Case study

AT&T Mt Patterson – 74% Reduction in Fossil Fuel Consumption

SUPERCAPACITORS ENABLE WINTER OPERATION WITHOUT GENERATOR REFUELING

AT&T Mt Patterson – 74% Reduction in Fossil Fuel Consumption

LEAD ACID BATTERIES VS. SUPERCAPACITORS

Genset Runtime:

Lead Acid Batteries required generator to run 4,824 hours per year

Supercapacitors required generator to run 1,023 hours per year

This site is under 10' of snow from November to May. With lead acid batteries we would have run out of fuel by January and wouldn't be able to keep the site on air. With the supercaps, we only refuel the generator tanks 1 time per year and it's only 1/2 empty when we do. We could not keep this site going year around without supercaps.
Charles Newdigate ,
Cell Site Technician

42.6kWh:

42.6 KWh of Supercapacitors

POWER HANDLING:

16kW Vertiv Rectifiers
7 Solar Controllers

Solar provides primary power

  • 15 KWs of solar power
  • 6,000 gallons of propane

COST

GENSET RUN TIME (Hrs/Annum)

TOTAL BATTERY LIFE / YEARS

4G and 5G implementation was increasing the load of the site by a factor of 5 at this AT&T communication site. Constructed more than 10 years prior as a solar site, a PV panel upgrade increased the PV gain by a factor of 4 but more power was needed. Additional real estate for the PV array was not available. Additional power must come from a generator. But at 10,000 foot elevation it would be impossible to refuel in the winter. The solution - optimize generator runtime and minimize generator fuel consumption using supercapacitors as the storage medium.

Using lead acid batteries was not an option. It would require 5 strings equalling 240 KWh of storage and at 5:00 PM each day the stored battery power would be called upon, completely drained by midnight and needing a recharge. Due to the slow charge rate of lead acid batteries (.2 C), the generator would run another 8 hours to charge the battereis and the 6,000 gallons of fuel would be consumed in 3 months. Additionally, at this daily cycle rate, the lead acid batteries would need replacement within 3 years.

Supercapacitors can be rapidly charged (1.7 C), allow for a 90% Depth of Discharge (high availability of stored energy) and have a very high cycle life (over 25 years at daily cycling). Due to these advantage, fewer KWh of storage would be needed to provide the needed energy for the site, making for a much smaller footprint and reducing the generator runtime by 74% over the lead acid batteries.

CIC prepared the engineering and cost benefit analysis using its proprietary energy analysis software, and provided the complete turnkey solution - engineer, furnish and installation. Monitoring and follow up have proven that the system continues to operate as designed and the site’s minimal generator runtime means that the site is fueled just one time per year cycling the supercapacitors two times per day since October 24, 2019.

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