Energy, Mines and Resources

Energy Branch / Energy Solutions Centre

Northwestel’s remote microwave stations get a boost from solar energy generation

Northwestel maintains and operates 156 microwave stations within Yukon and Northwest Territories. Of these sites, 87 are off-grid and rely on independent power sources with 37 accessible only by helicopter. Depending on their size, these off-grid systems rely on two air-cooled diesel generators.

The operation and maintenance costs for these remote stations is significant, costing Northwestel up to $5/L in fuel and up to $2.5 million dollars per year to maintain (2013 costs).

In 2013, Northwestel worked with the Government of Yukon’s Energy Branch to examine the feasibility of operating a solar/diesel hybrid power system at one of the remote microwave stations. The study looked at using a solar photovoltaic (PV) installation tied to the existing diesel generator at a station to see if it could reduce Northwestel’s base energy costs.

The results of that feasibility work were very positive and Northwestel partnered with the Energy Branch and the Cold Climate Innovation to install a large solar array at their Engineer Creek site. At the time, the series of solar panels at the Engineer Creek microwave station became the largest PV array in Yukon.

This proved to be a successful pilot project, reducing energy costs by about 80%. It estimated that capital investment costs will be reimbursed within four and a half years.

Construction of solar photovoltaic hybrid system at NorthwesTel’s Engineering Creek microwave station.
Credit: Courtesy of NWTel/Fritz Mueller Photography.

Following the 2013 pilot project, Northwestel implemented eight additional solar/diesel hybrid power systems within their telecommunications infrastructure.

Project benefits

  • Reduced use of diesel: the solar/diesel hybrid power system reduced reliance on diesel fossil fuels as an energy source.
  • Maintenance cost reduction: Solar/diesel generators demand fewer helicopter trips to the remote microwave sites for maintenance and diesel delivery.
  • Significant reduction in greenhouse gas (GHG) emissions: using solar generated electricity reduced diesel use by 60% thus creating a greener site.
  • Short-term return on capital investment: by reducing energy costs by 80%, the upfront capital investment costs in the solar/diesel hybrid power system can be reimbursed within four and a half years.

Project profile

In 2013, Northwestel partnered with the Government of Yukon’s Energy Branch and Cold Climate Innovation  at the Yukon College’s Yukon Research Centre to investigate options to reduce its dependence on diesel systems at its remote microwave sites.  A pilot project was proposed to implement a solar/diesel hybrid power system as a way of reducing fuel costs and maintenance.

The Government of Yukon’s Energy branch was able to provide support and expertise in investigating the potential for using renewable energy technologies within Northwestel’s telecommunications infrastructure.

Arial view of diesel/solar photovoltaic hybrid power system at NorthwesTel’s Engineer Creek microwave station.
Credit: Courtesy of NWTel/Fritz Mueller Photography.

The Government of Yukon’s Energy branch was able to provide support and expertise in investigating the potential for using renewable energy technologies within Northwestel’s telecommunications infrastructure.

Researchers analyzed the potential use of a solar PV array at the Engineer Creek microwave site with an operational load of 1.8 kilowatt (kW) to 2.8 kW.

The Energy branch examined the relationship between useful energy generated and the installed PV system’s capacity. As a PV system’s capacity increases, the useful energy generated increases. However, the rate of increase drops sharply as the system capacity approaches 50 kW. This is because the installed PV system is providing more energy than is useful to the system. This relationship suggests that the optimal systems capacity is below 50 kW regardless of the operational load.

Following an analysis of optimal system capacity, it was decided that that a 15 kW PV array would be appropriate for the Engineer Creek site. The base cost of an installed 15 kW system was estimated to be $0.28/kWh which is significantly lower than the $1.53/kilowatt hour (kWh) base cost of diesel required for the same site.

Typical solar-diesel combination generators use an average of 30 L daily (about 10,950 L annually), corresponding to greenhouse gas emissions of 30 tonnes of carbon dioxide equivalent (CO2e).  Strictly diesel generators use an average of 50 L daily (about 18,250 L annually), corresponding to 50 tonnes of CO2e. It was determined that the solar-diesel hybrid site could save up to 20 CO2e compared to the strictly diesel ones. 

In the spring of 2013, a 15 kW PV array was constructed at the Engineer Creek site with financial support from CCI and the Government of Yukon’s Energy branch.

The systems worked very well. From March to September, solar contributions are very significant which rendered diesel use negligible.  Diesel use increased during the darker months when solar resources were less.

Considering the cost of getting diesel to fly-in sites could be as high as $5/L at the time, the hybrid generators reduced significant costs associated with delivering fuel. Following the pilot project, Northwestel estimated that the fly-in site saved about $44,000 in diesel per year compared to the strictly diesel-powered remote sites.

In the end, the solar-diesel remote station used roughly 60% the amount of diesel and correspondingly lower GHGs compared to a strictly diesel site.

Following the success of the 2013 pilot project at the Engineer Creek site, Northwestel added solar/diesel hybrid power systems to eight remote microwave sites requiring helicopter fly-in. The sites are Peterson Lake, Brown Lake, Mackay Lake, Courageous Lake, and Wolverine Lake in the Northwest Territories and Weasel Lake, McEvoy Lake, and Mt. Murray in Yukon.

Lessons learned

  • Weather and the elements: Given the remoteness and lack of shelter from the elements, snow fencing is required. The effects of local terrain, prevailing wind direction, and the height of solar panels from the ground are all considerations when constructing remote PV array installations.
  • Damage to panels: Muskox and other wildlife have been known to use solar panels as scratching posts which could conceivably lead to cracking. In a remote location, things can happen to panels, potentially from weather impacts such as high winds carrying debris.  Despite cracking on some panels, Northwestel says energy generation has remained steady.
  • Lightning: Lightning’s effect on the solar panels themselves is minimal. However, it can damage the controllers and monitors if struck, making the PV systems unusable until repaired.
  • Snow reflections: The light bouncing off the snow is a big bonus and provides significant power to the PV array, even on even overcast days. Northwestel has been pleasantly surprised with solar gains recorded in March, and even February.

Project outcome

With the demonstrated economic and environmental benefits of tying solar to diesel generators, Northwestel is looking at other potential solar opportunities. They have addressed their economic and logistical challenges by connecting solar to some of their helicopter-access only microwave sites.

Northwestel is exploring solar generation options closer to towns and in areas accessible by ground transport. While the savings from displaced diesel may not be as significant as recorded with the remote sites, the prospect of solid economic and environmental benefits is attractive to the company. 

The Energy branch will continue to work with Northwestel on exploring how it can further integrate solar generation into its operations.