Posts tagged with "mi-grid"

Toilet Paper? Australians Panic buy PV Solar & Batteries

PV Magazine is reporting that Australians are panic buying PV with batteries. No need to panic, we can help you with your energy needs.

Mi-Grid is different! It connects PV Solar plus batteries with a back up generator. Combined, you’ll never lose power. With the generator, the battery bank can be smaller, saving money. And the generator can intermittently provide power for those high demand appliances, like electric stoves, dryers and electric hot water heaters.

Mi-Grid is available in both grid-tied and off-grid systems. Fixed stationary and mobile. Mi-Grid also has add-on systems for existing PV grid-tied systems.

Give us a call today! 1-713-849-3881, or use the contact form.

Forget toilet paper, Australians are panic-buying PV

Novel Coronavirus / Covid-19 & Panic

Coronavirus

There are a lot of concerns about this new virus. And many are valid. It is “new”. It spreads fairly easily. Humanity does not have an immunity to it. And at the moment (3/10/2020) there is no vaccine. Scary stuff.

The good news comes from South Korea. They are doing extensive testing of the population, finding everyone who has the virus. If this is correct or close to correct, the mortality rates drops significantly. Worse than the average flu, about the same as recent “bad flu”, but nothing like the medieval “Black Death” in any of its forms.

With extensive testing, South Korea seems to be finding all of the cases. If the data is correct, the fatality rate is ~0.69%. The Flu in the US, by comparison, last year had a fatality rate of only around 0.1%. So, yes, Coronavirus is worse than the flu. The 10 year average for flu is around ~0.2%. Which means some years are worse and some are better.

https://www.cdc.gov/flu/about/burden/2018-2019.html

I tried to find a WHO report on Korea, but the latest Korea specific report is a month old. These three up to date articles match on the basic data.

https://www.worldometers.info/coronavirus/country/south-korea/

https://www.businessinsider.com/south-korea-coronavirus-testing-death-rate-2020-3

https://www.statista.com/statistics/1095848/south-korea-confirmed-and-suspected-coronavirus-cases/

Don’t panic. Don’t willy nilly buy lots of items, especially things you do not use on a regular basis. If you need hand sanitizer, buy only what you need so others can buy some.

Wash your hands! I think most people in the USA have been very lax about basic hygiene. This needs to change. Wash your hands often, especially after risky behavior (Hand shaking, visiting the toilet, touching your face, touching stair rails, door knobs, etc.). https://www.who.int/gpsc/5may/Hand_Hygiene_Why_How_and_When_Brochure.pdf

We need to reduce “nice” but risky behaviors. Hand shaking, cheek kissing, casual hugging, etc. Wave hello instead. Many of my friends are Spanish and French and they are having a hard time not cheek kissing. We need to make sure we “cover our cough”. We need to stop touching our faces, eyes, mouths. And when we absently do these things, we need to wash out hands. Again!

Listen objectively to verified news. If someone is passing around “information” on social media, and it doesn’t link back to a source, the information may be suspect. Don’t forward or share it. And when it does link to a source, verify that it is a source you trust. You can even use a search engine to verify, before you forward. This is a serious time, but we should not make it worse with potential misinformation or exaggerations.

I’ll update this page as more information in known.

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.

Battery Options for Mi-Grid

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

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

AGM

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 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 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.

Update: The lithium batteries continue to fall in price, including LiFePo4. If you take into account the life of the battery, LiFePo4 is now cheaper than any form of lead-acid.

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 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

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.

Mi-Grid vs. the Powerwall

1 Reply

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.

http://www.solaredge.com/sites/default/files/se_storedge_inverter_datasheet_eng.pdf

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

Getting ready for a Hurricane – from Mi-Grid

Run or Hide?

The saying is run from the water, hide from the wind. It means if your area will flood, get out of there! If your area won’t flood, you can “hunker down”, protect yourself and generally stay in your area.

Run from the water. Flooding is no joke. There isn’t anything you can do except evacuate. If you are in a flood-prone area, your preparedness is to have an inland location in mind, and your irreplaceable items “ready” to go. Know your evacuation route. Consider side roads and county roads which the rest of the public are not familiar. Keep extra fuel handy since there is usually a run on fuel just before the storm. Be prepared with a few days of food and water, since it may take time to evacuate. Remember, there will be LOTS of other people, so it will take much more time to get out of your area than normal.

Hide from the wind. Most people should stay where they are. First, the roads will be clogged with the people who need to evacuate. People in areas which won’t flood do not need to leave. If they do, they make the evacuation routes worse. So stay if you are not in a flood-prone area.

What do you need if you will be in a place to stay?

Food, water, and shelter. Your house is generally enough for shelter. If you are inland, the winds may be strong, but they generally not high enough to destroy your house. Most serious damage is storm surge and flooding. You may consider boarding up windows. Focus on the south and east windows, as this is usually where the wind comes from. Also look around your yard and remove anything which the wind can move. If you have a pool, tables and chairs can go in the water.

Food and water. Most people think they need bottled water. The water that comes out of your tap is EXCELLENT. But the power may be out and the water pumps off. So store water. How? Trash cans. Buy new ones!!! And you might want to put line them with trash bags. You also want to fill bathtubs and have a small bucket for pouring into toilets for flushing. Just buy the trash cans early and store them away unused.

Food you have a lot of choices if you prepare ahead. You can buy survival food. Not super tasty, but it is better than nothing. You can buy canned food. If anything needs heat to prepare, make sure you have a portable stove and fuel. Have a minimum of 2 weeks of food for every person in the house. That is about how long it will take to get emergency systems in place!

One real issue is post hurricane. In many places, the power may be out for weeks. Many people use generators to help them through. Portable generators need fuel and long-term storage of enough liquid fuel for 2 weeks can be a problem. They are loud!

Permanently installed natural gas or propane generators are much better. They have a big fuel source and they are not as noisy as portable units. They do require maintenance, so be prepared to change oil and spark plugs every 100 hours or every 4 days!

The best solution is a hybrid solar system combining solar panels, energy storage and a generator. It provides the power you need with minimal use of the generator. And the solar panels will save you money the rest of the time!

For help with hurricane preparedness, contact Tetra West Technology and ask about a Mi-Grid!

Save the world from Cow Farts!

Update: Absorbed Glass Mat Batteries vs. The Tesla Power Wall

I’m updating this blog post based on recent revelations about the Tesla Power Wall. The 10kWh Power Wall was abandoned and never produced. The 7kWh Power Wall has been down graded to 6.4 kWh and has a different cycle life than what we were lead to believe. See this article at InvestorIntel.

http://investorintel.com/cleantech-intel/tesla-energys-incredible-shrinking-powerwall-warranty/

There are a few things to consider here with comparing the capabilities of stored energy. First, the best way to compare apples with apples is to compare the total kWh life vs cost. Total kWh life is the usable energy storage multiplied by the cycle life at that usable storage level. This even allows comparison of the same battery using different depths of discharge.

Storing Energy

This “cost” is the battery portion of electric cost in storing and then using the power, only. You still have production costs associated with your solar array! Here are the facts:

PW7 has a cycle life of “3000 cycles”, 6.4 kWh usable storage and costs $3000.
3000 / (6.4kwh * 3000) = $0.143/kWh – Update, the PW7 actually is 6.4 kWh. So the real value is $0.156/kWh
- BUT – Based on the above article, the battery will degrade quickly, losing 20% of it’s capacity in under 1000 cycles.
- It will LAST for many years, but by end of life at 3000 cycles, it has lost 40% of its capacity.
- This will increase the effective cost of the power pack to around
- Total Capacity over 3000 cycles will be 14,720 kWh. –> $3000/14720 kWh = $0.204/kWh
- This is type of degradation is TYPICAL of all Lithium-Ion batteries

High-quality AGM batteries at a 50% DOD have a life of 1800 cycles. A 2.4 kWh battery costs around $350.
$350 / (1.2 * 1800) = $0.162 / kWh – still less expensive than Power Wall

Nano Carbon AGM batteries at a 50% DOD have a life of 3000 cycles. A 2.4 kWh battery has a cost of $400.
$400 / (1.2 * 3000) = $0.111 / kWh

In conclusion, the PW7 has a higher total life cost compared to a standard AGM battery, and is 50% more expensive than a Nano Carbon AGM.

Mi-Grid vs. The Tesla Power Wall

Now let’s compare a PW7 system to a Mi-Grid 2000. The Mi-Grid 2000 is designed to connect to 8-10 kW of Solar, produce 8kW of inverter power, has 38.4 kWh of battery storage. It also includes a 12 kW Natural Gas Generator. The total cost to install a Mi-Grid 2000 with 8kW of solar panels is around $45K.

The Power Wall needs a Grid Tied inverter that is designed to work with it. Fronius makes one that is 8kW. It ties to the battery & solar panels to your utility power. It needs a separate automatic disconnect to separate it from the utility when the utility power fails.

The PW7 is limited to a maximum discharge of 2kW. To match the Fronius Inverter you will need to supply four PW7s. The PW7 system is not integrated. It must be assembled on site, using an electrician. Total cost to install 8kW of solar panels, PW7, Fronius inverter, control system, safety equipment and a backup generator will add up to $60K.