Image: Matt and Betty: Clayton Falls License: CC BY-NC-SA 2.0
The electrical grid in Bella Coola is an isolated micro-grid. That is it is not connected to the main grid; all of its electricity is produced and consumed locally. The two primary sources of electricity are a 2.1MW run-of-river hydro installation and 6.2kW of diesel generators. The Hydrogen Assisted Renewable Energy Power (HARP) project is a project whose purpose it is to reduce the dependence of Bella Coola on diesel as a source of energy. According to a smart grid report from General Electric (one of the organizations involved in the HARP project), the peak consumption in the valley is about 4.7MW and the average consumption is about 3.2MW. The purpose of the HARP project was to store some of the energy from the hydro installation during non-peak hours in hydrogen fuel cells, and then use the stored energy during peak hours to offset some of the diesel usage. From what I can gather, this cycling of storing and then using the energy will be on a daily basis. Store energy at night in the fuel cells and use it during the day.
The reported savings will be 200,000 liters of diesel a year. Here are some rough calculations to support that number. According to the GE report mentioned above, the storage capacity of the fuel cells is 3.3 MWh (MegaWatt-Hours). If you assume that about 3 MWh can be stored at night and then consumed during the day every day of the year, at 67% efficiency then the fuel cells will be offsetting 3MWh * 365 * 0.67 = 733.65 MWh. Further, if you assume that diesel contains about 10 kWh/liter and diesel generators are about 35% efficient, then 200,000 liters of fuel will deliver 10kWh/liter * 200000 liters * 0.35 = 679,000 kWh = 700 MWh. That’s pretty close to what we estimated the fuel cells would be able to deliver. Obviously there are a lot more subtleties that would go into the actual calculations, but as an estimate, we’re pretty close.
The other main aspect of the installation (and in fact what makes the Bella Coola microgrid a “smart grid”) is a microgrid controller from GE that automatically determines what should be turned on/off to respond to changes in demand.
This all sounds fantastic and sustainable and green and fantastic (oops, I said that already), but how much diesel did the community use before these updates, and what percentage of their diesel use are they replacing with the HARP system? I would like to know these numbers and even further, I would love to see this community and others like it replace 100% of their diesel use with non-carbon producing sources. Bella Coola seems to have potential for even further micro-hydro production, so I wonder if they have any future developments in the works.
To give a rough answer to my first question in the above paragraph, it looks like there is an average of 1.1MW of power production shortage between the production from the Clayton Falls microhydro plant and the average consumption. This is making another assumption that Clayton Falls produces an average of 2.1 MW of power, but I think that that number is the peak, not the average. Let’s go ahead with the calculations anyway…therefore, in a day, the energy shortfall will be 1.1MW * 24 hours = 26.4 MWh. HARP is providing 3 MWh per day, which is 11.4% of the shortfall (3/26.4 * 100). So, if my assumptions are anywhere near correct (and they may not be), it looks like in the absolute best case scenario, Bella Coola is saving 11.4% of the diesel that they used to consume. That’s a good start.