West Wales Heating

Biomass Boilers

What is it?

Biomass covers several different technologies. The main two are wood gasification systems, which are systems that use traditional logs that have been seasoned, and pellet boilers and pellet installations. Pellet is still pure wood but it is processed. To understand the word processed, if you imagine a pencil that has been chopped up into a number of equal lengths, each piece of pencil would be the size of a pellet.

How it works

There are no glues or additives used in the process. They take virgin wood, such as wood that has come straight out of woodland or often factories that are producing wood materials such as joinery’s. It is then taken to a pellet factory and cut up into very small pieces and put into a process that compresses the wood together into these small pellets.

Moisture removal

Moisture removal is a crucial thing as the moisture level of a pellet is very low, less than 5%. This means that it is very dry and caring for that is an important part of a biomass boiler installation to make sure that it doesn’t absorb more moisture whilst it’s in store. But because it’s so dry the commercial biomass boilers are automatically ignitioned,  so they light themselves.

Installation of biomass pellet boilers

Most of the installations of pellet boilers are almost fully automatic. But because the pellets are so high in calorific value and there’s so much energy in these little pellets, that most of it burns away and the amount of ash that you generate from burning pellet is very small.

How much ash is generated from biomass boilers?

Because there is so little ash content in biomass boilers, it means that you can have a container alongside the pellet boiler that takes the ash from where its generated into a little storage bin. This means that you will only have to empty the ash bin once every 3 months.

How does a pellet biomass boiler compare to an oil or gas boiler?

You will have a little programmer on the wall, the same as you would for an oil or gas boiler, to time whenever you want the heating to come on and you will have a delivery once a year. The pellet boilers also self clean as it is all programmed into the machine, so there is very little input from the customer’s side required.

How popular are biomass boilers?

Biomass boilers are getting very popular because people want this. Also, because of all of the renewable that West Wales Heating install, the RHI, Renewable Heating Incentive, comes into consideration.

What is the RHI?

The Renewable Heating Incentive is a government thing and it pays people for having renewables in their home and using renewables rather than using oil or gas. The RNI is there to encourage people to put renewables in and in a domestic situation, it is paid over 7 years and you get a cheque every 3 months.

Is a biomass boiler system expensive?

To put renewables in your home, it must all be paid for up front. It is a more expensive system to install compared to oil and gas boilers, but the running cost of a biomass boiler is much lower so as soon as it is in, it will cost you less. With the help of the RNI payments, within 3 or 4 years those payments will have more than covered the cost of the installation.

How is the pellet biomass boiler system maintained?

With a pellet biomass boiler you are looking at the same thing as any oil or gas boiler. You are looking at an annual servicing and it is a quite straight forward process as there are no huge amount of replacement parts required. It is just to check that everything is clean and the controls of the system are working properly.

What about the wood gasification boilers?

The other main type of biomass boilers are wood gasification boilers where. This is where logs are used that have been cut and are then burnt. Log gasification boilers is a batch burning log boiler and in the depths of winter, you would do 1 firing a day. It’s a traditional firing boiler so you manually light it when it is full of logs and just walk away, as it manages itself from that point on. The wood gasifaction biomass boilers burns the wood quite quickly. They also include a large accumulator, which is just a large cylinder that acts like a battery for the heat. The log boiler burns the wood and it is then transferred into the accumulator and stored there. Then as the house requires hot water and heating, it is extracted from the accumulator.

What about the constant refiring of the wood gasification boilers?

West Wales Heating size these log boilers so that when they are in the highest demand, when you are using your hot water and heating the most in the winter, you will be doing 1 refiring a day. Where as in the summer, when the heating demand is less, you should be doing one every 3 or 4 days.

Is there more maintenance required for these log boilers?

Because the wood gasification boilers are boiling logs and they contain a certain amount of moisture content, around 20%, there is more maintenance required by the owner. The flutes will have to be cleaned and the boiler itself will also have to be kept clean. There are more expensive wood gasification boilers that will clean themselves however, but that is down to the particular budget.

Does the wood gasification boilers generate more ash?

A lot more ash will be created with these log boilers because the logs have bark in it and it still has a reasonably high moisture content. This means that there will be more ash produced.

Can the ash produced be re-used?

The ash that is produced from the wood gasification boilers is still wood ash so it can be re-used. It can be scattered over vegetables and wood trees as they will benefit from pot ash. The only ash that you can’t use is the ash produced when you are burning coal as this can be quite harmful.