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.

With all of that in mind, I typed: “Why is solar…”  In the search box and let the auto complete fill out the rest.  This is the response:

It is Martin Luther King Jr. day, which explains the graphic at the top of the search results.  It is heartening to see that people are looking into reasons why solar is important or good.  I’d expect result #4, “Why is solar so energy expensive?” to be number one primarily because it is a question that is asked at least once on every sales call.

I believe that the general public is beginning to catch on in that most searches are looking for positive aspects of solar energy.  There is still a long way to go until the preception of solar moves from “alternative energy” to “main stream energy”  source.

They have been not making as much money as in previous years.  Meanwhile, Xcel Energy has come right out and said it:  Customers who have PV panels installed are getting a free ride.  They would like to charge those customers for energy that they might use, which in the face of things sounds a little off to me.

So what is the role of a utility company for those customers who choose to install renewable energy systems?  Are they a giant battery, ready to give and receive power at the whim of a customer?  Can they charge for goods and services that might or might not be used?

This leads to several questions about the way we distribute electrical power in this country.  The customer who invests thousands of dollars to generate a portion of his own power should not be penalized because he doesn’t use utility company power.  On the other hand, utility companies incur significant expenses maintaining the distribution grid.

Then there are the power generators supplying the grid.  Those companies have to anticipate load demand and start or stop entire generating facilities to meet that demand.  Power plants cannot be simply switched on and off, it takes a good deal of effort to get some of these facilities on line.

Clearly some type of working arrangement needs to be implimented between small renewable energy generators and traditional utility companies.  Most of the PV systems being installed today, at least in my area, are grid interactive.  Take the grid away and the system shuts down.  Perhaps some small fee for storing the renewable enery system’s excess kWh until they are used would be fair.  After all, if not grid interactive, the other option is to install a battery storage system, which is expensive and maintenance intensive.   The utility grid is not free for the utility company, they should get something for providing a storage service.

To that end I purchased a book called Oil 101.  It is, indeed, a fascinating book that details the complexity of our current energy structure.  The book is an excellent primer on the oil industry, it is well written and easy to understand.  Anyone who drives a car, uses oil to heat their house, uses plastics or any other petroleum product should read this book.  That is to say, everybody should read this book.

What strikes me is how much effort is put into exploration, extraction, refining and shipping.  We take all of this for granted in this country, but any failure in any one of those steps would create a disaster of epic proportions.  Think Hurricane Katrina for the whole county.  The fact that so much of this energy depends on technology, specialized methods, and huge capital outlays should be at least slightly alarming.  That, and our entire economy is build on the availability of cheap energy.  As we have just seen, economic down turns can really put a damper on large cumbersome corporate operations.

It may seem natural to be angry at the oil companies when gas is $4.25 a gallon and electricity is $.20 a kWh.  However, when I read about all of the work and investment these companies have to make, all of the variables from bad weather to bad governments they have to deal with, it also makes me respect the oil companies for all that they do.

For me, the day starts right after I finish my shower, around 6 am.  I turn on the laptop and check my e-mail.  As the business owner, it is important that I keep abreast of events like equipment shipments, appointments, work schedules and so on.  All of that is organized on line through iGoogle. It makes like much easier to keep track of.

After I look at my appointments, I get dressed, shave and head out into the big world.  I look at my appointments before I get dressed so I know the appropriate attire.  Placing solar collectors on a roof, Carharts and steel toed work boots.  Meeting somebody for a sales presentation, a nice shirt and kakis.

On my way to the “office” I pick up a cup of coffee.  I only started drinking this stuff about 4 years ago when I turned 40.  I find the day starts better when I have a medium with milk and 1 sugar.

Yesterday, the job involved finishing a warranty repair on a SDHW system.   Seems one of the collectors sprung a leak in the manifold header.  We had to remove it from the roof, bring it back to the shop, braze new parts in, cart it back to the work site, place it back on the roof, then pressure test and refill the system.

I also installed a flow balancing valve in the attic, which involved crawling over pipes and insulation, cutting 3/4 soft copper tubing, soldering in two 1/4 turn ball valves, all the while being careful not to set the very old dry wood or attic insulation on fire with the torch.  I have a hard rule that fire extingushers are on hand and ready to be used whenever torches are lit.  Very important not to burn the customer’s building down as that type of activity will give a company a bad reputation.

I also took the time to explain to the customer what happened, what was done to fix it and what they should to if it happens again.

Once the system was up and running, a grabbed a bite to eat for lunch.  I came back and watched it run for a little longer then labeled all of the valves and tanks, and cleaned up the floor in the mechanical room.

On the drive home, I returned a few calls on the cellphone.  Once home (the other “office”), I checked and answered e-mail again.  Set up my schedule for tomorrow, typed up two proposals for photovoltaic systems, printed out receipts for this years tax filing, and read a few trade news items on line.

In between all that, I had dinner, gave my kids a bath and did their night time routine (read books with my son, tell stories to my daughter), watched a little news, paying close attention to the weather forcast.

I switched off the laptop at about 9:30 pm.

“To get maximum efficiency when converting solar power into electricity, you want a solar panel that can absorb nearly every single photon of light, regardless of the sun’s position in the sky,” said Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university’s Future Chips Constellation, who led the research project. “Our new antireflective coating makes this possible.”

It is possible by using nano technology to create seven layers nano rods.  Each layer is designed to transmit a specific wave length (color) of light.  The result is an absorption efficiency of greater than 96%.  This is indeed great news for PV cell producers, as the current light absorption efficiency is about 67 percent for the typical PV panel.

The seven layers, each with a height of 50 nanometers to 100 nanometers, are made up of silicon dioxide and titanium dioxide nanorods positioned at an oblique angle – each layer looks and functions similar to a dense forest where sunlight is ‘captured’ between the trees.

The major implication for solar manufactures is smaller more powerful PV cells can be produced with less raw material.  Is this the breakthrough the solar industry has been waiting for?  Maybe.  In any case, it certainly seems like a step in the right direction.

The one problem I see with all of this is the efficiency of the photovoltaic cell itself.  A PV cell is essentially a large exposed transistor.  When a photon strikes a P-N junction, one of four things happens; it bounces off, it passes through to the other side, it gets converted to heat, or it knocks an electron free.  Of course the first situation is mostly cured by the selective coating.  The last situation is the desired outcome.  Conversion to heat remains a problem.

Currently manufactured PV cell technology has roughly a 15% efficiency from insolation rate to electricity production.  As we learned above, some of this efficiency loss is due to reflection of light from the surface of the PV cell.  A comparison of the total light reaching the PN junction (67% of the available sunlight) compared to the output of the PV cell, shows that the actual conversion efficiency of the PN junction is about 22%.  The remainder either passes through the PV cell substrate or generates heat.  The selective coating applied to a PV cell will increase the heat in the PN juction by 25-30%.

Heat is a major problem to semiconductors.  Heat reduces efficiency and lifespan of a traditional silicone based PV cell.  The computer industry has gone to great lengths to improve the heat tolerances of the semiconductors used in computer chips, therefore, this is not an insurmountable problem.  It does, however, need to be addressed in cells that will use the selective coating developed at RPI.

It will likely take several years for this technology to make it onto the general market.  In the mean time, every watt of installed PV is one less watt generated by fossil fuels.

The Yahoo! groups that I belong to are:

1. awea-wind-home. American Wind Energy Association, a great place to learn about wind power from the pros
2. axialflux. This group is dedicated to making small axial flux wind turbines and using them. Good if you want to learn how to make your own well designed wind mill
3. Biodiesel. Self explanatory
4. microhydro. For those interested in small hydro electric generation projects
5. homeenergysolutions. A good resource for renewable energy around the house, plus great ways to save energy by making conventional systems more efficient.
6. SolarHeat. Solar thermal people talk about their heating projects.

There where also numerous PV groups, but I didn’t join any because it seemed like they were discussing old news.
One caveat, not everything that is published there is correct or the best was to do things. I have found that there are a few people that are attempting to sell snake oil. There are also a few well meaning people who don’t know what they are talking about. Generally speaking, however, the majority of contributors do know what they are talking about and are a valuable resource for somebody who want to do it themselves.

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:

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.

I install both types, and lately I have been receiving quit a few calls regarding solar thermal (i.e. solar hot water, or radiant floor heating) systems. I think this will continue as the price of energy goes up.

A solar thermal system move fluid through solar collectors, which collect heat.  The fluid is then stored or used in the building. In reality, a solar thermal system is about plumbing.  A Solar Domestic Hot Water (SDHW) system has three unique parts that other hot water systems or heating systems don’t have. The first is the solar collectors, the second is some type of heat exchanger and the third is some type of controller. As regarding the solar collectors, I believe that SDHW systems work best with flat plate collectors.

The flat plat collector design has been around for many years. Newer solar selective coatings have been created that increase the system efficiency. In addition to that, better insulation and better high transmisity glass have all improved on the flat plate collector design. Evacuated tubes run at higher temperatures and have problems with the seals between the glass tube and the copper pipe on the inputs and outputs of each tube.

The next unique thing in a solar system is the heat exchanger. The heat exchanger takes the hot fluid from the solar collector and cools it with the fluid from the solar hot water tank. This can be implemented in a number of ways. Some heat exchangers are part of the solar storage tank, some are a part of a drainback tank, and some are external.  All heat exchangers are made of metal (stainless steel or copper) and use counter-flow properties to move the heat from one fluid reservoir to another.

Finally, the system controller, which measures the temperature of the collector outputs and the solar storage tank. If there is enough energy in the collectors to transfer to the storage tank, the controller turns the system on, which begins collecting energy.

Beyond that, a solar system is copper piping, valves, drains, hot water tanks, pumps, and other miscellaneous hardware which is all available at the local plumbing supply house.

Solar thermal systems that are designed for space heating are very similar to SDHW, only they are usually quit a bit larger with more storage.

In most cases, all solar thermal systems should have some way of operating in backup mode in case there is a long period of inclement weather. These back up systems entail some type of conventional heating system installed in parallel with the solar system. For example a SDHW system may have an electric tank or electric element in the solar tank designed to turn on if the water temperature gets too cool. A radiant floor heating system may have a small oil or gas fired backup furnace in standby duty.

A well designed solar system should be designed to produce about 80 to 85 percent of the energy needs. More than that and the system design will be too large, causing it to over produce and over heat under normal operating conditions. Less than that and you are leaving a good deal of money on the table, to be taken by the gas/oil companies.

Dave, at the Solar Power Rocks blog, pointed out that for every $1.00 saved in annual energy costs, the value of a property increased by $20.73. This is from the Appraisal Journal, Evidence of Rational Market Values for Home Energy Efficiency.

Two years ago, I added insulation to the house and replaced four old single pane windows with energy star replacement windows. Our heating oil use went from 630 gallons per year to 450 gallons, for a savings of 180 gallons, or at today’s prices $650.00 per year. The total cost of the project was around $2,000.00 dollars, but the increased value to the house is $13,474.50. That is a nice payback, and readers should note that increasing efficiency and reducing use is the first step in considering any renewable energy system.

Last year, I installed a Solar Hot Water system on my house. The total cost for that project was around $5,000.00. With federal and state tax rebates the final cost will be about $2,200.00 Since we have not operated the system over an entire year, it is hard to calculate exactly what the savings are for this system. I have, however, been able to project the savings based on the performance so far.

Before the solar system, our hot water was heated by electricity. Our electricity cost per kWh is creeping up, now somewhere around $0.14 or so. If the estimated reduced electrical use hold true, we should save around $560.00 per year, which translates to an increased property value of $11,608.80. It seems fantastic, but by my math, that is an 870% return.

We are not selling our house anytime soon, so the increased property value is dismissed for now, as completely irrelevant. A calculation of simple payback shows the following:

*Utility inflation calculated at 2.3 percent per year
**Initial system cost, less refunds and rebates
***Replacement of circulator pumps, expected life 10 years
****Replacement of storage tanks, expected life 12 years

Over the twenty four year life of the solar thermal collectors, a $12,871.98 savings will be realized, which leads to a net return of 268% on the initial investment. Oh, and by the way, the IRS has not figured out a way to tax people for saving money, so that is tax free, at least for now.

Also note; solar thermal collectors manufactured today could well last 35-50 years depending on the climate.

For the sake of argument, lets say in year 8 we sell our house and realize the property value increase stated above. Our return in investment would then be 991% (property value increase plus savings, or 870% plus 121%). Okay, that seems very unrealistic, so lets say we realize half of the property value increase noted above, or 556%. Geez, that is still too high so we only see a quarter of the property value increase, or 338%.

My 401K was (before the current stock market troubles) earning 16%. My CD’s are around 7%. Savings, 4.1%.

Ummm, 338% vs 7%? I am not an accountant or anything, but it seems to be like installing the solar system last year was a pretty good idea.

I am going to work an a “Solar as an Investment” page with a savings/property value increase calculator that can spit this out for anyone who wants to see what their return would be.