States are turning to more market based incentives as opposed to rebates, such as the Solar Renewable Energy Credits (SRECs), a cap and trade like credit granted to firms or individuals who have installed solar capacity, which can be sold on spot markets.

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The exchange will handle European allowances and renewable energy credits to help support solar plants and such.

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The RPS would require utilities to use a minimum percentage of clean power--such as wind, hydropower or solar energy--in their overall fuel mix, or it would require electric companies to buy renewable credits from each other.

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For example, MMA Renewable Ventures and its investors enjoy a 30% tax credit, have the benefit of accelerated capital depreciation schedules, and sell solar energy credits generated by the project to NV Energy, which must obtain 20% of its power from renewable sources by 2015.

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It's an investment that will double the amount of renewable energy produced over the next three years and provide tax credits and loan guarantees to companies like Namaste Solar, a company that will be expanding, instead of laying people off, as a result of the plan I am signing.

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