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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.

Energy Storage

17 Feb 10 | General

One of the main problems with solar power is that of storing energy for non-solar periods.  On any given point on earth, there are an average of 12 hours of sunlight per day over the course of a year.  Unfortunately, it is the times when the sun is not shining that we need it’s power the most.

With grid connected systems, during sunny periods, excess power is dumped into the grid, for a credit to be used later.  The problem with this approach is first, the grid has to be present.  If the electric utility is out, then no power is being generated by the solar array.  In most parts of the US, at least right now, this happens only occasionally, so it is not a big concern.  The second consideration is with fossil fuel based grid generation, there is something called the spinning reserve.  That is to say, a generator running at one half it’s rated capacity has the other half in reserve.  With any fossil fuel based generator, as the output from the generator drops, the efficiency drops as well.  Therefore, saving 1 kWh of electricity does not automatically correspond to a 3,412 BTU reduction in fuel input (or 5,732 BTU if considering 32% grid efficiency).  It would be some fraction of that, which is one of the reasons why renewable energy is such an up hill battle.

The real answer is better batteries.  The lead acid battery technology we are currently using has not been improved in over 100 years.  There have been some strides with things like laptop batteries and cell phone batteries, but those are relatively small.  The main issue is power density, e.g. very heavy large batteries storing not enough electrons.  In order for renewable energy to really be meaningful, better energy storage needs to be developed.  This would also help out things like plug in electric vehicles (PEV).

Lawrence Berkeley National Laboratory is on it.  They are working on batteries for vehicles, but by extension, that technology could be applied to renewable energy as well.  This is one of the critical steps in solar development.  You can keep up on developments by following Venkat Srinivasan’s blog, This week in Batteries. He explains things much better than I ever could.

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17 Feb 10 | General | Comments (0)

Prism Solar Technologies

28 Dec 09 | Solar Electric, Technology

Prism Solar Technologies is continuing to grow their manufacturing facility located in Highland, NY. They took over the PLASMACO plant last March, which coincidentally, had much of the equipment and clean rooms needed to manufacture their product. PLASMACO was a subsidiary of Panasonic corporation, they manufactured Plasma screens for TV’s and computers.

What Prism Solar makes is a proprietary holographic planar concentrator™ (HPC) film that, when used in conjunction with conventional silicon photovoltaic cells, increases the cell efficiency by about 40%. According to their website, the increased efficiency allows for use of 30-50% less silicon during the manufacture process, making the the cost around $1/watt.

Here are the advantages of HPC technology:

  • Less silicon reduces cost per watt
  • Passive tracking from holographic effect produces more energy from diffuse and reflected light.
  • Cooler operation than conventional PV module, most unusable light passes through module without being turned into heat.
  • Bifacial PV cells can increase module performance when mounted over a reflective surface.
  • Lower embodied energy, the energy required to manufacture the HPC film is much less than that required to mine and process silicon.

They have four prototype modules on line in Tucson, AZ connected to Enphase inverters. One can look at the module performance on the Enlighten website. There is also a specification sheet for a 160 watt module.

According to their latest press release, they are about to create 175 new jobs in the Hudson Valley (although there is nothing on the careers page yet). All of that is good news for the solar industry and I look foward to seeing their product out in the field. I must say, it certainly looks cool.

holographic optical photovoltaic panel

I previously wrote about them here.

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28 Dec 09 | Solar Electric, Technology | Comments (0)

Ground Source Heat Pump; same as a coal stove?

03 Jan 09 | Conservation, Environment, Geothermal

I read a lot of information on a daily basis.  A few months ago, somebody commented that a Ground Source Geothermal Heat Pump is the same as using a coal stove to heat your house.  The notion is that by purchasing and installing a GSHP, a homeowner is only pushing the problem further away (to the electrical generation plant), not actually reducing pollution.

Is that right?  Perhaps a little research is in order.

First, a little background.  A Ground Source Heat Pump (GSHP) uses a refrigeration cycle to move heat either to or from a heat sink which is typically a large coil of PEX pipe burried in the ground.  Wells, ponds and other sources can be used also.  The idea is that using the ground (or other source), which is a constant temperature of around 50 degrees F, a heat pump can be much more efficient than using resistance heating.

GSHPs are rated by a coefficient of performance, known as COP.  This is a comparison of the amount of electricity used by the heat pump vs. electricity used in resistance heating.  Thus a COP of 5 means the heat pump is producing 5 KW of heat for 1 KW of electric used.  The highest COP is about 6, or 600% efficiency compared to electric resistance heating. A COP of 5 is considered very good.

The electrical distribution system in the US is about 31.2% efficient.  Therefore, a head to head comparison of power used vs. heat produced would look something like this:

1 kWh = 3413 BTU

A GSHP using 1 kWh of electric with a COP of 5 produces 17,065 BTU heat.

The electric plant producing the current to run the GSHP burned 10,939 BTU of fuel to produce 1 kWh.  Therefore, a very well designed, well installed GSHP is about 156% efficient when all the energy requirements are considered.

A typical coal stove is about 60-65% efficient, therefore it would require 26,254 BTU to generate 17,065 BTU of usable heat.

Conclusion: A Ground Source Heat Pump ≠ a coal stove.  GSHPs are energy efficient and a good way to heat a home where solar resources are not available.  They are not 500% efficient, as some companies would have you believe, but are greater than 100% efficient if properly designed and installed.

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03 Jan 09 | Conservation, Environment, Geothermal | Comments (10)

Photovoltaic manufacturing starts in Kingston, NY

26 Feb 08 | General

More good news on the local renewable energy manufacturing front. From Mid Hudson News Network:

A projected 400 jobs could be coming to Ulster County within five years with the signing of Prism Solar Technologies to the Solar Energy Consortium.

For everyone who believes that the way forward is to build better renewable energy systems, this is a very good thing. From their web site:

Prism Solar manufactures a new type of photovoltaic module that uses transparent holographic optical elements in its design. This innovative, patented holographic technology, collects and spectrally selects useful wavelengths from the sun and focuses them onto the cell to create electricity.

They look like this:

holographic optical photovoltaic panel

Damn, now you have to admit, that is cool. I’d put a big array of those on a couple of tracking mounts in my front yard and call it “Performance Art.” The basic explanation of how they work and why they are better than plain old ordinary PV panels is:

(By) increasing the optical efficiency increases the structures ability to trap more of the light by better controlling the angles that the light is diffracted within the laminate. Through this process, Prism Solar can tap the sunlight at its most advantageous point in the spectrum.

This allows for several innovations:

  1. Lower cost – uses fewer cells per watt of power.
  2. Reduces the amount of silicon required up to 85%.
  3. Transparent properties, can be used as skin on large skyscrapers without completely blocking light into building.
  4. Intelligent Passive Solar Concentrator (IPSC), uses both sides of PV cell.

More information is available on Prism Solar Technology Page.

When will this start happening? Soon. Soon…

They will start production soon at their current location at the Center for Innovation on Grant Avenue in the Town of Ulster. Plans are to eventually move to Tech City. Prism Solar CEO Rick Lewandoski said production will begin as soon as machinery is installed, and that could be within just a few weeks.

Lewandowski said positions from secretaries to engineers and scientists are already in the application process, and that employment figures in the county have already been affected by the joint venture.

Courtesy of Mid Hudson News Network.

Yes, I’ll take more technology, please.

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26 Feb 08 | General | Comments (3)