Rewards and Expectations

Or maybe pros and cons.

Incentives - The Database of State Incentives for Renewables & Efficiency has federal, state, local, and even utility based incentives. Until 2016 the best incentive is probably going to be keeping 30% of your cost in the form of Personal Tax Credit - which is not capped, and can be carried forward to future years.

ROI - Whenever you purchase a hybrid, or undertake a solar project - one of the first questions you get is - "How long to recoup your investment?". But if you buy a Lexus with lamb skin leather, or put a pool in with a fountain at the end you do not get the same questions. However, there is a ROI on a solar project, I would not base a decision to attempt it based on that alone though as it is still many years in length, even with incentives and rebates.

Thermal - The water heater has the best ROI, prices vary - but an example DIY system for 3-5 people can be as low as $1800, lets say $2500 for the extra parts, and hiring a plumber to do the hard parts. You will be out $1750 after federal tax credit, $1250 if you live in an area with a utility $500 rebate (not uncommon). Most web sites determine a savings of $250 a year with solar over an electric water heater. If we know a normal electric water heater has 2 - 4.5 kW elements (an upper and lower), and we say solar will give us 1 hour a day where the electric heater does not kick in:

4.5kWh X 2 elements X 365 days X .10 cents (average rate) = $328.50 / year savings. $1250 / $328.50 = ROI of 3.8 years.

BUT, 4 years after you buy a 50" flat screen the best you can hope for is that you do not see it on clearance (if they even still make it) for a fraction of what you paid. 4 years after the solar water heater purchase - and now you are getting FREE hot water fo hopefully another decade or longer.

Isreal requires EVERY home to have a solar water heater, while in the Navy I went to Greece - virtually every roof had 1 or more. Can you imagine the energy savings of 100 million US housholds turing on solar water heaters?

Electric - The ROI on a solar array is still daunting. The incentives have fluxuated, but the cost has steadily declined. Consider that a program for Florida that ended June 2010 (but ran out of money around July of 2007!!) paid $4 / watt. Around the same time FPL briefly offered $1 / watt. If you scored both incentives today you would get an array AND a sizable check. But with no other incentives you will at least have a 30% tax credit, uncapped, until 2016. Thats not a bail out, or a hand out - just allowing you to keep YOUR tax money.

Here are some things I have noticed though so far (only been up 1 week)

Size vs Output - When I was looking at systems, the average sunlight per day is usually given as 5 hours. So I was calculating WATTS x # panels x .95 power factor (or efficiency of the inverter). So my system: 230W panels x 14 x .95 = 3059 watts x 5 hours = 15.3 kWh per day average.

Apart from the fact that the last full week of blaring sun was during the install - I have yet to see any panel producing more than 86% of the rating. I did find a site that shows (Panels x 95%)x(wiring and tracking loss x 91%)x(inverter x 90%) = 78% of panel rating - so I suppose 86% is really not bad.

On the upside is that the panels start producing as soon as the sun peaks above the horizon. Not much - maybe 200-300w for the entire array, but at 8:30 before the AC kicks on the meter was going backwards. Another benefit of micro-inverters - I believe a single inverter system requires that a "zone" of the array reaches a certain level before power is produced. Micro-invertors - Enphase is what I use - track the power of the panel it is connected to - and starts producing at nearly 0 watts.

Also, and this is why Germany and Italy just about out pace us in solar installations - it does not need to be sunny to produce power. I was bummed today because it was coudy all day - but still produced over 11kWh.