There are various methods of idea validation. I am listing the ways that are suitable in your case:

1. Run a Survey: You can ask the customers of the electricity company to fill up the survey form with questions like - whether they will use your service or not? How may they are willing to pay to the extra service/better service and other important questions. This will validate your idea and you can show it to the electricity company as a proof of prospective demand.

2. Expert Opinion: You can approach few experts in the electricity and distribution domain. Ask them to provide their opinion about your idea. If you get a positive feedback then you can show this to the electricity company for your support.

3. Influencing recommendation: You can approach people in Government/Administration who can recommend you for this idea. Take their views in written, this will actually serve as a validation and will also support you in pitching.

4. Competitor analysis: Prepare a competitor analysis report and find out whether such services already exist in the world. If you can find similar services that are successful then you can think the idea is validated.

5. Advisor: You can approach an advisor who can consult you about the idea and will validate through thorough analysis. I am an advisor who have validated more than 500 such ideas.

I will be happy to discuss more over a call if you wish. All the best. God bless you.