grid parity, page-41

Fact: 85kWh/m2/annum (from Austock report and consistent with previous DYE statements. I'll try to find which DYE statements rather than rely on my memory).

The reason DYE and Austock refer to kWh/m2/annum, is because there are many variables that determine output power in any day and these vary over time (daily, weekly, etc). By measuring the power output over a year, all daily, seasonal variations can be averaged into a yearly rate. Even a yearly output should be averaged over a number of years. DYE believe a key variable for multi year averages is to use 1/3 sun for the target market.

To get to the annual rate, variables such as input sun, efficiency, system losses, average number of collection hours per day, etc are used. Whilst these can all vary depending on the product used, the annual output rate is the only figure that matters.

The problem for DYE is that no one talks about annual output power. They talk about peak watts, efficiency in full sun (something that doesn't happen in northern Europe), etc.

If you have a solar panel system (more likely now than in previous years), pay attention to how your system performs on cloudy/rainy days, in the morning, in the evening, when you system is in partial shade. These are the non ideal conditions which real world solar systems must perform in. It is in these non ideal conditions that DSC will out perform.

Another thing to remember with the TATA/DYE product, you will pretty well cover the whole roof, not just a section with panels. There is no mounting hardware costs or panel structure costs. The roof is the panel, hence lower costs.

Grid parity means the tipping point of whether to install a normal roof and buy power, or install a TATA/DYE roof in a designated market/region. If TATA/DYE can achieve grid parity, the product should walk out the door.

How much power for 1/10th, 1/2, full sun? Once a preliminary product specification is published, there should be operational curves (charts) that show various performance scenarios. Joe Public isn't going to get these specs any time soon, so just focus on what has been provided - 85kWh/m2/annum.