I think the principle of energy efficiency is paramount, because you need to reduce the demand for energy that your house has on the grid or on fossil fuels, whatever it is. That's job number one.
The thing is that at some point it becomes uneconomical for you to become more energy efficient because the costs are going up, so you need to look at renewable sources of energy, as you pointed out, to replace your fossil fuels. You also need to look at that very carefully, because you can generate some of them on site, depending on where you live. If you have land area, you can use solar and you can use geothermal.
You're absolutely right. You need to balance that. It cannot be universally applied, but you know that energy efficiency is job number one, because otherwise you'll need to supply too much renewable energy and that might affect your operating costs: what you pay for the solar panels or if you get electricity. It's that balance between.... At the end of the day, it comes down to cost. It comes down to cost for the best solution that suits your needs and gets you a low-carbon building.