Network Dec/Jan 2020

Issue link:

Contents of this Issue


Page 24 of 35

Why is the technology so different? The system for cleaning the syngas cleaning is unique and patent pending. Cleaning the gas before you use it takes out the tar and other contaminants, and makes it more suitable for electricity generation and other applications. How do the economics stack up? The scale is quite small for a commercial plant, so that gives it a better chance to be self- supporting. There are multiple revenue streams – combined heat and power, electricity to the grid, purified gases. Other, larger plants found that couldn't keep up efficiencies at smaller scales. We have an overall ef - ficiency rate of 30 per cent, and plenty of opportunity to improve that over time. Meanwhile, electricity generation via the gas engine is already at 41% efficiency, up from 36%. What was the idea behind the project? The Sustainable Energy Centre was conceived as a research and development site that neverthe- less makes enough money to cover the equity investment costs, so it's not just a "demon- strator". In terms of the payback period, a plant should be able to make £2m a year, so if the overall costs is £10m for a 2 MW capacity facility, that's a 5 year payback period. We estimate that the plant would have at least a 25 year lifespan. These are all ball park num - bers, and there are also the site costs, planning and develop- ment costs, and operating costs on top. But the capital costs would be repaid in five years. Other demonstrators, such as Cadent's BioSNG trial in Swin - don [where the consortium be- hind a commercial version went into administration in December 2018] and the ECN project in the Netherlands were designed to prove the concept, but their permits had restrictions, so they built up the technical position but they can't offer a commer - cial operation. So we called it an "R&D commercial demonstra- tor" – although that meant we couldn't unfortunately claim R&D tax credits! What would potential customers be buying? Kew Technology's vision is to productise this and sell modular units built in a factory, then transport them to the site, offer- ing cost savings and health and safety advantages. The goal is to reach an in- stalled cost of less than £5m per MW of generating capacity, and to sell it to customers as a turn- key package. It's designed to fit into 10 to twelve containers, the type you see on HGVs, measur - ing 40 x 8 x 8 feet. Once it is delivered to site, it is a question of "plug and play". If you had all twelve, you could run all the processes offered, or you choose fewer but adapt over time. For instance, you could have the gas engine and hybrid fuel plant, so you could supply elec - tricity and low emission metha- nol fuel to HGVs, with additives. Or you could use a methanisa- tion process to offer energy storage and grid injection. These possibilities are perhaps two to four years away. Who is interested in the concept? At the moment the energy from waste market is pretty dominated up by the big three players – BIFFA, Sita and Veolia [which operate Energy Recovery Facilities selling steam turbine- NETWORK / 25 / DECEMBER 2019 / JANUARY 2020 LOCALISED ENERGY generated power to the grid]. The big three also export RDF to partner sites elsewhere in Europe, as there aren't enough processing facilities here, so this concept could add capacity at a reasonable cost. So the idea is to engage with local authorities, and to offer plants as a turn-key package wrapped up with warranties. Lo - cal authorities are o¤en interested in district heating, where a facility like this might be one of multiple providers you would need. What about the cost of raw materials? It depends on where in the country you are – in the Mid- lands, RDF feedstock might cost £50 to £100 a tonne, in Hull and Humberside area, it might be just £25 to £60, so the difference in costs can make a big impact and the market is uneven. There's also a lot of interest from overseas, such as South Africa and Asia – in other words developing countries that typi - cally have high electricity costs, perhaps 25 p per kWh. However, in developing countries, you'd expect to have to pay to get the feedstock, because there is no organised supply chain when waste is simply being dumped, and you'd need to set that up. What about the impact of the site and chimneys in an urban environment? It runs with ultra-low emissions, making it ideal for integration into wider sites. The site at Wednesbury is 50% bigger than it needs to be, as the original plan changed. We have a 30m chimney flue, but technically there is no need for it to be more than 12m, although you may want it to higher if air quality is a concern, for instance if it's very close to housing. Did you have any technical difficulties? To connect to the local grid we were hit with a bill of £200,000 to add capacity at the substa- tion. Then we had to synchro- nise our power to the grid, and on the day we connected the power for the first time we had to change the settings or we would have tripped the site. We had to shut down temporarily while we found a solution, but luckily we had the right people in the room to find a solution. What about hydrogen? At the moment the outputs are electricity and heat, but from the syngas we can produce pure hydrogen, liquid fuels and methane. The syngas is a build - ing block for other things. Kew has demonstrated it can produce hydrogen with CO2 sequestration. There is a lot of interest in hydrogen and, on cost, Kew's technology has the potential to compete with other providers; it could be exciting. However, the cost rises if you want pure hydrogen. Some customers want 99.999% purity, others don't need "five 9s", as 99.5% might be enough. Kew has done a desk top study for BEIS on the market potential.

Articles in this issue

Archives of this issue

view archives of Network - Network Dec/Jan 2020