Micro-generation: a new frontier

Throughout Europe, onsite renewable energy, and particularly processes capturing biomethane from organic waste, has been booming in recent years.

The most popular method by far is that of anaerobic digestion (AD). AD is term applied to a range of processes where organic material is broken down by micro-organisms in the absence of oxygen, typically occurring in a sealed tank.

For projects such as those run by the Local Energy Adventure Partnership (LEAP), it is much easier to find £5,000 or £10,000 to help build their facilities than it is for the larger CHP schemes to find £5 million

Methanogen’s Angela Bywater

The AD process produces a methane-rich gas that can be used as a fuel, and a digestate that provides a source of nutrients that can be used as a fertiliser.

According to UK trade body the Anaerobic Digestion & Bioresources Association (ADBA), last year was a record year for installations of all sizes, with 102 plants commissioned.

Indeed, the number of biogas plants in the UK has risen 600% over the past five years.

There are now 405 operational AD plants in the UK, with a further 60-100 in the planning pipeline.

These plants can be broadly broken down in to three categories: the larger-scale Combined Heat and Power Plants (CHP), and the smaller heat-only and biomethane plants.

Currently the bulk of installations (370 AD plants) are the larger CHP facilities, which together generate 388MW of electricity, and nearly half of these have been installed in the water sector at wastewater treatment plants.

However, the smaller (sub 500kw) biomethane plants and heat-only plants have witnessed rapid growth over the past few years.

It is a similar story across Europe, which explains why Mitsubishi Electric has scaled down its control technology to create a product dedicated to the micro-process plant - PSMXmicro.

Speaking at waste and recycling exhibition RWM at the NEC last month, Mitsubishi Electric’s director for the Process Industries in Europe Louis Meyer said his company was launching PSMXmicro because it recognised the growing demand for such technology.

According to Angela Bywater, project manager for AD equipment supplier Methanogen and network manager for the University of Southampton’s AD Network, the three main areas where AD has been embraced is onsite generation for business, community schemes and use by the agricultural sector.

Onsite generation in industries such as the water sector dominates usage, but the relatively low cost of smaller facilities means there is a noticeable groundswell of support at the micro level.

“For projects such as those run by the Local Energy Adventure Partnership (LEAP), it is much easier to find £5,000 or £10,000 to help build their facilities than it is for the larger CHP schemes to find £5 million,” she says.

Initially formed by London-based community organisation Community by Design, LEAP is a cross-sector partnership seeking to support urban food waste management through the development of small-scale AD.

While Mitsubishi Electric isn’t the first to launch a micro-control solution - Rockwell Automation, for example, has its Micro800 controllers and supporting software - Community by Design director Rokiah Yaman says there is huge appetite for AD at the micro-level, but it has been a struggle to source appropriate and affordable technology at this scale.

Indeed, this lack of suitable technology is evidenced by one project she is currently working on where the team is trying to develop a control solution using Raspberry Pi’s, the basic computer board designed by academics to teach children how to code.

If affordable, Yaman says she would happily welcome control technology from market leaders such as Mitsubishi Electric.