I find this question to be quite flawed. We perpetually fail to consider that forming the grid is a real-time interconnected machine. There isn't really any excess energy, unless you are storing excess energy (e.g., in batteries, etc.). Otherwise, because we're working in power, you're just not generating what you're not using. That's the concept of spinning reserve, you're just not running full-tilt: https://en.wikipedia.org/wiki/Operating_reserve

If we insist on answering the question as-is: if you have a big area with large potential to generate electricity, just build the power resource and connect it to the grid, and bid on the local real-time & futures power market in your interconnection region. If the numbers don't look good for you, maybe you can mine crypto, but in reality you'll actually get a better return on your investment by investing in energy storage and playing the market with your generated energy to shift its use to peak times on the grid.

This isn't the answer that people are suggesting, because it's not glamorous.