How Biomass can save money, reduce carbon emissions, and boost the local economy

December 16, 2013
Posted by in Blog, Microgeneration | Tagged , , , , , , , , , , , , , |

Demand in the UK for Biomass installations is increasing, with installers and feedstock suppliers reporting a surge in demand in 2013. This is set to increase further in 2014 with the impact of increases in energy prices, and especially for smaller Biomass with the introduction of the domestic RHI.

With rising fuel prices, the cost of heating buildings is a considerable challenge. For owners of rural buildings and infrastructure, Biomass boilers offer a significant reduction in these costs. In September of this year, I visited one such example of the transformative impact of Biomass at Hever Castle in Kent.

Hever Castle is one of Kent’s foremost visitor attractions, with multiple buildings, commercial and residential on its site. The site owners are committed to becoming more environmentally friendly and efficient and are replacing old equipment with more energy efficient solutions.

Hever Castle is one of Kent’s foremost visitor attractions, with multiple buildings, commercial and residential on its site

Hever Castle is one of Kent’s foremost visitor attractions, with multiple buildings, commercial and residential on its site

Hever Castle represents a prime example for successful, sustainable and profitable roll out of small–medium Biomass across the country. This includes the installation of a Herz 995kW Biofire with two 20,000 litre buffer tanks, which are connected via a heat main to the castle and other buildings. This provides heat not just to the castle but also to the Tudor Village, as well as a number of dwellings on the estate. The entire project for specifying and installation was delivered by Douch Biomass, whose owner, Toby Douch, also showed me round the site.

The procurement process from start to finish of biomass projects such as Hever tends to take between 1 and 2 years including the decision making process, seeking planning permission and installing equipment on the ground. Toby Douch pointed out that the main obstacle tends to be the decision making process itself; in particular the lack of detailed understanding of biomass leads to commitment levels not necessarily being as high as they need to be to expedite decision making.

Critical to a successful biomass operation is the sourcing of a secure and sustainable supply of feedstock. At Hever Castle, the wood used to fire the boiler is grown on the estate or sourced very locally from Kent and Sussex woodlands where local woodsmen/contractors cut the wood and local hauliers deliver it. This ensures Hever Castle remains self-sufficient in its heating requirements.

Wood from local suppliers being stored on site at Hever Castle

Wood from local suppliers being stored on site at Hever Castle

In the same location as the plant is a large multi-stage fuel store, where un-chipped wood is stored for a year or more. The process of drying the wood from when it is felled in the yard adjacent to the boiler house takes approximately a year depending on species and size and when chipped will result in chip at about 30% moisture content. The level of moisture content is important to allow reliable operation and prevent feed blockages.

The saving on the fuel cost is approximately two thirds from when it was using oil. The cost of the wood chip is approximately 2p per kWh as opposed to oil being 6p per kWh – and subject to potential spikes in price. Hever’s use is approx. 1.5 million kWh per year, equating to a saving of £60,000 per annum. The estimated CO2 saving at Hever is 6218 tonnes of CO2 over 20 years.

Taking into account RHI income and fuel saving, the payback period for Hever Castle (using the benchmark of a project started from scratch, including the building, heat main etc.) would be approximately 6-7 years. Douch Biomass stated that in general they were seeing payback periods between 4 and 7 years on rural projects where there is a reasonable availability of local wood.

Practitioners in the biomass industry regularly point out the importance of understanding life cycle costs for each project up-front, instead of just focusing on the capital costs of installation. The life-cycle costs can be mitigated by good design and specification of all elements of the system with specific attention to the fuel handling systems and rigorous maintenance routines. Another consideration to account for is the future up-scaling of sites.

The Wood fuel store at Hever Castle where wood is chipped and placed in the hopper

The Wood fuel store at Hever Castle where wood is chipped and placed in the hopper

In order to maximize savings and to reduce the cost of O&M, optimal operation in a biomass system can be achieved through sufficient buffering and controls to run the boiler for sufficient periods and avoid stop-start operation. It is clear that organisations planning a biomass heating system must fully understand their heat load throughout the year.

Overall, the impact of the Biomass Heating System at Hever has been to not only save two thirds of heating costs, and avoid price volatility, but also to boost the local economy, in particular through the sourcing of local wood supply. So successful has this been that a second boiler is now being installed at the golf club nearby, also owned by the Castle’s owners, replacing the existing LPG fired system.

Projects like Hever Castle show clearly the benefits of biomass when undertaken in the right context and also how the
Government’s projections that Biomass will constitute in the region of 20% of the UK’s renewable energy by 2020 will be achieved (Source: DECC).

Many thanks to Duncan Leslie, CEO at Hever Castle and Toby Douch, owner of Douch Biomass for contributing to this post.


A massive thank you to our guest blogger, Andre Burgess, for this post.

This blog first appears on EMVC Solutions.

EMVC is an energy advisory business, delivering solutions in distributed, low carbon energy generation and energy efficiency services, including smart energy control and monitoring services.