Use this Web service documentation to access and use energy data via application programming interfaces (APIs) in these renewable energy categories. You'll need a key to use these APIs. [Sign up for an API key](/signup).
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### General Information
- [API Key Usage](/docs/api-key) - How to use your API key after signing up.
- [Web Service Rate Limits](/docs/rate-limits) - Daily and hourly rate limits on accessing NREL's Web services.
- [General Web Service Errors](/docs/errors) - General error codes that can be returned by any NREL Web service.