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Everything you ever wanted to know about cooling towers

Close up image of Drax cooling tower

Cooling towers aren’t beautiful buildings in the traditional sense, but it’s undeniable they are icons of 20th century architecture. They’re a ubiquitous part of our landscape – each one a reminder of our industrial heritage.

Yet despite the familiarity we have with them, knowledge about what a cooling tower actually does remains limited. A common misconception is that they release pollution. In fact, what they actually release is water vapour – similar to, but nowhere near as hot, as the steam coming out of your kettle every morning. And this probably isn’t the only thing you never knew about cooling towers. 

What does a cooling tower do?

As the name suggests, a cooling tower’s primary function is to lower temperatures – specifically of water, or ‘cooling water’ as it’s known at Drax.

Power stations utilise a substantial amount of water in the generation of electricity. At a thermal power plant, such as Drax, fuel is used to heat demineralised water to turn it to high pressure steam. This steam is used to spin turbines and generate electricity before being cooled by the cooling water, which flows through two condensers on either side of each of the steam turbines, and then returning to the boiler. It is this process that the cooling towers support – and it plays a pivotal role in the efficiency of electricity generation at Drax’s North Yorkshire site.

To optimise water utilisation, some power stations cycle it. To do this, they have cooling towers, of which at Drax there are 12. These large towers recover the warmed water, which then continues to be circulated where chemistry is permitting.

The warmed water (about 40°C) is pumped into the tower and sprayed out of a set of sprinklers onto a large volume of plastic packing, where it is cooled by the air naturally drawn through the tower. The plastic packing provides a large surface area to help cool the water, which then falls in to the large flat area at the bottom of the massive structure called the cooling tower pond.

As the water cools down, some of it (approximately 2%) escapes the top of the tower as water vapour. This water vapour, which is commonly mistakenly referred to as steam, may be the most visible part of the process but it’s only a by-product of the cooling process.

The majority of the water utilised by Drax Power Station is returned back to the environment, either as vapour from the top of the towers or safely discharged back to the River Ouse. Each year, about half of the water removed from the river is returned there. In effect, it is a huge amount of water recycling and in environmental terms, it is not a consumptive process.

Close-up of side of Drax cooling towers

How do you build a cooling tower?

The history of cooling towers as we know them today dates back to the beginning of the 20th century, when two Dutch engineers were the first to build a tower using a ‘hyperboloid’ shape. Very wide on the bottom, curved in the centre and flared at the top, the structure meant fewer materials were required to construct each tower, it was naturally more robust, and it helped draw in air and aid its flow upwards. It quickly became the de facto design for towers across the world.

The Dutch engineers’ tower measured 34 metres, which at the time was a substantial achievement, but as engineering and construction abilities progressed, so too did the size of cooling towers.

Today, each of 12 towers measures 115 metres tall – big enough to fit the dome of St Paul’s Cathedral or the whole of the Statue of Liberty, with room to spare. If scaled down to the size of an egg, the concrete of each cooling tower would be the same thinness as egg shell.

The structures at Drax are dwarfed by the cooling towers at the Kalisindh power plant in Rajasthan, India, the tallest in the world. Each stands an impressive 202 metres tall – twice the height of the tower housing Big Ben and just a touch taller than the UK’s joint fifth tallest skyscraper, the HSBC Tower at 8 Canada Square in London’s Canary Wharf.

The industrial icon of the future

Today’s energy mix is not what is used to be. The increased use of renewables means we’re no longer as reliant on fossil fuels, and this has an effect on cooling towers. Already a large proportion of the UK’s most prominent towers have been demolished, going the same way as the coal they were once in service to. But this doesn’t mean cooling towers will disappear completely.

Power stations such as Drax, which has upgraded four of its boilers to super-heat water with sustainably-sourced compressed wood pellets instead of coal, the dwindling coal fleet, and some gas facilities still rely on cooling towers. As they continue to be part of our energy mix, the cooling tower will remain an icon of electricity generation for the time being. But it’ll be a mantle it shares with biomass domes, gigantic offshore wind turbines and field-upon-field of solar panels – the icons of today’s diverse energy mix.

View our water cooling towers close up. Drax Power Station is open for individual and group visits. See the Visit Us section for further information.

Why you shouldn’t be surprised by another record-breaking quarter for renewable energy

Field of solar panels shot from above

It’s been another record-breaking quarter for Britain’s power system. During the first three months of 2017, biomass, wind and hydro all registered their highest energy production ever, while solar recorded its highest ever peak output.

And while this is all worth celebrating, it shouldn’t come as a surprise – the last few years have seen Britain’s power system take several significant steps toward decarbonisation and this year is no different. Electric Insights, the quarterly report on Britain’s power system by Dr Iain Staffell from Imperial College London, commissioned by Drax via Imperial Consultants, documents the new gains and confirms the trend: renewables are fast becoming the new norm and in 2017 they continued their growth.

Biomass domes at Drax Power Station

The renewable record breakers

Over this quarter biomass electricity generation hit a record production figure of 4.4 TWh, which means that biomass generators ran at 95% of full capacity – higher than any other technology has achieved over the last decade.

Hydro went 4% better than its previous energy production best by generating 1.6 TWh, while Britain’s wind farms produced 11.3 TWh (10% higher than the previous record, set in 2015). This was helped in part by several new farms being built which increased installed capacity by 5% over last year, but it was also indebted to the mild, windy weather.

Wind farms produced more electricity than coal, 57 days out of 90 during the first three months of 2017

Solar hit a new record peak output at the end of March, when it generated 7.67 GW – enough to power a fifth of the country. In fact, during the last weekend of March, for the first time ever, the country’s demand for electricity from the national grid was lower during an afternoon than during the night. This was because solar panels, which only generate power when the sun is up, tend to sit outside of the national high voltage transmission grid.

Understanding how this happened is to understand how solar energy is changing our national power system.

A reverse of the trend

Electricity demand on the national grid – think of it as the power system’s motorways – is typically higher during the day and early evening (when people are most active, using lights and gadgets) than overnight. However, on the last weekend in March 2017, the opposite was true because of how much solar energy was generated.

Solar panels and some smaller onshore windfarms are ‘invisible’ – they don’t feed into the national grid. Instead, these sources either feed into the regional electricity distribution networks – the power system’s A and B roads – or, as many of them are on people’s roofs and used in their own homes or business premises, it never gets down their driveway. This can mean when solar panels are generating a lot of electricity, there is a lower demand for power from the grid, making it appear that less of the country is using electricity than it actually is.

This was the case during the last weekend of March, when solar generated enough power to satisfy a large part of Britain’s demand. And while this is another positive step towards a lower carbon energy mix, it is about to change the way our power system works, particularly when it comes to the remaining coal power stations.

What the power system needs to provide, today and in the future, is flexibility – to ramp up and down to accommodate for the shifting demand based on supply of intermittent – weather dependent – renewables. Thermal power stations such as gas, coal and biomass can meet much of this demand, but even more rapid response from technologies such as the Open Cycle Gas Turbines that Drax is developing and batteries could fulfil these needs quicker.

Today’s dirty is yesterday’s clean

The record breaking and increased renewable generation of the period from January to March 2017 would mean nothing if it wasn’t matched by a decrease in emissions. During the first three months of 2017, emissions dropped 10% lower than the same period in 2016 and a massive 33% lower than 2015. Coal output alone fell 30% this quarter compared to Q1 2016.

To put the scale of this progress into context we need only look at the quarter’s ‘dirtiest hour’ – the hour in which carbon intensity from electricity generation is at its highest. Between January and March, it peaked on a calm and cold January evening with 424 grams of CO2 released per kWh (g/kWh). The average for generation between 2009 and 2013 was 471 g/kWh. In short, this quarter’s dirtiest hour was cleaner than the average figure just four years ago – yesterday’s average is today’s extremity.

If we want to continue to break records and further progress towards a fully decarbonised power system, this needs to be a consistent aim: making the averages of today tomorrow’s extremes.

Top line stats

Highest energy production ever

  • Wind – 11.3 TWh
  • Biomass – 4.4 TWh
  • Hydro – 1.6 TWh

Record peak output

  • Solar – 7.67 GW
  • Enough to power 1/5 of the country

Yesterday’s average is today’s extremity

  • Average carbon emissions per kWh – 2009-2013
    • 471 g/kWh
  • Average carbon emissions per kWh – Q1 2017
    • 284 g/kWh
  • Peak carbon emissions per kWh – 2009-2013
    • 704 g/kWh
  • Peak carbon emissions per kWh – Q1 2017
    • 424 g/kWh

 

Explore the data in detail by visiting ElectricInsights.co.uk

Commissioned by Drax, Electric Insights is produced independently by a team of academics from Imperial College London, led by Dr Iain Staffell and facilitated by the College’s consultancy company – Imperial Consultants.

The forestry industry’s cleaning company

The three countries that make up the Baltics (Estonia, Latvia and Lithuania) are some of the most heavily forested in Europe. Approximately half of Estonia is covered by forestland – the same is true of Latvia.

It’s no surprise, then, that commercial forestry is one of the Baltics’ most important industries. For centuries wood has been used to build homes, make tools and create energy. But unlike other countries with robust forestry industries, the Baltics have never had a robust pulp and paper industry.

The low grade wood, thinnings and forest harvest residues that would typically be used for pulpwood to make paper have historically either been shipped to the Scandinavian pulp and paper producers or left to rot in the forest. Over the last two decades that’s changed and much of that is down to companies like Graanul Invest. Rather than leave that wood to decay, it is turning it into renewable fuel.

“Our target is to be the cleaning company for the forestry industry,” says Raul Kirjanen, Graanul Invest CEO.

Humble beginnings

When Raul Kirjanen started Graanul Invest in 2003, it was just him, a computer and a small office in Estonia, but growth came quickly.

By 2005 the company had opened its first compressed wood pellet mill in Imavere, Estonia. Ten more followed and today, Graanul Invest is Europe’s largest manufacturer of compressed wood pellets, producing more than 2 million tonnes of sustainable biofuel every year.

Growth has been based on a simple principle: making use of a plentiful resource that otherwise would’ve been wasted. “We’ve designed the plants so that we’re able to use raw materials that aren’t needed for any other industry,” says Kirjanen.

Of course, that would mean nothing were it not for a growing market to support it – and in Graanul Invest’s case this is the bioenergy market, which over the last two decades has developed thanks to companies like Drax, who Graanul Invest supplies.

The benefits of the new market have been widespread. “The opportunity to efficiently use thinnings, forestry harvesting residues, low quality uncommercial wood and wood processing residues has given a huge boost to the total industry,” Kirjanen explains.

Today, half of Graanul Invest’s raw material comes from low-grade roundwood and the rest from wood-industry residues, which puts them in a unique place within the industry. “We’re not a competitor to the traditional wood industry, but rather a necessary part of the chain so the industry can function efficiently.”

Second to none for sustainability

Graanul Invest’s approach to business is guided by its aim of being a responsible part of the forestry industry. They are in the process of becoming certified by the Sustainable Biomass Program (SBP) with four of their facilities already approved, which assures that its compressed wood pellets are produced using legal, sustainably sourced wood. More than that, since 2010 the company has built combined heat and power plants (CHP) at five of its facilities to help power and heat them using renewable energy.

Powered by forest chips and bark, these CHPs generate a combined capacity of nearly 30 MW of electricity, while the residue heat from the generation process is used to both dry the wood feedstock and heat the facilities. The result is a self-sustaining plant not only producing renewable energy, but using it.

The company is looking to extend its use of cleaner energy further with the use of two ships powered by liquid natural gas (LNG) that will be able to transport pellets to Graanul Invest’s Scandinavian customers on this cleaner-burning fuel.

These are also great examples of how the compressed wood pellet industry is continuing to make use of new technology.

A natural resource, a human impact

Graanul Invest and bioenergy has not only brought benefits to the forestry industry, it’s making a substantial human impact to the areas in which it operates, too.

“We employ more than 600 people directly and around five times that indirectly. It makes a strong impact on local communities,” Kirjanen says. Despite the growth and success of the company, it’s this opportunity to affect people’s lives – especially in certain areas of the country – that has left the biggest impact on him.

“We’ve seen educated young people coming back to the rural areas to work, start families and live,” he says. “That’s something I personally am enormously proud of.”

Inside the machine shop

A klaxon sounds and a crane big enough to lift 160 tonnes moves slowly across the inside of a cavernous warehouse. Below, a team of engineers stand around a turbine spindle the size of a double decker bus but weighing four times as much at 65 tonnes, waiting for the crane’s descent.

Around them, other engineers work on similar-sized equipment. One uses a wrench the size of an arm. Another programs a computerised lever to carefully strip millimetres from a piece of steel. It’s just a normal day inside Drax Power Station’s machine workshop.

For the last 15 years, this workshop has been refurbishing, repairing and manufacturing tools and equipment for use at the power station – a fact that sets Drax apart from other stations like it.

“We’re envied by a few stations because we do most things in-house,” says Turbine Engineer and head of the workshop, Andrew Storr. “We’re leagues in front of everyone else in the UK because we’ve got our own manufacturing and machining facility. We can do all this work on site. We’re not relying on other people.”

Storr set up the workshop in 2001 after being asked to reverse engineer a replacement set of governor relays (components that help regulate the flow of steam going into the turbines) for one of Drax’s steam turbines. Today, it’s a thriving centre of activity filled with heavy-duty machinery and ingenious engineers.

A look inside the workshop

“When you’re manufacturing spares it’s not a matter of going down to our machine shop and just saying ‘make one of those’. You’ve got to have the correct grade of material, the correct size, the correct certification for the material – you can’t just have a scrappy piece of steel that you find. It’s got to have paperwork with it to say it’s certified up to whatever it’s supposed to be,” says Storr.

Turbine bearings need to be bored to size using a horizontal borer that very accurately shaves out the lining of the inner bearing. Getting it right is incredibly important, explains Storr: “If it’s made too large it causes the turbine shaft to vibrate. If it’s made too small the bearing becomes too hot and the white metal will melt and pour out the bearing. We need to avoid both of these issues at all cost.”

The inside of the turbine blading needs to have seal strips administered by hand as they’re delicately made to limit any damage to the spinning shaft should they touch each other. Despite the wealth of equipment at the disposal of the team in the shop, success depends on the skill of the engineers using it.

There are three 160-tonne cranes in the turbine hall, each installed before the turbines were built. This meant the construction companies who erected the turbines could lift all heavy components into place with ease. “Due to their size they move slowly. It takes approximately 20 minutes for the largest hook to travel from the ground all the way to the top,” says Storr.

“In mechanical engineering it’s sometimes necessary to fit one part inside another, and once these parts are assembled they must stay locked together and not come apart,” Storr says. One way the team does this is by shrinking some components, and for this they use liquid nitrogen.

The team places the component that needs to fit inside another into a bath of liquid nitrogen and shrink it at -190 degrees Celsius. Once shrunk, the team assembles the two, placing the now smaller component into the larger one. “Eventually the inner part warms up to ambient temperature and grows in size, making the fit very tight and preventing them from coming apart,” explains Storr.

In the past, Drax would send the work they now do in the machine shop to companies off site. And because all other power stations in the area would do the same thing, wait times would often be long and the quality of the output could vary.

“When we do it in-house I can keep my eye on it,” says Storr. “I can re-prioritise things depending on what is going to be needed back on the turbine first – we’ve got 100% control over it. We can make sure everything’s hunky-dory.”

4 amazing uses of bioenergy

Large modern aircraft view of the huge engine and chassis, the light of the sun

Bioenergy is the world’s largest renewable energy source, providing 10% of the world’s primary supply. But more than just being a plentiful energy source, it can and should be a sustainable one. And because of this, it’s also a focus for innovation.

Biomass currently powers 4.8% of Great Britain’s electricity through its use at Drax Power Station and smaller power plants, but this isn’t the only way bioenergy is being used. Around the world people are looking into how it can be used in new and exciting ways.

algal blooms, green surf beach on the lakePowering self-sufficient robots 

What type of bioenergy?

Algae and microscopic animals

How’s it being used?

To power two aquatic robots with mouths, stomachs and an animal-type metabolism. Designed at the University of Bristol, the 30cm Row-Bot is modelled on the water boatman insect. The other, which is smaller, closer resembles a tadpole, and moves with the help of its tail.

Both are powered by microbial fuel cells – fuel cells that use the activity of bacteria to generate electricity – developed at the University of the West of England in Bristol. As they swim, the robots swallow water containing algae and microscopic animals, which is then used by their fuel cell ‘stomachs’ to generate electricity and recharge the robots’ batteries. Once recharged, they row or swim to a new location to look for another mouthful.

Is there a future?

It’s hoped that within five years the Row-Bot will be used to help clean up oil spills and pollutants such as harmful algal bloom. There are plans to reduce the tadpole bot to 0.1mm so that huge shoals of them can be dispatched to work together to tackle outbreaks of pollutants.

multi-coloured water ketttlesPurifying water

What’s used?

Human waste

How’s it being used?

The Omni Processor, a low cost waste treatment plant funded by the Bill and Melinda Gates Foundation, does something incredible: it turns sewage into fresh water and electricity.

It does this by heating human waste to produce water vapour, which is then condensed to form water. This water is passed through a purification system, making it safe for human consumption. Best of all, it does this while powering itself.

The solid sludge left over by the evaporated sewage is siphoned off and burnt in a steam engine to produce enough electricity to process the next batch of waste.

Is there a future?

The first Omni Processor was manufactured by Janicki Bioenergy in 2013 and has been operating in Dakar, Senegal, since May 2015. A second processor, which doubles the capacity of the first, is currently operating in Sedro-Woolley, Washington, US and is expected to be shipped to West Africa during 2017.

Closer to home and Drax Power Station, a similar project is already underway. Northumbrian Water was the first in the UK to use its sludge to produce renewable power, but unlike the Omni Processor, it uses anaerobic digestion to capture the methane and carbon dioxide released by bacteria in sludge to drive its gas turbines and generate power. Any excess gas generated is delivered back to the grid, resulting in a total saving in the utility company’s carbon footprint of around 20% and also multi-millions of pounds of savings in operating costs.

Jet plane leaves contrail in a sunset beautiful sky, copy space for textFlying across the Atlantic

What’s used?

Tobacco

How’s it being used?

Most tobacco is grown with a few factors in mind – taste and nicotine content being the most important. But two of the 80 acres of tobacco grown at Briar View Farms in Callands, Virginia, US, are used to grow tobacco of a very different sort. This tobacco can power aeroplanes.

US biofuel company Tyton BioEnergy Systems is experimenting with varieties of tobacco dropped decades ago by traditional growers because of poor flavour or low nicotine content. The low-nicotine varieties need little maintenance, are inexpensive to grow and flourish where other crops would fail.

The company is turning this tobacco into sustainable biofuel and last year filed a patent for converting oil extracted from plant biomass into jet fuel.

Is there a future?

In the hope of creating a promising source of renewable fuel, scientists are pioneering selective breeding techniques and genetic engineering to increase tobacco’s sugar and seed oil content.

In 2013, the US Department of Energy gave a $4.8m grant to the Lawrence Berkeley National Laboratory, in partnership with UC Berkeley and the University of Kentucky, to research the potential of tobacco as a biofuel.

Fukushima Japan

Powering repopulation of a disaster zone

What’s used?

Wood exposed to radiation by the Fukushima nuclear meltdowns

How’s it being used?

Last year it was announced that German energy company Entrade Energiesysteme AG, will set up biomass power generators in the Fukushima prefecture that will generate electricity using the lightly irradiated wood of the area.

It’s hoped they will help Japan’s attempts to repopulate the region following the 2011 earthquake, tsunami and nuclear accident. Entrade says its plants can reduce the mass of lightly irradiated wood waste by 99.5%, which could help Japanese authorities reduce the amount of contaminated material while at the same time generating sustainable energy.

Is there a future?

The prefecture aims to generate all its power from renewable energy by 2040 through a mix of bioenergy and solar power.

How much does it cost to charge my iPhone?

It’s difficult to imagine life without electricity. Its ubiquity means it’s easy to forget the incredible feats of science, engineering, and infrastructure that allow us to undertake a task as simple as plugging in our smartphones.

In fact, so expansive are the nationwide infrastructure networks that lie beyond the wall socket, keeping a top-of-the-range mobile phone charged for a year can cost as much as… 67p.

To work out how much electricity an appliance uses there’s a relatively straightforward equation we can follow of power (kilowatt, kW) x time (hours used) = energy transferred (kilowatt-hour, kWh). To then work out how much that costs in real terms we need to take the wattage of the appliance (worked out in kilowatts as this is the metric electricity tariffs are measured in), multiply that by the number of hours it is being used for, then multiply that figure (kWh) by your energy tariff (£).

In the case of an iPhone, it works out like this: a typical iPhone charger is 5W (0.005 kW) and a full charge from empty takes a maximum of three hours (a conservative estimate). The average electricity tariff in the UK is 15p per kWh, which leads to an equation that looks like this:

0.005 x 3 x 0.15 = £0.00225 a day

And if we assume that an iPhone owner might fully charge their phone roughly 300 times a year, the total annual sum amounts to a princely 67.5p.

There’s no other way of looking at this – it’s a very low number. But it’s important to think about this number in scale. Extrapolate it across the number of devices in the country and it grows significantly.

A 2016 study on UK smartphone owners suggests three quarters of all adults have smartphones, which would put the country total somewhere in the region of 40 million. Per day, that’s 600 MWh of electricity needed to power their smartphones. That’s the equivalent of 200 MW of power generation, or enough to power 565,000 households, for one hour.

Charger with device on wooden desk

How much electricity do my other appliances use?

Unfortunately, not all appliances are as modern, efficient and cost effective as your average smartphone. In fact, when it comes to household appliances, charging your Apple iPhone, Samsung, Sony or Windows Phone device is one of the least power-hungry activities you can undertake.

A bigger offender is your fridge-freezer, but not because they need a lot of electricity to run. Instead, it comes down to the fact it is plugged in and drawing power for a significant amount of time. A fridge freezer is plugged in for 24 hours a day, seven days a week, and even though modern fridge freezers have good energy efficiency mechanisms to limit their usage, they can very easily use 427 kWh a year, leading to an annual cost of over £50.

To put that into perspective, here’s how much your other household items cost per hour according to the same equation used earlier.

How much does it cost to charge an iphone

What’s new?

As our homes, workplaces and industries have become more energy efficient, the country as a whole is using less power. Nowhere is this more evident than in our lighting – today, the common LED lightbulb uses just 17% of the power needed for an incandescent lightbulb of equivalent brightness.

The news has been full of stories about how much more power 4K TVs use compared to high definition TVs. But because most of us buy a TV once every decade or so, replacing your 2007 1080p full HD TV with the UK’s best-selling 4K model and watching it for an hour will actually use around 70% less power.

This continued trend towards efficiency has had a marked effect on the country’s use of power. In March 2017, the government published its latest electricity demand data for the UK, showing the country’s power needs falling all the way through to 2020.

But then something interesting happens. From 2026 the forecast shows us beginning to use increasingly more power than we are due to in 2017. To the point where by 2035, we’re using more power than we are today – 19% more. Why is this?

One possibility is electric cars. In 2015, electric vehicles (EVs) consumed 0.25 TWh of power, but that’s set to grow significantly. In its Future Energy Scenarios report published in 2016, National Grid projected EVs will consume 19 TWh in 2035, but it has already said it believes its projections might be understated. In short, the EV revolution could drive demand far higher, which leads to the question, ‘Where is all of this extra power going to come from?’.

Charging an electric car

Understanding the smart home 

Our future energy needs are not just going to be met by more electricity generation capacity, they will also be assisted by something closer to home. With the introduction of smart meters, pinpointing the devices and appliances in our homes that use the most electricity will become more widespread. More than this we’ll be able to identify what time of day they’re using the most energy and when we might be able to turn them off. With this information we can optimise our usage and save money.

And while cutting down your yearly phone charging budget from 67p to 50p might not sound like much, if three quarters of the country are joining you, those pennies can quickly add up.

Sustainability, certified

Drax Morehouse woodchip truck

Of all the changes to Drax Power Station over the last decade, perhaps the biggest is one you can’t see. Since converting three of its six generating units from coal to run primarily on compressed wood pellets, Drax has reduced those units’ greenhouse gas (GHG) emissions by over 80%.

And while this is a huge improvement, it would mean nothing if the biomass with which those reductions are achieved isn’t sustainably sourced.

For this reason, Drax works with internationally-recognised certification programmes that ensure suppliers manage their forests according to environmental, social and economic criteria.

Thanks to these certification programmes, Drax can be confident it is not only reducing GHG emissions, but supporting responsible forestry from wherever wood fibre is sourced.

Sustainability certifications

The compressed wood pellets used at Drax Power Station come from various locations around the world, so Drax relies on a number of different forest certification programmes, the three main ones being the Sustainable Forest Initiative (SFI), Forest Stewardship Council® (FSC®)1 and the Programme for the Endorsement of Forest Certification (PEFC).

The programmes share a common goal of demonstrating responsible forest management, but adoption rates vary by region. European landowners and regulators are most familiar with the FSC and national PEFC standards, while North American landowners generally prefer SFI and American Tree Farm System (also members of the PEFC family). In instances in which Drax sources wood pellets carrying these certifications, or in instances in which Drax purchase pellets sourced from certified forests, these certifications offer an additional degree of assurance that the pellets are sustainable.

Over 50% of the pellets used at Drax Power Station come from the southern USA, where SFI and American Tree Farm System are the most widely implemented certification programmes. Overall adoption levels in this region are relatively modest. However, the SFI offers an additional level of certification that can be implemented by wood-procuring entities, such as sawmills, pulp mills and pellet mills.

This programme is referred to as SFI Fiber Sourcing, and to obtain it, participants must demonstrate that the raw material in their supply chains come from legal and responsible sources. These sources may or may not include certified forests. The programme also includes requirements related to biodiversity, water quality, landowner outreach and use of forest management and harvesting professionals. Together, these certification systems have long contributed to the improvement of forest management practices in a region that provides Drax with a significant proportion of its pellets.

And since the SFI and ATFS programmes are endorsed by PEFC, North American suppliers have a pathway for their region’s sustainable forest management practices to be recognised by European stakeholders.

These certification programmes have been in use for many years. But with recent growth in the market for wood pellets, a new certification system has emerged to deal specifically with woody biomass.

Trees locked up in a bundle

New kid on the block

The Sustainable Biomass Program (SBP) was set up in 2013 as a certification system to provide assurance that woody biomass is sourced from legal and sustainable sources. But rather than replacing any previous forest certification programmes, it builds on them.

For example, SBP recognises the evidence of sustainable forest management practices gathered under these other programmes. However, the PEFC, SFI and FSC programmes do not include requirements for reporting GHG emissions, a critical gap for biomass generators as they are obligated to report these emissions to European regulators. SBP fills this gap by creating a framework for suppliers to report their emissions to the generators that purchase their pellets.

When a new entity, such as a wood pellet manufacturer, first seeks certification under SBP, that entity is required to assess its supply base.

Feedstock which has already been certified by another established certification programme (SFI, FSC®, PEFC or PEFC approved schemes) is considered SBP-compliant.

All other feedstock must be evaluated against SBP criteria, and the wood pellet manufacturer must carry out a risk assessment to identify the risk of compliance against each of the 38 SBP indicators.

If during the process a specific risk is identified, for example to the forest ecosystem, the wood pellet manufacturer must put in place mitigation measures to manage the risk, such that it can be considered to be effectively controlled or excluded.

These assessments are audited by independent, third party certification bodies and scrutinised by an independent technical committee.

In conducting the risk assessment, the wood pellet manufacturer must consult with a range of stakeholders and provide a public summary of the assessment for transparency purposes.

Sustainable energy for the UK

Counting major energy companies including DONG Energy, E.ON and Drax as members, the SBP has quickly become an authoritative voice in the industry. At the end of 2016, the SBP had 74 certificate holders across 14 countries – including Drax’s pellet manufacturing arm, Drax Biomass, in Mississippi and Louisiana.

It’s a positive step towards providing the right level of certification for woody biomass, and together with the existing forestry certifications it provides Drax with the assurance that it is powering the UK using biomass from legal and sustainable sources.

Like the fast-reducing carbon dioxide emissions of Britain’s power generation sector, it’s a change you can’t see, but one that is making a big difference.

Read the Drax principles for sustainable sourcing.

1 Drax Power Ltd FSC License Code: FSC® – C119787

More power per pound

As the country moves towards a lower carbon future, each renewable power generation technology has its place. Wind, solar, hydro and wave can take advantage of the weather to provide plentiful power – when conditions are right.

Reliable, affordable, renewable power

But people need electricity instantly – not just when it’s a windy night or a sunny day. So, until a time when storage can provide enough affordable capacity to store and supply the grid with power from ample solar and wind farms, the country has to rely, in part, on thermal generation like gas, coal and biomass. Reliable and available on demand, yes. But renewable, low carbon and affordable too? It can be.

A year ago, a report by economic consultancy NERA and researchers at Imperial College London highlighted how a balanced mix of renewable technologies could save bill payers more than £2bn. Now, publicly available Ofgem data on which its newly published Renewables Obligation Annual Report 2015-16 is based reinforces the case for government to continue to support coal-to-biomass unit conversions within that technology mix. Why? Because out of all renewables deployed at large scale, biomass presents the most value for money – less public funding is required for more power produced.

Renewable costs compared

Drax Power Station’s biomass upgrades were the largest recipient of Renewable Obligation (RO) support during the period 2015-16. The transformation from coal to compressed wood pellets has made Drax the largest generator of renewable electricity in the country. And by a significant margin. Drax Power Station produced more than five times the renewable power than the next biggest project supported under the RO – the London Array.

Dr Iain Staffell, lecturer in Sustainable Energy at the Centre for Environmental Policy, Imperial College London, and author of Electric Insights, who has analysed the Ofgem data commented:

“Based on Ofgem’s Renewables Obligation database, the average support that Drax Power Station received was £43.05 per MWh generated. This compares to £88.70 per MWh from the other nine largest projects.”

“Biomass receives half the support of the UK’s other large renewable projects, which are all offshore wind. The average support received across all renewable generators in the RO scheme – which includes much smaller projects and all types of technology – is £58 per MWh. That is around £15 per MWh more than the support received by Drax.”

Ending the age of coal

Drax Group isn’t arguing for limitless support for coal-to-biomass conversions. And Drax Power Station, being the biggest, most modern and efficient of power stations built in the age of coal, is a special case. But if the RO did exist just to support lots of biomass conversions like Drax but no other renewable technologies, then in just one year, between 2015-16, £1bn of costs saving could have been made for the public purse.

Drax Power Station may be the biggest-single site recipient of support under the RO – but it does supply more low carbon power into the National Grid than any other company supported by Renewable Obligation Certificates (ROCs). In fact, 65% of the electricity generated at its Selby, North Yorkshire site, is now renewable. That’s 16% of the entire country’s renewable power – enough to power four million households.

Thanks to the support provided to Drax by previous governments, the current administration has a comparatively cost effective way to help the power sector move towards a lower carbon future. Biomass electricity generated at Drax Power Station has a carbon footprint that is at least 80% less than coal power – supply chain included. Drax Group stands ready to do more – which is why research and development continues apace at the power plant. R&D that the company hopes will result in ever more affordable ways to upgrade its remaining three coal units to sustainably-sourced biomass, before coal’s 2025 deadline.

Commissioned by Drax, Electric Insights is produced independently by a team of academics from Imperial College London, led by Dr Iain Staffell and facilitated by the College’s consultancy company – Imperial Consultants.

Forests are more powerful than you think – here’s why

Almost one third of the earth’s land mass is covered by forests. That’s an area of around 4 billion hectares, or roughly four times the size of the US.

In addition to being a prominent feature across the global landscape, forests also play a significant role in how we live. They make the air cleaner in cities and absorb carbon from the atmosphere. They provide bio-diversity and habits for wildlife. They also provide essential forest products such as paper, building materials and wood pellets for energy.

To celebrate the UN’s International Day of Forests, we’re looking at some of the reasons why forests and wood fuel are more powerful than you might think.

They’re a major source of renewable energyFamily at home using renewable energy.

Nearly half of the world’s renewable energy comes from forests in the form of wood fuel. Roughly 2.4 billion people around the world use it for things like cooking, heating and generating electricity. In fact, about 50% of the total global wood production is currently used for these purposes.

However, it is critical that this resource is managed sustainably and responsibly. One of the key aims of the International Day of Forests is to encourage people to utilise their local forest resources sustainably to ensure it endures for future generations.

They can revitalise economiesA truck unloading.

Because wood fuel is such a widely used energy source, it also supports a healthy, vibrant industry. Roughly 900 million people work in the wood energy sector globally.

More than that, rural economies built on wood energy can be revitalised by modernisation, which can then stimulate local business. Investment can help finance better forest management, which in turn leads to forest growth, improvements in sustainability standards and in some cases, increased employment.

They can help mitigate climate changeYoung sapling forest.

The world’s forests have an energy content about 10 times that of the global annual primary energy consumption, which makes it a hugely useful resource in helping meet energy demand in a sustainable and renewable way.

When wood is used as fuel it releases carbon dioxide (CO2). However, if this fuel is drawn from a responsibly managed forest or sustainable system of growing forests this carbon is offset by new tree plantings. The only emissions produced therefore are the ones involved in transporting the wood itself. The US Food and Agriculture Organization predict that by 2030 forestry mitigation with the help of carbon pricing could contribute to reductions of 0.2 to 13.8 Gigatonnes (Gt) CO2 a year.