I'm currently coding R and SQL in healthcare, would love to code in energy as well at some point. Healthcare is an extremely tricky area, our data is MASSIVE and very very rich, many hundreds of variables to access taken over many years of time. It's very challenging though: old tech stack, slow bureaucracy, tons of paperwork, usually not on the "cutting edge" due to the myriad security/privacy concerns, people still using SAS up the wazoo. Contrast that to energy: much less issue of security/privacy, however much fewer jobs, arguably less complexity and less legacy practices, and less "humanity" at the core. Energy does have the benefit of saving the planet, without which all of our health would go to Mad Max situations...so, both are very very important, good luck choosing :)

I got into it via biological sciences, then epidemiology, then straight epidemiological data analysis, with a flavor of public policy and program implementation/effectiveness analysis. I was originally pre-med, but coding is IMO a lower stress, lower debt-ridden, and still remunerative field which gives higher rein to analytical talent than medicine, which to me is more about people skills and healing than raw analysis/technicalities.