There are a couple forums:
Home Power Magazine: Great place to start (Some useful free articles on website)
Wind-Sun: (hosted by AZ solar parts store)
Solar Guppy: (inverter design engineer out of Florida)
I can give you some rough suggestions...
In virtually every case, first spend your money on energy conservation. Replacing appliances, changing lights to CFL/fluorescents, better insulation, replace windows, attic ventilation (if you live in a hot climate), changing habits, unplugging/switching off appliances/electronics instead of leaving in Stand-By mode, installing Ground Sourced Heat Pumps, converting all electric heating devices (space heating, hot water) to fuel based heating, etc... Solar electric power is always very expensive to produce.
Next, the type of solar power you will need... Solar Hot Water / Hot Air is usually less costly to install and the collectors take up less space than Solar PV electric panels. Also, for example; saving $30 a month in electricity vs $30 in natural gas bills does not matter--either is still saving $30 per month.
Next, the "standard" type solar systems:
Hydroelectric--nice and reliable, but you need a good flowing stream--does not apply to most people.
Solar thermal panels (hot water, hot air), solar cookers (solar ovens). Generally the cheapest (per kWhr/BTU of energy collected)--and collectors/installation lend themselves well to home built projects. Thermal collectors also work well in partial shading situations (some trees, wires, etc.). From what I have seen, Thermal systems will require the most maintenance/fiddling to keep running. Also, because of plumbing/storage requirements--can be more expensive to install and find space for the storage/pump/etc. components.
Solar Electric / Photo Voltaic systems:
Generally two types, one is the typical Off-Grid/Battery based solution--useful for cabins and places too far from electrical grid. There is a hybrid version of battery based systems where they act like a giant UPS (interruptible power supply). Use Grid power when available, and switch over to battery when power is loss (or even switch over to solar panels when the sun is available). Power from these systems is expensive because of high parts costs and battery replacements (every ~5-10 years). Also, usually will have backup gas/diesel generator (and sometimes wind turbine) for backup power during cloudy weather/storms (3 days of battery storage for electricity is a typical goal--any more than 3 days of no-sun, you need an alternative power source).
The other solar electric system is Grid Tied Solar... Basically, install solar panels on your roof, connected them to a DC to AC inverter (DC solar to 120/240 VAC 60/50 Hz inverter), connect your inverter to the house circuit breaker panel, and away you go (after permits, utility approvals, and inspection). Grid Tied is the best "bang for the buck" in terms of energy production. No batteries to maintain/replace. Just keep the panels clean for the next 20-35+ years (and probably replace the inverter once or twice during the system life time). No Generators required. Downside, your utility will need to permit Grid Tied solar (not all do in the US, outside of the US--not many utilities permit). Also, you will need a licensed electrician, and if rebates are available, many times an approved installer. Not too difficult to install for a do-it yourself person (lots of manual labor, issues with roofs/falls/injuries)--but because of licenses, permits, and such--probably best to watch/help somebody else first to learn the basics.
Other "green power sources" are out there (bio-diesel, manure, wind, hydro, solar steam, wood, agricultural waste burning, co-generation, etc.)--but unless you have a specific source of energy to discuss--one can easily get lost in the details during a generic discussion.
How much does it cost? Solar Panels can range from $0.50 per watt (therm collectors) to $3-5 per watt (larger solar PV panels, smaller ones are 2-5x that cost). Installation and support equipment costs are probably 2x or more the basic panel costs.
Retail Solar Electric (Grid Tied) costs, very roughly, $10 per (rated peak) Watt of installed panel. In a reasonably sunny area (south of San Francisco, CA, behind a coastal mountain range so I don't get much fog from the Pacific Ocean), a 3kW (PTC rated, 3.5kW STC rated)/$30K Grid Tied system can generate ~4,800 kWhr per year. With the right rate plan, I can offset power costs of $0.09 to $0.50 per kWhour (my basic rate plan is $0.11 per kWhr--if I use more power, I pay higher rates). And I have 1 year net metering--basically the utility acts like a giant battery for me and can store/supply energy for "1 year" at a basic cost of $5 per month. At the end of one year, I either pay for the extra power I use, or any credits are zeroed out by the utility.
How much does Solar PV cost per kWhr? My Grid Tied system cost roughly $0.25-$0.28 per kWhr (including installation and permits, assuming 25 year life). After California and Federal Rebates/tax credits, about $0.14-$0.17 per kWhr. The solar panels have a 20 year warranty and the inverter a 5-10 year warranty (assuming the companies stay in business that long).
Off Grid Solar power, by the time you include extra battery costs and less efficiency because of battery storage and extra conversions, very roughly, $1.00 per kWhr.
Solar Hot Water, typically, has the best return for the $$$ invested. Issues with long term maintenance and issues with hard freezes will complicate the design.
Wind Turbines--I would be very careful about them. The Wind Turbines themselves are not too expensive. However, installing a 30+ foot tower, servicing, (from what I have seen) short turbine life/storm damage/maintenance, noise, etc. increases the real costs quite a bit. Also, it takes quite a bit of wind to make electricity--most will advertise that they start generating at ~6 MPH, but that is 1 watt of power. To get any real power, you would need at least ~12-15 MPH of pretty constant wind (and you will rarely ever see the turbine's rated output--except during wind storms. If you don't live in a very windy area (like on a ridge line clear of trees/obstructions), wind seems to not be the best place to spend your money for a home system. From what I have read, the more successful installations use an electric wind turbine in conjunction with solar panels--the Panels generate power during good weather, and the turbine generates power during the bad weather--reducing the use of a fuel driven generator.
I will stop here for now--because I really don't know where you want to take this thread. As always, the above is just my personal observations--I do not own or work in any solar power company, and your personal situation may be different from what I have guessed at in my discussion.
Questions/Observations?
-Bill
