Solar Energy in the Midwest

Posts tagged ‘solar renewable energy’

Scientists create first solar cell with over 100 percent quantum efficiency

Scientists create first solar cell with over 100 percent quantum efficiency

By posted Dec 19th 2011 6:01AM

Researchers over at the National Renewable Energy Lab have reportedly made the first solar cell with an external quantum efficiency over 100 percent. Quantum efficiency relates to the number of electrons-per-second flowing in a solar cell circuit, divided by the number of photons from the energy entering. The NREL team recorded an efficiency topping out at 114 percent, by creating the first working multiple exciton generation (MEG) cell. Using MEG, a single high energy photon can produce more than one electron-hole pair per absorbed photon. The extra efficiency comes from quantum dots ‘harvesting’ energy that would otherwise be lost as heat. The cell itself uses anti-reflection coating on a transparent conductor, layered with zinc oxide, lead selenide, and gold. NREL scientist Arthur J. Nozik predicted as far back as 2001 that MEG would do the job, but it’s taken until now for the concept to leap over from theory. The hope is, of course, that this will lead to more competitively priced solar power, fueling the transport of the future.

sourceScience Mag

Solar in the Midwest – is it practical? By Valerie Jenner

Solar in the Midwest – is it practical?

By Valerie Jenner

The hard part about being a solar installation company in the Midwest is the common skepticism that solar, as a renewable energy source, is not practical or efficient in a state like Michigan. Thanks to forward thinking clients we have thousands of solar thermal systems installed for pool heating, residential and business water heating and space heating appliances that work seamlessly over decades. The problem is that we have no means to easily measure these systems and demonstrate to others how well they work and how much they save, except by “no gas” bills and regular updates from our clients. Solar electric is a different story.

While true that the solar electric, or photovoltaic (PV), industry was in need of better costs and efficiencies in the past, and were not competitive with utility rates – that is a problem of the past. Emerging and established solar manufacturers now reveal even higher efficiency panels, market competitive pricing, supported by legislative tax credits. A whole financial industry was created through buying and selling of Solar Renewable Energy Credits on the open market that solar electric is a new and solid option to fossil fuel power generation. The industry as a whole is innovative and dynamic, and improving daily. Just try to tell a solar customer today that their system does not work, and is not cost-effective and you will come across as uninformed and not up on the field.

Now, because of the real time monitoring available because of micro-inverters attached to the back of each solar panel, we can demonstrate over and over how well a solar panel or system actually operates. This data can also be compared to other locations around the states using the same system to fully evaluate the value and efficiency of solar PV panels under different climatic and seasonal influences.

The Enphase Energy micro inverters are the means that make this system visible for every minute the panels are exposed to daytime solar energy. With this system actual kWh or solar electricity generated can be measured and is solid evidence whether it is a practical application in Michigan. We now have 300 kW systems and over 1,000 panels installed that can be monitored and viewed by the general public in real-time, and historically.

Garden City, MI

Figure 1: A graph of a solar PV system installed in Garden City, MI by Mechanical Energy Systems, The Solar Specialist, illustrating solar system activity from 01/04/10 to 12/8/11. The system is composed of 36 x 234 kW Sharp panels and each is equipped with an EnPhase Energy M190-72-240 micro-inverter for a total of 8.4 kW system installed on a south-facing roof garage roof. In less than two years this system has generated 18.1 MWh’s of electricity.

Debary, Florida

Figure 2: This graph demonstrates the same time period 01/04/10 to 12/8/11 in Debary, Florida with a system that has 34 panels with micro inverters. Panel type is assumed as 15% efficiency (the same as the Sharp panels in Fiq.1). In less than two years this similar system has generated 21 MW.

The difference in actual electrical energy returned to the grid over 2 years, is 21 MWh (Florida) – 18 MWh (Michigan) = 3 MWh. This is an average of 1.5 MWh difference per year. This represents a 14.2% difference in total solar energy production which is exactly what is predicted given the climate and geographical differences of the two systems. While the solar systems do work well in sunny Florida, Michigan is also a viable and practical application of solar energy and our solar customers seem very happy with the monthly lower, to negative bills, from the utility companies.

A note from our Florida reference, Sherrie. “I am very, very happy with my installation. All you need is sun.  The more the better. Oh, let me tell you one more thing:  Solar panels do better when cold – they operate better in cold than hot.   The panels would do well in Michigan (as long as they get a good amount of sun). By the way, I would never recommend a solar panel system that didn’t have Enphase or a product similar to Enphase.” Sherrie continues, “Everyone wants payback NOW! and the solar costs seem to be too high now and people  are waiting for solar prices to go down. I am older so I know about inflation.  The interest rate today is close to .00 so if you have a few bucks I would tell you to use it on solar. Your electric companies will raise rates year after year & you will not like it. Best of Luck” Sherrie Slaboda, Debary, Florida.

We will be posting our installations as they reach anniversaries and compare them to warmer climate systems as a means of documenting solar performance over time. Years vary with solar optimization and climate changes and aside from informative we love proving that the Midwest and solar are mutually conducive. The links to the solar installations pictured above are live and can be compared at any time.

Update! 4/5/2012

Susan in Florida loves her system and has added 9 more panels and if you link to the live system she is now generating more electricity on a regular basis. The systems were similar in size for the first two years.

I will try to find another system that is the same size as our Garden City installation and track those two. It may be helpful if I can find an east coast and a west coast system to compare Michigan to. So far we see excellent generation here in Michigan, certainly nothing to deter anyone from considering it for their home or business.  – Val

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