Green Energy Engineering

Wood pellet boilers?

Wood pellets are manufactured from compressed sawdust. The saw dust can be either be a by-product of timber production or specifically for the manufacture of wood pellets. Wood pellets for use in modern 'biomass' heating systems are ususally 6mm diameter and of varying lengths of up to 25mm.

Wood pellet boilers operate similarly to oil and gas boilers. The transport the fuel into a burn chamber and burn the fuel with air to produce heat. The heat is subsequenlty circualted through a heat exchanger when the heat is transferred into either a fluid or in some cases tranferred to air. The main difference between wood pellet boilers and oil/gas boilers is the unique way it is possible to modulate the burn process of wood. By altering the fuel feed rate and the amount of air it is possible to maintain the heated fluid or air at a consistent temperature.

Heating water (or heat transfer fluid) from cold (<30Deg C) to hot (>60Deg C) requires considerable energy. Keeping the fluid hot requires significantly less energy and this is where wood pellet boilers come in to their own. By reducing (modulating) their output wood pellet boilers can keep fluid hot thus giving significant efficiency advantages over oil or gas boilers. 

Renewable energy or Green energy - wood pellets are considered carbon neutral as trees absorb carbon dioxide during their life and when they burn they release the caerbon back into the atmosphere as part of the carbon cycle.

Why do we need renewable energy or Green energy?

At the moment, most of the energy in the world comes from burning fossil fuels, such as coal, oil and gas. This produces carbon dioxide and other gases that trap dangerous energy from the sun close to the earth’s surface. This is known as the greenhouse effect and is responsible for global warming and climate change throughout the world. This includes an increased frequency and severity of storms, floods, hurricanes and droughts which, in their turn, will cause a variety of worldwide economic, social and health problems. The UK Government has made commitments to reduce greenhouse gases by 20% on 1990 levels by 2019 and to require energy companies to supply 10% of electricity from renewables by the same year (the current figure is just 2%).

What are the benefits of Renewable energy or Green energy?

The most obvious benefits of renewable energy are that it is far less polluting than conventional energy and will not run out. Renewable energy can also be produced more locally. This means that it can help local and national economies by using local resources and creating jobs. It will also help reduce the country’s dependence on overseas countries that may be politically unstable. This will help ensure supply and avoid price fluctuation.

Renewable energy is also much safer than nuclear energy which some people regard as ‘clean’. Accidents in nuclear plants can be catastrophic and there is the added problem of having to deal with nuclear waste.