February 12, 2019

During our initial discussions with Ed he informed me the KBBC was planning on building a large “Great Room” (Dining/Meeting Hall) with additional buildings in the future for housing. The issue KBBC was facing was that their existing system had become woefully inadequate even before these upgrades were being contemplated. The KBBC had two Schneider 6kw inverters and a Surrette Rolls lead acid battery system all on a 48 vdc nominal system. During meal times the load was so extensive that the system was operating at or beyond its maximum capabilities which would have inevitably led to a potential system wide crash due to the rapid voltage drop of the lead acid batteries.

Even with the generator running and the inverters being on assist, this system was showing telltale signs it was going to suffer a system wide crash sometime in the not too distant future. This is a common problem with 48 vdc nominal systems of 20 kW or higher. We limit 48 vdc nominal lead acid and Li systems to 20 kw. Anything above that, we go to 240 vdc or 512 vdc nominal. The rational is simple. Current, conductors, switch gear and the issue of lead acid batteries rapid voltage drop. 20 kW @ 48 vdc nominal is over 416 amps. 20 kW at 240 vdc is 83.3 amps. At 512 vdc it is only 39 amps.

When Ed first came to visit us he saw firsthand the difference between Li systems vs. lead acid and immediately recognized that the lead acid batteries could not perform to the specifications and requirements he was asking. Our rule of thumb with lead acid systems is once a system uses more than 20% of stored power the system will experience voltage drops that will affect inverter performance.

When we showed Ed that our Li systems can be loaded down with a 50% load and it dropped by only .02 vdc he was amazed and said “that’s the ticket! That’s what I need.” Plus these systems are over 98% efficient. Charge/Discharge tests we have done with our 252 AH cells showed us the we could remove 250 AH and replenish it with 251 AH and the system was full. Plus our Li chargers are also very efficient and clean. The power they produce is power supply quality and the efficiency is again, over 98%.

Ed was initially planning to stay with the 48 vdc system by adding another inverter and replace the 1000 AH lead acid battery bank with a newer and bigger bank. However, the more we discussed KBBC’s situation along with its projected future growth potential, the more it became abundantly clear that even if KBBC’s 48 vdc system were upgraded, it would not provide the power to reliably and safely meet their current and future power demands.

This was the basis for KBBC’s decision to go with LiFePO4, 240 vdc energy storage system and a 40 kW, Ametek inverter. We are the only company in the world that utilizes Ametek inverters for primary power systems. Ametek inverters are industrial grade, beyond heavy duty. They are primarily used as nuclear power plant and refinery backup control systems around the world. Almost every nuclear power plant in the world utilizes these inverters. They are designed for a 30-year life, with routine maintenance and periodic swap out of critical components.

KBBC had an existing PV system, that we were able to rewire to accommodate the 240 vdc nominal Li system. We control the PV charging with the Li system BMS. We also installed two 10kW VAWT for additional power production. Plus multiple AC chargers for the Lipo4 battery system. They have two 14kW diesel generators that supply power for the AC chargers based on Li system voltage. The 30-kW inverter has static power loses of approx. 1 kW. This might sound like a lot, but actually for a system like this it is marginal.

Efficiency is very important, but it takes a back seat to reliability. It is imperative that systems like this function/work or what’s the point? Especially as logistically isolated as this system is. Ed demanded that all components had 3 characteristics, reliability, durability & serviceability as it will be operating in an environment that it’s not uncommon to see 90 mph+ winds, snow and rain. Additionally, given KBBC remote location made these requirements all the more imperative. Each system component we designed with Ed met his requirements and the system has been operating flawlessly since June 2017.

Advance Power designed KBBC’s system to not only meet their current demands, but their future needs as well. KBBC’s future includes adding more solar panels and removing the two small generators for one larger generator to meet all the power demand in the remote possibility a catastrophic failure should occur with the renewable energy system. The single larger generator (50kw) will enable the KBBC carry the entire load and allow them to run multiple Li chargers at the same time while minimizing generator run time and fuel consumption to keep up with demand when there is inadequate solar and/or wind available to keep the batteries charged. With diesel fuel nearing $10 gallon by the time it’s delivered to the KBBC, minimizing generator run time is crucial.

Advance Power concurs with KBBC’s risk management perspective to have redundancies and backups built into the system to sustain operations. The upfront cost for these redundancies far outweighs the cost progressive damage would have on KBBC’s state-of-the-art utilities, infrastructure and buildings should it ever lose all renewable power, regardless of the time of year.

Advance Power assembled most of the components in advance at our warehouse in Redwood Valley, CA. Once completed we disassembled them and put them into a 20’ watertight Conex shipping container along with other equipment needed for the install for its 3,000 mile (4,828 km) trip north to Kodiak, Alaska. The two 10kW VAWT’s were shipped from Asia which was a Herculean logistical challenge in itself. Clearing customs, freight, insurance etc.

Once all the components and equipment arrived in Kodiak they were loaded onto a 100’ landing craft for its 12/hr journey from the city of Kodiak to Uyak Bay on the southwest side of Kodiak Island. All components and equipment were air lifted 6 miles (9.6 km) through a mountain pass to the KBBC on Karluk Lake using a Bell 214B helicopter that had a 7,000lb (3,175kg) lifting load capacity. This was the largest commercial helicopter available in Alaska at the time. With the tower sections and the 10kW VAWT generator ends weighing over 4,000lbs (1,880kg) each, the KBBC needed a piece of equipment that would provide large measure of safety lifting these heavy loads.

KBBC’s remote location presented some very unique installation challenges by preventing the KBBC from having ready access to a boom truck or crane to do the install and more importantly, delivering and keeping one of these pieces of equipment on site to perform maintenance. So we designed a split monopole tower that could be assembled with a 5-ton gantry & 5-ton hand chain hoist so the main tower section could be raised and lowered with a 20-ton, counterbalanced hydraulic ram.