Should You Wait for the Latest, Greatest PV Modules?

| 5/14/2010 10:42:00 AM

Tags: solar electricity, solar electric system, Dan Chiras, PV modules, energy efficiency,

bifacial PV modules 

Every year we hear about a breakthrough in solar electricity — usually a new solar cell with a very high efficiency rating. Knowing that new PV technologies are on the horizon, many people ask us if they should wait a bit before they invest in a solar electric system. Does it make sense to delay your installation until the new, more efficient PV technologies hit the market?

This is a fair question, but the answer is no.

Newer, more efficient PVs are certainly on their way, however, one of the key considerations when installing a PV system is not the efficiency of the PV modules, but the cost of the modules based on the installed capacity. Those of us in the business refer to this as the cost per watt of installed capacity.

An even better measure is the cost per kilowatt-hour of electricity produced by a PV system array over its lifetime. What you’ll find when comparing modules by these parameters is that new technologies, while more efficient, typically cost more per watt of installed capacity. A 2 kW system that utilizes the most efficient modules on the market, for instance, may cost 10 to 30 percent more to purchase than a 2 kW system that uses slightly less efficient modules. Yet both arrays produce the same amount of electricity. Why pay more to produce the same amount of electricity?

In some cases, though, a higher installation cost actually results in a lower cost of kilowatt-hour of electricity over the life of the system. PV modules fitted with micro-inverters, that is, small inverters mounted on each module, for instance, may cost more per watt installed capacity, however, the increase in efficiency may result in a lower cost per kilowatt-hour. So, if you are considering a solar electric system be sure to analyze your decision using both cost per watt installed capacity and cost per kilowatt-hour over the lifetime of the system. A competent installer should be able to do this for you.

6/4/2010 6:18:04 AM

I have dreamed of using solar for years but our problem (actually a blessing in north Alabama) is shade. We have the south side of our roof shaded by water oaks that leave little sun available space. We couldn't afford to use an out building, also in shade, or have to start from scratch for a structure for panels. Is there any thing available that is efficient enough to overcome heavy shade which does mean little or mostly no air conditioning and lower heating costs in winter. It would be nice to offset some of the other power costs. HBT

b knight
5/30/2010 9:47:52 AM

Hi Dan... good article. Another consideration would be the various incentive programs available - looking into the tax incentives are grants available in your area and when they will end.

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