As discussed elsewhere on this website, the Xeni Gwet’in will soon have a solar-diesel system based on photovoltaic (PV) panels and a large Li-ion battery. Their reliance on diesel is expected to be decreased by about 40% compared to diesel-only.
A 40% reduction in electricity-related GHGs is quite an achievement for a solar-hybrid system in British Columbia, where the solar resource (highest in summer and lowest in winter) is at odds with typical community demand (lowest in summer and highest in winter). Typical GHG displacement achieved by solar-hybrid systems in BC is around 30%, and this system is expected to do better thanks to aggressive demand management practices.
The Xeni Gwet’in First Nation asked Brevifolia to explore the potential of bioenergy to close the gap and get to 80+% diesel/propane use reduction. Specifically, the Nation wants to demonstrate the feasibility of integrating a small biomass gasification combined heat & power (CHP) plant with the solar-hybrid system. The gasification plant would provide clean baseload electricity in the winter months when little solar energy is available, while the thermal energy would be used to heat community buildings through a district heating system (displacing propane). In the summer, excess energy from the solar system would be used to process (dry and chip) the biomass required for winter operation (as opposed to using a diesel-powered dryer/chipper). Overall, combining solar and bioenergy for electricity and heat could potentially result in the Nemiah Valley being nearly 100% renewable for electricity and heat. This feasibility study is expected to be completed in spring 2020. If shown to be feasible, combining solar and bioenergy could provide a blueprint for many other remote communities in BC and Canada.