Posts made in July 2016

How does Mi-Grid Save 90% Fuel?

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A generator running all the time is not very efficient.

Generators must be sized for maximum load, even if that load only lasts a tenth of a second. This is startup surge. Surge current is the bane of generators; generators must be sized for maxi-mum starting surge, like starting a motor or air conditioner. Electric motors can take up to 5 times operating power to start them. All regular loads plus surge loads must be added together to decide on the generator minimum size.

This means the generator runs most of the time at low loads. Look at the chart. At 25% load, over a gallon per hour is used just to run the generator, while about 1/3rd gallon is used to produce electricity.

Mi-Grid instead cycles the generator, using it only to re-charge the batteries as needed. The rest of the time the genera-tor is shut off.

For example: an RV air conditioner operates with 1650 Watts, but needs 4000 Watts to Start.
Over 24 hours, the AC runs on average 30% of the time. 70% of the time the generator is idle. A 4Kw generator may use over 7.4 gallons of fuel per day, producing only 12kWh of electricity.

If the generator runs only at full load (4000 Watts), it would need run only 3 hours to produce the 12kWh, using less than 2 gallons of fuel. Even with conversion losses (10% in and 10% loss out), there is a reduction by 60% fuel consumption, simply by running the generator at maximum load. To further reduce fuel consumption, add 1000 Watts of solar panels attached to the RV. The solar panels will produce 6.5 kWh of electricity per day.

This will further reduce the amount of power produced by the genera-tor to 5.5 kWh per day. The generator will run less than 1.5 hours per day using .55/gal per hour, or about 0.825 gallons. This example shows a reduction.

What is the payback for Mi-Grid?

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Grid-Tied
Mi-Grid doesn’t sell power to the utility. It saves all of the extra energy in the batteries to use later. If the utility pays less for your solar power than you pay them for electricity, you save 30% more than if you sell your power.

Example: Electricity is $0.20/ kWh and the electric company buys excess solar for $0.10/ kWh. Our models show that approximately 50% of grid-tied solar is sold to the utility.

If 100 kWh is normally consumed in a day, the cost is $20. If 100 kWh of solar are produced, but 50 kWh are sold to the utility, $10 is avoided, $10 is purchased and $5 is paid to the end user. Net electric cost is $5. Net savings is $15.

Mi-Grid stores all excess solar energy produced. No power is sold, savings a full $20. This is a 33% additional savings over standard grid-tied solar.

The battery based system adds about 20% cost compared to grid-tied solar. This is more than off-set by the additional savings. Payback is faster than Grid tied.

Off-Grid
There are two type of systems for off-grid. 1) Off-Grid Solar. 2) A generator.

Off-Grid Solar
Off-Grid solar uses no fuel. But it requires a sizable capital investment. You must size the batteries to carry you through multiple days without sun. And the solar array must be designed to produce enough pow-er to recharge the batteries.

Mi-Grid uses a generator to cover contingencies. This allows the solar array to be sized for average power used and the battery bank sized just to absorb the extra solar power. This reduces the battery bank to about 1/3rd to 1/6th the size and reduces the solar array by 30-50%. Capital costs are reduced by at least 50%.

Generator
Generators need small capital investment for off grid. But this is quickly overwhelmed by operational costs.

Generators use fuel, but they also require maintenance. And Generators have a finite life.
Fuel costs are typically reduced by 90% when using a Mi-Grid when compared to a generator.
Generator run time is reduced by 90% as well. This increases calendar time between maintenance and increases calendar life of the generator.

Case Studies

Grid tied House
Electricity cost $0.20 per kWh
Avg. daily usage is 75kWh/day.
Mi-Grid 2000, installed with 11kWh of Solar. Cost $50,000
System will produce 71.5kWh/ day avg., or 26.1MWh/year. Savings is $5225/yr. US Tax Credit is 30% price of system.
Payback With ITC / Without
0.10— 13.4 years / 19 Years
0.20— 6.7 years / 9.5 Years
0.30— 4.5 years / 6.3 Years
0.35— 3.4 years / 4.7 Years

Food Truck
4kW Generator cost: $600, Generator life 1000 hours, 50hr Maintenance: $10, Gasoline $2/ gallon, Generator runs 50hr/ week, Average load is 1kW. 10kWh/day

Mi-Grid 250, with 1kW of solar installed: $7200
Average fuel consumption is 0.35 gal/hr. or 3.5 gallons per day, $35 per week. Generator life value is $0.60 per hour or $30/week. Maintenance is $10/ week. Total weekly cost $75

Mi-Grid will recharge overnight and consume 2.5kWh, $0.50, 1 kW of solar will produce 5kWh of electricity. Balance is 2.5kWh to be produced by the genera-tor. Generator will run 1 hour at 2.6 kWh load, 0.45 gal/hr. Total is 2.25 gallons per week, $4.5. Maintenance cost is reduced to $1/week and life cost to $3/ week. Total is $9/week, savings $66/wk.

US Government tax savings (ITC and MCARS) reduce system to $4122.

Payback is 62 weeks or 15 months.

Off-Grid House (weekends)
12kW Generator cost: $8000 life 10,000 hours. 500hr Maintenance: $100. Propane $2/gallon. Runtime:60hr/week. Average load is 2.5kW. 60kWh/ day, 1.32 gal/hr. $160/week. Maintenance cost/week: $12. Generator Life cost/week:$48. Total cost per week:$220.

Mi-Grid 2000, Installed cost with 10kWh of Solar. $50,000. After US Govt. Tax savings: $35,000. Produces 65kWh/ day.

Payback is 160 Weeks or 3 years.

Off-Grid House 7days/week
Generator runs 168hr/week. Average load is 2.5kW. 60kWh/ day, 1.32 gal/hr. $450/week. Maintenance cost/week: $35. Generator Life cost/week:$135. Generator cost per week:$620.

Payback is 56 Weeks or 1 year.

Off-Grid House Solar Only
Mi-Grid stores 1/2 day of solar. Fully off-grid needs 3 days of storage or 6x battery bank. Solar array 50% larger. No Generator. Total installed cost $98,900.

How does Mi-Grid Work?

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Mi-Grid
Mi-Grid is most similar to an Off -Grid solar energy system. It takes solar energy and makes DC power. It uses this power to run an inverter, making AC power, or stores it in batteries, or both.

How does it Differ?
Mi-Grid also connects AC power from multiple sources, a generator and/or utility power. In-stead of an oversized battery bank and solar array, it uses the generator as a backup. Mi- Grid is about half the cost of a similar off-grid solar system.

How is that different from regular solar on houses?
“Standard” Solar energy systems installed on residential houses are usually called “Grid Tied” or “Utility Connected”. They simply convert the DC power from the solar panel to AC power. It is directly connected to house power. They do not store solar power. Either the solar power is used locally or it is sent to the utility.

Mi-Grid Saves 30% more
Mi-Grid doesn’t sell power to the utility. It saves all of the extra energy in the batteries to use later. If the utility pays less for your solar power than you pay them for electricity, you save 30% more than if you sell your power.

What if the power goes out?
With standard solar, if the utility system shuts down, so does the solar. This is for safety.
Mi-Grid can operate independent from the utility. During the day, a Mi-Grid system is disconnected from the utility. You won’t even notice an outage.

At night, Mi-Grid connects to utility power if the batteries are low. If the utility goes out, it automatically switches to the batteries. With the batteries low and the utility out, the generator automatically starts.
The Generator supplies power and recharges the batteries. Once the batteries are charged, the generator shuts off. On a stormy day, with the utility out and no sun, the generator may cycle several times.

How is Mi-Grid compared to a generator?
Without solar, Mi-Grid can reduce fuel consumption by 50%. It does this by running the Generator at a higher load for a shorter time. Add in the solar panels and Mi-Grid may use no fuel at all. It averages out to a 90% reduction in fuel and run time. Plus, backup generators come on after the power goes out.
Mi-Grid keeps the power on. Never lose power.

Mobile Energy Independence – Never Lose Power, Save More with Solar

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Hybrid Energy System
Energy management system combines power from multiple sources including: Solar, Utility Power, Energy Storage and Auto-starting Generator.

Power RVs, Food Trucks, Mobile Businesses and More
From 2kW to 8kW continuous pow-er, surge power for starting Air Conditioners, pumps and motors, 6kW to 16kW.

Solar Powered
50-80% power from Sun – even works on cloudy days. Solar and batteries supply power during the day. Switches to generator power once batteries are depleted. Generator runs 1-3 hours/day supplying power while recharging batteries, then shuts down, reducing fuel and noise. Solar panels charge even while driving.

Large Storage system
Inverter/Batteries can operate standalone for many hours, including air conditioning!

Fully Integrated system
Includes Energy Management system, Inverters, Charge Controllers, Transfer switches, Energy Storage, Outlets and Generator – Pre-packaged and tested assuring high quality.

Easy Installation
Solar panels and installation kits Available. Flexible Flat Panels kits for easy roof mounting.

Utility Recharge
Recharge batteries from Utility, when available.

Never Lose power
Seamless transition between sources. Power never goes out.

Saves Fuel
Generator fills in when renewable and utility sources are not sufficient. Operates at high power, running everything & recharging batteries. Shuts down when batteries full. Up to 90% savings versus traditional generators.

Reduced Maintenance
Mi-Grid generators typically run only a few of hours per day. Time before maintenance is significantly increased. Traditional mobile generators run all day. Inexpensive generators are loud and require constant maintenance, typically lasting only a season or two.

Freedom
Independence. Go anywhere the road takes you. Always have pow-er. Save money. Less noise. Reduce or eliminate your carbon footprint.

Remote panel and remote generator start switch included. Generator delete option requires a self supplied remote start genera-tor, for example an ONAN. Mi-Grid 500 High power includes 220VAC.

Up to 4 flexible solar kits can be connected to a Mi-Grid.

Choose Predesigned configurations or customize for your application.

Options include NEMA4 or NEMA4X enclosures, special long life batteries, Wall Mounting, Air Conditioning and motor soft starters.

Off-Grid Energy Independence – Never Lose Power, Save More with Solar

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Hybrid Energy System
Energy management system combines power from multiple sources including: Solar, Utility Power, Energy Storage and Auto-starting Generator.

Remote Power for Power Anywhere
From 2kW to 80kW continuous power, surge power for starting Air Conditioners, pumps and motors, 6kW to 160kW.

Solar Powered
Power from Sun – even works on cloudy days. Solar and batteries supply power during the day. Switches to generator power if batteries are depleted. In times of high power demand or low sun-light, Generator supplements pow-er while recharging batteries, then shuts down, reducing fuel and noise.

Large Storage system
Inverter/Batteries can operate standalone for many hours, including air conditioning! In times with-out fuel, system can provide critical power.

Easy Installation
Pre-packaged primary systems minimizes electrical installation costs. Solar panels and mounting hardware Available. Multiple de-signs for your unique needs. 130- 150 mph designs available.

Never Lose power
Seamless transition between sources. Power never goes out. Like a computer UPS!

Saves Fuel
Generator fills in when renewable and utility sources are not available. Operates at high power, running everything & recharging batteries. Shuts down when batteries full. Up to 90% savings versus traditional generators. Pays for itself in as little as 6 Months.

Reduced Maintenance
Generator only runs when needed. Mi-Grid generators run at most a few of hours per day. Time before maintenance is significantly in-creased. Traditional generators run 24/7. With run time reduced by run 90%

Not just for Off-Shore
But Mi-Grid is not just for off-grid. Mi-Grid works great in high cost power areas, or areas with unreliable or intermittent power. Typical Electrical savings are 30% over standard grid-tied solar while providing multi-source power reliability and backup. With Mi-Grid you never lose power.

Energy Independence – Never Lose Power, Save More with Solar

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Hybrid Energy System
Energy management system combines power from multiple sources including: Solar, Utility Power, Energy Storage and Auto-starting Generator.

Power RV
From 2kW to 8kW continuous power, surge power for starting Air Conditioners, pumps and motors, 6kW to 24kW.

solar power efficiency

Solar Powered
50-80% power from Sun – Even works on cloudy days. Solar and batteries supply power during the day. Switches to utility or generator power once batteries are depleted. Generator runs 1-3 hours/day sup-plying power while recharging batteries, then shuts down, reducing fuel and noise. Solar panels charge even while driving.

Large Storage system
Inverter/Batteries can operate standalone for up 8 hours overnight – including air conditioning!

Fully Integrated system
Includes Energy Management system, Inverters, Charge Controllers, Transfer switches, Energy Storage, Disconnects and Generator – Pre-packaged and tested assuring high quality.

Easy Installation
Solar panels and installation provided by your local installer. 1kW and 2.5kW Solar Panel and Mounting kits available for cabins and RVs.

Never Lose power
Seamless transition between sources. Power never goes out. Like your computer UPS!

Saves Fuel
Generator Fills in when renewable and utility sources are not available. Operates at maximum, powering everything & recharging batteries. Shuts down when batteries full. Up to 90% savings versus traditional generators.

Reduced Maintenance
Generator only runs when needed. Mi-Grid generators run typically 1-2 hours per day. Time before maintenance is significantly increased. Traditional RV generators run 24 hours per day. In expensive generators are loud and require constant maintenance, typically lasting only a season or two. Onan generators last much longer but are 4-10 times the price!

Freedom
Independence. Go any where the road takes you. Always have power. Save money. Less noise. Reduce or eliminate your carbon footprint.

Remote panel and remote generator start switch included. Choose Predesigned configurations or customize for your application. Options include NEMA4 or NEMA4X enclosures, extra batteries, Wall Mounting, Air Conditioning and motor soft starters.

The Story of Mi-Grid

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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.

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.

What is Net-Metering?

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Net Metering is a method of billing used by some utilities. Solar Production in excess of your immediate needs is exported to the utility. The utility measures the outflow and credits them against your inflows of electricity. You pay only on the “net” inflow.

For most Grid-Tied Solar PV, the solar energy is converted and fed into the existing AC electric system. This is done without regard to how much power is needed at any given time. The excess flows “Out” into the electric lines. The energy is available to be used by others.

Net metering is a simplified method of compensation for these out flows. Your electric bill is calculated at the “net” difference between what you consume and what you produce. You use 2000 kWh per month. The solar array produces 1500 kWh. You pay for 500 kWh. Simple, huh?

Except, the price you pay your utility really comes from two different pieces: Energy and transportation. In electric bills in most of Texas, you see both retail electric energy charge and the energy transportation charge. Remember, there are costs in maintaining the electric lines, PLUS the cost of maintaining the power plants you use when the sun isn’t shining.

When I “make my own” energy, I am reducing the energy I buy from the utility. When the sun isn’t shining, or not enough, I buy power from the utility. But if I make too much, I have to do something with it. I sell it to the utility. But this energy I sell has to be transported to other users. The utility transports the power.

Most grid tied users see the utility as a “storage” system. They “store” power and then use it later. But it isn’t really stored. When power is pushed onto the grid, a power plant somewhere has to reduce output to compensate. But the power plant can’t shut-down because it has to be available to provide power in case more power is needed. For example, when a cloud goes by.

When solar makes up a tiny percentage of the network, it doesn’t affect the overall economics of the power system. It may in the end be cheaper for the utility to bill “net meter”. But as the percentage of installed solar goes up, the “loss” by the utility goes up with it. It must compensate by raising the price of electricity. Your neighbors without solar pay.

It really is fair to compensate a solar producer only for the electric generation portion of the power. As renewables become more wide-spread, net metering will be reduced and eventually abandoned. Hawaii, California and Germany are abandoning net metering. Massachusetts, like many states, reached the limit of net metering.

Mi-Grid stores your excess renewable energy for your own use later. You truly are “NET” with the meter, since you do not sell power to the utility, you save it for yourself to use when you need it.

Net Metering is going, going, gone!

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Germany, like most of the utilities in the United States, are limiting or abandoning net-metering. Mi-Grid allows you to effectively net-meter without a Utility Net Metering Plan. Battery based system store excess energy for you to use later. You only buy power used beyond what the renewables produce. Power is only sold if usage is very low and renewable production is high.

Germany Votes To Abandon Most Green Energy Subsidies