For most power station operators the idea of using fuel that is not just free, but that they are actually getting paid to take, is probably something of an alien concept. But there is one generating industry where just such a model prevails, finds Ben Messenger

Viridor’s 7.25 MWe WtE facility in Peterborough, UK

Credit: BW Vølund

Burning waste is not a new concept. It’s been going on at an industrial scale since the 1870s. In the UK that decade saw the responsibility for collecting growing quantities of waste shift to the municipal authorities. With that came the need to not just collect, but dispose of, large quantities of municipal waste.

While large-scale incineration had been previously attempted unsuccessfully at a facility in London, in 1874 the first ‘destructor’ was built in Nottingham. Proving a success, the technology caught on and over the following years destructors became a common sight in Victorian Britain.

The Victorians were no strangers to combustion. They burned huge quantities of coal to power everything from steam trains to cotton mills, so it’s hardly a surprise that they soon began utilizing the energy being released from burning wastes in the destructors. Often heat from the plants would be used to produce steam to power sewage pumping stations. But as the use of electricity became more widespread, the capability of these plants to generate electrical energy became increasingly important.

According to Dr John Clark, a lecturer at the University of St Andrews School of History, by 1912 there were over 338 destructors in Britain, over 80 of which also generated electricity for local use. And the UK was far from alone in its recovery of energy from waste. In 1898 the US’s first waste-to-energy (WtE) plant opened in New York, while in Denmark the first plant opened in 1903.

The role of WtE today

In the 140 years since the first destructor entered service the world has changed massively. The demand for energy has skyrocketed, as has the volume of wastes being generated. In 2012, the total waste generated in the EU-28 by all economic activities and households amounted to 2.5 billion tonnes – and it all has to be collected and properly disposed.

In many parts of the world, the way in which that waste is disposed is coming under increasing scrutiny. In the EU, Directive 2008/98/EC has provided a legal framework aimed at the whole waste cycle from generation to disposal, placing the emphasis on recovery and recycling, but favouring energy recovery over landfilling for wastes which cannot be recycled.

In order to better protect the environment, the Directive obliges member states to take measures for the treatment of their waste in line with the Waste Hierarchy, which is listed in order of priority:

• Prevention;

• Preparing for reuse;

• Recycling;

• Other recovery, notably energy recovery;

• Disposal.

Further, in July 2014 the Commission adopted a legislative proposal to review waste-related targets in the Landfill Directive as well as recycling and other waste related targets. The proposal aims at phasing out landfilling by 2025 for recyclable waste (including plastics, paper, metals, glass and bio-waste) in non-hazardous waste landfills, corresponding to a maximum landfilling rate of 25 per cent.

Clearly there is a concerted effort to increase the quantity of material being recycled from waste, but many in the industry are sceptical about the economic feasibility of recycling all of the material that would previously have been landfilled. Instead, they argue that it is more sensible to recover energy from those materials at dedicated WtE plants.

In the UK the drive to divert waste from landfill has led successive governments to rapidly increase the Landfill Tax to its current £82.60 per tonne – and it’s working. However, in spite of the increased diversion of waste from landfill, the country’s recycling rate has been increasing only slowly in recent years. Instead, much of what is being diverted is now being processed into Refuse Derived Fuel (RDF).

Mind the gap

There is currently a significant gap in the UK between the amount of residual waste (waste which has been through a recycling process to recover materials) being produced and the country’s capacity to process that fuel domestically. Fortunately, thanks to excess capacity in a number of north European countries including Sweden, Germany and the Netherlands, there is a buoyant export market. This year the UK is expected to export more than 2.5 million tonnes of RDF – up from just 270,000 tonnes in 2011.

Gate fees of between approximately €65 and €85 ($70-$90) per tonne are paid to the receiving facilities. A recent report from Tolvik Consulting, RDF Exports: Here for Good?, estimates that, on average, the energy efficiency of Swedish incinerators means that they have a €30/tonne gate fee advantage over incinerators in the Netherlands and Germany.

Some see the situation as a failure to recycle more materials, others as a missed opportunity to keep gate fees in the country while reducing reliance on imported energy, and some argue that it’s simply the invisible hand of the market at work.

“Arguably you could recover more materials,” Kristian Dales, Sales and Marketing Director at waste management firm FCC Environment, told PEi. “But when the cost of extracting those materials is higher than the cost of producing RDF, especially with the low rates for shipment overseas, then it becomes an economic decision. What ‘commercially viable’ recycling is has got a big question mark over it.”

Barriers to entry

Over recent years the issue of finance has been one of the biggest barriers for potential WtE developers in many countries. But at the recent Waste to Energy Cities Summit in London, the general consensus of the Finance Panel was that the cogs of the financial machine are slowly beginning to loosen. However, according to Dales there are still issues surrounding financing and planning.

“If you’re running a mass burn incinerator, getting planning through is always a problem,” he says. “Even when you’re granted permission, then the Secretary of State can overturn that. There’s been a few large companies that have had fairly major investment programmes derailed. We’ve had a situation whereby the local authority has awarded us a waste project, but then the same authority won’t give planning permission for the build of that project.”

The UK is not alone in its struggles to get to grips with EU targets. In Ireland there has been fierce debate over a new 600,000 tonne-per-year WtE plant in Dublin. The plant is being built under a PPP deal with US-based firm Covanta and has been hit by delays in the planning and financing process. However, having successfully cleared all the obstacles, the plant is now under construction.

Speaking with PEi, Stephen J Jones, recently appointed chief executive and president of Covanta, explains: “There are a number of things that need to fall in place to develop a new waste-to-energy plant. You need supportive policies and regulations, you need a certain energy pricing, and it’s important what size the facility is, where it’s located and what technology is used.

Smaller-scale projects make heat utilization easier

Credit: BW Vølund

“We see energy from waste as an excellent investment for communities, and that’s played out over the years. For the environment we’re reducing the impact of landfill, especially in relation to greenhouse gases, and we’re also able to recover metals. And from an economic standpoint, in places like Dublin it creates good green jobs,” he continues.

In the pipeline

In spite of the recent economic and political headwinds, the UK does have considerable new capacity in the pipeline. For example, Multifuel Energy, a joint venture between US-based WtE operator Wheelabrator and utility SSE, has recently combusted its first waste as part of the commissioning process at its £300 million ($456 million) 68 MW facility at SSE’s Ferrybridge C power station.

The plant will process a range of fuels, including RDF from various sources of municipal solid waste, commercial and industrial waste and waste wood. The company is also in the planning stage for a second similar facility.

In May of this year Keppel Seghers, the environmental technology arm of infrastructure firm Keppel Corporation, handed over control of phase two of the Runcorn WtE facility to Viridor EfW (Runcorn) Limited, a special-purpose vehicle owned by Viridor Waste Management. Combined with the existing phase one plant, the facility will process some 850,000 tonnes of RDF, generating 80 MW of electricity and 52 MW of thermal energy in the form of steam. The plant supplies the neighbouring INEOS chemicals manufacturing facility with energy, reducing its reliance on fossil fuels.

Denmark’s Copenhill WtE plant

Credit: ARC

But it’s not just municipal waste that needs managing. There are also huge quantities of Commercial & Industrial (C&I) and Construction & Demolition (C&D) waste, as well as large amounts of waste wood – much of which is extracted from C&D waste. That wood is something that Danish WtE technology manufacturer Babcock & Wilcox Vølund is looking to tackle. (Babcock & Wilcox Vølund, together with The Babcock & Wilcox Company, is exhibiting at POWER-GEN Europe 2015 at stand number 1R9.)

In a departure from being simply a technology supplier, the company has recently signed contracts to build, operate and maintain two new facilities in Rotherham and Port Talbot to recover 45 MW of heat and 40 MW of power from wood waste. Speaking with PEi about the Welsh facility, Ole Hedegaard Madsen, Sales Director at B&W Vølund, says: “We’re building the plant and then we’ll operate it for 15 years afterwards so it’s a Build Operate Transfer contract. In the company we call these projects multi-fuel. They are 80 per cent to 90 per cent biomass, but because you have contamination of the wood it means that when it comes to regulations it will have to meet the Waste Incineration Directive.”

Great Danes

Outside the UK, B&W Vølund is also supplying technology to Copenhagen’s new Copenill plant, a facility which would not be out of place in a Hans Christian Andersen fairy tale. With a ski slope on the roof and the world’s tallest man-made climbing wall, the plant will sit proudly near the heart of the Danish capital.

The facility, which will replace the capacity of an existing end-of-life plant, features two B&W Vølund grate-fired 35 tonne-per-hour boilers, and a wet flue gas cleaning system supplied by LAB – a CNIM subsidiary – including a flue gas condensation system with heat pumps. The generators will be spun by a high efficiency 67 MWe SST-800 steam turbine from Siemens.

In many countries the prospect of building a 550,000 tonne-per-year WtE plant in the heart of a city would be a tough sell. There would be protests organized and leaflet campaigns warning of heavy metals and dioxins. There would be little mention of the incredibly stringent emission controls to which such plants operate, or that a single New Year’s Eve fireworks show is said to emit more dioxins than 100 years of continuous operations at a modern WtE plant.

In Denmark, however, the public takes a pragmatic approach. In part that’s because they see the benefit of not only disposing of waste and generating electricity for the grid, but of heating their homes during the cold Scandinavian winters.

The benefits of heat

According to Ramboll, the engineering consultancy which is working on the project, the Copenhill facility will supply enough heat, to three different heat networks, to keep some 140,000 of Copenhagen’s homes warm.

“If you have the opportunity to supply district heating, then of course it will be a big benefit for the operator. It’s another income source. A rule of thumb: for every one tonne of waste you can produce approximately 0.7 MWh of electricity, but at least 2 MWh of heat,” Bettina Kamuk, head of the WtE department at Ramboll and Board Member at the International Solid Waste Association, told PEi.

While the recovery of heat massively increases the efficiency of WtE plants, it’s not always possible where no district heating network exists and there’s no suitable industrial customer. For example, a number of the facilities either recently completed or under construction in the UK are ‘CHP capable’, but have nowhere to send the heat.

In a bid to increase the use of heat from WtE plants, in June 2014 the Confederation of European Waste-to-Energy Plants (CEWEP), the European Suppliers of WtE Technology (ESWET) and Euroheat & Power launched the ‘Warmth from Waste: A Win-Win Synergy’ initiative.

According to the organizations, in Europe, the energy recovered from WtE plants for district heating currently represents 50 TWh per year – around 10 per cent of the total heat delivered through district heating systems. But there is significant room for improvement.

“Heat is where we have the most potential,” Dr Ella Stengler, Managing Director of CEWEP, told PEi. “In some cities heat from waste-to-energy already covers half or more of the local heat demand. It’s quite something, and there is huge potential. There are studies suggesting that by 2050 the TWh amount of heat being produced by waste-to-energy could be quadrupled.”

Going local

Another debate surrounding WtE is the question of size, and the ability to process waste more locally. In the UK and Ireland, Hedegaard Madsen sees potential for growth in the delivery of smaller-scale plants, such Viridor’s Peterborough facility which is the first in the UK to feature B&W Vølund’s Dynagrate combustion technology. Once operational, the plant will process around 85,000 tonnes of waste per year and generate 7.25 MW of electricity.

According to Hedegaard Madsen, smaller-scale projects make it easier to utilize the heat, and that’s a view reinforced by Matt Drew, Managing Director of Saxlund International. The company recently secured a contract to supply biowaste combustion and fuel handling solutions to a 3.4 MW facility in Bedfordshire, UK.

“One of the good things the government is doing under the Contract for Difference, is that to get an uplift on your electricity sales you have to have somewhere to sell heat to as well,” he told PEi. “But the downside of that is that trying to secure a customer for the amount of heat that these plants generate is very, very difficult. There are not many places that take megawatts of heat.

“Fortunately the guys in Bedford have got a specialist leisure centre next door which has a wind tunnel for sky diving, and they’re planning to put in a huge diving tank which will be a huge heat sink,” he adds.

Outlook

In many northern European countries there is limited scope to develop new facilities, as sufficient and even excess capacity already exists. However, there are opportunities for new developments in the UK and Ireland, as well as some potential in Eastern Europe and further afield in Asia, particularly China.

There is also the prospect of new technologies coming to market. In Teesside, UK, Air Products is nearing completion of a 50 MW facility using AlterNRG’s plasma gasification technology to process some 350,000 tonnes of waste per year, and has a already started work on a second adjacent plant.

In the UK these so called Advanced Combustion Technologies benefit from additional subsidies, and at a recent conference Ofer Dresler, director of Israel’s Haifa Bay Municipal Association for Environmental Protection, said that the country is willing to spend more for the right advanced technology. However, traditional mass burn incineration is the tried and trusted technology and will remain the dominant force in the industry for the foreseeable future.

While WtE facilities may look expensive to build and operate in terms of cost per MW compared to most other generating technologies, when their role in managing waste and avoiding landfill is factored in, they make a lot of sense.


Ben Messenger is a freelance journalist at www.technicaljournalist.com