Getting RNG from dairy farming to market
- Manure from dairy farming is a major source of methane, which is a potent greenhouse gas
- Capturing biogas can divert it from the atmosphere, as well as providing a source of fuel to produce energy
- Farm-produced biogas is considered a renewable resource, and currently can be sold at about three times the price of standard natural gas
- Pipelining farm-produced methane to the natural gas network is subject to federal, state and other regulations
- Engineering firms with the right skills can help design, construct, and operate a biogas gathering, sales, and transmission pipeline system
Pipeline expertise is helping to solve one of the most important aspects of reducing carbon in the atmosphere – carbon emissions from agriculture. Widely accepted figures show that food production is responsible for a quarter of global greenhouse gas emissions, and of that portion, 31 percent comes from livestock and fish farming.
Now, a Michigan dairy farm is helping show the way forward in reducing greenhouse gas emissions and, at the same time, producing biogas that supplements natural gas reserves. HT Engineering contributed its expertise to help make that possible.
With over 3,000 head of dairy cattle, this farm produces a lot of milk – and a lot of manure. Traditionally, much of the manure from dairy operations is spread on cropland, where it acts as fertilizer to improve crop yields. The problem is that as it decomposes, that manure emits significant quantities of methane, a potent greenhouse gas.
But is there a way to keep that methane out of the atmosphere, and instead capture it to produce energy? There is.
Anaerobic digesters – typically aboveground tanks, some two stories tall and 30 feet across – use natural bacteria to process manure to produce methane. This gas, once treated to remove impurities, can be burned to produce energy. In many cases, the methane is transported via pipeline to where it can be blended into the natural gas stream, as in the case of this Michigan farm.
The US Environmental Protection Agency says that as of 2021, there were 221 anaerobic digester systems processing dairy cow manure in the U.S., and these systems reduce approximately 4.29 million tons of carbon dioxide equivalent each year. It’s a well proven and established technology.
What makes this economically viable is the push by governments around the world, including the US, to promote carbon-reduction technologies. One way they do this is by issuing carbon credits, which are tradable certificates or permits, representing the right to emit a set amount of carbon dioxide or the equivalent amount of a different greenhouse gas. Because methane is such a potent greenhouse gas, its capture ranks high in terms of generating carbon credits.
This means that methane capture systems such as the one at the Michigan dairy farm produce gas that can, at the time of this writing, be sold for roughly three times the price of regular natural gas, making the gas capture and processing system profitable.
Also, the byproducts from anaerobic digestion of manure, including the solid “digestate,” a nutrient-rich fertilizer, can be used to improve soil health and crop yields without releasing all that methane to the atmosphere.
In addition to animal manure, other biological sources of methane are considered renewable, including landfills and sewage-treatment facilities. In some cases, particularly at landfills, the captured gas is burned on site or nearby to generate electricity or to fuel a process rather than being sold into the transmission or distribution pipeline system for use elsewhere.
While convenient and efficient, the economics of some of these cases are being shifted by government incentives, and the gas owners are seeking to bring it to market instead of using it directly.
How pipeline expertise helps support biogas application
The pipeline sector – operators, contractors, vendors, consulting engineers and others – can add value to the inclusion of renewable natural gas in the energy mix by providing reliable support to cleantech entrepreneurs seeking to work with farmers and other sources of RNG.
Meet your regulatory obligations
Many aspects of safe pipeline operation can present a steep learning curve to people from outside the pipeline industry. Methane-carrying lines can fail, resulting in unplanned releases, and, in the worst case, deadly explosions.
To deal with the hazards of transporting flammable gas, many federal and state agencies put significant regulatory obligations on pipeline operators. In the case of the Michigan farm system pipeline, it was designed as piggable and safe, and in a way that it will require minimal regulatory oversight.
Meet buyer specifications
Anaerobic digestion is a complex process, and changes in feedstock and other conditions such as ambient temperature can produce variability in the product. If it’s to be acceptable to the buyer, the product must meet tight specifications. At biogas installations such as the Michigan farm, the product is continuously analyzed at the point of sale, and will be rejected if it’s off-spec.
Gain access to the right expertise
As with much of life, having access to the right skills and knowledge is vital to success in developing farm sourced RNG. Here’s how consulting engineering firms focused on pipelines, such as HT Engineering, can be your key source of support, know-how, and connections:
Designing the pipeline
Many people new to pipelines may be surprised at how complex pipeline design can get, particularly if the pipeline must cross property lines, roads, railroads, and other utilities. There may be environmentally sensitive areas such as streams and wetlands along the planned pipeline route that require special care.
The measurement, analysis, and control system of a pipeline is highly specialized. The list of equipment to be specified and purchased may be long, and some items have long lead-times.
A consulting engineering firm with this area of expertise can help you develop a design that will meet safety and regulatory requirements as well as being economical to build and operate.
Working with contractors and vendors
As with designing pipelines, pipeline construction is a highly specialized field.
There are myriad things that can go sideways, like when there’s a “strike” on an existing pipeline. One of the primary causes of pipeline failure is third party damage, which often occurs when an excavator bucket hits a utility that is not actually located where it was marked on the map. Schedule delays due to a lack of knowledge of the specifics of procurement and construction are common.
An experienced consulting firm such as HT Engineering can help you build a realistic execution plan that accounts for common contingencies, find the right contractor, and provide construction management services to make sure your work gets done right, on time.
Commissioning and startup
A consulting engineer can help make sure all is in readiness for putting the new line to work – and can be on hand to see that no problems derail your line’s startup.
Ongoing operation and maintenance
Methane is a flammable, explosive, hazardous gas. The main federal regulatory agency for pipelines, the Pipeline and Hazardous Materials Safety Administration (PHMSA), along with state agencies, take steps to make sure lines are operated safely. A consulting engineer familiar with the expectations of PHMSA and other regulatory agencies, can help you develop and implement operating, maintenance, and emergency response plans that will lay a firm foundation for ongoing compliance.
Contact us to learn about transporting your RNG to where it can be sold to market.