Tag: biomass energy

A positive negative

18 January 2017

Carbon capture
Tubes running in the direction of the setting sun. Pipeline transportation is most common way of transporting goods such as Oil, natural gas or water on long distances.

This story was updated in June 2018 following the announcement of Drax’s pilot BECCS project.

Is there a way to generate electricity not only with no emissions, but with negative emissions?

It’s an idea that, after decades of being reliant on coal had seemed almost impossible. But as Drax has shown by announcing a pilot of the first bioenergy carbon capture storage (BECCS) project of its kind in Europe, it might not be impossible for much longer.

A few years on from the historic Paris Agreement – which sets a target of keeping global temperature rise below two degrees Celsius – innovative solutions for reducing emissions are critical. Among these, few are more promising than BECCS.

It sounds like a straightforward solution – capture carbon emissions and lock them up hundreds of metres underground or turn the carbon into useful products – but the result could be game-changing: generating electricity with negative emissions.

Capturing carbon

Carbon capture and storage (CCS) technology works by trapping the carbon dioxide (CO2) emitted after a fuel source has been used and moving it to safe storage – often in depleted oil and gas reservoirs underground.

There are a number of CCS technologies available but one of the simplest is oxyfuel combustion. Fuel such as coal, gas or biomass, is burnt in a high oxygen environment and CO2 – rather than carbon (C) or carbon monoxide (CO) – is produced. Other impurities are removed and the resulting pure CO2 is compressed to form a liquid. This CO2 can then be transported via pipeline to its designated storage space, normally hundreds of metres underground.

The UK is well-placed to benefit from the technology thanks to the North Sea – which has enough space to store the EU’s carbon emissions for the next 100 years.

It’s a technology that can drastically reduce the emissions from fossil fuel use, but how can it be used to produce negative emissions?

Two technologies, working as one

Biomass, such as sustainably sourced compressed wood pellets, is a renewable fuel – the CO2 captured as part of its life in the forest is equal to the emissions it releases when used to generate electricity. When coupled with CCS, the overall process of biomass electricity generation removes more CO2 from the atmosphere than it releases.

A report published by the Energy Technology Institute (ETI) looking at the UK has suggested that by the 2050s BECCS could deliver roughly 55 million tonnes of net negative emissions a year – approximately half the nation’s emissions target.

It’s not the only body heralding it as a necessary step for the future. The Intergovernmental Panel on Climate Change (IPCC), stated in a 2014 report that keeping global warming below two degrees Celsius would be difficult if BECCS had limited deployment.

Support is widespread, but for it to lead to a practical future, BECCS needs suitable support and investment.

Morehouse BioEnergy pellet plant

Mills such as Morehouse BioEnergy manufacture compressed wood pellets – a sustainably-sourced fuel for BECCS power plants of the future.

Positive support for negative emissions

There are only a handful of CCS projects in operation or under construction across the world and many simply re-use rather than capture the CO2. Part of the reason is cost. It’s estimated that optimal CCS technology can cost about as much as the power station itself to install, and running it can consume up to 20% of a station’s power output. This means more fuel is needed to produce the same amount of power compared to a conventional power plant of similar efficiency.

Without government support, it remains a prohibitively expensive solution for many power generators. With government support in the form of multi-decade contracts, large CCS or BECCS plants could leverage economies of scale. They could deliver energy companies and their shareholders a return on the investments in the long-term.

Drax research and development

Past plans by Drax could have put the company on a timeline towards becoming the world’s first large scale negative emitter of CO2. It would have achieved it firstly with the construction of a CCS power station at its Selby, North Yorkshire site.

The 428 MW White Rose power station was to be fuelled by a mixture of coal and biomass and once in operation, could have paved the way for similar facilities elsewhere as carbon capture technology improved and costs came down, but unfortunately the project never went ahead.

There are some positive signs that carbon capture technologies are developing around the world. The first ‘clean coal’ power station became operational in the US earlier this month – and a second CCS plant is on the way. A UK-backed carbon capture and use (CCU) project in India recently opened at a chemicals factory, involving the capture of emissions for use in the manufacturing process.

Back in the UK, where the government outlined plans to end coal-fired power generation by 2025, carbon capture power stations must become financially competitive if they are to become a major part of the country’s low carbon future. But if the world is to achieve the targets agreed in Paris and pursue a cleaner future, negative emissions are a must, and BECCS remains a leading technology to help achieve it.

Building a 21st century port

16 November 2016

Sustainable bioenergy

In its long history, the Port of Liverpool has dealt with a number of industries. It’s a port characterised by its ability to adapt to the needs of the time. In 1715 it emerged as one of the world’s first ever wet docks. In the 18th century it was used as a hub for the slave trade.

When slavery was abolished in the early 19th century, Liverpool switched to bringing in the goods of the thriving Empire, such as cotton. When goods like cotton dried up, it switched to the fuel of the Industrial Revolution: coal.

Now as the world (and the UK government) moves away from fuels like coal and towards lower-carbon and renewable resources, the Port of Liverpool needed to adapt once again.

Gary Hodgson, Chief Operating Officer at Peel Ports, explains: “About three years ago everyone was asking, ‘What happens after coal?’”

Biomass silos at the Port of Liverpool

What happens after coal?

Peel Ports is one of the biggest operators of Liverpool’s shipping infrastructure, including Liverpool Port. Seeing that the future of coal was finite, it recognised there was a need for a port that could bring in alternative, renewable fuels.

At the same time Drax was looking for a logistics partner to facilitate the importing of compressed wood pellets. Since 2009 Drax Power Station had begun a process of upgrading its coal-fired boilers to run on sustainable biomass, sourced from huge, well-established working forests. More than this, it had plans to set up its own pellet manufacturing plants in the US South and needed to import large quantities of wood pellets.

The relationship with Peel Ports and Liverpool was obvious. This began a £100 million investment that helped transform the region’s port-station transport infrastructure.

“It’s about working in partnerships with companies,” says Hodgson. “Working this way helps develop solutions that really work.”

The central element of the partnership between Drax and Peel Ports was a radical redesigning of the technical infrastructure. Not only do compressed wood pellets have fundamentally different physical properties to other fuels like coal, they are more combustible and need to be handled safely.

For the three-million-tonne-capacity facility that Peel Ports and Drax wanted to build, innovative supply chain solutions had to be developed.

A tool used to transfer compressed biomass pellets

Shifting biomass in bulk

The first challenge was getting the high-density pellets off giant ships. For this, Peel and Drax designed a solution that uses an Archimedean screw – a long tube with a spiral winding up the inside that allows liquids, or materials that can behave like a liquid (like wood pellets), to defy gravity and travel upwards.

At the top of the screw, the pellets are emptied onto a conveyor belt and carried to one of three purpose-built silos tailored to safely storing thousands of tonnes of biomass.

Here the pellets wait until another conveyor belt deposits them onto specially-design biomass trains where they are transported across the peaks of the Pennines to Drax Power Station near Selby in North Yorkshire.

Each step at the port is automated, designed with supreme efficiency in mind by a team of Drax and Peel Port engineers. End-to-end, port to power station, the whole process can take as little as 12 hours.

Drax biomass ship in the Port of Liverpool

A new chapter for the north

In the varied history of the Port of Liverpool the new facility is another chapter, one that is helping transform the logistics infrastructure and the economic growth of the North West.

Now open and operational, the facility directly employs 50 people – around 500 additional contractors have worked on the project during its construction and development. More than that, it’s an investment in the country’s energy future. It secures a fourth port for Drax –  three others are on the east coast – helping with security of supply.

“We made this investment because we recognised this as the future of the energy mix of the country,” Hodgson explain. “We can’t just rely on one form of power – there has to be an energy mix and we see biomass as a key part of that.”

The cleanest year in Britain’s electricity

14 November 2016

Power generation
Cleanest year in Britain's electricity history

Amid the political upheaval that is characterising 2016 you may have missed the quiet victory of the UK’s low-carbon energy sector: for the first time ever, the third quarter (Q3) of 2016 saw more than 50% of the Britain’s power come from low-carbon energy sources. Five years ago, low-carbon sources made up just over a quarter.

This doesn’t necessarily mean that renewable energy sources made up the full 50% – in fact, nuclear made up a considerable chunk – but it hints at the big changes we’re seeing in the way the country is sourcing its power.

For one, it’s a further sign of coal’s diminishing life. During the period July to September 2012 coal supplied 38% of Britain’s electricity – during this year’s Q3 it supplied just 3%. As a result, per-unit carbon emissions from electricity consumption are at their lowest levels ever. The Carbon Price Floor – also known as the carbon tax and designed to assist energy companies like Drax invest in renewable and lower carbon generation – has played a big role in reducing coal’s contribution.

The findings come from Electric Insights, an independent report produced by researchers from Imperial College London and commissioned by Drax, that looks at the UK’s publicly available electricity data and aims to inform the debate on Britain’s electricity system.

Beyond the continued decline of coal, it shows there’s a growing diversity in low-carbon energy sources fuelling the country and that there’s a positive outlook for a cleaner electricity future.

Here we look at those low-carbon sources and how their use has changed over the last five years.

Nuclear produces 26% of Britain's power (Q3, 2016)

Nuclear

At 26% of the total, nuclear made up the largest proportion of low-carbon power generation across Q3 2016.

That was good news for the sector, which went through a turbulent summer after plans for the Hinkley Point C reactor were momentarily threatened following the dissolution of the Department for Energy and Climate Change (DECC) after the Brexit vote.

The eventual decision to continue with Hinkley C, however, means that more baseload nuclear power, in the form of large power stations and also possibly small modular nuclear reactors (SMRs), will be coming on to the system in the coming years. They will in the main replace older nuclear power stations set to be decommissioned.

Wind produces 10% of Britain's power (Q3, 2016)

Wind

Wind power made up 10% of total low-carbon power generation between July and September, and was the largest renewable source of the quarter.

As recently as 2011, electricity generated by wind accounted for just 4% of Britain’s low carbon energy supplies – a 150% increase in just five years. This is in part due to huge offshore projects such as the 630 MW London Array in the Thames Estuary and the 576MW Gwynt y Môr situated off the coast of North Wales, which have contributed to bringing the UK’s installed capacity to around 14 GW

The UK is now the world’s sixth largest producer of wind power behind China, the USA, India, Germany and Spain.

Solar produces 5% of Britain's power (Q3, 2016)

Solar

Following wind power as the second largest renewable contributor to the country’s low-carbon energy needs was solar.

Five years ago solar’s contribution was so negligible it didn’t even chart in the Electric Insights data. Fast forward to 2016 and Britain has a total installed solar capacity of nearly 10 GW. Again, this places the country sixth in the world for capacity behind China, Germany, Japan, the USA and Italy.

Biomass produces 4% of Britain's power (Q3, 2016)

Biomass

Biomass – a unique low-carbon fuel in that it can deliver both baseload and flexible power – made up 4% of the UK’s power needs in Q3 2016. A good proportion of that came from Drax, which has over the last five years been upgrading from coal to run on compressed wood pellets.

Like solar, biomass generation didn’t even chart in 2011, but today. In fact, between July and September biomass, along with solar and wind, supplied 20% of the country’s electricity – a huge proof point for the rise of renewables. Where biomass sits apart from those two sources, however, is that it isn’t dependent on weather and even though the country has less much less biomass generation capacity than the two intermittent technologies, it produces nearly as much energy as them. This makes it an ideal baseload partner for sources that do (i.e. wind and solar) as it can be dialled up and down to meet the energy demand of the country in seconds.

In the future there’s potential to increase this biomass capacity while saving bill payers money. Three of Drax’s six generating units run on biomass, but if all were to be upgraded as they could be in less than three years – Drax plus Lynemouth power station and one or two smaller biomass power stations – could generate roughly 10% of Britain’s electricity using compressed wood pellets by the time unabated coal power stations come off the system before the end of 2025.

Hydro produces 1% of Britain's power (Q3, 2016)

Hydro

Hydropower made up just 1% of Britain’s power generation over the quarter. However, this is still up by 20% since 2011, when hydropower contributed just 0.8%. Total installed hydropower capacity is around 1.65GW.

However, studies have found the country has a potential hydropower capacity of close to double this amount, but as many of these sources are located in mountainous, rural landscape areas of natural importance, it’s doubtful whether hydropower will be deployed up to its full capabilities in the coming years.

Closing an historic year

May the 5th was an historic day in the UK – it was the first time since 1881 Britain burnt no coal to produce its electricity. It wasn’t an isolated incident, either. In the third quarter of 2016 Britain was completely coal free for nearly six days.

It’s a situation that is likely to continue in the future as low carbon energy sources – and in particular renewables – continue to grow in the country’s energy makeup. The outlook is a positive one. 2016 may have been the cleanest year in UK electricity we’ve seen so far, but it won’t be the cleanest year ever.

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.

If you’re afraid of heights, don’t do this job

27 October 2016

Power generation
Reparing the colling tower at Drax Power Station

Be they for nuclear, coal, or biomass power, cooling towers and their colossal, tapering silhouettes are the most iconic element of the architecture of energy. Drax has 12 of them.

But a structure of that size poses a considerable maintenance challenge. For the first time since Drax’s six towers were constructed between 1967 and 1974, one of them was in need of repair.

Ladder up a Drax cooling tower

What could possibly go wrong?

No matter how well you build something, things can go wrong after more than five decades of continuous operation. Each tower is made from concrete that varies in thickness from seven inches in the middle to around 15 inches at the top and bottom. Over time, even a structure this solid can begin to weaken.

Cooling towers are reinforced with steel bars embedded within their concrete which can rust and expand, causing the concrete around it to crack – a process called spalling. Water vapour, which passes through the towers on an almost constant basis, can also migrate into poorly compacted concrete inside the tower and cause further cracks.

Before the Drax team could set about repairing the towers, they needed to know where these cracks were. Inspecting a structure that tall needed an innovative solution. It needed drones.

Surveying the damage

Drones were used to make a comprehensive, photographic record of the towers that could be inspected for signs of damage. The drones also helped produce a 3D model of the structure to visualise the tower’s defects. It was the first-of-a-kind for the company.

The drone survey found that on tower 3B there were a number of cracked concrete patches on the towers that needed repairing and maintenance was scheduled to coincide with Drax’s 2016 outages – periods during the summer months when electricity demand is lower and parts of the power station undergo routine repair work.

The next challenge was how to carry out these repairs on a structure taller than the Statue of Liberty.

A 3D model of a Drax cooling tower

To inspect the cooling tower, Drax created a 3D model with the help of CyberHawk.

Engineering at an altitude

Drax tower 3B is nearly 115 metres tall, enough to fit in the Statue of Liberty or St Paul’s Cathedral with room to spare.

How do you go about repairing a structure like this? The answer: Steeplejacks. Steeplejacks were called so because, originally, they were the people used for scaling the side of church steeples to make repairs. But a cooling tower presents a distinctly different structure that can’t necessarily be climbed up from the bottom. To scale it and make the repairs, a different approach was needed.

Drax reached out to specialist steeplejack contractors Zenith Structural Access, who build devices that allow the scaling of industrial-scale structures.

Zenith’s solution was to fix a metal frame to the top of the tower, which then lowers a walkway suspended by strong metal cables down its side. From a perch suspended from the top of tower 3B, workmen were deployed to make the repairs – more than 100 metres above ground.

Suspended in their cradles, the teams sealed the surface of each crack and then injected resin to fix the cracks in the concrete shell. Where the concrete had spalled, new specialist repair mortars were applied.

Repairs on Drax Tower 3B

Regular repairs

With the identified defects on the tower fully repaired, attention can now move on to others on site. Routine inspections using drones and binoculars have been planned to take place every three years. These will monitor the condition of all the towers and allow for future maintenance to be planned in advance.

Two more towers are already scheduled for repair in 2017’s outages. Once again, it’ll be case for engineering work at elevation.

How one company helped transform the biomass business

6 October 2016

Sustainable bioenergy
Westfield terminal

If asked to picture Canada, its beautiful forests often spring to mind. In fact, 38% of the country is covered by them. Little wonder that Canada has one of the world’s biggest lumber industries. But all that lumber milling means a lot of sawdust.

It was in this sawdust, and the other ‘waste’ products the milling process creates, that one fledgling Canadian company spotted an opportunity.

Making the most of waste

Started by two brothers in the 1980s, Pinnacle originally made animal feed for farmers – compressed pellets of grass and grain.

Then, in the late Eighties, after hearing about wood pellet production in Scandinavia, and taking a look at all the sawmilling residues being burned up around them, they had an idea for a new direction.

At the time the Canadian government was looking to make the sawmilling industry a lot cleaner and more sustainable. “There was a lot of fibre around that needed to find a home,” explains Vaughan Bassett, a senior executive with the company.

Canada needed a way to put to good use materials that were previously just thrown away or even burnt out in the open, releasing greenhouse gas emissions, and wood pellets seemed like a natural fit. Even better, because there was so much waste fibre around at the time, Pinnacle was able to get its raw material for free and help to avoid the unnecessary emissions. All it had to do was pick it up and take it away.

Pinnacle Lavington grand opening

Finding a new business model

Making the transition from feed pellets to wood pellets involved a lot of trial and error.

“There was a lot of entrepreneurial spirit that went into this thing,” says Bassett. “It was untried, untested, unknown and there was no real market. It was just a couple of entrepreneurs trying stuff out.”

Initially, Pinnacle produced its wood pellets for local domestic markets – people looking to heat their homes, local businesses, and schools that used wood burners. This is a particularly convenient and efficient form of fuel for communities in off-the-grid, remote areas of Canada. But Pinnacle was keen to grow and make an even greater impact.

Rising demand for sustainability

By the early 2000s, some in the power generation industry were starting to rethink their long-term futures, looking to shift from fossil fuels like coal to cleaner alternatives in order to meet the challenges of sustainable energy production.

Central to Pinnacle’s business is a commitment to sustainability – something being based in Canada, where forest management is particularly advanced, makes possible. Being owned by the Crown, there are very tight controls over how Canadian forests are run – and how the trees are used.

“We’ve probably got the most sustainable wood fibre in the world. The numbers are just mad. Something like 95% of all the forests in Canada are ‘forest management certified’, which is unbelievable. Look at the next best country and it’s probably nearer 30%,” says Bassett, “It’s left us with an incredible asset that keeps growing every year. The industry never takes more wood than what grows.”

Indeed, carefully managed forestry is key to environmental sustainability. Fully-grown older trees don’t absorb as much CO2, so replacing them with younger, growing trees that do, can benefit the environment. Meanwhile, the waste product of sawmilling is converted into biomass, which produces further benefits by reducing reliance on fossil fuels.

Pinnacle and Drax: A sustainable partnership

Pinnacle first started supplying Drax with compressed wood pellets in 2009, marking a turning-point for the company. “Since 2011, our production has doubled,” says Bassett.

Pinnacle now contracts a fleet of ships and has its own dedicated port facility. Each vessel can transport 60,000 tonnes. Given that Drax uses around 16,000 tonnes a day with two of its three biomass units at full capacity, one shipment keeps a third of the huge power station in North Yorkshire going for nearly four days.

“Pinnacle now produces in the region of 1.5m tonnes of pellets a year, about half of which goes to Drax. So they’re a very important part of what we do,” says Bassett.

Read the Burns Lake and Houston pellet plant catchment area analysis here, part of a series of catchment area analyses around the forest biomass pellet plants supplying Drax Power Station with renewable fuel. Others in the series can be found here. 

Forests, sustainability and biomass – the expert’s view

Matthew Rivers, Director of Corporate Affairs, Drax, Group Special Advisor

Opinion

It was a forestry catastrophe that first inspired Matthew Rivers’ interest in forests.

Dutch Elm trees, an iconic part of the UK landscape for over 250 years were becoming infected with a fatal and fast-spreading disease. The race was on to save them.

A schoolboy in North London at the time, Rivers joined the after curricular school team tasked with saving its trees – first by injecting them with insecticide, and when that didn’t work, by felling and replanting them. It was an early foundation in how forests work and the challenges of keeping them healthy.

Decades later, Rivers is Director of Corporate Affairs at Drax. It’s a role he finds himself in following a career as a forester, helping to manage forestry businesses, and supporting the setting up of wood product manufacturing plants.

His own estimation of his working life is a humble one, however. “I think I’m probably a failed farmer,” he says.

“A forester always plants in hope.”

Rivers studied forestry at university in Scotland before taking up jobs in the forestry industry across the UK, Uruguay and Finland. Working in this industry, he says, is one that requires patience.

“In the UK we’re talking about 30- or 40-year growth cycles. The trees I planted at the start of my career are only just coming to maturity now,” he explains.

But more than the long investment of time, being a forester relies on faith. “A forester always plants in hope,” he says. When a forester plants a tree, he or she most commonly does not know who the end customer will be.

So when the call came from Drax for a forestry expert to help guide the company through an important transformation – upgrading the power station from coal to biomass – the challenge was one he was ready to take.

“Drax already had ambitions of converting three boilers to run on biomass. That would mean consuming tonnes of compressed wood pellets,” he says. The business needed a supply, and Rivers was drafted in to set this up.

As part of the supply solution, and Chaired by Rivers, Drax set up Drax Biomass, a pellet manufacturing business in the USA that makes and supplies compressed wood pellets to Drax Power Station.

Setting up its own manufacturing plant not only means Drax needs to rely on fewer external suppliers, but also that it can use the learnings about the technologies, the economics and the sourcing of the process to continually hone its supply chain.

To operate responsibly and receive governmental support, Drax has to be sustainable, and this is particularly important when it comes to where and how it sources its fuel. This comes with its own challenges.

No universal definition of sustainability

“To my understanding, there is no universal definition of sustainability,” says Rivers. So how do you proof your business for an unclear entity?

“At its heart, sustainability is about not doing anything today that would prejudice doing the same thing for the next generation or generations to come.”

A responsibly managed forest is one that is as healthy, productive, diverse and useful in 100 or 500 years’ time as it is today. They key to this, is to think of forests as a whole.

Rivers explains: “Think about a single tree – you fell it and use it to heat your home over one winter. But it’s going to take perhaps 30 years for that tree to grow back,” he says. “What do you do for the next 30 years?”

“In a sustainably managed forest you have all different ages of tree represented – one thirtieth devoted to each age- and, when you use an older tree to warm you in winter, you plant a replacement. That way, for every year you’ll have trees reaching maturity ready to provide your power.” It’s a cycle that, if managed responsibly, keeps delivering a useful resource as well as maintaining the health of the forest.

Rivers continues: “Sustainability is the very nature of what a forester does; because if we don’t take care of our forests, and ensure we have a crop to harvest year after year, we lose our livelihood.”

forests_trees_growing_for_winter_heating_smh4nj

Becoming a private forester

Two decades ago, Rivers completed a loop he started decades ago amidst the Dutch Elm crisis and became a forest owner himself. In Scotland, he bought, and now manages, his own private forest.

“We’ve had kids’ birthday parties, we’ve dug out a pond, we harvest chanterelles in the autumn – there’s a millennium capsule buried somewhere,” he says.

It’s not only a family heirloom. It’s a place for him to exercise a passion – maintaining and managing a responsible and healthy forest.

 

A solution for cheaper, cleaner power

Sustainable bioenergy
Senior couple checking their bills

Britain has some big energy targets ahead of it – namely an 80% reduction in carbon emissions by 2050 compared to 1990 figures. A renewable energy future is not an optimistic target, it is a necessary one.

But for this picture to also be a practical one it needs to be affordable. A study from NERA and Imperial College London, commissioned by Drax, suggests there are ways for renewable technology to be cheaper than it currently is.

In fact, in one scenario they looked at, there could be savings to the tune of £2.2 billion.

Incentivising decarbonisation

It’s a positive and necessary support mechanism. However, some renewable technologies, like compressed wood pellets, a form of biomass, are excluded from participating in upcoming the auctions scheduled between 2017-20. Why is this?

Missing the bigger picture

Currently, CfD support is based on how much a particular type of electricity costs combined with how much it takes to build and maintain the facility used to generate it. This figure is what’s called the ‘levelised cost of energy’ (LCOE). The spanner in the works comes in that not all costs are considered in making this judgement.

Powering a country requires more than just a power source. We need ancillary services like backup power to get the country back on the rails in the event of large-scale blackouts, and voltage control to ensure electronic devices continue to work and that power can move around the network. The costs associated with these services – system integration costs (SICs) – are excluded from the CfD equation.

Sources like wind and solar, being intermittent, can’t offer most of these on-demand ancillary services but we still need them to play a part in the UK’s energy supply. Biomass facilities can provide a number of these itself, meaning it actually has a negative SIC cost.

However, in the current pricing system – ignoring these associated costs – biomass is considered more expensive than onshore wind and solar. With the high SIC costs for wind and solar included, biomass is in fact the cheapest option.

Finding the right mix

This is not to say that solar and wind are not an integral part of a more renewable future. A truly flexible low carbon, high voltage electricity grid should be a mix of elements. Current rules do not look at the full picture, and are ruling out important alternatives, but there are possible solutions. One could be unifying the markets.

There are four markets that feed into the UK’s electricity supply and there’s little transparency or cohesion between them. This leads to inefficiencies.

Jens Price Wolf, Regulations and Market Director at Drax, explains: “Solar is the cheapest renewable, diesel is the cheapest option in the capacity market and gas will be the cheapest for energy production.”

By considering each market as separate you end up buying the cheapest solution for that individual purpose rather than considering its performance across all. This misses out solutions that can benefit the whole system.

“Biomass might be the second cheapest option in each field,” says Wolf. “So supporting investment to upgrade existing coal power stations with biomass technology satisfies multiple needs and leads to it being ultimately cheaper than the old mix.”

A single market approach that treats all technologies and generation methods in the same way could lead to significant cost savings, and those savings could be passed on to bill payers in households and businesses.

While this could be a longer-term solution, there are ways short-term actions that can make a difference. If the government were to include biomass in the mix for the next round of CfD auctions it could bring about savings of over £2 billion over the next 15 years, or a £85 saving per household over the same period. And, it would do this while ensuring the grid remains adaptable without sacrificing emissions targets.

The 4 most common myths about renewables

Power generation

Renewables make up more of the world’s energy mix than ever before. And yet, misconceptions about these new or alternative technologies – such as biomass, solar and wind – are common.

Some of these concerns are – for the time being – partly justified, some completely subjective, and some are demonstrably wrong. Here’s a closer look at the most pervasive myths and what truth there is behind them.

Renewables are unpredictable

An oft-repeated misconception is that renewables aren’t a full-time solution to our power needs. It’s true that solar isn’t generated at night and wind turbines don’t operate in still weather, but the canon of renewables is bigger than its two most well-known technologies.

Tidal power still depends on environmental factors, but tides are much more predictable than wind or sunlight. For countries lucky enough to have ready access, geothermal power – which uses heat from the earth’s core to power generators – is even more reliable.

Biomass solutions, such as compressed wood pellets, are a fuel-based power source, meaning they are flexible so can be used to generate electricity on demand and operate as a base-load power option, much like coal or gas. At Drax Power Station renewable electricity is generated on demand using compressed wood pellets and delivered to the National Grid 24-hours-a-day.

Now, thanks to advances in weather forecasting, the National Grid can plan ahead to balance the system with other renewable and low carbon technologies when the sun isn’t shining and the wind isn’t blowing. Just a few years ago the primary fall back was relying on coal power stations to pick up any slack.

It might not be possible to power the world entirely with one renewable source, but the right mix of technologies could provide an answer to the question of how to ensure a stable and secure low carbon energy supply.

Heavenly Scene Stormy Skies

Renewables are expensive

There is some truth in this, but it’s important to note that these costs are falling. Many of the high costs associated with renewables have been down to a lack of infrastructure investment.

A number of the components required in construction of structures like wind turbines and solar panels are expensive. And, as many renewable facilities need to be located in different areas to existing traditional facilities, extensive power grid extension is often needed. But these are problems that once set up, should bring down the costs of renewables such as solar and wind.

Setting up biomass-powered facilities is considerably cheaper. Compressed wood pellets can be used in upgraded coal power stations, so there’s no need for expensive new connections to the high-voltage electricity transmission system.

There are even ways renewables could bring about cheaper power for consumers. Research commissioned by Drax and published by NERA Economic Consulting and Imperial College London found that, if the same government support offered to some renewable technologies (i.e. wind and solar) were open to all (such as biomass), consumers could see potential savings of £2 billion on their energy bills.

Renewables are ugly

While this isn’t necessarily an opinion shared by everyone, it is one that is often cited. Onshore wind farms often draw the most ire, but they aren’t alone. Large investments are being made in offshore wind farms, which are both more discrete and better positioned to take advantage of stronger offshore currents.

And hydropower projects like dams and tidal barrages can in the long term create whole new habitats, ecosystems and leisure facilities in the form of artificial lakes and surrounding forests.

Nobody uses renewables

In 2015, 99% of Costa Rica’s electricity came from renewable sources, including hydro, geothermal, wind, biomass and solar. Closer to home, Sweden draws more than 50% of its electricity from renewable sources, including 22% from bioenergy – 90% of which comes from forestry.

In the UK, renewables use is steady and rising, accounting for 25% of all electricity generated domestically in 2015. In the first half of 2016, 20% of the UK’s renewable power was supplied by Drax. Contrast those figures against coal, which in the UK declined from supplying 30.8% of UK power needs in Q1 2015 to just 15.8% in Q1 2016, and our increasing use of renewables is even more evident.

Consumers have been buying 100% renewable electricity tariffs from companies such as Good Energy for more than a decade. Businesses are increasingly getting in on the act too. Two thirds of the power generated by Drax in the first half of 2016 was sold directly to companies via Drax Group’s business electricity supplier, Haven Power.

And with campaigns such as RE100 challenging the world’s biggest firms to commit to renewable-only power, household brands such as Ikea, M&S and Google are either already 100% renewable or only a few years away.

Misconceptions about renewables will remain as long as we’re still in the transition out of fossil fuel use. But the industry has made huge strides from where it was just 10 years ago.

Thanks to better, more affordable technology, an increasingly friendly corporate sector, and a greater awareness of environmental issues at large, these products and services will continue to improve, grow and increasingly becoming more mainstream.

Inside the dome

Sustainable bioenergy

There are four storage domes at Drax Power Station and each of them can hold 80,000 tonnes of compressed wood pellets. It’s these biomass pellets, a sustainable fuel, that Drax is being upgraded to run on and produce renewable electricity.

Wood pellets are an incredible fuel that can match coal for efficiency – the challenge is you just need more of them as the density and calorific value of coal is greater. However, storing such large quantities in a confined space presents risks that have to be managed, 24/7.

Atmospheric control

The crucial difficulty with storing the pellets is their chemical volatility. Wood, which the pellets are made from, emit carbon monoxide (CO). In a confined space such as the storage dome, this CO can build up and – due to CO’s extreme flammability – require the entire internal atmosphere to be regulated by a set of highly sophisticated engineering solutions.

As long as materials are emitting more heat into the atmosphere than they are storing in themselves, there is no risk of combustion. A single wood pellet in a fuel store poses no fire risk. Nor does a small pile. But when thousands upon thousands are piled together, the pressure builds up and causes the pellets to heat up.

Gradually, the rate of temperature increase speeds up, and before you know the flashpoint threshold has been crossed and there’s potential for danger.

However, remove or limit the oxygen supply in the silo and purge the CO that’s emitted from the pellets, and the risk of a thermal event is substantially reduced. The challenge for the engineers at Drax constructing the domes was finding a way to manage temperatures within the dome.

Neutral nitrogen

To do this they created a system to automatically inject nitrogen into the storage dome. While nitrogen isn’t a truly inert gas, it is much less reactive than CO and oxygen.  With this pumped into the dome’s atmosphere it is a much safer environment.

To get a steady supply of nitrogen, regular air from our atmosphere – which is 78% nitrogen – is passed through a molecular filter, which removes the larger oxygen molecules. The gas collected at the other end is 96% nitrogen.

This nitrogen-rich air is then injected from underneath the dome and continually distributed around it. Not only is this a fire prevention method, but also a firefighting one that can be pumped in larger quantities in the event of combustion. Separate to the above measures which are there to manage fuel temperatures, the dome is also fitted with a carbon dioxide (CO2) injection system and water deluge system which are there as fire extinguishing precautions.

The big ear inside the dome

The next problem facing the designers was how to accurately monitor the quantity of compressed wood pellets inside the dome. To achieve this, each dome is fitted with a sonar system – which sounds a bit like a chirping bird – that provides continuous feedback on how full the dome is.

The sonar monitoring system provides level, profile and volume information which is translated into a 3D image of the stored biomass. This method of volumunetric measurement allows the operators to view and monitor in ‘real time’ the effects of their actions when filling and unloading domes, so they can target specific areas particularly when unloading and for fuel accounting purposes.

Other tools and tricks

Five thermocouple arrays measure the pile temperature and provide feedback in real time to the operators to allow them to assess the status of the dome and effectively plan material filling and reclaim. Gas monitors measure the levels of CO and CO2 as well as O2 depletion within the head space of the dome.

A dome breather vent (a two way acting valve, which as its name suggests, allows the dome to breathe) is fitted to the top of the dome and acts as a vacuum breaker maintaining a relatively even pressure allowing air in during unloading and releasing head space gasses during nitrogen inserting.

The final piece of the atmospheric control puzzle is regulating pressure. At the top of each dome is a controllable aperture called a slide gate which is closed unless the dome is being filled to allow material to enter. A dome aspiration system is installed here to filter and remove displaced air from within the head space during filling, but also allow a route for CO and other offgassing products to escape.

All the hidden systems within these four huge white domes allow the operator to effectively control their atmospheric conditions and crucially to store massive amounts of potentially volatile biomass safely on site.

Find out more about these giant storage domes – read the story about how they were constructed.