
YucaLandia

Jul 10, 2013, 6:01 PM
Post #4 of 23
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If you are slightly able to do minor constructions, you can import some very fine 200W solar panels from China for roughly $200 USD a panel - because the Chinese government is giving very heavy subsidies to their solar panel producers. The panels come with fine aluminum frames that are easy to mount. A good grid-tied inverter costs about $2,000 - $2,500 USD. By using a grid tied inverter to produce 120V AC power, you can then get CFE to change you over to a meter that (metaphorically) "runs backwards" during the times of day when your solar system is making more power than you use at that time. This means that a big solar system actually feeds power back onto the grid during the daytime - giving you credits on your bill. Then, at night, your house automatically "switches" back to CFE power - meaning you need NO batteries. If you set-up ten 200W panels, and keep them clean, and keep them oriented towards the sun between 9AM and 3PM, then you can easily get 2 kW per hour during full sun times. A few questions spring to mind: ~ We need to know how many cloudy/overcast days you can have every year. ~ It is helpful to know how many hours of good sunshine you get on the shortest days of the year... ~ Do you have space to mount panels, in a way where the air can circulate around them, keeping them cool (do not plan to mount them in boxes or other enclosed spaces - instead mounting them in configurations that allow air flow around them). Answers to these questions allows one to calculate how many panels you need to mostly offset your DAC rate power bills. Actually, if you can just get your monthly moving average for a year, below the maximum allowed average power usage to keep the subsidies, we could quickly get your net CFE power usage well below those thresholds. ... Guessing an average 7 hours per day of good quality sunlight on your panels**, we can expect 14 kW per day. That turns into 420 kWh per month. That further translates to roughly a 5000 kWh per year reduction in your CFE usage, for a rough cost of $5,000 - $6,000 USD if you do it yourself. Similar Mexican supplied and Mexican installed systems can cost $12,000 USD or higher. Depending on what CFE Tarifa Zone you are in, the system could pay for itself in as little as 3 years like in Tarifa Zone 1B (while we in Merida, Tarifa Zone 1C, pay a lower $2.7 pesos per kWh for Excedente Rates which translates to a savings of $13,800 pesos per year - and a full payback in 5 years). Note that when you your running average CFE power usage gets consistently below that monthly DAC threshhold, you start getting the 3X lower power rates on the rest of your power, and you also recover the 78% government subsidy - giving some people a full payback in 2 years... (because of the Chinese govt. subsidies lowering the prices on panels ordered directly from China). If you want more than 5000 kWhr of solar power per year, we need to know how many hours of sunlight you expect per year, and then you can extrapolate from our 10 panels of 200 W each at 7 hours per day of sunlight - model. ... e.g. If you want 2X more power, then double the number of panels - but still use the same good quality grid-tied inverter - so, you could double the size of the 5000 kWhr per year system for an expenditure of roughly another... $3,000 USD. Note: The Chinese panels are expected to have 15 yr life spans producing roughly 90% of their rated values, and that output then falls gradually for the following 10 to 15 years. Also note that combination of the heavy Chinese Govt. subsidies of solar panel production, and the higher efficiency of the newer generation panels mean full system $$ paybacks much faster than people who bought PV systems even just 5 years ago. steve **The averages listed above are for very good conditions for solar power - like in Sonora and US Southwest states like Arizona and New Mexico. If Mazatlan has significantly less sun than Sonora, et al, then adjust that 5000 kWhr per year down proportionately - reducing the solar PV power expected by the % reduction of sunny days from the calculated 360 sunny days. All of the estimates provided above are for a system we set up on a friend's home 6 months ago - where he has reduced his power bills from a previous $400 USD a month, down to $67 pesos on his last bill. ... using panels imported from China, and a grid-tied inverter imported from the USA - all at a total cost that was less than half of quotes from local Mexican firms. - Read-on MacDuff E-visit at http://yucalandia.com
(This post was edited by YucaLandia on Jul 10, 2013, 8:02 PM)
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