Renewables / Alternative Energy 15 Jul 2014

A Step-by-Step Guide to Biomass

By Bruno Berardelli, Managing Director at HWEnergy: Build

Like any capital project, building a biomass system doesn’t start until the owner completes the feasibility/design process and secures the necessary finance.

When it comes to the actual installation stage the build process should be very straightforward, as long as these vital steps are completed carefully.

A biomass system is an impressive piece of kit. It consists of a wide range of components including fuel storage and handling equipment, fire suppression mechanisms, pumps, fans, emissions controls, ash handling systems as well as the actual boiler.

There are many important considerations at build stage. These include planning or building warrant requirements, fuel storage needs, ventilation and access to water and energy services. Finally, roles and responsibilities between the owner of the installation and the supplier must be agreed.

It’s worth remembering that the installation will be in place for the next 15 to 30 years, so it’s important to spend the time getting it right first time. The best approach is, as always, to keep the process as simple as possible.

Planning Permission and Building Warrants

For anyone wishing to install a biomass appliance, building regulations will likely apply – although in practice the advice can vary according to local areas.  For a building warrant you will need to take into account factors such as ventilation, noise, fire prevention and general safety.  Building regulations also apply to other aspects of the work such as electrical installation and plumbing work.

Planning permission is generally required for most non-domestic biomass installations above 45kW.

Some biomass systems may require the construction of outhouses or areas to store the wood materials. They may also require the development of a new means of access for service vehicles – the provision of which may need planning permission.

The planning authorities may be concerned about theheight and visual impact of the flue as well as environmental health implications (predominantly the emissions of very small particulates). These will generally be unlikely to cause aproblem with modern biomass systems unless it concerns a listedbuilding or the development is in a conservation area or an air quality management zone (the last of which thankfully doesn’t affect many farms).

The planning authorities may also ask about vehicle movementsassociated with fuel delivery. Again, problems are not likely tooccur unless the boiler is very large and the fuel storage is small.

Biomass installers and the relevant local authority should be able to provide all the necessary information and advice about planning and building warrants for biomass developments.

Other Needs

The most obvious requirement when making the switch to biomass is to arrange fuel storage and a means of delivering the fuel easily. During the feasibility and design stage the owner of the project will have decided where the system will be housed and whether a new building will be required to house the system and fuel supply.

When fitting biomass boilers to existing buildings, the space required for installation can be an issue. Biomass systems require a significantly larger storage space than oil and gas systems as the energy density of the fuel is lower. Consequently, a large volume must be stored on site to avoid over-frequent deliveries and to maintain a sufficient safety reserve.

The store must also be accessible by delivery vehicles and located close to the actual combustion equipment to avoid an unacceptably long fuel feed as this can increase the risk of blockages.

In addition, the store must keep the fuel dry. It can naturally biodegrade in storage, particularly when wet. This will lead to loss of energy content and potentially the formation of moulds which can be dangerous if the spores are inhaled.

As an alternative option, biomass heat cabins feature pre-fabricated boiler rooms and integral fuel stores and come with all heating plant, plumbing, electrical wiring and control systems pre-installed ready for connection to an external heating system. The units are available in a range of outputs, sizes and finishes and provide a convenient way of installing biomass heating, particularly where there are space restrictions on creating an in-house biomass system. The flexibility afforded by heat cabins means they can be moved, re-sited and re-configured as required.

The boiler house itself must conform to local and national building regulations. It must also have access to both power and water supplies. Most boilers require a three-phase supply although some smaller boilers can work on single phase. The quality of the onsite water resource may also be an important consideration for the efficient operation of the system. You may need to identify the delivery pressure as well as provide a chemical analysis. This should be available from the water authority, or if using one’s own supply, from the appropriate regulatory authority.

Wood-fuelled boilers require more excess air than oil or gas boilers, which means they need increased permanent ventilation. The supplier/installer should be able to provide details of the level of ventilation required.

Due to their large size, the boiler house should be set up in a way that allows access to the boiler tubes for cleaning. For vertical tubes this would be above the boiler, and for horizontal tubes space is required in front of the boiler.

Roles and Responsibilities

Last but certainly not least, one of the most important considerations is to ensure that both the client and the boiler supplier and any other contractors are clear on their roles and responsibilities throughout the build process.

Generally, projects are split into a number of jobs and it is vital that all parties are clear on where their responsibilities lie at the start of the project.

The jobs that need to be delegated to specific owners include:

  • System Design – incorporating all the elements below.
  • Securing planning permissions.
  • Biomass boiler and supporting equipment supply
  • Assembly, installation and commissioning of biomass system
  • Providing machinery to support the offloading of equipment
  • Supply and installation of other mechanical and electrical equipment in the biomass boiler room
  • Supply and installation of any underground heating pipe connecting up different buildings
  • Supply and installation of heat interfaces within any buildings and integration with existing heating and hot water systems
  • Civils and enabling works.  This can include constructing the boiler house and fuel store, creating access for flues, trenching for any underground pipework (including sand and reinstatement) and coring into buildings to create an access way for the heating pipes. In many cases farmers will opt to undertake these civils and enabling works in-house.

In our experience having absolute clarity on who is responsible for each of the above areas of the project is critical to ensuring a smooth and well run project. Delays in one element of the project can have a knock on impact on other areas and disrupt the overall programme and timescales.  The lowest risk approach is to appoint a single supplier who will provide a turn-key installation covering all of the key mechanical and electrical elements and take responsibility for the overall design of the system.  Good companies will have professional indemnity insurance ensuring that they take responsibility for the design and installation of their systems.

The owner of the project should also take responsibility for arranging access for contractors, and they should work with them to agree timelines and procedures for communication and feedback. They should also take care of basic aspects like the provision of welfare facilities and the approach to health and safety on site.

Without seeming biased, I would always recommend working with professional biomass specialists who can demonstrate a strong track record of successful projects. They will have the experience behind them to guide any project owner through the process to ensure the job is completed safely, legally and to the highest standard.

Above 45kW there is no requirement for biomass suppliers and installers to be members of a professional organisation or adhere to any specific industry standards. This means it is very much a case of “buyer beware” for those undertaking a project.

The RHI (Renewable Heat Incentive) provides 20 years of significant financial support for biomass installations, but only for systems that are working and delivering heat.  It is therefore worth taking the time and effort and investing well to ensure you receive a high quality installation that will reap rewards for many years to come.

 

Plant roomPlant room for large installationInstalling the flue