Renewable Energy Certificates in SAM

Hi,

I'm modeling an IPP for a Linear Fresnel and I was wondering if you know anything about how/where to input information for Renewable Energy Certificates. I have been looking for information about this and there is a wide variation for their cost. I was thinking about putting it as a Production Based Incentive but everywhere I find information it is given in $/MWh and in SAM that type of incentive is in $/kWh. Do you think this is the correct way?

Thanks,

Vanessa