The Story of Mi-Grid

The problem
Mi-Grid started as most things do with a request from a client. Tetra West Solar was approached to help an agricultural concern in South America. They had multiple pumps in multiple locations, powered by diesel generators. The cost of the fuel plus delivery was quite high. They wanted a solar energy solution.

Standard Solar
The pumps would run from 12 hours, from 6AM to 6PM. The smallest pump was 30kW. This required a generator set of 75kW. Unfortunately, this also meant the generator ran about 40% load, not an efficiently. The cost to run the pumps, around $60,000-75,000 per year, depending on the price of diesel fuel. A full size off-grid solar energy system with 2 days of storage was a sizable capital investment. Too much to consider.

Solar Offset
The first idea was to add some supplemental solar. A Grid-Tie type system would be connected, but size to 90% of maximum power consumption at noon. Based on the modeling, the solar would produce about 64% of the power. But the generator would still run continually. Fuel consumption would be reduced by only 43%. There was also concern about a grid-tied solar system tied with a generator. It is not recommended, even on large systems. Some sort of diversion system would be needed if the pump shut down and the generator continued running.

Add in storage
The new idea, add storage. But how? Grid-Tie systems aren’t designed to store power. How do you know when the power needs to
be diverted?

Back to off-grid
Off-Grid systems have storage and can buffer the solar energy. But some can connect more energy sources than simply solar. Maybe wind, maybe a generator.

Energy Management
A way was needed to combine all of these disparate energy sources together. This was the birth of Mi-Grid. Multiple sources of power with a way to pick the least expensive, most reliable source at any moment.
With the energy storage, solar and control over the generator, the modeling showed a 90% reduction in fuel. Most of the fuel use came on cloudy days. Mi-Grid and more While Mi-Grid started as a system for off-grid, even utility power could be connected. Mi-Grid can replace standard grid-tied systems, but more features and multi-source reliability.

Save 30% more than Grid-Tied
As the grid-tied Mi-Grids were compared with standard grid-tied solar, it was found that keeping the power saved 30%.

Increased reliability
Standard Solar save money, but doesn’t help when the power goes out. Mi-Grid keeps the power on.

Never lose power
One problem with backup generators, you have to lose power before the generator turns on. With Mi-Grid, all power sources are monitored. Switching between sources occurs in 1/60th of a second, and there is always enough residual power to keep you on while the generator warms up.

Save energy
The battery bank isn’t just for solar. The generator only runs long enough to recharge the batteries. Saving energy saves money, reduces noise and makes the system more reliable.

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