Geocoding using google api
While the Google API has an unauthenticated limit of 2,500 requests per day per IP, using an API key currently gives free a quota of 100,000 requests per day, with additional requests by payment.

You'll need a recent-ish (4.7.9, 4.6.23 or greater) version of CiviCRM to use the API key for geocoding: CRM-18830: Google Geocoding - use SSL, restore API key.

With this you should be able to geocode a larger number of addresses.

Your API key should be configured with the following permissions:


Google Maps Geocoding API (for geocoding)
Google Maps JavaScript API (for displaying / mapping)