The concept of biomass energy is still in its infancy in most parts of the world, but nevertheless, it does have an important role to play in terms of sustainability in general and net-zero buildings in particular. Once processed, biomass is a renewable source of energy that has amazing potential. But there is a lot of work to be done to exploit even a fraction of the possibilities that would play a significant role in providing our homes and commercial buildings with renewable energy.
According to the U.S. Energy Information Administration (EIA), only about 5% of the total primary energy usage in the U.S. comes from biomass fuels. So there really is a way to go.
The Concept of Biomass Energy
Generally regarded as any carbon-based material including plants, food waste, industrial waste, reclaimed woody materials, algae, and even human and animal waste, biomass is processed to produce effective organic fuels.
The main sources of biomass include wood mills and furniture factories, landfill sites, horticultural centers, wastewater treatment plants, and areas where invasive and alien tree and grass species grow.
Whether converted into biogas or liquid biofuels, or burned as is, the biomass releases its chemical energy in the form of heat. Of course, it depends on what kind of material the biomass is. For instance, solid types including wood and suitable garbage can be burned without any need for processing. This makes up more than half the biomass fuels used in the U.S. Other types can be converted into biodiesel and ethanol.
Generally:
- Biogas forms naturally in landfills when yard waste, food scraps, paper and so on decompose. It is composed mainly of carbon dioxide
- Biogas can also be produced by processing animal manure and human sewage in digesters.
- Biodiesel is produced from animal fats and vegetable oils including soybeans and palm oil.
- Ethanol is made from various crops including sugar cane and corn that are fermented.
How Biomass Fuels Are Used
Ethanol has been used in vehicles for decades and ethanol-gasoline blends are now quite common. In fact, some racing drivers opt for high ethanol blends because they lower costs and improve quality. While the percentage of ethanol is substantially lower, it is now found in most gasoline sold in the U.S. Biodiesel can also be used in vehicles and it is also used as heating oil.
But in terms of their role in net-zero buildings:
- Wood and wood processing waste is burned to heat buildings and to generate electricity.
- In addition to being converted to liquid biofuels, various waste materials including some crops like sugar cane and corn can also be burned as fuel.
- Garbage, in the form of yard, food, and wood waste, can be converted to biogas in landfills and anaerobic digesters. It can also be burned to generate electricity.
- Human sewage and animal manure can be converted to biogas and burned as heating fuel.
Biomass as a Viable Clean Energy Source for Net-Zero Energy Buildings
Don’t rely on what I say, let’s look at some research, specifically, a study published just last year (2018) that deals with the development of net-zero energy buildings in Florida. It looked at the capacity of biomass, geothermal, hydrokinetic, hydropower, marine, solar, and wind power (in alphabetical order) to deliver renewable energy resources. More specifically, the study evaluated Florida’s potential to utilize various renewable energy resources.
Generating electricity from wind isn’t feasible in Florida because the average wind speeds are slow. The topography and hydrology requirements are inadequate and both hydrokinetic and marine energy resources are limited. But both solar and biomass offer “abundant resources” in Florida. Unlike most other renewable resources, the infrastructure and equipment required are minimal and suitable for use within building areas, and they are both compatible with the needs of net-zero energy.
The concept of net-zero buildings has, of course, been established by the World Green Building Council (GBC), which has set timelines of 2030 and 2050 respectively for new and all buildings to achieve net-zero carbon goals. Simplistically, what this means is that buildings, including our homes, will need to become carbon neutral, using only as much renewable energy as they can produce on site.
But nothing is simplistic when it comes to net-zero energy buildings (ZEB) ). Rather, different categories offer different boundaries in terms of how renewable energy strategies are utilized. These show that net-zero energy buildings are not all the same:
- ZEB A buildings utilize strategies within the building footprint
- ZEB B within the site of the property
- ZEB C within the site but from off-site resources
- ZEB D generate renewable energy off-site
While solar works for ZEB A and both solar and wind work for ZEB B buildings, biomass and biofuels are suitable for ZEB C and D buildings, particularly in Florida.
Even though this particular study is Florida-specific, it indicates the probability that the role of biomass energy will ultimately be limited, but that it can certainly help buildings reach a net-zero status.
There will be different requirements and benefits in different areas, but certainly professionals offering engineering solutions in Chicago, New York, London (Canada and the UK), and all the other large cities in the world will be in a position to advise whether it is feasible to use biomass rather than other forms of eco-friendly energy for specific buildings.
Biomass might offer a more powerful solution than many people imagine.
