A growing number of organisations responsible for aged landfill sites are facing costly environmental emissions legacies, as many suppliers of generation services are walking away, citing diminishing gas yields making it uneconomic. One of the UK’s pioneers in landfill generation, Ylem Energy Ltd, begs to differ and offers hope for sites facing this problem.
As the gas produced at landfill sites diminishes over time, many are left with an oversized generation capacity when compared to the available gas. When this happens, many suppliers and operators are seemingly abandoning their clients by withdrawing their generation plant and services. This leaves the site’s owner with an environmental problem as the decomposing waste will still be producing gas for many years to come – albeit at a reducing volume. When considering that this gas is largely methane, which is around 30-times more harmful to the environment than carbon monoxide, it still poses a serious threat.
Clearly, these sites can continue to collect the gas, but they simply have to neutralise its effects by combusting it in a flare. When generating electricity, not only is the landfill gas utilised and will generally offset other fossil-fuel-generated electricity, but it can of course produce an income from the sale of energy exported to the grid.
The Salford-based generation specialist, Ylem Energy has been generating electricity from landfill for over thirty years. With its generation systems having amassed some 20-million hours of operation, they have been able to analyse the data gained and develop systems and procedures that significantly lower the operational costs, which makes the vast majority of these abandoned sites economically viable.
Stuart Watson, Ylem Energy’s operations and engineering director, commented: “We have a simple approach that matches generation capacity to the available gas. We have a large fleet of generation units and it’s relatively simple for us to swap-out larger units for plant with lower capacities – either new or fully-refurbished by our in-house team of engineers.”
“Over the years, we’ve developed our very own technologies that help increase the reliability of the generation systems. This includes non-OEM advanced spares, control systems, lubrication and general operation and maintenance procedures that result in a lower cost of generation.
“This is helping many more sites continue generating power long after other providers would have walked away and this not only manages the harmful gases, but also lowers the cost for the site owners – who are often supported by the public purse.”
Stuart went on to explain that many of these sites should also still have Renewable Obligation Certificates (ROCs) available until the scheme ends in 2026 and they will make the financial case even more viable by adding additional revenue to any power exported to the grid.
As a case in point, Ylem Energy has highlighted a system that it has been operating at the Chester Road landfill site in Greater Manchester since the early nineties. The site’s generation systems have collectively amassed some 250,000 hours of operation, which if applied to an average family car it would have travelled somewhere in the region of 15-million miles (*). The site currently has a generator rated at 165kWe but is currently operating at around 60kWh (net).
Stuart Watson continued: “Even in the worst case, a low-gas-yield landfill site should be able to generate sufficient energy to offset the expense of operating and maintaining a flare system and importing power. This will help our clients negate the cost of dealing with their environmental legacies and hopefully generate some additional income for them.”
Seeking out other ways of making these sites perform, Ylem Energy has in early 2019, successfully fitted the very first large-scale battery energy storage system to a landfill site on the outskirts of York, which is allowing the landfill generation to actively participate in balancing the UK’s national electricity grid – helping keep the lights on during times of system stress.
(*Assuming 60mph average speed based on RAC Foundation figures of 50mph on single carriageways and 69mph on motorways.)