For solar hot water installation it is usually the responsibility of the company doing the installation to receive the grant and deduct that from the invoice the client pays.

You can read about the grant system as it applies to Andalucia on Pretasols grants and Feed-in Tariffs web page.
http://www.pretasol.com/en/about-solar/grants-feed-in-tariffs/
The company carrying out the installation needs to be certified by the region in which it is working.

For solar electricity (photovoltaic) there is a feed-in tariff, which is a fixed contract over a 25 year period for selling the power you generate.

 

This is not true for Valencia region, the responsibity is with the property owner, and the submission process is quite tortuous, I would advise the use of a specialist Gestoria, we have successfully applied for grants over the last 4 years and have to day a 95% success rate, ( one failure due to the developer not providing the right paperwork on time!!!) so critical to use a Spanish profession gestoria who has the knowledge of the process and the key people to improve chances of sucess
Mike
www.solar-sky.com