Solar Towers

A solar tower is a proposed type of renewable energy plant. It combines three old proven technologies including the greenhouse effect, the chimney effect and the wind turbine. All together, these three concepts create a renewable energy source equivalent to a set of solar panels. The air is heated by the sun and is stored in a very large greenhouse at the base of the tower. The result is convection and hot air rising through the chimney which in turn, causes the wind turbine at the top to begin spinning. While this turbine is spinning, mass amounts of energy is produced.

While the solar tower has a power conversion rate considerably lower than many other designs in the solar thermal group of collects, the low investment cost per square meter of solar collection balances this out. According to model calculations, a simple solar tower with an output of 200 MW would need a collector seven kilometers in diameter and a 1000-meter-high chimney.

Location is a main factor in the amount of energy the tower produces. Depending on the altitude of the solar tower destination, there may be less or more energy generated than usual. Other factors like wind, rain and temperature may also effect the energy output of the system.

There is an ongoing debate of which type of renewable energy is most effective and productive. While we may never know which will save you the most money, or which is truly the best for the environment, we all know that using any of them will help do our part to save our world.

PTC vs. STC Ratings; Learn what the difference can save you!

PTC refers to PVUSA Test Conditions, which were developed to test and compare PV systems as part of the PVUSA (Photovoltaics for Utility Scale Applications) project. PTC are 1,000 Watts per square meter solar irradiance, 20 degrees Celsius in air temperature, and have a wind speed of 1 meter per second at 10 meters above ground level. PV manufacturers use Standard Test Conditions, or STC, to rate their PV products. STC are 1,000 Watts per square meter solar irradiance, 25 degrees C cell temperature, air mass equal to 1.5, and ASTM G173-03 standard spectrum. The PTC rating, which is lower than the STC rating, is generally recognized as a more realistic measure of PV output because the test conditions better reflect "real-world" solar and climatic conditions, compared to the STC rating.


Neither a PTC nor a STC rating can account for all "real-world" losses and situations. Actual solar systems will produce lower outputs due to soiling, age of the system, technical difficulties, and other criteria. These loss factors can vary by season, geographic location, mounting technique, azimuth, and array tilt. Taking this into consideration, it is crucial to know how well your system has been constructed and how it is being rated.

To give an example, on an average 10 kW system, taking into consideration several factors, the overall DC (or the STC) rate to AC (PTC) rate can provide you with anywhere from 55% savings, to 100.8% savings. Based on these numbers, an average of 4 hours of maximum sunlight per day, and a cost of twenty cents per watt of energy, you could be saving anywhere from $1606.00 to $2943.36. Though many get these ratings confused, it is apparent from this example how important it is to know the difference between them, especially when it could be saving you thousands of dollars.

Want to save money on your energy bill?

Connecticut Light and Power is offering certified energy audits for a $75 fee to make your home more energy efficient! Contractors approved by CL&P will come to your house to assess possible energy wasting problems with your house, and then come up with solutions to these problems to make your house greener and more energy efficient.  The process, while simple and short, can be a tremendous help in lowering your energy bill.

For those interested in getting their house audited, you must either apply online at http://www.cl-p.com/forms/HomeEnergySolution.aspx and CL&P will assign an able contractor to OR pick a contractor from the approved list at http://nuwnotes1.nu.com/apps/clp/clpwebcontent.nsf/AR/HesContractors/$File/HES_Contractors.pdf and call them to schedule an appointment.

Inspections can/will include the following:

-A blower-door test to pinpoint critical drafts and air leaks.  Once they are found, the contractor will seal them properly in the duration of the visit.

-A duct test to assess air leaks within the ductwork system.  Significant leaks will be sealed.

- Hot water-saving meaures including low-flow showerheads and faucet aerators (which will be installed).

- Rebates for qualifying central air conditioning systems and for replacement of certain inefficient appliances with qualifying energy-efficient models.

-Installation of energy-efficient compact fluorescent light bulbs.

-Incentives for insulation upgrades

-A "wrap up discussion" where the contractor will review the work done and inform you of additional resources that can be potential energy and money savers.

For more information on these energy audit process, be sure to call 1-877-WISE-USE (1-877-947-3873).

Commercial Savings; Are They Worth It?

With the green energy movement in full effect, it is no wonder that the Connecticut Clean Energy Fund, and the New York State Energy Research and Development Authority have an abundance of commercial financial incentives for using renewable energy. While these incentives are readily available for people to find, the real question is whether or not they are useful and realistic.


In Connecticut, the CCEF has implemented a rebate program for those users of energy efficient equipment during peak energy using hours. Those who save up enough energy during these peak energy consumption times may be eligible for a state rebate of up to 100% of the systems cost.

Connecticut is also running a state rebate program through October of this year that allows consumers purchasing EnergyStar appliances to apply for a rebate for up to 50% of their appliances cost.

New York has also done its part to promote energy efficient utilities to its citizens. The Commercial and Industrial Efficiency Program provides a set rebate for customers who install an efficient energy saving system of a specific size as long as they are not residential consumers. Also, according to the Commercial Energy Efficiency Rebate Program, companies looking to install multiple energy efficient systems in their business can receive up to $10,000 per project upon inspection.

While these incentives may look fantastic on paper, there are some doubts that we and PurePoint have about them. All of the incentives listed do not list many specifications as to when funding is anticipated to dry up, and what the specific qualifications to receive the funding are. Also, while these incentives may cover some costs of these expensive and technologically advanced utilities, there is still a high portion of the total that is not covered which many businesses cannot afford.

No matter what your take on the subject is, none of us can deny that switching from a low energy saving utility to a high saving one is a good investment and decision.

From BBC News.

An experimental aircraft that draws its power from the sun is making a round-the-clock test flight.

The aim is to assess whether the plane can fly in darkness, using solar cells on its wings to generate enough power to stay in the air for 24 hours.

The HB-SIA plane, which took off from Switzerland, has the weight of a family car but the wingspan of a big airliner.

The test flight was initially due to take place last week but was postponed because of a technical problem.

"For seven years now, the whole team has been passionately working to achieve this first decisive step of the project," said pilot Andre Borschberg as he entered the cockpit at an airfield in Payerne, in the west of Switzerland.

He is to take the aircraft to an altitude of 27,900ft (8,500m) by late Wednesday, when the sun's rays stop being strong enough to supply the solar cells with energy.

The prototype will then start a slow descent using energy stored in its batteries until sunrise.

"The big question is whether the pilot can make efficient use of the battery energy to fly throughout the night," the team said in a statement.

"If this mission is successful, it will be the longest and highest flight ever made by a solar plane."

'Solar future'

The plane, which has 12,000 solar cells, is the latest step in the Solar Impulse project, which Mr Borschberg leads with his business partner and fellow adventurer, Bertrand Piccard.

Mr Piccard made the first non-stop circumnavigation of the globe in a balloon in 1999.

The pair want to prove that solar power has a practical future in aviation and, more generally, in powering society at large.

The plane incorporates composite materials to keep it extremely light, and uses super-efficient solar cells, batteries, motors and propellers to keep itself in the sky.

The vehicle was unveiled last year and has since been undergoing daylight trials. The first full-day flight was completed on 7 April.

The HB-SIA will be succeeded by HB-SIB. It is likely to be bigger, and will incorporate a pressurised capsule and better avionics.

The group plans to use this vehicle in two years' time to make the first manned transatlantic solar flight, followed in 2013 by an even more daring circumnavigation of the Earth.

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