SolarByTheWatt.com

Do Solar Photovoltaic Modules Have to be UL Listed? Are There Other Certification Options?

Ok here were coming back to an issue that was brought up by us early on and we were trying to get different opinions on. That is UL listing or photovoltaic equipment being listed, at all.

It seems like everyone who purchases photovoltaic modules in the US is verifying whether the modules are UL listed.

What does that mean and where does the concern come from?

Well here is the latest of what we find.

The requirement really comes from the National Electric Code (NEC), but the requirement does not directly specify that the listing should be by UL (Underwriters Laboratories – a company).

The exact requirement states:

We are continuing our series of articles on lowest prices per watt for solar photovoltaic panels where every time we have changes in the price ranking we will publish a new article with corresponding date in the title.

We list the cheapest panels dollar per watt that we can find on the internet and through direct research. We also include listings of products our readers submit to us through or Contact Us form or in the comments. Representatives of the different vendors are welcome to submit info about their products too. Very differently from other “cheapest solar panels lists” out there we will not charge you for that and we will not tell you the list is already full – yep, this is what some publishers of lowest prices in solar have told some of the vendors of realistically the cheapest panels in certain sizes.

Low prices of solar photovoltaic panels fighting the $2 per watt range make it possible for investors to build economically efficient, profitable solar power plants and installations.

The prices of solar photovoltaic panels has fallen dramatically in recent months. News about manufactures starting to feel oversupply of production despite the growing activity in solar power plant construction has made many of them lower prices of modules that are commercially available.

A Review of Total Investment Cost, Dollar per Watt Peak and Euro per Watt Peak for Large Solar Photovoltaic Power Plant Projects.

A reader of SolarByTheWatt.com commented in a letter to us (via the Contact Us page/form) on how important it is for publications when price of solar photovoltaic is discussed – dollar per watt – to point out the difference between cost of solar just for the modules or panels and the cost of completing a whole system.

The price to complete a whole system in addition to the price of panels will include price of mounting, installation hardware, wiring, junction boxes, disconnects, price of the inverter or inverters, wiring and disconnect boxes from inverter to grid switch box, price of installation service (usually specifically trained and certified professionals are involved). In the case of a large scale projects the part of the project involving connection to the grid can be of substantial value too. In these project the price of the land used and all permits for the land and for the utility project also add to the cost.

We are continuing our series of articles on lowest prices per watt for solar photovoltaic panels where every time we have changes in the price ranking we will publish a new article with corresponding date in the title.

We list the cheapest panels dollar per watt that we can find on the internet and through direct research. We also include listings of products our readers submit to us through or Contact Us form or in the comments. Representatives of the different vendors are welcome to submit info about their products too. Very differently from other “cheapest solar panels lists” out there we will not charge you for that and we will not tell you the list is already full – yep, this is what some publishers of lowest prices in solar have told some of the vendors of realistically the cheapest panels in certain sizes.

A specialist from one of the companies distributing and retailing solar panels brought up a question for discussion that is not usually very specifically talked about but was raised by a client of theirs. The client was looking for the most efficient panels in terms of peak power (rated watts) per square foot of the panel (module) the way it was commercially available.

He was not interested to hear about the comparison between the different technologies in particular because they are usually compared on cell level and the data available is usually from scientific lab test not necessarily directly related to the realistic efficiency of the finished panel. When cells are actually implemented in the configuration of the panel there might be numerous factors additionally affecting the power-to-physical-area efficiency of the panel.

One of the most frequently asked questions to consultants and specialists in the solar energy industry is how efficient is the investment in a solar power installation – small or large.

We want to look at a very simple model of economic efficiency where are interested in the annual return on investment. A project involving a solar photovoltaic installation requires certain amount of capital to be built and will expect certain amount of annual revenue. The simple indicator of efficiency that we want to study is this annual return in invested capital.

Similarly to the analysis we have done for solar we are putting the number together for the capacity needed of to replace coal, oil and natural gas with wind as sources for electricity.

We want to jump here directly to a graph comparing the different levels of electricity capacity currently generated from oil, coal, natural gas and the rest (nuclear, hydro etc) with the capacity wind power fields, farms need, the cost of investment needed and the land area used.

Solar power alongside the applauding it gets it is also being criticized by the opponents of it especially in terms of the different measures of efficiency – physical, economic (investment) and land area use efficiency. Land area use efficiency is the topic of this study. Let’s look at the definito0ns for the other measures of efficiency just to put our essay in proper context.

Is solar energy capable of providing so much power that to offset the need for use of fossil fuels?

We want to look at the needs of energy of the United States and the world and compare with the practical size installations of solar power stations needed to replace that.

The question of completely replacing all fossil fuel or all other sources of electricity and other energy is much more complex than just looking at the numbers. Probably replacing the other sources in just electricity production is simpler but still in addition to simply adding capacity, changes of large scale are needed in the national grid configuration.