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Sun Volt

Sun Volt Solar

earth, the final frontier

Clean Energy, Clean Environment

We are at a cross roads in human history, we can choose to continue on as we have been, or we can make a change to improve our future and quite possibly the future for several generations to come. We are here to promote energy independence, a better environment, a secure future and a higher return on investment for your hard earned dollar. It is what I believe in, it is why I am in the solar business.

Developments in LED lighting

31 Dec 08 | Environment, Solar Electric
Philips Lumiled high power light emitting diode

Philips Lumiled high power light emitting diode

As part of a general trend toward more efficient energy use, LED (AKA solid state) lighting shows promise.  From EE times.com:

White organic light-emitting diodes (OLEDs) are already producing more light per watt than incandescent bulbs, according to engineering professor Stephen Forrest, but it is trapped inside the device. By fabricating a tandem system of grids and micro lenses on a white OLED, the device can achieve a brightness of over 70 lumens per watt, compared with 15 lumens for incandescent bulbs–almost as much as fluorescent tube lights (90 lumens).

And from Scientific Blogging:

Current white LED’s require a substrate made of sapphire and an additional mirroring layer to reflect light that would otherwise be lost… Researchers at Purdue University have found one method of significantly reducing the cost of a white LED by eliminating the expensive layer of sapphire. Instead, they used silicon as the substrate (the material the diode is printed on) and zirconium nitride as the reflector.

And from RPI:

Solid-state lighting that replaces incandescent and fluorescent bulbs with light-emitting diodes can reap enormous savings in cost, natural resources and pollution, according to a recent study by Rensselaer Polytechnic Institute. RPI’s Troy, New York-based Smart Lighting Engineering Resource Center claims that over the next 10 years savings of more than $1.8 trillion will eliminate the need to burn almost a billion barrels of oil in power plants that would otherwise produce 10 gigatons in the carbon dioxide emissions.

Lighting accounts for 22% of all electrical consumption in the United States.  If even half of the reduction claimed in the RPI report is realized, a significant step has been made toward reducing pollution and increasing energy efficiency.  For most people, the current color rendition of solid state lights (SSL) is harsh with too much blue light used.  This problem is being worked on.

Further, SSL systems are great companions to off grid PV systems that can use DC power distribution.  In an AC (alternating current) system, losses come from inverters, power supplies, and the LEDs themselves.  In a DC (direct current, e.g. 12 or 24 volt) system, the only losses are the LEDs.

Look for more developments in SSL in the near future.

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31 Dec 08 | Environment, Solar Electric | Comments (0)

Is this coal clean?

27 Dec 08 | Environment

The dam around a retaining pond a TVA’s coal fired Kingston power plant burst and an estimated billion (B) gallons of coal ash and sludge flowed out covering more than 300 acres of adjacent land.  Several neighbors had to be evacuated from there homes as fears of water and airborne contamination spread.

There is no technology that can get rid of coal ash, also known as fly ash, which is a byproduct of coal combustion.   The TVA insists that fly ash is non toxic, however the EPA is of a different mind, from the New York Times:

A draft report last year by the federal Environmental Protection Agency found that fly ash, a byproduct of the burning of coal to produce electricity, does contain significant amounts of carcinogens and retains the heavy metal present in coal in far higher concentrations. The report found that the concentrations of arsenic to which people might be exposed through drinking water contaminated by fly ash could increase cancer risks several hundredfold.

The post industrial revolution development scheme tends to use the strategy of building super regulated subdivisions miles away from power plants or other industrial activities.  After all, who want there back yards to look like this:

This merely pushes the problem further away, which allows the problem to grow bigger and bigger and bigger until it takes over and ruins the entire area. Our coal use should be getting smaller with an eye toward phasing it out all together. Soon.

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27 Dec 08 | Environment | Comments (0)

Cheap oil=Less solar?

18 Dec 08 | Conservation, Solar Electric, Solar Hot Water, solar thermal

The price of a barrel of oil has dropped more than 70% since it’s all time high of $147.00/bbl in July.  Prices for home heating oil, gasoline, propane and kerosene have dropped accordingly.  All of this seems like welcome relief and great news for the ordinary homeowner especially as this winter looks to be a bad one weather wise.

OPEC meet yesterday and agreed to cut production by 2.2 Million Barrels per Day (MBD).  Non-OPEC oil producers have promised to follow suit.  Will this have an effect on the plummeting value of crude oil?  Apparently not, as oil prices fell below $40.00 per barrel today.  What really seems to be driving the price of oil down is the recession and the fact that people are driving less.  How much less?  About 5% or so.

It might be reasonable to extrapolate a few things from this:

  1. A 5% reduction in driving translates to a 70% reduction in the cost of a barrel of oil, then a relatively small conversion (about 10-15%) of the US fleet to Plug in Electric Vehicles (PEVs) powered by solar, wind or non-fossil fuels would have a significant effect on the price of gasoline.
  2. Use of hybrid technology for public service vehicles, taxi’s, government business, mail delivery, police, etc could reduce government fuel use, costs, and reduce pollution.
  3. Rail transport is the most efficient way to move bulk goods across land.  A typical freight train can transport 1 ton goods 450 miles on one gallon of diesel fuel.  A typical Tractor Trailer (18 wheel truck, 80,000 lbs GVW) moves 1 ton of freight about 250 miles on one gallon of fuel.  Reducing cross country truck transport, using rail instead, then using truck for the last mile deliveries would significantly reduce diesel fuel usage, thus prices.

That is, if the markets are not manipulated by traders to drive up energy prices.  I have a strong feeling that in the next year or two we will find out that the $147.00 barrel of oil was a farce, just like the ENRON induced electrical shortages in California a few years ago.

To all those that say a 10 or 20% renewable energy target by 2015 will make not matter, I beg to differ.  Every little reduction matters.  Many many small reductions through improved efficiency, better technology, and renewable energy systems will add up to a large number.

If anything, the low price of oil shows that we are still vulnerable to unscrupulous operators that would seek to profiteer.  As energy prices drop, we should look at is as an opportunity to install renewable systems while prices are favorable.

For example, the cost of raw materials is coming down.  The price of copper (a significant part of solar thermal collectors are made from copper) has dropped from $9,000 per metric ton to a little under $3,000 per metric ton. Pure Silicon (major component in PV cells) is still high, but has dropped slightly over the last year.

One other possible bad effect of cheap oil.  The oil companies are not going to do any exporation and development of new fields as there is no profit in it for them.  Even if the regulations were relaxed and new leases signed, the whole “Drill baby, Drill” mantra may be met with “No thanks, we’ll just sell what we already have.”  In which case, we may indeed be driving ourselves over a cliff.

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18 Dec 08 | Conservation, Solar Electric, Solar Hot Water, solar thermal | Comments (6)

Photovoltaics or Gas Generators, what is the best backup power?

16 Dec 08 | Solar Electric, Training

Based on my experience during the Northeast Ice Storm of 2008, I thought I would do a comparison of a Photovoltaic system with battery back up vs. gas powered generators.  To be sure, a portable gas powered generator is the fastest least expensive way to get the power back on in an emergency.  They can also be dangerous, as several people have died of Carbon Monoxide poisoning over the last couple of days.

An installed system that automatically restores power can save time and money in the long run.  For that there are two basic options, a gas or diesel powered generator or a PV system with battery backup.

Here is a chart for comparison:

System category Photovoltaic system w/battery backup Portable gasoline generator Installed generator with auto transfer switch
Design Design intensive No Design Design moderate
Installation cost Initial cost high, approximately $20-27K Initial cost low, about $1-2K Initial cost moderate to high, about $10-20K depending on generator type/size
Installation labor Installation intensive No installation Installation intensive
Running cost Negative cost to run Cost to run high Cost to run moderate
Maintenance cost No maintenance High Maintenance High Maintenance
Environmental Non-polluting High polluting Moderate polluting
Fuel Non-fuel dependent Fuel availability dependent Fuel availability dependent
Load size Partial load sizing Partial load sizing Full load sizing
Operation Silent running Loud running Moderate noise running
Hazards Some batteries can produce Hydrogen if improperly charged Carbon monoxide hazard, fueling hazard, fire hazard No carbon monoxide hazard if properly installed
Other In use full time, can be configured to sell power back to grid when batteries are charged, reduces electric bill Standby use only, must be moved into position and use extension cords, does not reduce electric bill Standby use only, does not reduce electric bill

Notes:
1. PV design includes identifying critical electrical loads and doing a load analysis. Also includes local weather considerations, solar resources, sub panels, battery placement, etc.
2. Cost to run includes fuel and maintenance costs. Since PV systems can be configured to sell excess power to the utility grid thus reducing utility bills, it can make money, therefore have a negative cost to run.
3. Maintenance refers to mechanical maintenance, e.g. oil changes, belts hoses, etc. PV systems usually require no maintenance, properly charged batteries require no maintenance and will easily last 10 years if not discharge too deeply.
4. Load sizing refers to the house electrical load.  A PV system will usually be sizing to run critical systems, a generator can run the entire house.  This is a consideration for those that have electric houses (e.g. electric stoves, electric hot water, electric heat, etc)

To that end, I have put together a standard PV with battery backup package that will run most critical household loads during a prolonged power outage.  These include:

  1. Non-electric furnace or boiler and circulator pumps
  2. 1 HP well pump
  3. 1/2 HP sump pump
  4. Standard 20-23 CF refrigerator/freezer
  5. 1200 watt microwave oven (10 minutes per day)
  6. 20 inch TV and DVD player (5 hours per day)
  7. Table top or clock radio
  8. DSL or cable modem and network switch
  9. Battery charger for laptop computer
  10. 5 13 watt CFL lights (6 hours per day)

This system will have 3-4 days autonomy (no sunshine to recharge batteries).  A small wind generator can be added to create a hybrid solar/wind system.  These work well because usually when the sun is not shining, the wind is blowing and vice-versa.

Contact us to learn more about these systems.

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16 Dec 08 | Solar Electric, Training | Comments (2)

Solar Green Houses

06 Dec 08 | Solar Electric, Technology, solar thermal

So what you say, all green houses use solar energy.  True enough, but where I live, in the Northeastern US, the growing season is about 6-7 months.  The rest of the year, produce is trucked in from down the Southern US or South America.

What if we could extend the growing season to 10 months?  This would really help out the farmers, who can make more money.  It would help simulate the local economy.  It would reduce the embodied energy in our food.  In all likely hood, the local fresh produce would taste better.  Remember taste?  When was the last time you had a really good hot house tomato grown 1,000 miles away.  How about that fresh local corn?  Why have we settled for bland mass produced vegetables?

There are two main problems with this scenario:

  1. In the Northeast, the cold arrives toward the end of September and does not depart until around May or so.
  2. Coincidental with the cold weather, the amount of sunlight decreases shortening the available energy for plants to convert to the produce we want.

For the first part, the greenhouses can be heated.  Conventional heating systems would waste an inordinate amount of fossil fuel, thus contributing to the problem.  Using an array of solar collectors connected to an insulated underground drainback/storage tank would work nicely.  If the system where designed correctly, it could conceivably extend the growing season into the middle to end of November.  There should be enough solar resource to start the growing season around the middle of February.   Additionally, cold weather/frost tolerant crops, such as broccoli, spinach, lettuce, cauliflower, brussel sprouts, carrots, onions, turnips, beets, et. al. could likely be grown over the winter time, as long as the soil and roots do not freeze.

Then there is the issue of light.  All plants rely on Photosynthesis to convert the sun’s energy into vegetable matter.  Through a process called “Carbon Fixation” plants take in CO2 and H2O (water), using photons (light energy from the sun), create complex sugars which are used as energy for the plants to grow.  By this process, they also release O2 (Oxygen) into the atmosphere, which we need to live and breath.   According to this chart, Plants need specific wavelengths of light to thrive:

Plants required light wavelengths

Plants required light wavelengths

Plants need specific wavelengths of light. If you shine a green light on a plant, it will shrivel up and die. They thrive, however, in the deep blue (430-460 nm) and deep red (630-665nm) regions.  To that end, LED grow lights are becoming all the rage among hydroponics growers.

Therefore, I have been working on a prototype design for a PV power LED grow light.  Something that can be used on grid with a power supply, or off grid with a Photovoltiac panel.  So far, my small panel works quite well, I am growing some spinach with it in my basement.  What is really cool, under the grow light, the plant’s leaves look black or dark gray.  That means that it is absorbing all of the light from the LED’s and not reflecting any of it back.

This light is a bunch of 5mm LEDs wired in series.  It is designed to work on a 12 volt system.  It covers about 1 square foot of growing area and uses 12 watts of power.  It cost $125.00 to prototype (or $1.15 per square inch), although production costs would come down considerably if it were mass produced.

I am currently working on a high powered design that will cover 5-6 square feet of growing area.  It will use 88 watts of power and cost $398.00 to prototype, or about $0.49 per square inch.   Again, costs would come down considerably on a production run.

Larger arrays of these lights would cost even less per square inch as economies of scale takes effect.

There are some advantages to LED’s over conventional grow lights:

  1. LED’s are much more efficient, producing less heat (thus less wasted energy) than conventional grow lights.
  2. Long life.  My prototype LED lights are rated for >90,000 hours.  Using a LED grow light for 12-16 hours per day, that translates to 17 years.  If they are used for supplemental growth (e.g. 8 hours per day for half the year) then the life span would be about 60 years.
  3. It is generally though that LED’s are about 4 times as efficient as High Pressure Sodium (HPS) lights, so a 90-100 watt LED light could replace a 400 watt HPS light.
  4. Light can be tailored to plants or desired outcomes.  Most experiments show adding more blue light (430-450nm) increases vegetative growth.  Adding more red light increase flowering. Other wavelengths can be added depending on the plants needs.

The question is this; will this technology become economical in the future for ordinary growers to use?  Growing food locally would certainly cut down on the transportation costs and the associated polution of long distance farming.

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06 Dec 08 | Solar Electric, Technology, solar thermal | Comments (3)