Developers need to consider how much heating they will need to avoid risk of costly mistake

Barny Evans

Since the introduction of the Renewable Heat Incentive in 2011, as part of the government’s ambition to increase renewable heating from 2% to 12% by 2020, biomass heating as a sector has boomed. The scheme makes a payment per kWh generated depending on the technology and scale.

Although the scheme also supports solar hot water, heat pumps and the production of biogas/methane, 92% of applications by number and 98% by capacity have come from biomass heating, almost all of that on the <1MW scale. Essentially the scheme has become a biomass incentive scheme. (The government has just announced a change in tariffs to increase the incentive for the use of heat pumps.) The reason is that biomass heating is relatively easy to retrofit. Biomass boilers can be connected to an existing heating system using fossil-fuels without significant changes. It is much more difficult to do this with heat pumps.

One key issue still holding back biomass roll-out is the cost of the plant which is 10-20 times the price of fossil fuel systems

WSP have worked on several projects now and it is amazing how quick the supply chain has and continues to develop. From effectively nothing there are now a host of companies offering biomass heating from the single domestic scale to large commercial systems. In parallel with this the fuel supply market is now well established, with standards in place with regard to quality. However, one key issue still holding back biomass roll-out is the cost of the plant which is 10-20 times the price of fossil fuel systems.Companies are now starting to address this by offering to install systems free where the end user makes a payment per kWh of delivered heat.

Biomass heating offers a good commercial return and official carbon emission savings if you are in the right situation. Ask yourselves these questions:

  • Do you have a consistent thermal demand for a process or even a large space heating load? The savings come from operation; the more heat you need, the more you save.
  • Do you have access to mains gas? Where mains gas is available the financial and carbon savings are less as you are generally using more expensive fuels with higher carbon intensity, e.g. LPG and oil.
  • Do you have space on site? Biomass boilers are themselves much bigger than a comparable fossil-fuelled boiler and obviously require storage for the pellets or woodchip, access for maintenance, as well as access for delivery vehicles.
  • Aesthetics may be a consideration. Although the plant can be designed to fit in an existing building, it is more common for them to come in pre-fabricated containers for ease of construction and delivery. These can be clad to fit in with their surroundings, but they will not be to everyone’s taste. In addition, it can be necessary for the flue to be conspicuous.

On the downside, there are complex arguments about the true carbon savings from biomass, and there are concerns about fuel prices in the future if supply cannot match demand. Therefore it is worth considering what a significant price increase would do the sums, although most fuels are expected to increase in price over the next few years. Despite this, current returns, which can be higher than 20% a year on a good site, are likely to continue to drive the market.

Barny Evans is principal consultant, renenwables and energy efficiency, at WSP