Biomass is one of the most varied fuel substances known to man. There are quite a few different uses for biomass as fuel, and biomass fuel can be derived from nearly anything. Biomass itself is defined as any substance derived from living, or recently living organisms. This includes plants, animals, and trees of all kinds, manure, and everything in between. Each of these can be turned into a green energy source, and can be used by man as a source of power. So how exactly can we use biomass as an energy source in our day to day lives?
We use biomass to live! Our entire diet is derived from biomass. That awesome steak you had last night, that’s biomass. That salad you had? Biomass. Even that atrocious grease covered McWhopper is biomass, believe it or not. All living things rely on biomass to live and all living beings are biomass themselves. Our eating habits aren’t our main focus though, but how can we use biomass and an external energy source to power our vehicles and our electrical and heating devices? Biomass can actually do all three, while we aren’t at the point where this technology can do it all; we are working our way there.
Energy in Biomass
Energy in biomass comes from stored energy that is absorbed from the sun. When the biomass is burned in some manner it creates heat, and releases the energy. As simple as this sounds, it’s only simple in concept. At the end of the day biomass can be processed into several different forms to make it more efficient for energy use, which leads us back to our question, how can we use the energy residing in biomass?
Thermal conversion is a fancy method for saying let’s set it on fire. There is a little more to it than that, but the basis of this conversion method is fire, or extreme temperatures. The most useful form, and most efficient when you factor in time and cost, is direct combustion. The idea behind the direct combustion of biomass is the same idea we use when burning coal.
The burning biomass can be used for a variety of different roles. It can be used in its simplest form to provide heat, and keep people warm. This is probably the original use of biomass, and it goes back to prehistory. Burning biomass can also be used to cook with, and to heat water. In terms of heating water, it can turn water to steam, which can spin turbines, and create electricity. This is the exact same matter in which we use coal.
Pyrolysis is a method in which we can make biomass into charcoal. This is especially true when it comes to wood. Wood is an excellent source of direct combustion material, but can be more efficient when turned to charcoal. To do so we have to go to another thermal conversion process known as pyrolysis. In pyrolysis you apply direct heat to the wood; the difference is you do so in the absence of air and oxygen. This drives off the volatile matter, a property of biomass, and what’s left is charcoal.
At this point you are dealing with something close to pure carbon. This charcoal has twice the energy content per unit mass as regular wood. This makes charcoal superbly efficient and capable of burning at a much higher heat. This makes transporting and storing wood based biomass much more effective than using wood.
One great untapped source of biomass energy is biomass based waste. This includes paper, cardboard, food scraps, plant scraps and even manure. Organic waste makes up 50% of landfills and could all be converted to biomass based energy. To do so, the material is placed in a digester, and anaerobic digestion takes its time breaking down the materials. As the materials break down, they release carbon and methane based gas that can be collected via the digester. This gas can be used for cooking, heating and producing electricity.
Liquid Fuels and Biomass
Liquid fuels are the most popular method of biomass power when you consider the sheer volume at which they are used. It’s difficult replacing crude oil and fossil fuels entirely with biofuels at this time, but it’s a work in progress. As of now our nation couldn’t produce enough biomass to even create enough biofuel to power the nation. Even if we covered the entire nation in corn it wouldn’t be enough. So for now most biofuels are simply additives to fossil fuel based gasoline and diesels.
Ethanol is the most common form of biofuel, and production is in the tens of billions of gallons per year. The vast majority of gasoline sold in the United States is complimented with up to 10% ethanol additives. Most commonly, ethanol is derived from corn or sugarcane. Ethanol is made via fermentation, a biological process that occurs when yeast is added to a sugary substance. The yeast will convert the sugar to alcohol, and this is of course combustible. Sugar cane processes faster, but is harder to grow, and prefers tropical conditions. Corn can be grown across the United States, but requires the starchy material to become sugar based.
Biodiesel is produced from vegetable oils and grease and fats coming from animals. To turn either of these into biodiesel they must be processed with a catalyst and alcohol. Any standard vegetable oil can be made into biodiesel, including used cooking oil or soybean oil. There are small experiments being made to produce biodiesel from algae, but is still in its infancy.
Biomass has the ability to fuel our future in a wide variety of different ways. Again we lack the technology to completely replace biomass as the dominant fuel source, but the industry is making leaps every day. We have the entire world dedicated to limiting, and eventually eliminating our need for fossil fuels, and biomass energy in all its form will be a major contributor.