Tag: wood pellets

The Sustainable Biomass Program

21 March 2018

Sustainable bioenergy

In 2013, Drax co-founded the SBP together with six other energy companies.

SBP builds upon existing forest certification programmes, such as the Sustainable Forest Initiative (SFI), Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC). These evidence sustainable forest management practices but do not yet encompass regulatory requirements for reporting greenhouse gas (GHG) emissions. This is a critical gap for biomass generators, who are obligated to report GHG emissions to European regulators.

There is also limited uptake of forest-level certification schemes in some key forest source areas. SBP is working to address these challenges.

SBP certification provides assurance that woody biomass is supplied from legal and sustainable sources and that all regulatory requirements for the users of biomass for energy production are met. The tool is a unique certification scheme designed for woody biomass, mostly in the form of wood pellets and wood chips, used in industrial, large-scale energy production.

SBP certification is achieved via a rigorous assessment of wood pellet and wood chip producers and biomass traders, carried out by independent, third party certification bodies and scrutinised by an independent technical committee.

Working with our suppliers

Sustainable bioenergy

Pinewells, Lda. is part of Grupo Visabeira with global interests in the telecommunications, construction, manufacturing, technology, real estate and energy sectors. Constructed in 2009, the biomass plant in Portugal is one of the strategic investments of the group in the renewable energy sector. The plant has an annual biomass production of 150,000 tonnes, supplying both the international industrial and the internal domestic biomass markets.

Drax worked closely with Pinewells in 2017 to ensure the feedstock used for production is both harvested lawfully and sustainable by meeting the requirements of the Drax supplier data return and third-party audit. Working with the forest and quality engineers at Pinewells, we have supported the company to develop and implement their monitoring and inspection system within their own supply base.

Key features of this system include desk-based research to determine the characterisation of harvesting areas and field audits to approve the felling areas, highlight the Good Forest Practice Guide and deliver focused training. This work has provided a valuable foundation for Pinewells to implement the Sustainable Biomass Program (SBP) within their supply chain.

“Working with Drax this year has provided us guidance and understanding towards the requirements of SBP certification. The encouragement and advice from the Drax sustainability team proved both valuable and practical.”

— Alexandra Pedro, Pinewells’ Overseas Sales Director

Drax Group plc: Full year results for the twelve months ended 31 December 2017

27 February 2018

Investors
RNS Number : 9871F
Drax Group PLC
Twelve months ended 31 December20172016
Key financial performance measures
EBITDA (£ million)(1)229140
Underlying profit after tax (£ million)(2)321
Underlying earnings per share (pence)(2)0.75.0
Total dividends (pence per share)12.32.5
Net cash from operating activities (£ million)315191
Net debt (£ million)(3)36793
Statutory accounting measures
(Loss) / profit before tax (£ million)(183)197
Reported basic (loss) / earnings per share (pence)(37.2)47.7

All areas of the business contributing to positive EBITDA for the first time

  • EBITDA up 64% to £229 million – improving earnings quality from biomass generation and Opus Energy
    • Pellet Production – EBITDA up £12 million to £6 million – 35% growth in production
    • Power Generation – EBITDA up £64 million to £238 million – contribution from biomass generation
    • B2B Energy Supply – EBITDA up £33 million to £29 million –acquisition of Opus Energy
  • Strong cash flow generation and balance sheet – 1.6x net debt to EBITDA
  • Final dividend of £30 million, representing 60% of the recommended full year – £50 million
  • £50 million share buy back programme consistent with capital allocation policy
  • Statutory loss before tax principally driven by unrealised losses related to foreign currency hedging of £156 million

Delivering strategy and remain on course to hit >£425 million EBITDA target by 2025

  • Accelerated energy supply growth with acquisition and on-boarding of Opus Energy
  • Increased biomass self-supply through acquisition and commissioning of third biomass pellet plant, LaSalle Bioenergy
  • Government support received for fourth biomass unit conversion at Drax Power Station
  • Development of options for future generation: coal-to-gas repowering option, two OCGTs (4) to enter next capacity market auction in December 2018

Focused on operational excellence and investment in strategy

  • Continued focus on safety, operational excellence and project development
  • Targeted investment in long-term growth opportunities
  • Continued growth in EBITDA and cash generation
  • Sustainable and growing dividend, with opportunities to return capital in line with policy

Will Gardiner, Chief Executive of Drax Group plc, said:

“We continued to transform the business in 2017, delivering a strong EBITDA performance, in line with expectations. This was delivered by all parts of the business making positive contributions for the first time.

“We also made good progress delivering our strategy, which is clear and unchanged. We are increasing biomass self-supply, developing projects to diversify our generation mix and growing our B2B energy supply business.

“The UK is undergoing an energy revolution, starting with a significant reduction in carbon emissions, and to support that we are helping to change the way energy is generated, supplied and used.”

Notes for analysts and editors

2017 Group Financial Review

  • Underlying earnings per share decreased to 0.7 pence
    • Accelerated depreciation of coal-specific assets, amortisation of intangible assets associated with the acquisition of Opus Energy and an increase in net finance charges.
  • Reported basic earnings per share – a loss of 37 pence, which includes unrealised losses on derivative contracts of £156 million (principally related to the foreign currency hedging programme) in addition to one-off items – transaction costs relating to the acquisition of Opus Energy (£8 million) and refinancing (£24 million)
  • Tax – one-off non-cash charge of £16 million – a reduction in US federal tax rates from 35% to 21% resulting in a revaluation of deferred tax balances, offset by £13 million cash tax credit from UK Patent Box tax regime, which rewards Drax patented innovation in biomass generation
  • Investment in line with guidance
    • Acquisition of Opus Energy (£367 million)
    • Acquisition and commissioning of LaSalle Bioenergy (£48 million)
    • Maintenance and improvement (£133 million) including pellet plant optimisation, strategic spares, Haven Power information systems, research and innovation and Opus Energy office consolidation
    • Continue to expect ongoing maintenance capital investment of £50-60 million per year
  • Net debt of £367 million (31 Dec 2016: £93 million), including cash on hand of £222 million

2017 Operational Review

Pellet Production – Focus on good quality pellets at lowest cost

  • 35% increase in pellet production to 0.8M tonnes (2016 0.6M tonnes)
  • Low-cost expansion of Amite and Morehouse plants complete
  • Improving operational performance whilst providing supply chain flexibility
  • LaSalle Bioenergy commissioning ahead of plan from November 2017, increasing output through 2018
  • Biomass self-supply increased

Power Generation – Focus on optimisation of existing assets and development of projects

  • Electricity output (net sales) 20.0TWh (2016: 19.6TWh)
  • 65% of generation from renewables (2016: 65%)
  • £88 million from system support and flexibility
  • £90 million capacity market payments secured for 2017-2022

B2B Energy Supply – Profitable business with growth in sales and customer meters

  • 12% increase in customer meter points to more than 375,000
  • 46% of energy sales from renewables
  • Opus Energy EBITDA in line with plan; Haven Power exceeded EBITDA breakeven target
  • Continued investment in next generation IT systems

Notes:

(1)  EBITDA is defined as earnings before interest, tax, depreciation, amortisation and material one-off items that do not reflect the underlying trading performance of the business.

(2)  2017 underlying earnings exclude unrealised losses on derivative contracts of £156 million and material one-off items that do not reflect the underlying performance of the business (2016: unrealised gains of £177 million).

(3)  Borrowings less cash and cash equivalents.

(4)  Open Cycle Gas Turbine.

Contacts

Enquiries:

Drax Investor Relations: Mark Strafford

+44 (0) 1757 612 491

Media:

Drax External Communications: Ali Lewis

+44 (0) 1757 612 165

 

View full report

View investor relations presentation

How do you keep a 1.2 tonne steel ball in prime condition?

18 January 2018

Power generation

There are 600 giant balls at Drax Power Station. Each one weighs 1.2 tonnes – roughly the same as a saloon car – and is designed for one simple, but very specific, purpose: to pulverise.

Every day thousands of tonnes of biomass and coal are delivered to the power station to fuel its generators. But before this fuel can be combusted, it must be ground into a powder in pulverising mills so it burns quicker and more efficiently. It’s the giant balls that do the grinding.

And although these balls may be incredibly durable, the constant smashing, crushing and pulverising they go through on a daily basis can take its toll. Maintaining the 600 balls across the power station’s 60 mills is a vital part of keeping the plant running as effectively as possible.

Surviving the pulveriser

Each of the six generating units at Drax (three biomass and three coal) has up to 10 mills that feed it fuel, all of which operate at extreme conditions. Inside each one, 10 metal balls rotate 37 times a minute at roughly 3 mph, exerting 80 tonnes of pressure, crushing all fuel in its path.

Air is then blasted in at 190 degrees Celsius to dry the crushed fuel and blow it into the boiler at a rate of 40 tonnes per hour. To survive these extremities, the balls must be tough.

Drax works with a local foundry in Scunthorpe, Lincolnshire to manufacture them. First, they are cast as hollow orbs of nickel steel or chrome iron and then smoothed to within one millimetre of being perfectly spherical.

After 8,000 hours of use, engineers check how rapidly they’re wearing down by measuring their thickness using ultrasound equipment and, if deemed to be too thin (which usually occurs after about 50,000 hours of use), replace them.

For this, they must first remove the top of the mill – including the grinding top ring – and then individually lift out and replace each massive ball. Those that are removed are typically shipped back to Scunthorpe to be recycled.

Transforming for a decarbonised future

When Drax Power Station was first built in the 1970s, the mills were designed to only crush coal, but since it was upgraded to run primarily on biomass, in the form of sustainable wood pellets, they have been adapted to work with the new fuel.

For the most part, this requires only minor changes – the primary difference is that coal is harder to fully pulverise. Coal typically does not get entirely ground down in the first cycle, so a classifier is needed in the mill to separate the heavier particles and recirculate them for further grinding.

The process of switching one mill from biomass to coal takes about seven days and nights. This work was carried out on Unit 4’s mills ahead of this winter, following biomass trials in the spring and summer of 2017. Now that the decision has been made to permanently upgrade that fourth power generation unit, converting one of its 10 mills from coal to biomass later in 2018 will take about twice as long.

Using the same essential equipment and process for both fuels helps to quicken the pace of decarbonisation at Drax Power Station as the UK moves to end the production of unabated coal-fired electricity by 2025. Come seven years from now, one thing will remain consistent at the huge site near Selby, North Yorkshire: the giant pulveriser mills will continue their tireless, heavy-duty work.

Fourth biomass unit conversion

17 January 2018

Investors
RNS Number : 1114C
Drax Group PLC

Drax welcomes the UK Government response to the consultation on cost control for further biomass conversions under the Renewable Obligation scheme, which will enable Drax to convert a fourth unit to biomass.

The response proposes that, rather than imposing a cap on ROC(1) support for any future biomass unit conversions, a cap would be applied at the power station level across all ROC(1) units. This would protect existing converted units and limit the amount of incremental ROCs attributable to additional unit conversions to 125,000 per annum.

The response would enable Drax to optimise its power generation from biomass across its three ROC units under the cap, whilst supporting the Government’s objective of controlling costs under the Renewable Obligation scheme.

Drax will now continue its work to deliver the low cost conversion of a fourth biomass unit, accelerating the removal of coal-fired generation from the UK electricity system, whilst supporting security of supply.

Drax plans to complete the work on this unit as part of a major planned outage in the second half of 2018, before returning to service in late 2018. The capital cost is significantly below the level of previous conversions, re-purposing the existing co-firing facility on site to deliver biomass to the unit.

The unit will likely operate with lower availability than the three existing converted units, but the intention is for it to run at periods of higher demand, which are often those of higher carbon intensity, allowing optimisation of ROC(1) generation across three ROC(1) accredited units. The CfD(2) unit remains unaffected.

Will Gardiner, Chief Executive of Drax Group, commented:

“We welcome the Government’s support for further sustainable biomass generation at Drax, which will allow us to accelerate the removal of coal from the electricity system, replacing it with flexible low carbon renewable electricity.”

“We look forward to implementing a cost-effective solution for our fourth biomass unit at Drax.”

Enquiries:

Investor Relations:

Mark Strafford

+44 (0) 1757 612 491

Media:

Ali Lewis

+44 (0) 1757 612 165

 

Website: www.drax.com/uk

Notes

  1. Renewable Obligation Certificate
  2. Contract for Difference

END

 

 

Giving up coal

Tony Juniper, Author, adviser and environmental campaigner

7 December 2017

Opinion
Tony Juniper at Drax Power Station between coal stock and biomass wood pellet storage domes

Tony Juniper* is an environmental campaigner, author and director at Robertsbridge, a consultancy helping advise Drax on its sustainability programmes

Back in 2006 while working as Director at Friends of the Earth I approved a new report to be published in support of our then campaign for a new Climate Change Act. We wanted to show UK government ministers how it would indeed be possible to make cuts in emissions so that by 2050 the UK could progressively have reduced greenhouse gas pollution by 80 per cent compared with emissions in 1990. It was a radical and demanding agenda that we’d adopted and it was important to show the practical steps that could be made in achieving it.

The analysis we presented was based on an electricity sector model that we had developed. Different data and assumptions could be inputted and using this we set out six possible lower carbon futures.

In our best case scenario we foresaw how it would be feasible to slash emissions by about 70 per cent by 2030.

This was based on an ambitious energy efficiency programme and a shift away from fossil energy and toward renewables, including wind and solar power. In that renewables mix was also an important role for biomass to replace coal in the country’s largest power station – Drax.

This was not only crucial for backing up intermittent renewable sources but also a key piece in a future electricity sector that we believed should avoid the construction of new nuclear power stations. In November 2008 our campaign succeeded and the UK was the first country in the world to adopt a new national law for the science-based reduction of greenhouse gas emissions. Since then I’ve been working as an independent sustainability advisor, including with the advisory group Robertsbridge, of which I was a co-founder.

My work has included assisting various companies in meeting the targets set out in that new law. For example, I was the Chair of the industry campaign Action for Renewables which sought government and public support for the large-scale expansion of wind, tidal and wave power.

Different campaigners tried to stop the expansion of these renewable sources of electricity, however, and succeeded in derailing support for on-shore wind power developments.

Although in its infancy, concerns were also raised about proposals for different kinds of tidal power.

In the years after the Climate Change Act I was encouraged to see that Drax began to switch over to wood pellets to generate power but concerned to see that this too had come under attack. The broadly agreed view that sustainable biomass could have a role in the phase out of coal had gone, and in its place were claims  that it was actually worse than burning coal. It was against this backdrop of changed perspectives that myself and Robertsbridge colleagues were pleased to be invited to help Drax in devising a new sustainability plan.

Early on in our conversations with Drax it became clear that part of the challenge with biomass — deciding the extent to which it is a rational choice to help with the process of decarbonisation, is how the answer to that touches so many different issues.

For example, when it comes to the exit from coal, cleaner alternatives must be brought forward to replace it, including wind and solar power.

But although these sources of renewable energy are growing rapidly, they still come with their own challenges, especially because wind can’t generate on still days and solar ceases at night. This intermittency raises issues about what the best electricity storage or complementary clean power sources might be to back them up when needed.

There are important questions about the best sources of biomass and the extent to which long-distance transport of that fuel is desirable. On top of that are issues linked with the management of the forests from which the raw material is sourced, and whether the extraction of wood to generate power can be compatible with carbon neutrality. There is the matter of nature conservation and the extent to which wood fuel demand will affect the status of species and habitats of conservation concern. For example, to what extent might the wood pellet industry be driving the conversion of semi-natural woodlands to plantations?

All of this is bound up with the economic and social conditions prevailing in the landscapes from which the wood is derived and the extent to which those buying wood fuel can pursue positive outcomes for the environment, even when carbon and wildlife are at best of marginal concern to the local forest owners growing the wood.

Then there is the extent to which economic incentives might be linked with the carbon stocks held in the forest. For example, strong demand for wood is held to be the main reason why since the 1950s the volume of carbon stored in standing timber in the forests of the US South has increased by over 100%.

Demand for wood might seem counter-intuitive as a positive factor in maintaining tree cover, but in the US South it has been a big part of the picture.

On top of all this is the question of what would happen if there were no demand for wood fuel. In landscapes that have seen volatility in demand arising from the decline in newsprint in favour of digital devices and the slowdown in US house building following the 2008 financial crisis, this is not easy to answer.

Although seeking answers is a complex task, our advice to Drax was that it should work with its many stakeholders in finding the best possible fit between its business planning and these and other questions.

One way of doing that would be to set out the different issues in an accessible manner and hence the production of the film that can be seen here.

It’s called ‘The biomass sustainability story’ And while most of us can agree with the basic idea that we have to stop burning coal, it seems the big questions are about what might be the best ways to do it? Might biomass have a role? I believe it does.

Have a look at the film and see what you think, especially if you feel as though you’ve already made up your mind.

7 principles of a sustainable forest biomass policy

28 November 2017

Sustainable bioenergy

Biomass is playing an important role in moving the UK away from coal. At Drax Power Station, in the form of compressed wood pellets, biomass is already supplying roughly 17% of Great Britain’s renewable power.

But more than just being a low carbon replacement for fossil fuel generation, it is also crucial in maintaining the stability of the power network. Among renewable sources of power, biomass is unique in being able to provide the same range of ancillary services that can be provided by coal power stations – such as frequency control and inertia. This inherrent flexibility is vital in maintaining stability on Britain’s high voltage transmission system. Wood pellets can also reliably generate power, helping to fill in the gaps left by intermittent renewables when the wind doesn’t blow and the sun doesn’t shine and avoiding reliance on diesel, coal and gas.

However, for the UK and the wider global environment to reap the maximum benefits from biomass, it must be produced sustainably. More than this, its supply chain must be low in emissions so that clear savings can be made versus power generation with fossil fuels.

To ensure this, the use of biomass is regulated in the UK under EU Timber Regulations and the Renewables Obligation (RO). But further guidelines are set to be introduced as part of the European Parliament’s update to the Renewable Energy Directive (RED), which will specify criteria for all biomass.

There is a clear need for this, but for these to be truly successful they need to be based on a set of robust key principles. A new report by Drax outlines seven of these which can ensure sustainable biomass usage in the future.

1. Forest biomass for bioenergy should be sourced from sustainable forests

The sustainability of the forests from which biomass is sourced is key to ensuring its usage has a positive impact on the environmental, social and economic health of that supply region.

For example, a properly managed forest can boost carbon stock as the younger, faster growing trees that are replanted after felling absorb more CO2 than older, over-mature trees.  Thinning operations also increase the growth of the biggest and best trees, ensuring more carbon is stored in longer term solid wood products.

Generators should be able to demonstrate they are avoiding biomass sourced from higher-risk areas where extracting biomass could cause long-term carbon stock decreases in soils or ecosystems, as well as other factors such as biodiversity loss, soil erosion or depletion of water sources.

2. Bioenergy from forest biomass should not be produced from high-risk feedstocks

Feedstocks, the raw materials turned into biomass pellets, must come from sustainable sources and avoid protected and sensitive sites that could be considered a risk.

In 2016 around 40% of all feedstock supplied to Drax originated as a sawmill residue. Processes such as thinning also serve as a source of biomass feedstock, while also benefitting the overall health and quality of the forest. Thinning a semi mature stand of trees allows the forest owner to maximise the production of higher value saw-timber trees, storing more carbon and generating more stable revenue streams. Having a variety of wood products markets from saw logs through to biomass incentivises land owners to maintain healthy forests and reduces the risk of conversion of forest to agriculture or urban development.

3. Carbon savings and emissions should be properly accounted

To understand the effectiveness of biomass sustainability policy, carbon savings need to be measured.

Factors such as fossil fuel substitution and the emissions associated with harvesting, processing and transporting biomass are relatively straightforward to measure.

4. Bioenergy should be limited to what can be sustainably supplied

Unlike coal or oil, which will eventually run out, more trees can be planted, grown and harvested.

That said, there is a natural limit to the amount of biomass available on the planet, and so it should not be considered an infinite resource. This is why it’s crucial biomass is sourced from sustainable forests managed following set guidelines. In short, to ensure biomass truly is sustainable, it is essential that working forests are actively managed and maintain or increase productivity.

5. Support should be given to all technologies that achieve significant carbon savings

One of the major advantages of biomass over other renewable sources is its potential to help the UK rapidly adapt to meet the EU target of achieving 27% of final energy consumption from renewables.

The fastest way for biomass to make an impact to the UK’s carbon emissions is through converting coal power stations to biomass, as is the case at Drax Power Station.

This repurposing of existing facilities not only offers rapid adoption of renewable energy, but also the ability to provide vital ancillary services other renewable sources can’t.

Quickly deploying biomass solutions in this manner will serve to help it become an established part of the energy system as it continues to decarbonise.

6. The efficient use of raw materials is supported by encouraging buoyant forest biomass markets

Globally, there are substantial amounts of forest residue and forestry industry by-products that currently go unused.

Biomass should be sourced from regions where the largest surpluses exist and the forest carbon balance can be maintained. To enable this to function effectively on a global scale, trade restrictions should be avoided.

Pelletisation offers one of the most efficient ways for this raw material to be used by making it safe, cost-efficient and low-carbon to transport around the world.

These principals are tried and tested by Drax and known to protect forests and ecosystems, as well as optimise supply chains to ensure carbon emissions are kept to a minimum. Ultimately, Drax’s experience in sustainably using biomass serve as a guide for other producers and governments to quickly decarbonise energy systems.

7. The sustainability of forest biomass should be independently verified

One of the best ways to guarantee biomass is sourced sustainably is by introducing third-parties and official guidelines that generators and suppliers can work with.

In Europe, forest level management certification schemes can act as an effective indicator that forests are managed in accordance with the guidelines laid out by Forest Europe. Outside of Europe, where Drax sources most of its biomass, independent, third part auditors can ensure the UK’s stringent criteria are being met on the ground.

Read the full report: The 7 Principles of a Sustainable Forest Biomass Policy – Proven to Work

Keeping the options open

19 October 2017

Sustainable bioenergy

Roughly 750 million acres of the US is covered in forestland – an area nearly 12 times the size of the UK. Approximately two-thirds of that land is working timberland, producing wood used for construction and furniture. In short, US forestry is a massive industry.

Enviva is the world’s largest wood pellet producer and biggest biomass supplier to Drax Power Station, but in the context of the US forestry industry in which it operates, Enviva does things differently.

“We’re leading the industry in sustainability and transparency in our sourcing practices,” says Jennifer Jenkins, Vice President and Chief Sustainability Officer at Enviva. “We’ve created unique tracking systems and we conduct science-based sourcing, both of which encourage sound forest stewardship.”

Specifically, Enviva draws on best practices to make decisions about which areas it sources from and how it protects the areas it doesn’t.

Protecting bottomland forests

A bottomland forest is an area of low-lying marshy area near rivers or streams that can be home to unique tree and wildlife species. These forests are flooded periodically and they can be ecologically important. However, they’re also a part of south-eastern America’s working forest landscape.

In fact, Enviva sources 3-4% of its wood from these areas, but only where harvesting improves the life of the forest. For example, in some cases, harvesting mimics naturally occurring storms, clearing the canopy so young seedlings and forest floor species thrive. More than that, harvesting can also help keep forests as forests.

“In the areas where we work, one of the biggest threats to forests is being converted to another use – specifically to developed or agricultural land,” explains Dr. Jenkins. “Our goal is to keep forests as forests. We want to preserve those with the highest risk of being converted for another use.” If landowners can gain a steady income from regular harvests, they’re likely to keep their land as working forests.

However, this is only true for carefully assessed forests where harvesting is deemed safe. Any land that doesn’t meet Enviva’s set of strict criteria means Enviva won’t source from it – it can simply walk away. The landowners, on the other hand, don’t have that luxury.

“Isn’t it our responsibility to provide another option for a landowner who might not want to facilitate a harvest?” asks Dr. Jenkins. “Maybe they recognize its value. Maybe they would prefer to conserve it instead. In recognition of our responsibility, we made a commitment.”

A fund that keeps forests as forests

Enviva’s commitment was to partner with the US Endowment for Forestry & Communities to set up the Enviva Forest Conservation Fund, a $5 million, 10-year programme designed to protect tens of thousands of acres of sensitive bottomland forests in the Virginia-North Carolina coastal plain.

It works by inviting submissions from projects looking to protect areas of high conservation value. Last year it awarded its first round of funding to four projects. More recently, in June 2017, the Enviva Forest Conservation Fund announced a total of $500,000 to go toward a second round of projects with partners such as Ducks Unlimited, an organization which – with the grant – plans to acquire more than 6,000 acres of wetlands to operate as a public Wildlife Management Area.

The Fund follows a history of proactive sustainability programmes, including a strict supplier assessment process and the company’s Track & Trace tool, a one-of-a-kind publicly-accessible system that tracks every ton of primary wood Enviva purchases back to the forest from which it was sourced. It is entirely transparent and is a testament to Enviva’s commitment to sustainability and doing things differently.

As Dr. Jenkins explains, this approach stems back to the origins of the company in 2004: “As a company that makes wood pellets, Enviva’s reason for being is to help lower greenhouse gas emissions. An emphasis on sustainability has always been a part of Enviva’s DNA.”

How lasers reduce emissions

25 July 2017

Power generation
Drax laser

Of the air that makes up our atmosphere, the most abundant elements are nitrogen and oxygen. In isolation, these elements are harmless. But when exposed to extremely high temperatures, such as in a power station boiler or in nature such as in lightning strikes, they cling together to form NOx.

NOx is a collective term for waste nitrogen oxide products – specifically nitric oxide (NO) and nitrogen dioxide (NO2) – and when released into the atmosphere, they can cause problems like smog and acid rain.

At a power station, where fuel is combusted to generate electricity, some NOx is inevitable as air is used in boilers to generate heat. But it is possible to reduce how much is formed and emitted. At Drax Power Station, a system installed by Siemens is doing just that.

It begins with a look into swirling clouds of fire.

Not your average fireplace

“Getting rid of NOx is, at heart, a problem of getting combustion temperatures to a point where they are hot enough to burn fuel effectively. Too hot and the combustion will form excess amounts of NOx gases. Too cool and it won’t combust efficiently,” says Julian Groganz, a Process Control Engineer who helped install the SPPA-P3000 combustion optimisation system at Drax. “Combustion temperatures are the result of the given ratio of fuel and air in each spot of the furnace. This is our starting point for optimisation.”

An industrial boiler works in a very different way to your average fireplace. In Drax’s boilers, the fuel, be it compressed wood pellets or coal, is ground up into a fine powder before it enters the furnace. This powder has the properties of a gas and is combusted in the boilers.

“The space inside the boiler is filled with swirling clouds of burning fuel dust,” says Groganz. Ensuring uniform combustion at appropriate temperatures within this burning chamber – a necessary step for limiting NOx emissions – becomes rather difficult.

Heat up the cold spots, cool down the hotspots

If you’re looking to balance the heat inside a boiler you need to understand where to intervene.

The SPPA-P3000 system does this by beaming an array of lasers across the inside of the boiler. “Lasers are used because different gases absorb light at different wavelengths,” explains Groganz. By collecting and analysing the data from either end of the lasers – specifically, which wavelengths have been absorbed during each beam’s journey across the boiler – it’s possible to identify areas within it burning fuel at different rates and potentially producing NOx emissions.

For example, some areas may be full of lots of unburnt particles, meaning there is a lack of air causing cold spots in the furnace. Other areas may be burning too hot, forcing together nitrogen and oxygen molecules into NOx molecules. The lasers detect these imbalances and give the system a clear understanding of what’s happening inside. But knowing this is only half the battle.

A breath of fresher air

“The next job is optimising the rate of burning within the boiler so fuel can be burnt more efficiently,” explains Groganz. This is achieved by selectively pumping air into the combustion process to areas where the combustion is too poor, or limiting air in areas which is too rich.

“If you limit the air being fed into air-rich, overheated areas, temperatures come down, which reduces the production of NOx gases,” says Groganz. “If you add air into air-poor, cooler areas, temperatures go up, burning the remaining particles of fuel more efficiently.”

Drax Laser 2

It’s a two-for-one deal: not only does balancing temperatures inside the boiler limit the production of NOx gases, but also improves the overall efficiency of the boiler, bringing costs down across the board. It even helps limit damage to the materials on the inside the boiler itself.

Thanks to this system, and thanks to its increased use of sustainable biomass (which naturally produces less NOx than coal), Drax has cut NOx emissions by 53% since the solution was installed. More than that, it is the first biomass power station to install a system of this sophistication at such scale. This means it is not just a feat of technical and engineering innovation, but one paving the way to a cleaner, more efficient future.