IEEE Power & Energy Magazine - September/October 2017 - 89

Simulations have demonstrated the effectiveness
of BESSs in mitigating the negative impact of RES
fluctuations on system performance.
PV units and wind turbines, assuming that 30% of the electricity
demand is used to meet the space heating requirement during
the winter season; a 300-kW PV plant and 300-kW wind-generation plant were considered in the case study.
A unit commitment model was coded in the General Algebraic Modeling Systems for a day with time resolution of half
an hour for the 181 days (starting 1 November 2014 and ending
26 March 2015) and solved using CPLEX. The results obtained
from the study are summarized in Table 2. Observe that replacing electric heating with TESSs reduces the operating cost of
the KLFN microgrid by up to 21% for the considered time window; also, significant reduction in fuel consumption and CO2
emissions are observed, and approximately 645 kWh of RES
generation curtailment can be avoided. Based on these results,
we can conclude that replacing wood pallets and heating oil for
space heating with TESSs facilitates the integration of RESs in
the KLFN microgrid.
Note that with TESSs, the 600-kW diesel unit is dispatched more frequently due to its lower fuel consumption,
thus reducing operating costs: TESSs charge when energy
from RESs is available and discharge to meet the thermal
demand for space heating.

Bella Coola
Bella Coola Valley comprises a group of remote communities
located 439 km north of Vancouver, British Columbia, Canada,
with a population of 1,919. The communities are accessible by
road, air, and marine ferry. These communities form the Bella
Coola microgrid, which has a main 25-kV distribution feeder,
with the two major load centers at Bella Coola and Hagensborg
representing a combined peak demand of approximately
4.3 MW in winter and 2.3 MW in summer. (The summer peak
load is relatively stable, but the winter peak load depends on
weather conditions and ranges from 4 to 5 MW.) There are
eight diesel generators installed at the Ah Sin Heek generation
station, with a total capacity of 7,200 kVA. In addition, there
are two run-of-the-river hydro generators, a 720-kVA unit and
a 1,400-kVA unit located at the Clayton Falls hydro plant,
7 km away from the Ah Sin Heek station. The total available
generation capacity varies during the year, depending on the
number of units available and the weather conditions.
During summer, which runs from April/May to late
November, the demand is lower than the rest of the year; at the
same time, the share of hydro generation is at its maximum
due to adequate water supply. Thus, the hydro units, along
with a few smaller diesel generators, are sufficient to meet
the peak load. Throughout this period, the larger hydro unit
september/october 2017

runs in isochronous mode, while other smaller generation sets
run in parallel to keep the frequency within tight ranges. During winter, the hydro power output can change considerably
within hours, and thus diesel engines run in isochronous mode
to regulate the frequency. In addition, the load is higher during
winter compared to summer, and its variation over the 24-h
window is also higher because of varying consumption patterns during nights and days. As a result, all available diesel
units are operated to maintain spinning reserves and adequate
dynamic response capability, which results in the diesel generators operating at efficiencies below 35%.
Driven by the desire to decrease the system's O&M costs,
emissions, and dependency on diesel generators, the Hydrogen
Assisted Renewable Power (HARP) project was developed for
the Bella Coola microgrid. The project aimed to implement an
HFCESS to store the surplus hydro generation and discharge
it during on-peak hours, thus increasing the utilization factor
of hydroelectric power. In addition, the HFCESS was aimed at
shifting the energy production of diesel generators, thus increasing
the efficiency of these units. The implemented HFCESS comprises an alkaline electrolyzer, a compressor, high-pressure
hydrogen storage cylinders, and an air-cooled proton exchange
membrane fuel cell; this technology has a high energy density,
zero standby losses, and an efficient electrolysis process. The
technical specifications of the HARP project are as follows:
1) The electrolyzer produces up to 5 kg/h of hydrogen;
the maximum and minimum charging powers are 320
and 120 kW, respectively.
2) The compressor has a rated power of 50 hp and is able
to pressurize the hydrogen up to 2,850 psi.
3) The hydrogen storage tanks hold up to 100 kg of pressurized hydrogen, equivalent to 3,300 kWh of electrical energy.
4) The fuel cell has a rated power of 100 kW and a minimum runtime of 30 min.

table 2. The Kasabonika microgrid model analyses
with and without TESSs.
Item

PV + Wind
+ Diesel

PV + Wind
+Diesel + TESS

Operating costs (CAN$million)

1.39

1.094

Fuel consumption (million liters) 0.75

0.59

Emissions (metric tons)

2,000

1,585

RES curtailment (kWh)

645

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