Renewable Natural Gas. Those unfamiliar with the concept might initially think of it as an oxymoron. “How can natural gas be renewable?” you might ask. The major difference lies in timescales. While renewable natural gas can be produced from last weekend’s leftover brunch, conventional natural gas could be derived from an ancient, decomposing pterodactyl. Confused? Read on.
Conventional or fossil-fuel based natural gas is produced when layers of decomposing organic matter are subject to extreme temperature and pressure, under the surface of the earth, over millions of years. Renewable natural gas (RNG), a term coined by FortisBC, is produced from much shorter-lived organic materials. RNG or biomethane is derived from biogas, which is a gaseous product of the decomposition of organic matter. Biogas can be used raw or upgraded to biomethane (99% methane). Biogas has been utilized by different civilizations throughout history. It has been used for heating bath water in the 10th and 16th century B.C. in Assyria and Persia respectively. Leaping forward in time, in 1859 A.D. the first biogas digestion plant was built in Bombay. In 1895 the British created a sewage treatment facility to recover biogas which was then used to fuel street lights in Exeter. At present time, biogas is mainly produced in developing countries such as China, India, and Nepal, with European countries such as Germany, Austria, and Denmark focusing more on large-scale industrial plants.
There are various sources from which biogas can be produced. In BC, the three main sources are 1) decomposing waste in landfills, 2) wastewater from treatment facilities, and 3) agricultural waste. The latter involves anaerobic digestion, a series of processes in which microorganisms break down biodegradable materials in the absence of oxygen. Conveniently, these 3 sources of biogas are commonly located within close proximity to urban environments. There is great potential for biogas to be captured and purified into biomethane, and further blended into natural gas distribution systems leading straight to stratas and households.
FortisBC has been providing RNG to residential and commercial customers since 2010. Currently there are 4 operational facilities that supply biogas in BC: the Salmon Arm Landfill, Fraser Valley Biogas (agricultural and food processing waste), Glenmore Landfill (in Kelowna), and Seabreeze Dairy Farm in Delta (dairy cattle manure and Metro Vancouver organic waste collection). Lulu Island Wastewater Treatment Plant in Richmond and Dicklands Farm in Chilliwack are two additional facilities likely to become operational RNG producers in the next few years.
Since the creation of the RNG program there have been debates between FortisBC and the BC utilities commission over the price of RNG. The remarkably low price of conventional natural gas has severely hindered the competitiveness of RNG. However, the commission has recently approved a price cut to RNG, making it more accessible to customers while kickstarting an upward trend in sales. Various factors could lead to further reductions in the price of RNG. A potential factor could be the technological breakthrough that allows BC’s abundant wood fibre supply to be converted into biomethane. While this conversion is currently not feasible, scientific advancements may reveal how to make this feasible in the near future. This potential technology would unlock enormous volumes of supply of biomethane, further reducing costs. Other potential factors for the reduction of cost in RNG include rises in the market price of conventional natural gas or government intervention limiting greenhouse gas (GHG) emissions.
As a critical distinction to fossil-fuel based natural gas, RNG is a carbon-neutral energy source. As described by Bill Andrews (legal counsel for BCSEA and SCBC in BC utilities commission proceedings) there are several environmental benefits to using RNG over conventional natural gas. The basis for these environmental benefits lie in the fact that methane has a much higher Global Warming Potential (GWP) than carbon dioxide. Methane traps up to 100 times more heat than carbon dioxide over a 5-year period. Why is this important? It means that by collecting methane that would have otherwise been naturally released to the atmosphere through anaerobic digestion, RNG is effectively reducing overall GHG emissions. Additionally, the production and use of RNG displaces the wasteful and disruptive operations involved in the upstream fracking of fossil-fuel natural gas. It is important to note that the burning of RNG will contribute to GHG emissions, but not nearly as much as the burning of conventional natural gas.
Several climate change reduction targets have been set at various government levels. The BC Climate Leadership Plan has 80% reductions in provincial emissions by 2050, while the City of Vancouver has 2050 targets to power the city with only renewable energy sources. While BC’s electricity production is almost 100% clean, there is significant room for improvement in reducing the emissions from the burning of fossil-fuel natural gas. RNG has enormous potential in the phase out of conventional natural gas and will certainly play an important role in achieving government GHG reduction targets.
In the upcoming BCSEA webinar The Road to Sustainability: Renewable Natural Gas in BC, on January 31st, Colton Aston (Energy Solutions Manager with FortisBC's Renewable Natural Gas program), and Ethan Werner (Director of Operations with CHFour Biogas) will provide an overview of the utility program, the evolving technology of anaerobic digestion, and the unique world of biogas project development. Take a look and click here to register!
Marco Sanelli is a 4th year student in the Natural Resource Conservation major in the Faculty of Forestry at UBC.