News

Hurricane Harvey

Summertime and it is Hurricane season

Losing power anytime is bad. But it is really bad in the summer. For the areas along the US coasts where the hurricanes hit, we need our air conditioning in the summer. Losing power in the hurricane is bad. But when the hurricane is gone, the heat comes back.

Portable generators are a cheap way to have some power. The downsides: buying fuel, running electric cords, noise and maintenance. You can mitigate the second part by buying and installing a manual transfer switch. This lets you power the house with the generator.  Maintenance: most portable generators need to have the oil and spark plug changed every 50 hours. That is every other day! This matches with your lawnmower, once a year oil change and plug = 50 one-hour mowing jobs. And portables are noisy.

Permanent installed are great. They eliminate the short-term issues above and the power cords. But most still require maintenance every 100-200 hours or 4 days to 1 week, depending on model and size. You also lose power for at least 30 seconds to a minute until the generator starts. Permanent generators have better sound insulation and are quieter than portables. But they still make noise.

In any case, if you have a grid-tied solar system, they cannot be used during a power outage. UL 1741 requires this, to prevent back feeding the power grid. And a generator does not work well with solar panels.

With Mi-Grid, it is a hybrid solar energy system with PV panels, a battery bank, inverter/control system, transfer switches (if needed) and backup generator.

With battery-based inverters, power switches in milliseconds, as soon as the power goes out, typically in 1/60th of a second. The solar system is designed to work off-grid, so it keeps producing power, even when the utility is out. And if solar energy is not enough or your power usage is high, the generator can supplement your power and recharge batteries. This means the generator doesn’t run all the time. Typical properly sized systems, the generator runs on average 2-3 hours per day. Heavy use days or days without much sun, it may run up to a total of 8 hours. Quiet hours can be setup for overnight, so the generator doesn’t disturb your sleep.

Finally, Mi-Grid can be setup to only cover your essentials: lights and outlets. Large appliances and whole house air conditioners will run only when the generator turns on. You can control how much time they run. And in most applications, you can still air condition one room all the time, with a window or mini-split air conditioner. For those on a budget, small solar and inverter with a large generator is the way to go. You can always upgrade the solar, inverter and batteries.

And Mi-Grid isn’t just for Hurricanes. It will protect you against any kind of power loss, while saving you electricity all year long.

Systems are eligible for Federal and State tax credits and incentives, in all 50 states through 2021, with maximum savings installed before the end of 2019. We work with your local solar installer. Available world wide.

Add some piece of mind to your life. Install a Mi-Grid system!

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.

On-Grid

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.

Off-Grid

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.

RVs

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 sales@tetrawest.com

Infographic on grid-tied vs. off-grid solar power.

How Mi-Grid’s Comprehensive Solution is Better Than Grid-Tied Solar

Congratulations, you installed a solar array at your home and the system is tied to the utility grid. If the solar doesn’t generate enough electricity, you can rely on the utility and you might even net meter power back to the provider. Sounds great, but what happens when the utility loses power?

You are out of luck. Utility distribution is susceptible year-round to storm outages, whether from snowstorms, thunderstorms or hurricanes because of the extensive network of strung wires. Ice weighs them down and downed trees yank them loose. Your solar array may be standing, but UL 1741 requires your grid-tied inverter to shut-down for safety’s sake. This prevents any power from a home from reaching the grid when repair workers are on the lines.

Here’s the beauty of a Mi-Grid energy management system: while disconnected from the grid, it operates on a stand-alone basis. Solar power can keep the lights on and that energy can also be stored to batteries within the configuration. If the batteries run low, a generator automatically kicks in to power the home and recharge the batteries, shutting down once the batteries are recharged.

Making Renewable Power Reliable

This is why the Mi-Grid can be installed as a grid-tied system or an off-grid system. It technically doesn’t need to be grid-tied. Hence, the smaller Mi-Grid sizes are ideal for remote locations as well as mobile applications, such as food trucks and RVs.

The brains of the operation can be installed in a variety of packages, including wall-mounted, indoor, outdoor or trailer mounted. The outside options are housed in NEMA 4 enclosures for durability. Mi-Grid systems range in size from 1 kW to 2 MW and can serve residences as well as businesses that want complete electric reliability.

When a Mi-Grid is connected to a distribution grid, that utility power enters the mix. The Mi-Grid is essentially a dispatch system that selects the lowest-cost available power at a given time. When grid-tied, the utility supplies power at night and can take excess power from the solar system during the day.

The batteries are kept full for backup and the generator sits in stand-by mode. This cycle runs daily, with solar power providing electricity during the day and the utility providing any needed power overnight. Mi-Grid ties together all of the energy sources, providing multi-layered power and backup.

As the consumer, you won’t see lights flickering because the shifts among power sources are seamless. For example, a customer of ours who lives in a rural area was surprised to hear at a community breakfast that everyone else lost power the day before when the local supplier dropped offline. He did not realize his inverter had kicked in under the Mi-Grid system.

Think of times when you have lost power and were out of commission when it comes to connectivity and conveniences. But it’s not just major storms that can cut into productivity and quality of life. Local power outages are fairly common events. Also, if you wish to live off-grid but not entirely replicate a previous century’s lifestyle, then Mi-Grid gives you that personal freedom. And at a lower cost than either a stand-alone solar system or a generator alone.

The other benefit to Mi-Grid is you don’t need to manually mess around with the typical emergency generator that requires frequent refilling of the fuel tank as well as oil changes. Each time you tend to such a generator, the power is turned off. Instead, the Mi-Grid generator is only turned on when the system’s batteries are low. By cycling the generator only when needed, the system saves on fuel and maintenance. And you don’t have the constant roar of many generators.

Why invest in solar alone when you can invest in a fully-integrated system to provide truly reliable power? Mi-Grid has you covered, grid-tied or off-grid, sunshine or clouds, day or night, 365 days a year.

 

House with residential solar system for article about the cost of tariffs

Solar Panel Tariffs – What’s the Bottom Line for a Residential Project?

Before starting, this is not an article defending or attacking the newly imposed US tariffs on solar panels manufactured abroad. It is simply to put the panel tariffs into relation to an entire project.

Incidentally, the Trump tariff has precedent. In 2012, the US imposed punitive tariffs after a Solar-World complaint of “dumping,” or selling under cost, usually in an attempt to drive other companies out of the business. Afterward, the European Union followed in 2013 and imposed similar tariffs. It was estimated by the US Department of Commerce that the solar panels were being sold in the US for 31% less than the cost to manufacture.

At the time, tariffs were supported by U.S. and European solar manufacturers. Yet they were opposed by installers, who saw the “cheap” solar panels are helping sales.

In 2015, anti-dumping solar panel tariffs were kept in place.

As of 2017, almost all solar panels used in the USA are now imported. Even with the tariffs, the prices continued to plummet. The ITC (International Trade Commission) studied and found: “increased solar cell and module imports are a substantial cause of serious injury to the domestic industry. Although the Commissioners could not agree on a single remedy to recommend, most of them favored an increase in duties with a carve-out for a specified quantity of imported cells.”

Based on the above, 30% across the board tariffs are being imposed. They are for 4 years and decline each year, reaching 15% by year 4. Note, though, that according to the Commerce Department, the first 2.5 gigawatt of imported cells are excluded from the additional tariff.

A 30% tariff sounds scary! And if you listen to the news, doom and gloom are predicted. But what effect will a 30% tariff have on a solar project? The 30% only applies to the solar panels.

Typical solar installs are for “grid-tied” solar. This is where the panel “DC” power is converted to AC power with an inverter. This power is then connected to a house’s electrical power system where it is directly used, or exported to the grid.

In Houston, for example, typical pricing for 5kW of grid-tied solar, roof mounted, is around $15,000. The systems include: solar panels, roof mounted racking equipment, electrical combiners, disconnects, solar cables, grid-tied inverter, electrical disconnects, breakers, sales commission, storefront costs, vehicles and a whole lot of labor. Not to mention, some profit for the solar company! The PV panels make up about 40-50% of the cost of the equipment of the installation, but only 20% of the overall project.

Assuming the solar panels are Chinese, adding a 30% tariff will add about 6.7% to a job. On a $15,000 project, this could be about $1,000.

In other cities, the other costs are much higher. A friend from San Diego had 7kW installed on his home. It cost $27,000. The cost of imported solar panels should be similar in Houston and San Diego, so the delta from the tariffs will still be $1,000. In San Diego, the tariff will represent about 3.7% of the project.

While any price increase could hurt a business, these increases on a project basis are relatively minimal. And prices of solar panels continued to drop from 2012-2016 even with the solar tariffs imposed. And this article in Cleantechnica shows that prices are continuing to drop!

As a rule, we should strive for a “level playing field.” That said, even with these “safeguard” tariffs, their effect should be viewed in relation to the effect on a solar install, not as a single part.

Mi-Grid generally does not sell solar panels. Those are sold by the solar installer as part of the installation. But the Mi-Grid energy management system is made in the USA from parts made in the USA!

Seeking an estimate on a custom solar hybrid Mi-Grid energy management system?  Get in touch here to request an estimate.

House with solar power roof and batteries.

Battery Options for Mi-Grid

We are often asked, “What kind of batteries do you use?” Mi-Grid systems are offered with 3 choices:

  1. High-Quality Absorb Glass Mat (AGM) batteries
  2. Advanced Lead Acid – Nano Carbon batteries
  3. Lithium

AGM

Absorb Glass Mat (AGM) batteries

Absorb Glass Mat (AGM) batteries

Our standard offering uses high-quality AGM batteries. For a system where the batteries are a backup, or are not cycled very often, our standard AGM is the most cost-effective. AGM batteries are a form of lead acid battery. Instead of liquid sulphuric acid, the battery is filled with fiberglass mat and the mat is made “wet.” This allows the battery to be mounted in any direction, and there is no chance of spilling. If the battery case were damaged, it may dry out, but the acid fluid cannot leak. These are considered, “non-hazardous”.

For Mi-Grid systems connected to utility power, the batteries are kept full. Only when the utility power fails will the batteries be cycled. These batteries are also used wherever the system is set up for up to 80% depth of discharge (what percent of the total battery is used). AGM batteries, if treated properly should last a minimum of 5 years, possibly as long as 10 years.

Nano-Carbon

Nano-Carbon batteries

Nano-Carbon batteries

Nano Carbon batteries are called “Advanced Lead Acid.” The ones we use are also an AGM battery with all of the benefits. The internal parts of the battery are covered with a nanoparticle carbon coating. This increases the life of the battery in places where it cycles a lot. The batteries operate best in a “partial state of charge.” The controls are reprogrammed to operate the battery in the middle of its range and the usable portion is about 50-60% of “full” capacity. This is how they are able to achieve 3000 cycles.

These are great in high-cycling applications, where the batteries are charged and discharged every day, possibly more than once a day. They cost about 30% more than the regular AGM batteries. Great applications for these are off-grid, grid-connected cycling and mobile applications, such as food trucks and RVs.

Lithium

Lithium Ferro Phosphate batteries.

Lithium Ferro Phosphate batteries.

Lithium batteries, depending on the type, offer light-weight, smaller batteries with very high-cycle life. There are many types of lithium batteries. The type in your phone is typically Lithium Cobalt, due to the very high energy density. They are limited to about 500 charge-discharge cycles before losing significant capacity.

We use Lithium Ferro Phosphate batteries. They have a lower energy density (size vs. charge), but much higher cycle life. When used correctly, they may exceed 10,000 cycles! Typical is 5000-7000 cycles. For the same usable charge, they are about 2.5 times the cost of nano-carbon batteries. With the higher cycle life, they are comparative to the nano-carbon. You may never have to replace these batteries! They are also smaller and weigh about 60-70% less than either AGM battery.

These are best in high-cycle, mobile and applications in places where you do not want to change the batteries often. The prices are coming down, so these will probably be the best replacement battery, when the time comes.

Every type of battery has its place. I would say the Lithium batteries are “best.” But you may not want to pay that much at the beginning. If the batteries are in a grid-tied type system, the regular AGM batteries are best. The nano-carbons are the most cost-effective in a cycling application.

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.

AC VS. DC COUPLING MI-GRID

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.

Mi-Grid—DC

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.

Mi-Grid—AC

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 2000. a microgrid with 8kW of power output.

Mi-Grid Systems: How Our Models Are Sized for Different Applications

Our microgrids can be sized for any amount of demand and our Mi-Grid systems are configured for different applications, including residential, business and mobile (RVs, food trucks, etc.). Originally designed for off-shore platforms, we have systems configured from 2kW to 2MW!

Standard Models

Mi-Grid’s have 5 standard models. Even the “standard” models have options. They are configured based on size to match the demand (power load). Pricing can vary, some customers already own a component of the Mi-Grid system, such as a generator or a solar array.

Models also range in price depending configuration and options. Is the system grid-tied or off-grid? Is it AC or DC coupled to the solar panels? Is it applied to an appropriately sized dwelling for that model’s design or is a smaller-sized system applied to a larger dwelling, requiring additional sources of energy, i.e. a larger generator.

Other cost variables include installation costs, shipping, taxes and possibly duties. For each model below, we provide a price range, which does not include solar arrays and installation. As for the installed cost of solar panels, including mounting hardware and labor, that can range from $2.00-$4.00 per Watt, in the continental United States. Depending on where it is installed, there may be additional charges for shipping and duties. All price estimates provided here are in USD and for installations in the continental United States. These estimates are approximate as of January 2018.

Mi-Grid is an energy management system, meaning, at its core, it has a heart (hardware, controls and modules ) and a brain (software combined with our proprietary engineering design and safety considerations). All components are tested and certified to UL standards.

Mi-Grid 2000. a microgrid with 8kW of power output.

Mi-Grid 2000

  • Mi-Grid 250 & 500:

Both of these systems are 120VAC, single phase. They are DC coupled and were designed for off-grid. They are the least expensive/most cost-effective systems. They can be grid-tied, but cannot export/sell power.

  • Mi-Grid—250:

Tiny, but fierce! The main unit is 36” x 24” x 16”, and the batteries are inside! It is 2200 Watts and will power lights, outlets and a small window Air Conditioner. Up to 1.2kW of solar panels can be connected. Price range: $4,500 – $6,500, with standard batteries.

  • Mi-Grid—500:

Probably the most cost-effective system. The main unit is 48” x 24” x 16”, and the batteries are inside! It is 4000 Watts and will power lights, outlets and up to 1 large or 2 small mini-split Air Conditioners. Up to 3 kW of Solar can be connected. Price range: $7,500 – $10,000

  • Mi-Grid—1000-4000:

120/240VAC.  The generator is typically a home-style propane/natural gas unit and can be “oversized” to power more external equipment. Solar can be AC or DC coupled.

  • Mi-Grid—1000:

Similar power to a Mi-Grid 500, but split-phase 240VAC and can connect up to 8kW AC Coupled (6kW DC coupled) of solar. Price range: $14,000 – $22,000

  • Mi-Grid—2000:

Same as a Mi-Grid 1000, but 8kW of power output. Price range: $21,000 – $30,000

  • Mi-Grid—4000:

A double unit Mi-Grid 2000,  16kW of power output. And up to 20kW of solar. $40,000 – $65,000 (The $65,000 unit includes a 48 kW generator!!!)

Which is better?

  • For Off-Grid systems, any system can work.

If 120VAC only will work for you, then the Mi-Grid 250 and 500 are very cost-effective.

  • For grid-tied, generally where you might sell excess power or if you have an existing grid-tied system, the Mi-Grid 1000-4000 are best.

If you need 240VAC power, you must choose a Mi-Grid 1000-4000.

Options:

  • All systems may have a larger generator. It will allow more items to be powered when the generator runs. And some items can be setup to be powered only when the generator runs
  • Any System can be purchased without a generator. Only remote startable generators can be controlled by a Mi-Grid. Most home type permanently installed generators can be controlled. A limited number of portable type generators can be controlled.
  • More batteries and more solar (up to a point!) can be added for longer run time without generator help.
  • Systems with limited solar can still be useful minimizing generator run time and fuel consumption.
  • Special Lithium batteries can be used which have 3 times the life of our best Advanced AGM batteries. Expensive, but in the long run, cost effective.

For more information, Contact us or a local Representative.

    Never Lose Power

    Today I did a one year inspection on a Mi-Grid 4000. This is primarily a check on the batteries and to do the yearly maintenance on the generator. With the exception of a few dead bugs inside the generator enclosure (how did that cricket get into the air cleaner?!?), it looked as good as the day it started it up.

    One anecdote from the Owner. Earlier in the year, there was a terrible storm. They thought nothing of it. There was one flicker of the lights, but that was it. The next day, he attended a local luncheon where the primary topic was the 5-6 hour electric outage. He looked dumbfounded and said: “What Outage?”.

    EXACTLY!!!  With Mi-Grid, you never lose power.

    If Mi-Grid is setup in UPS/Backup mode, and the utility goes out, it switches in less than a second to the inverter and batteries. If the batteries become depleted, the generator starts up and comes to full speed, THEN it switches over. You don’t lose power. And when the Generator finishes charging the batteries? It switches back to inverter BEFORE the generator shuts down.

    With Mi-Grid, you simply never lose power!

    Lithium Ferro Phosphate batteries.

    Are Lithium Batteries safe?

    Hardly a day goes by without a news article about Lithium batteries exploding. This makes many people wonder if they are safe. The answer is more complicated because lithium batteries are complicated.

    First, there are many different kinds of lithium batteries. The actual chemistry can change between batteries. For a review of lithium batteries, take a look to “Battery University”, and the different chemistries. Some “flavors” of Lithium battery are less likely to cause issues, even with poorer quality or abuse. It is all about the proper design and implementation.  Here is a chart reprinted from Battery University of the Pros and Cons:

    Reviewing those advantages and disadvantages, we have high capacity batteries that require special circuits to be safe. The lithium battery voltage requires the battery use an electrolyte other than water. Typically, organic solvents are used. If the cells break, they release flammable liquids. Finally, battery charging is different than a constant voltage systems typical of other batteries.

    There are three sources of failure: 1) Poor quality cells. 2) Poor or missing battery management / protection circuits. 3) Poor quality charging system. ANY battery, lithium or not, will suffer from the same issues. The difference is the flammable solvent.

    In many cases, it is a stack up of multiple issues. Knock off devices, like the look-a-like “Hoverboard” devices, have lower quality components and are almost never tested to US or international safety standards. Samsung tried squeezing a larger capacity battery, that one in one-hundred thousand didn’t fit quite right, causing failure when over charged.

    So are they safe? When built by quality companies, used in quality equipment with quality chargers and tested, they usually are.

    Power Gen International 2016

    Tetra West and Mi-Grid will be in Orlando Next week (December 13-15, 2016) for the Power Generation International (PGI 2016). See us in the Texas booth, #4669

    Mi-Grid is a Hybrid Solar Energy System, combining solar with energy storage and a backup generator. Mi-Grid makes renewable energy reliable! Grid-Tied, Off-Grid what-ever you need! Never lose power!

    http://www.power-gen.com/index.html