The evolution of off grid generator power
Not all off grid power systems are built around solar energy. One such system is located on a remote, isolated island off the coast of Vancouver, British Columbia, Canada. There is no power on the island, or utilities of any kind. Yet this customer hosts a missionary camp for indigenous peoples, and is staffed year-round. The largest population on the island occurs from June to September when the camp is in session.
Power on the island is provided by three-phase diesel generators that used to run 24x7, 365 days a year. Running a large generator constantly would be expensive on the mainland, but on an island requiring everything and everyone to arrive by boat, it's extremely expensive. The island has two generators. One is 15kW and runs during the off-season. The other is 45kW and runs during the three months of peak season. Looking to reduce the cost of diesel fuel and its delivery to the island, our customer contacted us to help them build a hybrid generation system that would reduce the usage of the diesel generator, thus saving the non-profit mission a boatload (pun intended) of money each year.
One of the volunteer board members understands electrical systems, including three phase power, and had been researching off-grid power production options. Their research led them to Victron Energy, and ultimately to Off-Grid Power Systems in Delaware, Ohio. They were forthcoming in letting us know that solar power was not something they were considering - at least not yet - and the decision would be based solely on a quick return on their investment (ROI). Being knowledgable as they were, they understood that running a generator that was fully loaded wasted fuel. Indeed, a generator is most efficient when it is running at approximately 80% of its rated capacity. And since generators are often sized for peak loads, which occurs less than 15% of the running time, generator-based off-grid systems tend to be very inefficient. Enter the hybrid generator.
The hybrid generator
According to Victron Energy:
"Hybrid generators don’t just beat traditional generator-only installations in the business sense - they’re better in virtually every other imaginable parameter. A hybrid system significantly reduces fuel consumption, emissions, noise, service intervals and overall logistics while providing uninterrupted clean power at all times."
Hybrid generators involve inverters, batteries, battery chargers, and of course, a generator. Properly sizing an off-grid, hybrid generation system is a little more complicated than simply determining peak loads. To reach peak efficiency, a careful analysis must be done to determine the generator's most efficient load (i.e. maximizing peak kWh per liter of fuel), how high expected peak loads might be (which might be higher than the generator's own capacity), duration of peak loads, and the total cost of fuel (per liter cost plus delivery and storage costs). Once those are determined, only then can the inverter and battery capacity be determined.
Where are hybrid generators used?
- Remote, inhabited islands
- Broadcast radio and television transmitter sites
- Remote telecom and cellular sites
- Emergency response vehicles
- Disaster response
- Forward military bases
- Or anywhere generators are used to backup utility power in mission-critical situations: hospitals, communications, emergency operation centers, etc.
The system
Off-Grid Power Systems configured and tested the hybrid generator system in our shop in Ohio, and then shipped the components to Canada where they were physically installed by mission volunteers and staff. OGPS remotely commissioned the system using Victron's Remote Management Portal (VRM). The system consisted of:
- Three Victron Energy MultiPlus-II 48/3000 hybrid inverters configured for three phase 208V output
- 33kWh of battery storage
- A Victron Cerbo GX and Touch 50 GX touchscreen controller for remote monitoring and generator auto start/stop control
The results
According to the customer, they reduced their diesel fuel usage by approximately 70% during the nine month off season. Instead of the generator running 24x7, it now runs for almost three hours at a time, just three times a week. Previously, the generator was very lightly loaded and ran all the time. Now, the generator runs at a more efficient load and runs far less often. The customer plans to add an additional battery charger to bring the generator to its most efficient load, which will reduce overall diesel fuel costs by over 80%. The best part? The customer achieved a full payback on their investment in under a year.
If you're looking for reliable, cost-effective power for your challenging situation, contact Off-Grid Power Systems at 740.234.3434 or visit us at https://offgridps.com.