Ray- I believe alot of what you are triing to figure out is almost impossible to nail down a cosy on.
ELECTRICITY- this is almost dependant on the area you live in, and what electric company servivces you.
Repairs- agian this will mainly depend on the materials you decide to use for the track, the condition of the facilities, and if the repairs can be done using volunteers or professionals must be hired.
Transponders- The new carpet track in my area will be using the KO Propo lap counting system, if it works well I will repost for you. If it does the system costs about 1/2 the price of the AMB and the transponders retail for around $30, so getting guys to soak up the cost by getting their own personnal transponders will eliminate the problems and cost involed with lost, stolen, damaged transponders.......
Check out The Track
and e-mail Mimi, she may be able to help you with some of your questions. She is a very nice person, but runs a full service shop/track by herself and is open 60 some hours so she may be busy..... Her track hosts the TRINTY on-road carpet challenge every January and the track is quite large. She also runs the AMBRC system.
You may also want to e-mail Kenetix, or any other indoor carpet track to get answers, also remember when asking about electricity ask for a rough estimate on the number of kilowatt hours used on a monthly baisis during the peak season, then you can convert that into numbers that will be relevent to you.....