Posts tagged with "grid-tied"

Sunset for Earth Day blog about solar power.

Mi-Grid: For Us, Every Day is Earth Day with Hybrid Renewable Energy Management

For Mi-Grid, every day is Earth Day because our hybrid energy management system harnesses renewable energy. At its core, the system is clean, simple and economically sustainable.

The most earth-friendly aspect of the design is solar power or wind power, either of which can be controlled by Mi-Grid. We take it further, with batteries to store the renewable power for later use as well as with a generator running on either natural gas or propane, backing up the renewables as well as grid-tied power.

Mi-Grid’s controls cycles among power sources. For example, solar panels will generate energy during the day, supplying power and sending the excess to the batteries. As the sun sets, the system taps the energy stored in the batteries for power. If the battery storage drops to 50%, the generator takes over in supplying electricity. All of these internal dispatches by Mi-Grid are seamless to the consumer. You never lose power.

The Mi-Grid system is sized to different applications and demand (load) needs. Each provides reliable, environmentally friendly power.


In this scenario, a home or business is connected to a utility grid, but not reliant on it. Instead, the solar or wind power on-site is used first, again going green as the primary consideration. If the utility grid goes out for whatever reason, such as a thunderstorm, Mi-Grid disconnects from the utility and keeps the power on. Any excess solar-generated power goes to the batteries. By contrast, a conventional grid-tied solar power installation goes dark when the utility grid is down. With the grid-tied Mi-Grid system, you save money on electricity, never lose power and benefit from your own renewable energy.


If your location is off-grid, the Mi-Grid solution is more economical than relying on solar power or on a generator alone. Remember, the battery component stores excess solar power and the generator only cycles on when needed, not all the time, reducing fuel and maintenance. Less fuel lowers your carbon footprint and storing renewable energy in batteries is a cost-efficient mechanism, less expensive than solar only.


Hitting the open road in a recreational vehicle (RV) with Mi-Grid is in keeping with the pack it in, pack it out spirit because you are taking your own green power with you onboard! You are not running a loud, fuel-guzzling generator, but you have power anytime you want! Solar panels on the roof of the RV are controlled by a module housed easily within the camper. This system works beautifully for motor homes, food trucks and any mobile business. You can be powered up anywhere, anytime with the mobile version of Mi-Grid.

That’s why we can celebrate Earth Day all year round! More information on Mi-Grid sizes and pricing can be found here.

For more information, contact us at

How a Mi-Grid microgrid can be configured with AC power.

Mi-Grid Can Connect with Either AC or DC Coupling for Solar

We design our microgrids with flexibility in mind. For instance, Mi-Grid can be installed with either AC or DC power coupling. We can power you either way. Our systems can work with solar or wind power too.


Mi-Grid AC vs. DC

Solar panels can be connected to Mi-Grid in two different ways. They can be DC coupled or AC coupled. Coupling is simply the term we use for the connection of the solar panels to the Mi- Grid system.


DC coupling is the traditional way to connect solar panels to the Mi-Grid system. It is also the most efficient. Solar panels are DC (Direct Current), like a battery. It is easiest and most efficient to keep the power DC when storing to the batteries.


AC coupling means the power is converted to Alternating Current, like your household power, before connecting to the Mi-Grid system. This means Mi-Grid can be retrofitted onto existing grid-tied solar systems. The advantage is a more simple installation of the solar array.

Which is better?

For Off-Grid systems, where efficiency is extremely important, DC coupling is definitely preferred. With most Grid-Tied applications, the efficiency loss only shows up when the utility is offline. And AC coupling allows a larger solar array to be connected to a smaller inverter battery system, maximizing savings, while reducing installed cost.

Retrofit systems connect the Mi-Grid system with AC coupling. With little change to a standard grid-tied system, you gain peace of mind with battery storage and generator backup. Mi-Grid keeps you going.

AC vs. DC cost

At the time of a new installation, similar AC and DC systems are nearly the same cost.

Where the budget is constrained, an AC coupled essential system is best. The system can be upgraded later if more inverter power is needed.

DC systems are best when off-grid. Efficient storage of the energy provides the most predictable power around the clock.

Looking to build a custom solar power? Great, get in touch with our engineers by submitting a form with your specifications and needs here.

How a Mi-Grid microgrid can be configured with AC power.

Diagram of a Mi-Grid coupled with AC power.

Mi-Grid vs. the Powerwall

We’ve had a lot of requests to layout the difference between a Mi-Grid system and a Powerwall. So, here goes!

First, let’s define a “Powerwall”. It is a Lithium-ion battery pack. It is not a complete power system. Implementing it requires a StorEdge inverter from Solar Edge. If you have solar, you also need a SolarEdge grid tied inverter and all of the required safety systems, breakers, disconnects, to properly implement. The “cost” most people associate with the Powerwall is only the price of the battery pack.

The SolarEdge+Powerwall system is a Grid-Tied solution. It cannot be used for off-grid. The Powerwall+SolarStor is designed to supply short term power from its battery pack for short (hours) service interruptions. If solar is present, it can store and disperse energy from the solar panels after sunset. However, the cost to store and retrieve the energy may be above the cost to sell to the network, even without net-metering.

Mi-Grid was originally designed as an Off-Grid system, specifically for the Off-Shore oil industry. It is designed to allow long term or permanent power with or without a utility connection. Mi-Grid’s Energy Management System (EMS) can take in multiple AC and DC sources, supply power and recharge batteries, all at the same time. It is also rugged and can be implemented outdoors.

Mi-Grid is “Agnostic” with respect to AC power, type of and manufacturer of solar panels, battery systems, as long as they meet the specified voltage ranges. Mi-Grid even has modules which can make use of “dirty” unstable utility power and turn it into “clean” pure sine-wave power.

Mi-Grid can be connected to a generator, allowing off-grid or utility down operation. The generator is only used off-grid or if the utility is down. The Generator recharges the batteries on cloudy or high power usage days, then shuts down. Even when operating with the generator, the solar array can assist recharging the batteries and supplying power. If the batteries become full, the EMS will modulate the array to match the power required,

The StorEdge-Powerwall system cannot implement a generator safely, unless the entire Solar/PowerWall/Stor-Edge system is bypassed. It uses a grid-tied inverter which cannot modulate the solar array output. Once the batteries are full, if the solar array output exceeds the user’s needs, it would send power to the generator, probably damaging it, potentially catastrophically.

Cost: It depends. Don’t you hate it when people say that? Mi-Grid comes with a generator and many more AC and DC inputs. If you eliminate the generator, you can compare the costs of the systems. The most fair comparison would be a Mi-Grid 1000 or Mi-Grid 2000 setup in essential circuits configuration. A Mi-Grid 1000 costs around $28,000 installed with 4.7kW solar and a 10kW generator. A Mi-Grid 2000 costs around $47,000 installed with 9.4kW solar and a 16kW Generator. Depending on location and codes, these prices can vary. For a “fair” comparison, you would need to implement 2 Powerwalls with any StorEdge System. You also need to include a SolarEdge 5 or 8kW grid-tied inverter and Optimizers at each panel.

Capability Comparison

Mi-Grid 1000 Mi-Grid 2000 SE5000+PW SE6000+PW
Max AC Power 4000 8000 5000 6000 Watts
Max AC Surge 8000 16000 7300 7300 Watts
Maximum Battery Output 4000 8000 1xPW=3300, 2xPW=6600 Watts
Energy Storage 19.2 38.4 1xPW=6.8, 2xPW=12.8 kWh
Energy Storage Usable 9.6-15.4 19.2-30.8 1xPW=6.8, 2xPW=12.8 kWh
Noise <30dB <30dB 1xPW=56dB, 2xPW=61dB  dB
Generator for contingencies Yes Yes No No
Grid-Tied Yes Yes Yes Yes
Off-Grid Yes Yes No No
Sell Excess Power Yes Yes Yes Yes
Run Whole House Air Conditioner No Yes No Maybe
Battery Life 3000 or 1800 Cycles,

50%/80% DOD respectively

1000@20% capacity loss

3000@60% capacity loss

Outdoor Rating NEMA 4/IP66 StorEdge IP65, PW IP10