This USA solar map comes from a study conducted on the performance of 2-kW photovoltaic systems installed on highly efficient homes across the country. The results capture all aspects of PV system performance, including the temperature effect on cell performance as well as the efficiency of the conversion from DC to AC power through the inverter. (information source: FSEC)

How much solar power does an average home need to install and what is the economic and environmental benefit?

Here in south Florida, an energy-frugal home uses at least 400KWH per month. To produce this much electricity with solar power, you need to install 2.8 KW PV panels. With this, an estimated annual saving of about $700 can be achieved and a total pollutant of 5,090 Lbs CO₂ , 13.9 Lbs SO₄ and 8.7 Lbs NO_x per year can be eliminated, which equals to the effect of planting 1 acre of tree.

How to choose the PV panel?

The main parameters of a PV panel are:

Peak Power Output(W_p), Max. Power Voltage(V_mp), Max. Power Current(I_mp),

Short Circuit Current(I_sc), Open Circuit Voltage(V_oc), System Max. Voltage(V_ms),

Temp. Coefficient(W_p , I_{sc ,} V_oc), Conversion Efficiency(CE) and Insulation Grade.

Given the output(W_p , V_mp  and I_mp) of the solar power station, one can pick the panel with high CE. Also depending on the geographic location of the power station where the panels will be installed, proper consideration needs to be given to the temperature coefficient in order to generate the most power in a day. Generally, multi-crystalline panel has been in use for long and proven to be very reliable while mono-crystalline panel has better CE while being restricted to relatively smaller size and output W_p so far. One other important factor to consider is the cost efficiency of the panel, which varies wildly from one model to another and can have long-term impact on the solar project itself.

What is the estimated energy savings for an average household by using solar water heater?

The typical electrial water heater in an household has the water supply capacity of 40 Gallons and runs an average of 5000 KWH electricity per year, hence the estimated average savings for a household is $600 per year. With the soaring energy price, the expensive electricity cost will increase even higher. The solar water heater will save more and more in the years ahead.

How do I compare the thermal efficiency of different solar heat collectors?

1) To compare the thermal efficiency of different collectors, look at the Btu/(ft?day) rating; the higher the number, the better the solar energy collection efficiency (which means it takes smaller collector area).

2) To determine the collector that supplies the most energy per investment dollar, divide the Btu/day rating by the total installed cost of the system, then multiply the result by the number of collectors used. Example: A collector has a Btu/day rating of 26,000. If you spend $2,100 for an installed system consisting of two collectors. Calculate as follows: 26,000 ?100 = 12.38, 12.38 x 2 = 24.76 Btu/day per dollar invested.  

How can I save the enviroment by using solar water heater?

Solar water heater uses the solar energy which is clean and has no pollution to the environment. The traditional electrical water heater uses electricity supplied by the power plant whose flue gas is both polluting and feeding the serious problem of global warming due to the greenhouse gas nature. As mentioned above, an average solar water heater can save the electricity of 5000 KWH per year. Assuming that only ten thousand households use the solar water heaters, then a total energy saving of 50M KWH can be realized. A large modern power plant has the capacity of 2000 MW(Mega Watt), or 2M KW. The energy consumption of 50M KWH requires such a giant plant to burn fossil fuel at full capacity for 25 hours continuously(more than a day and night) in order to meet the energy demand. By the similar calculation, if 3.5 million households use solar water heaters, a total energy saving of 17500M KWH can be achieved which then completely eliminates the need of such a giant power plant and the associated emission of about 73 Million Tons of CO₂ over a 20-year period.

How much electricity was produced around the globe by the PV systems?

Production of PV electricity increased to 3,800MW(the max capacity) worldwide in 2007, up about 50 percent over 2006. According to the Earth Policy Institute, cumulative global production stood at 12,400MW(baseload), which is sufficient to power 2.4 million US homes. PV power generation has been doubling every 2 years, making it the world's fastest-growing energy source. 

Why do we prefer the solar and wind energy over the traditional fossil-fuel?

They are good neighbors. Wind turbines pay welcome royalties to farmers and ranchers who work around them. If installed with the PV systems, up to 107.6 billion square foot of solar-accessible residential and commercial rooftop space in US could produce up to 40 percent of total US electricity capacity in 2004. Solar and wind are labor-intensive in manufacturing and installation, which can greatly contribute to local economies. Once installed, solar and wind have zero fuel cost. Solar and wind are inherently terror-resistant because they are widely distributed rather than concentrated. Solar energy can offer some blackout protection because it can be integrated into the building.

The more the fossil-fueled power plants, the more the pollution and the faster the pace of the global warming. By using the solar and wind energy, we can cut the energy dependence on the nature-polluting resource and lower the nation's dependence on Middle East oil supply and hence ease the tension of that area, which in turn can help release enormous fund and social resources to be spent on other national issues such as education, health and high tech research and development etc., upon which sits this nation's sunny bright future.

Needless to say, its positive economic and social impact is enormous. By doing so, we not only benefit ourselves but also help protect the environment and the society we live in. The users of the solar and wind energy are indeed smart  and deserve everyone's respect.

Please contact us at:

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