The focus now is on maintaining the system.
The trade-off there is that the customer is then responsible for maintaining the system.
"Maintaining the system has got to become paramount, not political expediency, not political gamesmanship," Mr. Stringer said.
Under those terms, SolarCity pays for installing and maintaining the system in return for monthly payments for the electricity generated.
"I can never guarantee anyone there will never be an outage, but what we do is we are maintaining the system," he said.
Building a Web site that offers advertising to corporate partners is the only way to get their assistance in building and maintaining the system, Mr. Thompson said.
The costs of maintaining the system could also be significant, and past analyses indicated C.C.S. could add 15 to 30 percent to the cost of coal-generated electricity.
The issuer of the smart card holds the balance (float) and thus earns interest that may pay for maintaining the system.
Both ask not what the origin of any given social behaviour may be but how it contributes to maintaining the system of which it is a part.
Since 1991, Unisys has been maintaining the system, which allows the state Medicaid system to exchange information with the 53,000 health care providers who treat New Jersey's 700,000 Medicaid recipients.
The Romans financed their aqueducts through both public and private sources: about forty per cent of Romans paid a tax to have water piped directly into their homes, which covered the costs of maintaining the system.
