Celebrating 30 years with the future in mind

Founded in 1991, HoSt was originally born out of a joint venture between two well-established Dutch suppliers of energy systems – Holec Projects and Stork.

At the time Herman Klein Teeselink was an employee before buying out the joint venture.

I’d traveled all over the Netherlands and further afield installing and servicing industrial boilers of all shapes and sizes in all kinds of industries. Closing loops and efficiency are things that, as an engineer, I am passionate about. So, developing energy systems dedicated to utilizing organic residues generated onsite by a production plant became a mission for me. That’s basically why I ended up acquiring HoSt from the joint venture, explained Herman Klein Teeselink, Chairman and Owner of HoSt.

Thus from 1999 onwards, HoSt has been a fully independent business whose activities focus 100 percent on the technological development of waste-to-energy systems for converting organic residues into renewable energy and high-quality end products.

The latter has a particular bearing looking ahead but more on that later. In the meanwhile, HoSt has built up extensive experience and an international reference portfolio in the processing of diverse waste flows from the food-processing industry and agricultural by-products several of which have been covered by Bioenergy International over the years.

The company has grown into a global organization not least with the acquisition of Eurobiomass in early 2018, now with over 300 staff, a large service team throughout Europe, multiple offices in both the United States and Europe, a large network of sales representatives, and partner distributors with a like-minded passion for bioenergy done right.

This is no mean feat – to develop and build a world-class biomass combustion technology business based in the Netherlands considering that, generally speaking, the Netherlands is perhaps not the most biomass-friendly jurisdiction in the European Union (EU).

Yet it just may well be that this challenge of public perception has been a driving force for HoSt – to prove beyond any reasonable doubt that biomass, when done right, can be as good as or better than any other option on the project table in terms of technology, sustainability, efficiency, emissions, economics, and societal benefits – the best available technology.

High-efficiency plants

While the project portfolio has expanded over the years, so too has the product portfolio which covers the design, construction, operation, and maintenance of solid biomass-fired energy installations, as well as biogas plants and biogas upgrading.

The former ranges from 1 to 50 MW thermal and 1 to 12 MW electrical. For capacities above 25 MWth or 6 MWe in the case of combined heat and power (CHP), HoSt deploys two separate combustion lines. The latter, with a single large steam turbine.

In both cases, this modular approach enables cost-effective road transport and reduces the overall height of the building, an increasingly important consideration in many planning applications.

Modularity also provides greater installation flexibility for clients. HoSt specializes in high-pressure modular biomass- and waste-fired water tube boilers with pressures up to 90 bar and designed to operate with high availability and low maintenance.

Multi-fuel low emission combustion

At the heart of a HoSt biomass-fired installation is its proprietary multi-fuel step-grate furnace with a zone-controlled combustion process. The temperature of the grate is kept low while in the second combustion phase, higher temperatures are maintained.

The low grate temperature allows for a greater variety of biomass- and waste fuels with varying moisture content – 10 to 55 percent, and with low ash melting points to be used. Fuels such as straw, chaff, manure, olive pulp, chicken litter, and Refused Derived Fuel (RDF).

This flexible and optimal combustion process is performed using an intelligent configuration of the furnace and the temperature control system in various combustion zones.

Each grate zone has independent control of primary air intake and recirculation of flue gasses, allowing the temperature to be individually controlled.

The fuel is gasified on the grate with the process gas combusted above the fuel bed in three stages: just above the grate with primary air injection under the grate; further above the grate with secondary air and recirculated flue gasses injected in order to control the temperature, and finally in the venturi – a highly turbulent zone – by injecting tertiary air.

In this way, the temperature can rise to up to 1 000 °C so that complete combustion occurs with very low unburnt hydrocarbons (CxHy), carbon monoxide (CO), and nitrogen oxides (NOx) emissions resulting in low oxygen (O₂) concentrations of 3.5 to 5 percent in the outgoing flue gasses.

To reduce NOx further, urea can be injected into the furnace.

Operating our own plants gives us a lot of insight into our own installations compared to being a supplier only. This allows us to quickly implement improvements that are beneficial for availability and maintenance. Our installations have demonstrated practical availabilities between 92 and 94 percent, often with the availability of in excess of 8 400 operating hours per year, said Herman Klein Teeselink.

According to HoSt, its furnace concept has a number of other operations and maintenance (O&M) benefits in addition to multi-fuel capability, low emissions, and high efficiency.

These include long grate bar life-times thanks to the low grate temperatures.

The fully automated wet-chain bottom ash removal system collects ash from the end of the grate, ash through the grate, and ash from the multi-cyclone, the first phase of flue gas cleaning.

It is robust and relatively insensitive to stones, ash agglomerates, and other contaminants that may be present in the incoming fuel.

Furthermore, being wet minimizes the formation of dust over time in the boiler building which positively effects housekeeping and the lifetime of control systems and electric drives as well as mitigates any fire hazard on account of hot embers.

CHP with steam cycle

For combined heat and power, HoSt deploys a steam cycle system rather than an Organic Rankine Cycle (ORC) system on account of higher electrical efficiency in the former.

The difference increases significantly for installations above 1 MWe with up to 40 percent more electricity.

This is down to the combination of a high-pressure water tube steam boiler with an efficient multi-stage steam turbine, and lower parasitic electrical consumption – the thermal oil pump of an ORC can consume up to 10 percent of the generated electricity.

An additional benefit for a CHP plant with seasonal heat demand such as district heating is that there is extra high electrical efficiency during the summer thanks to a lower temperature of the heating water, allowing the steam in the turbine to expand further and therefore generate more electricity.

The higher boiler efficiency is a result of a lower flue gas flow in combination with a lower stack temperature achieved by the innovative combustion technology with a low oxygen surplus.

HoSt is able to supply installations as turn-key plants complete with ancillaries such as fuel reception, ash removal, flue gas condensers, flue gas cleaning systems such as electrostatic- and bag filters to minimize NOx, sulphur, chlorine, dust, and other pollutants to meet required emission standards.

Diversified business model

HoSt has installations across a wide range of industries and sectors including agriculture, municipal- and industrial wastewater treatment, food- and beverages, forest- and wood processing industry to mention a few.

Adding to this diversity is the business model – or rather business models as the company is not only a technology provider but in some cases also builds, owns, operates, and maintains its own facilities in the Netherlands.

Alternatively, it can also provide ancillaries such as a flue gas condenser fuel reception, boiler infeed, digesters, mixers, or other components to third-party suppliers.

A notable partnership on the biogas side is the “Jumpstart” initiative of the dairy cooperative major FrieslandCampina which started in 2018.

Here HoSt’s proprietary Microferm Green Gas mono-manure digester and upgrading technology for dairy manure are used as a qualified technology, supplying green gas to the grid and biofertilizer for the dairy farmer.

We have invested and will continue to invest in developing our own facilities, both in biogas and CHP. Typically, these investments are energy as a service model. But it could also be a joint-venture or BOOT (Build Own Operate Transfer) model. Or, as in a recent project here in Enschede, where we will buy biogas from the Grolsch brewery’s wastewater treatment plant, upgrade it onsite to biomethane, and will inject it into the gas grid. Our revenue will be from the sale of green gas. It’s about finding the right balance, the right type of project in the right place, with the right partners at the right time, said Herman.

Indeed, even public crowd-financing has been successfully used in the Netherlands for at least two biomass projects.

A Bright Renewables division

In 2017 a decision was made to launch Bright Biomethane, to offer well-proven systems with Evonik’s “Sepuran” membrane technology to upgrade biogas to biomethane aka renewable natural gas (RNG) or green gas with support throughout all process steps from engineering to commissioning and final acceptance.

Although we build our own biogas plants, we decided to brand our biogas upgrading technology separately. Bright operates as an independent company, explained Tamarah Swensen, Marketing Communications Manager at HoSt.

The smart design combined with high-quality components guarantees high system availability and low maintenance cost. The system arrives on-site fully pre-tested, which allows site setup and commissioning to be done quickly.

It operates fully automatically with a quick response to fluctuations in the incoming biogas supply. With remote monitoring and customized service and maintenance options, the efficiency of an operation can be optimized further.

There are tens of thousands of biogas plants around the world, the overwhelming majority of which have been built by other technology providers. By providing a containerized Plug’n’Play solution that is biogas plant provider agnostic, we can tap into both the retrofit- and new-build markets for biomethane, explained Tamarah Swensen.

The division, which develops, builds, installs, operates, manages, and finances biogas upgrading plants has since been renamed Bright Renewables, as additional ancillary technologies such as compressed biomethane (bioCNG), and biomethane liquefaction (bioLNG) are included.

In addition, carbon dioxide (CO₂) liquefaction (bioCO₂) along with in-house developed carbon capture technology have been added to the portfolio, both of which are already being deployed in projects.

Also located in Enschede, is Bright Maintenance Services which offers remote virtual maintenance for optimized maintenance service of biogas plants with smart glasses and remote support.

Manned year-round 24/7, it is here, Bright Biomethane service experts record and monitor maintenance work in real-time both of their own plants and those of customers, for many of whom biogas and biomethane are not the core business.

The COVID-19 lockdowns have accelerated the general adoption of digital and remote operation technologies. Our service technicians or customers on-site can also be connected through smart glasses with our service experts across the world to speed up maintenance, repair, and inspection processes. This results in very high availability of the plant, Tamarah Swensen said.

An even Brighter future?

Looking ahead it would seem that HoSt is really only getting started. For instance, the RNG market in North America, where HoSt has gained a foothold with first projects under construction, is rapidly expanding while in Europe, the current geopolitical turmoil has pushed biogas and biomass to the fore.

A planning application for an additional expansion of the recently expanded HQ has already been submitted, and talent recruitment from universities and relevant third-level institutions is ongoing.

Since the start, we’ve fostered strong relations with the University of Twente and other well-known international institutions to stay abreast of the latest combustion engineering and biogas science. We participate in academic R&D, sponsor students of various disciplines in their thesis work or via internships, and recruit graduates, explained Herman Klein Teeselink adding that the skilled labour market is extremely competitive in the Netherlands, a challenge for any company with staff needs growing at 20-25 percent.

BioCO₂ is an area where HoSt sees growth. The first Bright CO₂ liquefaction projects have been built and a first to the US has been sold. Carbon capture from the flue gas of biomass-fired plants is another area HoSt is hoping to commercialize in the near future.

The company acquired an amine-based technology and is developing this low-temperature carbon capture solution for its biomass energy offering.

There is a big demand for green CO₂ especially from the horticultural industry here in the Netherlands. We already have CO₂ separation and liquefaction technology from our biogas side, now we are looking at capturing it from the solid side. We expect to install a demonstration pilot at one of our biomass-fired CHP plants in the near term, ended Jelle Klein Teeselink, CEO of HoSt, without revealing any specific details.