The Technology

By harnessing household and processor organic waste along with other organic material and agricultural crops we can generate a valuable energy source for local use.

The organic materials are broken down by a series of natural biological processes. The result is production and capture of biogas which leaving a residue for use as a rich plant fertiliser.

The captured biogas produced from this efficient process is a mixture of gases, the main one being methane. This is used to power electricity generating engines or can be upgraded into biomethane and used as a road fuel. The capturing of the biogas has an enormous environmental benefit as the waste products would normally go into landfill. Greenhouse gas produced in landfill during the rotting process is released into the atmosphere contributing to global warming.

A by-product of the electricity generation is the production of heat. Some of the heat is used to increase the efficiency of the digestion process but the remainder can be used for other industrial and heating requirements.

The rich fertiliser and soil conditioner produced as a by-product of the Anaerobic Digestion process is used for growing food crops and animal feed. It is a totally natural organic product, with a low odour and a high nutrient value and is therefore a valuable plant food. By returning the fertiliser back to the land it completes a natural cycle of life. It also reduces or totally replaces the need for artificial fertilisers which are manufactured using fossil fuels and are ultimately damaging to the environment.

A liquid fuel derived from agricultural crops or from biodegradable waste which can be used to substitute some or all conventional fuel. Petrol and diesel are derived from the fast depleting fossil resource crude oil which is well known to be a major contributor to green house gas emissions and climate change.

Biodiesel is produced from vegetable oils or animal fats. New pressed rapeseed oil, used cooking oil or animal fats are put through a simple chemical process to remove water, glycerol and other contaminates resulting in a road fuel which is a direct replacement for fossil produced diesel. Produced in this way, Biodiesel is a sustainable fuel which helps to protect the environment. It has several advantages over normal road diesel in that it is non-toxic and biodegradable, is cleaner burning emitting fewer noxious gases and particulates, gives greater engine protection and gives very similar performance levels when compared with conventional diesel. It is possible to use Biodiesel as a direct replacement for normal diesel, without any engine modifications, either as pure 100% biofuel or as a blend with conventional diesel.

The by-product from the oil bearing rape seed is rape meal which is a valuable animal feed. Glycerine is another by-product produced in the Biodiesel process and this can be collected and used in the biogas plant as it is a valuable source of energy. By integrating different renewable energy technologies it is possible to improve the efficiency of each process while improving the environmental benefit

1 Hectare of rape will produce 1.1 tonnes of cooking oil. When recycled this oil will produce enough Biodiesel for 15000 miles and will produce 2.3 tonnes of high protein animal feed as a by-product.

Bioethanol is essentially a cellulose-derived alcohol produced through a fermentation process. Cellulose sources such as waste wood, biogas digestate and agricultural crops, for example, sugar beet and wheat which are high in natural sugars and starches go through the fermentation process to produce raw alcohol. The alcohol is then refined to produce a road fuel with better properties than petrol. Bioethanol is then blended with petrol before sale as some engine modifications are needed to enable high rates of use.

The by-product of the manufacturing process is wheat distillers which is a valuable feed for ruminant animals or can be used in the AD process to produce more biogas.1

1 Hectare of wheat will produce enough Bioethanol for 20,000 miles and will produce 12 tonnes of animal feed (50% dry matter) along with straw for feed or cattle bedding.

Most of today's hydrogen is created by reforming natural gas.

A renewable process to produce hydrogen is to use electrolysis of water. As the process is very energy hungry it is relatively inefficient, and the use of fossil fuel-derived electricity makes this environmentally unsustainable. However, it is possible to utilise surplus renewable generated electricity to drive this process.

The electrolysis of water will produce hydrogen and oxygen which can be used in fuel cell technology and in fertiliser manufacturing.

Given future competition for land under the Food v Fuel argument, it is clear that we cannot expect our insatiable demand for energy to come exclusively from land-based crops.

Hydrogen will certainly have its place alongside biofuels.

Hydrogen Fuel Cells

Technological advances are bringing the hydrogen fuel cells closer to being a commercial fuel source and several vehicle manufacturers have work in progress.

The overwhelming advantage of this technology is that it has zero emissions as long as the hydrogen is made and transported using renewable energy. When used, vehicles will only emit water vapour.

For info: http://en.wikipedia.org/wiki/Fuel_cell