Solar power is the basis for all life on earth! Solar heating has been used for thousands of years to warm dwellings (solar thermal). But solar electricity (photovoltaics) is a very new industry.
Solar Photovoltaic (PV) --a zero maintenance, zero fuel cost electric generator
Solar panels have no moving parts. You just mount them out in the sun, hook up the wires, and collect power, without adding fuel or replacing worn-out parts. It's amazing that nobody knows for sure how long a solar panel will last. That's because many of the very first photovoltaic panels are still producing power today.
Solar Electricity Basics
We often receive questions here along the lines of 'how many solar panels do I need to power my 3,000 square foot house?' We don't sell or install solar power systems, so we can't provide free consulting services and still keep our business running. However, we've written numerous articles on the topic and compiled a list of resources to help answer your questions and start you on the right track for doing your 'homework' on the topic:
The design, size and cost of a solar photovoltaic power system for your home depends on only a few simple factors:
How much energy in kilowatt-hours (kwh) do you use per month, and how much does it cost you?
What can you do to reduce your energy usage, and how much will that cost you? (Every dollar spent on conservation will save you $3-$5 on the cost of an RE power system).
What solar resource do you have available at your location?
Renewable Energy Basics -- This article guides you through answering ALL those questions above, in great detail. Includes information on grid-tied, off-grid and grid tie with battery bank systems.
If you are serious about moving to a solar power system for your home or cabin, most local solar dealers / installers will provide you with a free or low-cost estimate and energy estimate. Going local is an excellent choice!
Most internet solar power retailers have lots of free information online, including system sizing spreadsheets. Two retailers that we patronize frequently because of their great customer service are The Alternative Energy Store and Backwoods Solar -- but there are many more excellent retailers online.
Shopping by Dollars per Watt is the best way to choose solar panels. Photovoltaic panel prices have steadily been dropping at 3-5 percent per year for the last decade or so. However, prices may not seem all that low to you, because in general the technology is getting better, so each panel is making more watts than those of a few years ago. You have two options for buying photovoltaics, new and used:
New photovoltaic panels -- This page gives some details about new panels, including how the technology is advancing, and information about tracking mounts.
Used photovoltaic panels -- This page discusses how to inspect used panels for damage and test their output before purchasing.
We are no longer maintaining our used solar panel mailing list. Because of strong demand for large photovoltaic installations around the world, there has been a general shortage of new panels. This has increased demand for used panels too, and we have not seen any large lots of used panels available for 4 years now. The best places to look for used PV panels are your local newspaper classifieds, Craigslist, and Ebay.
Solar Thermal Panels -- using the suns energy directly for heat
Using solar power directly to heat air or water is the most efficient way to do it. Solar electric is not a very efficient way to heat things, but solar thermal works great! We don't have a huge amount of information here about solar thermal, but there are some links below for you.
Passive solar house design is an excellent way to heat a home. Generally it's designed into the home from the ground up, with south-facing windows, thermal mass to store heat, lots of insulation, and thermal blankets for the windows at night. DanF's home was designed this way. Until we do get a page up here about passive solar heating, you can search the internet for the term and get a wide variety of books and articles on the topic.
Solar hot water heating panels became very popular in the USA in the late 1970s and early 1980s for preheating a homes hot water. Government tax credits were offered by the Carter administration, and many companies sprang up designing and installing systems. When the Reagan administration cancelled the tax credits, many of these companies went out of business, and there were very few people left to maintain and repair these systems. Many of them are still sitting on roofs today, broken. HOWEVER, it became obvious very quickly that some of these companies were 'fly-by-night' and their products were poorly designed in the first place:
In general, we advise against purchasing these old systems used. It's actually easy to find one for free, which might be OK if you are experimentor and enthusiast. But these older systems used numerous active controls, sensors and pumps, and were very unreliable compared to the excellent, low-maintainance and reliable systems available today.
Solar water heating panels are NOT a new idea! This article about the history of solar water heating is an excellent read. Thousands of systems were installed and were very effective in sunny parts of the USA around 1900.
On the other hand, modern solar water heating panels are an excellent investment in most parts of the county! The technology has changed so much that these systems are now completely different in design than those from the Carter area that caused so many problems. Some industry analysts say that the loss of the tax credits, while it had a large negative impact on the industry at the time, ended up being the best thing that ever happened to the industry in the long run.
These systems are now often incorporated along with radiant floor heating pipes. The sun heats the fluid, which circulates inside the high thermal mass floor of the home. This is a VERY efficient way to heat a home!
Solar air heating panels are another new technology that's catching on quickly. It allows the homeowner to retrofit a house that was not orginally designed for efficient passive solar heating, and reap the benefits and energy savings of heating with the sun.