Biogas is at The Top
as Alternative Fuel
Biogas produced from different organic waste matters is one of the best
alternative fuel sources
as assessed by the transport sector. It shows the great advantage of
renewable energy.
So maybe this is a hit fuel? Well, keep on reading and see what you think.Biogas is produced when organic matter is broken down by microorganisms in the absence of oxygen, called
anaerobic digestion.
This process occurs naturally in many environments with limited oxygen, for instance in marshes, rice fields and in the stomach of ruminants. The gas can also be produced by
fermentation
of bio-gradable materials.
In a gas plant the natural process is utilized by adding - or pump - organic matter into a digester, which is a completely airtight container. In the digester a raw biogas is formed plus a nutritious digestate which can be used for fertilizer, which shall not be mixed up with sludge!
The gas content comprises mainly methane (55-70%) and carbon dioxide (30-45%). It may have some small amounts of ammonia, nitrogen, hydrogen sulphide, moisture and
siloxanes.
Many different organic waste sources can be used, as manure, sewage sludge, municipal waste,
food waste
(which has a greater potential than you may believe), plant and animal material, trees and different cash crops. Sources like
algae
and
seaweed
can also be used. When talking about manure we think of manure from farm animals, which is for sure right, and the most common practice. But there are also other interesting ways of reusing animal "poo". Like the
big poo from elephants
and other Zoo animals. Or making
"green" poo from dog poo.
And of course, our own
human manure!
Does it sound funny with poo power? Well, it may do, but it works! We just have to be aware of that it is easier to collect manure when animals stay indoors. To go out and pick it up on a wide meadow is not so easy. But this put pressure on having animals in an unnatural environment which wouldn't be supported. So if using animal manure for bioenergy we must implement some creative and animal friendly solutions for how we do this. The Gas Can Be Used For Different Purposes- Heating purposes, such as cooking.
- Run generators and make electricity.
- Be compressed and used in combustion engines.
- Waste recycling when waste matter is a feedstock.
Biomethane is the generic term for gases consisting mainly of methane and produced from
biomass.
Biomethane is the name being referred to when biogas has been cleaned and upgraded to the same standard as natural gas (fossil gas). When this upgrading is done the methane content is about 98%. Different pollutants are removed and the gas becomes completely odorless.
PROS
When biogas-systems are introduced, there are two factors which most affect the emissions of green house gases. One is the digestion of manure which emits less methane emissions compared with conventional manure management, even though it is difficult to estimate the indirect gain. The systems also reduce emissions from ammonia when manure is digested.
The second factor is that when renewable gas replaces fossil fuel, large reductions in emissions of green house gases have been shown in several studies.
According to research the climate impact is 93% less than from gasoline. The emission of carbon dioxide is about two thirds lower, and emissions of particulate matter and
formaldehyde
are virtually none. Emissions of acidifying substances also decrease when biomethane replaces fossil fuel. Then we have the important issue that the production doesn't require any land as the gas is usually made from waste products.
This also means – no competition with food production!
Biogas was nominated as the best
biofuel
2009 by the Swedish organisation "Gröna Bilister" (Green Car drivers). The big vehicle producer Volvo in Sweden (which is a forerunner country on green gas) is also claiming, based on their own research, that green gas is superior to most other renewable fuels.
And the very best one when looking into overall energy efficiency is
dimethyl ether
(DME.)The research made by the Volvo Group is from a European perspective, but is relevant for several other parts of the world. In Sweden the world's first train has been run on renewable gas.
Vehicles running on biomethane are less noisy
than conventional vehicles.
In developing countries biogas-production can improve health and sanitation as different waste materials are used as feedstock. Plus the benefit of having local energy supplies. And small scale production helps farmers to become more self-sufficient. The possibility of getting rid of waste products does of course benefit all countries, rich and poor. And the fact is, that if all people used as much resources as we do in the west, we would need 3 planets! So we absolutely need to re-use more of our waste instead of using up more natural resources. Green gas-production offers a good opportunity. The best environmental gain is estimated to be when the gas is upgraded to vehicle fuel. Not necessarily for the reason that it is better suited for this purpose, but because of the benefits gained from the decreased use of fossil fuel. CONSAn important aspect is that production by anaerobic digestion may release odour emissions. Many people are concerned that production plants will cause problems with smell, which often lead to resistance when new facilities are being planned in the vicinity of populated areas. A way to overcome this problem is to have the activities inside. Another problem is that methane is an aggressive green house gas, so it is important to prevent leakages from the plants. It is mainly when upgrading to biomethane as the emissions happens, and depending on the technique the amount of emissions varies. As with other gases, it might be a bit tricky to transport. A mixture of 5-14 % methane in the air is explosive and this can cause serious accidents. For that reason it is very important to prevent leakage and have the very best ventilation system where methane gas is stored. A ConclusionAs we have seen, biogas can be produced from different raw materials which don't compete with other important needs, and the gas can be used in a number of ways. This versatility is an important quality when developing alternative fuel for the future.
-----------------------------------------------------------------
References Biofuel Region. 2010-08-12. Fakta om biodrivmedel – Biogas.
http://www.biofuelregion.se/biobransle/index.cfm?open=biodrivmedel&meny=Biogas&id=66 Mattias Goldman, Gröna Bilister (Green Car Drivers). June 2009. Bästa biobränsle 2009.
http://www.gronabilister.se/17/6-grona-bilister-biogas-utsett-till-basta-bransle-2009
ENGLISH INFO - http://www.gronabilister.se/in-english Daniel Tamm and Martin Fransson, Naturvårdsverket (Swedish Environmental Protection Agency). 2011. Biogasproduktion för miljö och ekonomi.
http://www.naturvardsverket.se/sv/Start/Om-Naturvardsverket/Vara-publikationer/ISBN1/6400/978-91-620-6457-0/
ENGLISH INFO - http://www.naturvardsverket.se/en/ Volvo Group. Forskning om förnybara drivmedel.
http://www.volvogroup.com/GROUP/SWEDEN/SV-SE/SUSTAINABILITY/ENVDEV/RENEWABLE_FUELS/FUEL_COMPARISON/Pages/fuel_comparison.aspx
Return to Top
Return from Biogas to Alternative Fuel Sources
Return from Biogas to Best Alternative Fuel Sources Home page
New! Comments
Have your say about what you just read! Leave me a comment in the box below.
|
