PV Gap

Ross Said:

how can i use solar power to power up my house?

We Answered:

There are two basic choices for using solar power as a residential supply. One case is to remain hooked to the utility grid, and simply 'dump' the excess generated power back onto grid and use the grid when the solar generation is insufficient for the residential load. The other case is to employ a battery system, whereby the solar unit generates enough for the 'day' usage, and enough left over to charge the batteries for 'night' usage.

At the moment, the available (and reliable) technology is panels, rather than NASA's 'sail'. This is primarily due to the effects of weather on the sail's material, rather than power acquisition aspect. Depending on who you get as a supplier, the cost per panel can be quite low ... but covering an area that is 24 feet by 48 feet (like I did on my own home back in 2000), runs around $14000. This also includes the DC-AC conversion panel to allow the solar-generated DC power to be pumped back onto the grid's AC system.

The exposure (compass direction) and angle of the panels with regard to the sun is importnat for optimum power generation; depending on your roofline, you may have to ante up for some sort of support mechanism (I did not).

I didn't bother with battery storage - that is by far the most expensive part of the proposition. Obtaining sufficient battery capability for my power needs would have run me about $45000 ... for the batteries alone. If I still wanted to stay coupled to the grid (and the batteries), then I'd need another $15000 for an additional synchronizing panel and other harmonic filtering devices the local utility required.

The batteries that are the best for storage also have a limited life expectancy ... something like 5 years, at the outside. Which means that in 5 years' time (or slightly less), I'd have had to obtain another set of batteries ... at an addtional $45000 (or whatever the prevailing cost would be at the future time).

You can always plan to make the system operational on a smaller scale as well ... simply enough power for a water heater or a well pump, for instance. The scale would drop the price to around $5000 (there's still a chunk for the panels and DC-AC conversions to stay connected to the grid, which you'd have to do if the rest of the house was still grid-powered). Alternatively, you could even go to a small battery storage program for the heater and pump ... but it's pretty expensive even then, once you've factored in the recurring charges to obtain replacement batteries.

To decide what is realistic for you in terms of affordability ... get a good handle on your electric usage (for each item, on its worst day), and then investigate how much area you'd need to supply that load. Make your energy calculations based on the worst day of sunlight (usually midwinter) ... that way you won't be accidentally freezing anything when you least want to.

The return-on-investment figures in the initial (and recurring) costs of the COMPLETE solar setup, and the cost of electricity in your area TODAY. If you're satisified with the time frame required to recoup your initial outlay (my $14000 happened to equate to a 5 year payback), then go ahead.

As someone who has the solar capability installed ... check with your local utility for any possible loopholes they have regarding such installations. Then do some digging into panel suppliers (they usually have the whole package available, and most can talk more-or-less intelligently about it, as well as helping you understand your own residential electrical load). Then ... make your decision.