Depending on the geographical location first select which Renewable energy source is suitable for the location. Depending on the Maximum load demand design your renewable generation. Then developing a grid tie system for that RES developed. A lot of literature is available for implementation of energy management system. 

For me it was a problem to get information about equipment and loads in external grid to calculate a proper power flow.

It was necessary because campus transformer substations included into external grid loop and have loads of exterior consumers.

First understand the present load demand and have a projection of the future demand. Understand  the available renewable energy resources possibly at different scenarios and select the best. Other optimization techniques that will give you the best combination in terms of cost exist in open literature.

Thanks everyone for your valuable inputs. I agree, it is challenging to get information on all equipment and loads, especially when there are many labs etc. involved.

Quick follow up question:

For the power flow analysis, do I need info on all the loads, or can I use the connected load data available from single line diagram? 

yes you can use the load data available...hopefully all the loads are accounted in it...such as data from your substation..

Thanks Pavan. Carlos, thanks for the paper, it is a very comprehensive literature review and I am sure it will be of great help.

You may use HOMER PRO to model the microgrid. In fact, HOMER is very user friendly software for you to simulate the optimal model with various sensitivity analysis. You may consider the following information:

1. Electrical load profile - so that you can investigate the dispatch of energy

2. Solar irradiation

3. Electric tariff - if you wish to compare the cost of electricity for the system with and without microgrid