How to utilize user survey answers and the actual usage in forecasting power usage using LSTM? I have the pre-trial survey and post-trial survey conducted of around 5000 users for Smart Meter installation.

With this I have power usage reading recorded every 30 min for around one and a half years.

survey csv is like this

User Question 1 Question 2 .......
1000    a           a      .......
1001    b           a      .......
.       .           .      .......
.       .           .      .......
.       .           .      .......
5000    b           a      .......


power usage csv is like this

User date usage
1000 20001 0.003
1000 20002 0.025
.... ..... .....
.... ..... .....
.... ..... .....
.... ..... .....
.... ..... .....
1000 65047 0.52
1000 65048 0.14


I want to forecast power usage of the user based on the past power usage and the survey using LSTM.
How to start with this?
Check out the example "Multi-input and multi-output models" here in the documentation. It gives an example how to combine an LSTM time series model with additional input. You would use separate input layers for the power usage and for the survey data. After running the power usage data through the LSTM you combine the results using "concatenate". 

(You can ignore the Embedding layer in the example since your power usage data isn't text data.)