Carbon Policy Study. Download at: www.manomet.org/sites/manomet.org/files/Manomet_Biomass_Report_Full_LoRez.pdf

(12) Repo A, Tuomi M and Liski, J. 2010. Indirect Carbon Dioxide Emissions from Producing Bioenergy from Forest Harvest Residues. Global Change Biology Bioenergy, Vol. 3, pp. 107-115.

(13) Bernier P and Paré D. 2012. Using ecosystem CO2 measurements to estimate the timing and magnitude of greenhouse gas mitigation potential of forest bioenergy. Global Change Biology, online only. Download at: http://onlinelibrary.wiley.com/doi/10.1111/j.1757-1707.2012.01197.x/abstract

(14) Southern Environmental Law Center. 2012. Biomass Supply and Carbon Accounting for Southeastern Forests. Download at: www.southernenvironment.org/uploads/publications/biomass-carbon-study-FINAL.pdf

(15) Martinez E., et al. 2009. Life cycle assessment of a multi-megawatt wind turbine. Renewable Energy, Vol. 34, pp. 667-673. Download at: www.cynulliadcymru.org/sc_3_-01-09__p8__further_evidence_from_bwea_cymru_on_carbon_reduction_via_land_use.pdf.pdf

(16) Fthenakis VM, Kim HC and Alsema E. 2008. Emissions from Photovoltaic Life Cycles. Environ, Sci. Technol., Vol. 42, pp. 2168-2174. Download at: http://pubs.acs.org/doi/pdfplus/10.1021/es071763q

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Importance Of Bioenergy Should Not Be Underestimated