Remember, the maximum capacity of the system is 3,000 Watts (or 3.0 kilo-Watts), so you'll be able to compare the energy produced right now with the maximum. I am in the process of updating these features and will be adding more data such as Solar Insolation and total home energy. I want to thank Chuck Wright whose solar data loggers made this data available. Thanks Chuck!

Solar Economics

One method of comparing energy alternatives is to calculate a "levelized cost" for each alternative. The method for doing this can become a complicated discussion, and for those of you interested, I recommend reading this excellent survey paper by Simon Fane and Stuart White at the University of Technology Sydney, but this method generally answers the question "How much does it cost me to save energy (or produce energy), per unit of energy, using a particular method?". My calculations show that after all incentives, my solar system costs me about 4-cents per kWh to produce energy. I buy energy from Austin Energy at about 10-cents per kWh. Therefore, it's quite a good deal for me. This does not, of course, answer the question if this is a good use of public money. The solar system actually cost about 30-cents/kWh, but public funds picked up most of that bill. Thanks!

I will end this section saying that a truly sustainable energy policy would select the energy source with "lowest-marginal cost" of energy (including appropriate externalities and time horizons). With that criteria, energy-efficiency is by far much more economical than solar energy. Many studies have demonstrated that home energy can be reduced by over 50% for less than 4-cent-per-kWh that I paid for my solar system (let alone the 30-cents/kWh of real cost). The cleanest, greenest, and cheapest kWh is the one never produced. Having said that, solar PV can play an important role in a sustainable energy policy and we love our solar system! Thanks to all who helped us get it up and running!

Pictures of the Solar Installation

The final completed installation.

The House before the work was done.

The job was complicated slightly because the modules connected to an inverter on the left side of the garage.

These are the electrical components of the Solar System. The solar panels generate direct current (DC), but our homes use alternating current (AC) (This was the result of the famous "War of Currents" in the 1880's between Edison, the DC advocate, and Westinghouse, and AC advocate and victor.). Moving from left-to right, the devices seen here are as follows:
"DC Disconnect:" This is basically a switch to disconnect the solar array from the inverter.
"Inverter:" The actual device that converts the DC power from the solar array to AC power that will be compatible with the city's power and usable by standard home appliances. We used a Xantrex inverter that is about 96% efficient.
"AC Disconnect:" A switch to disconnect the AC power from the rest of the house
"Solar PV Meter:" This is an electricity meter that measures only the energy produced by the solar panels, after the inverter.
"House Meter:" This is the electric meter on our house. Since the solar panels do not produce enough energy to run our whole house all of the time, we still buy some energy from the city. This meter measure both how much energy we use and how much energy we buy from the city. Needless to say, we only pay for what we buy
"Main Service Panel:" The final large box on the left of the picture is our main breaker-box that connects to the circuits in our house.

We cut a trench in the concrete.

Preparing the solar modules. We used Kyocera 167 Watt Solar Modules.

We installed 2 arrays: One 2x4 and one 2x5 for a total of 18 modules

The aluminum rails hold the modules in place on the roof.

Attaching the modules to the rails

Attaching the modules to the rails

Meridian's crew of four professionals hoisted the modules the to the roof.

Installation progressed well!

This part went quickly!

This part went quickly!

Unfortunately, one of the 18 modules arrived damaged. We had to wait a few days to receive the final module and complete the installation

I will eventually also add more information about Solar PV systems. We first used the Solar Pathfinder to estimate the annual hours of clear sunlight. NREL has a website that calculates the annual kWh generated from a PV system using PVWATTS. Eventually, I will post more informative links.

Check back soon for more pictures!