Risk

You will need to weigh each of these risks for your particular situation:

• • New buildings or trees might block sunlight over the life of the system (40 years approximately)

  • Interest rates will vary

  • Although I consider it unlikely, the ACT Government of the day may stop paying the Feed In Tariff. If they do, you won't be paid the Tariff premium, however you will still be entitled to the market price of the day. As we move away from oil and coal to more expensive sources of energy, the market price of electricity will increase. This will help to offset the loss of the Tariff.

  • The inverter is likely to fail at some point during the life of the system and will need repair or replacement. Inverters do not last as long as quality photovoltaic panels

  • The photovoltaic industry is enjoying unprecedented activity, but quality systems remain expensive. Cheaper, untested knock-offs have become available, though they remain a lot of money. In my opinion, the size of this investment warrants a conservative approach limited to known brands with long warranties. Anything else is a multi-thousand dollar gamble. I for one intend to do this only once

  • The cost of grid-supplied electricity will rise over the lifetime of the system. This will close the gap between the market price of electricity and the Feed In Tariff. If your goal is to offset your electricity bill, you may find that that eventually you start receiving a bill as the price of electricity rises

  • You may choose to relocate. If you do, it is not clear how much value your photovoltaic system will add to the value of your house. In theory, as energy becomes more expensive, photovoltaic systems should increase in perceived value. Photovoltaic systems can be removed and installed elsewhere, however there may be a significant labor component and some materials

  • Falling off your roof (not as funny or as silly as it sounds)

  • Theft. In an urban setting like Canberra, I consider this risk to be very low. I have seen first hand how much labor is involved to put up a photovoltaic system. It is non-trivial. Reversing that process in the dark on a pitched roof would be foolhardy. Even in the daylight, the process would take hours

  • Damage and vandalism. If you haven't insured your multi-thousand dollar asset against damage and vandalism, you deserve to have rocks thrown at it. My home insurance covered this with a single phone call

  • There is inherent uncertainty when planning for contingencies over a forty year period

On the other hand, you will certainly make some money. My real world experience is now available in real time at this link:

Plant Performance