RENEWABLE ENERGY OPPORTUNITIES FOR A CITY: BIOGAS
- Jul 8, 2021 4:17 pm GMT
Biogas is renewable energy produced by breaking down organic matter without oxygen by anaerobic digestion with methanogen or anaerobic organisms. These digest material inside a closed system, called an anaerobic digestor, biodigester, or a bioreactor.
It consists of a mixture of gases, such as methane (CH4) and carbon dioxide (CO2), and may have a small amount of hydrogen sulfide (H2S), moisture, and siloxanes. Biogas production is due to raw materials from agricultural waste, manure, municipal waste, plant material, sewage, green waste, or food waste.
It has multiple applications, such as electricity production, cooking, heating, and fuel for vehicles. When compressed, it can replace compressed natural gas for use in cars. Biogas has to go through different processes depending on its use. In the case of using biogas for cooking, it has to go through a biogas upgrader. This facility concentrates the methane in biogas to natural gas standards. If the local gas network allows it, the producer of the biogas may use their distribution networks. In the case of producing electricity and heat, biogas is used in different internal combustion engines to convert into both heat and electricity. This process has inorganic matter not transformed into biogas, called digestate, which can be used for agricultural fertilizer.
Examples of the use of biogas:
- In 2002, the Central Vermont Public Service (CVPS) started the Cow Power Program to meet customer's electric renewable energy demand. It consists of Vermont's hardworking cows and farmers using cow manure to power 2,990 homes and businesses. The mitigating greenhouse gas emissions are the equivalent of taking over 9,000 cars off each year.
- The Southern California Gas Company (SoCalGas) has advocated mixing biogas into existing natural gas pipelines in California. In April 2012, they requested approval to process raw biogas for onsite use or pipeline injection. However, before biogas enters the pipeline, raw gas must be processed to increase methane content and remove trace constituents that harm human health and pipeline integrity. SoCalGas estimates that the project will provide environmental benefits in decreasing greenhouse gas emissions and can supply 20% of California's annual gas consumption.
- In Germany, biogas production has developed rapidly in the last 20 years due to created legal frameworks. One of these is the Renewable Energy Sources Act (EEG), a series of German Laws that initially provided a feed-in tariff (FIT) scheme to encourage renewable energy generation but since has transitioned to an auction system in 2014 and later revised in 2017. Put in place to accelerate the uptake of renewable energy technologies.
- In developing countries, domestic biogas technology is a proven and established technology in many parts of the world. The domestic biogas plants convert livestock manure and night soil into biogas and slurry, the fermented waste. The non-profit Netherlands Development Organization (SNV) is one organization that supports national programs on domestic biogas in Asia and Africa. The aim is to establish commercial-viable domestic biogas sectors in which local companies market, install and service biogas plants for households.
It is no secret I am a proponent of biogas. Knowing how much an individual produces in waste and how it rots in landfills. I love that it a closed system vs. a lineal one and how it continues to contribute. Instead of waste rotting in landfills, causing foul odors, infestation, and the production of vast amounts of methane gas released in the air, why not harness its possibilities?
In today's modern societies and economy, there is increasing organic waste from agricultural waste to animal manure, which can produce clean energy sources with multiple potential benefits for sustainable development. Currently, the world is using only a fraction of the potential to produce gas from organic waste. It could cover around 20% of today's global demand for gas.
Most of the production of biogas comes from crops and animal manure. The primary pathway for biogas has been landfill gas collection in the US, accounting for almost 90% of biogas production in the country. Its development has been disproportionate worldwide, depending on two main factors: policy support and feedstock availability.
Multiple cities worldwide have put in place sustainable development plans to reduce greenhouse gas emissions and increase the circular economy. Having this in mind, then biogas a great source of renewable energy to help with the bottom line. Using this interest as a basis, you can say there is the needed policy support to increase innovation and development of biogas. Cities also need to dispose of their waste correctly, so the feedstock (raw materials) required for biogas production is available, mismanaged, but available. Waste management is essential for the best results in biogas production. There are three strategies that a city can do to optimize the existing raw materials needed for biogas:
- Good dog poop collection: Roughly 84 million dogs in the US produce an estimated 11.6 million tons of poop each year. The pet waste collected in plastic bags is sent to landfills, releasing small amounts of methane, becoming substantial over time. Over the years, there have been studies to turn dog poop into biogas. An example is the Park Spark Project in Cambridge, Massachusetts. It consists of substituting the common trashcan and plastic bag with a public methane digester and biodegradable bag. The dog waste collected is transformed into energy to power an 'eternal flame' monument until someone proposes to use the flame.
- The use of organic waste bans: In the US, forty percent of food produced is wasted. Translating to 58 billion meals go to waste each year, occurring throughout the supply chain, from production (16%), manufacturing (2%), businesses (40%), and households (43%). Enormous amounts of energy, land, and water are used to get food from the farm to the fork. The US spends $218 billion to grow, handle, deliver, and dispose of uneaten food every year. The most significant component of municipal landfills is food waste, so organic waste bans are a great tool to encourage the proper handling of waste. It prohibits entities, such as retailers and foodservice providers), from sending food waste to landfills, promoting donation, composting, or anaerobic digestion (biogas). States like California, Connecticut, Massachusetts, New York, Rhode Island, and Vermont have passed laws to keep food waste out of landfills.
- Create detailed Waste Management Plans: Cities must have a clear and concise written plan for their waste, ensure proper segregation of waste at its source, and ensure that the waste goes through recycling and recovery streams. Waste Management Plans address the following components: source reduction, reuse, recycling, resource recovery (waste-to-energy), incineration, and landfilling. The emphasis on the separation of biodegradable waste from non-biodegradable waste is essential for the implementation of biogas.
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