Page 50 - SD_NG_BC

44 Downstream Natural Gas Copyright © 2014 by SDTC ™

9.7 Renewable Natural Gas

RNG Cleanup Technologies

In order for produced RNG to be used in many applications (e.g. pipeline), impurities such as moisture, tar, carbon dioxide, nitrogen, and siloxanes must be removed. There is a need for both lower cost methods of cleanup of produced gas as well as lower cost approaches to gas quality assurance. Examples of cleanup technologies include removal processes such as novel adsorbants (solid state and membranes) or in-situ conversion (e.g. catalytic tar cracking). Gas quality assurance could include economical alternatives to conventional gas chromatographs. Modular units for smaller applications could also lower costs.

Small Scale Anaerobic Digesters

There are significant dis-economies of scale with current anaerobic digestion technology. Given the distributed nature of raw materials (e.g. small farms), there is a niche for economic small-scale and potentially standardized (vs. site-specific) anaerobic digesters in order to harness a further share of Canada’s RNG production potential.

Gasification to RNG

Gasification and conversion to RNG has the potential to unlock significant RNG production by accessing additional feedstocks (e.g. forestry residues and other localized biomass that may benefit from a small or mobile gasifier). Gasification technologies are considered further from market than the other technologies in this sub-sector.

Table 21: Renewable Natural Gas Technology Summary

Stated Need Technology Descriptor

Impact Ranking Economy Environment

RNG cleanup technologies that improve cleanup economics RNG Cleanup Technologies 1.42 0.72

Cost-effective small-scale anaerobic digesters Small-scale Anaerobic Digesters 1.49 0.64

Cost-effective gasification technology where produced gas is converted to RNG

Gasification to RNG 1.22 0.65

Figure 28: Renewable Natural Gas Technology Plot

0.0

0.5

1.0

0.0 1.0 2.0

Economy

Gasification to RNG Technology

RNG Cleanup Technologies that Improve Cleanup Economics

Cost-Effective Small-Scale Anaerobic Digesters