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TRUE~TIE Grid-Intertie System
Conservative estimates put the cost of PV-generated power at between 20¢ and 40¢ per kwh over the life of the system. However, other factors such as net-metering, state-funded rebates and tax credits can reduce the overall cost in some locations by as much as half.
Net-metering allows a PV system to feed its surplus power into the utility's grid; the homeowner receives a credit (usually equal to the utility rate) and pays only for the net amount used.
Typically, rebates are given based on the amount of electricity systems can produce. California offers a rebate of $4 per watt, under its Emerging Renewables Program. Many other states offer similar incentives that can halve PV costs. To qualify, homeowners often must employ licensed installers. Other types of incentives include utility rebates, low-rate loans and grants. To learn the particulars of each state's incentives, visit www.dsireusa.org.
Estimating the lifetime cost of a PV system
Depending on locally available subsidies, a PV system can add tens of thousands of dollars to the cost of your house or put money in your pocket. Below is a way to get an idea of the rough lifetime cost of a PV system, using an average house as an example. To make it specific to your situation, plug in your daily hours of sunlight from the map below, your power usage and the cost per kwh in your area.
Doing the math
- To size the system, divide daily power consumption by the average hours of full sun per day. Our sample house uses 30kwh per day, gets 4.5 hours of sun and would need a 6.67kw system (30kwh ÷ 4.5 hours = 6.67kw).
- At a national average cost of $6,000 per kw, this system would cost about $40,000.
- Over the course of 20 years (a conservative estimate of the life of a PV system), this house's system would generate 219,000kwh of power. At 8¢ per kwh, that's $17,520 worth of electricity.
Cashing in?
After factoring in the value of the electricity generated, this PV system's net cost is $22,480. But wait: If this house were in Orlando's above-average sun and took advantage of a state subsidy of $3,000 per kw, the net gain to the owner over 20 years would have been $1,152. With California's $4,000 per kw subsidy, this system in Fresno would put $12,617 in the owner's pocket. The situation in Illinois is similar to California. (Totals do not reflect future increases in utility costs or interest rates.)
Data based on information courtesy of U. S. Department of Energy Office of Energy Efficiency and Renewable Energy:
(http://www.eere.energy.gov/states/alternatives/).
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