To generate and deliver energy we need raw materials. To produce materials we need energy. There is a clear connection.
For example, windmills contain a lot of copper. Overhead power lines which transport this electricity are made out of copper. The wiring in our houses is made out of copper. Anything that you connect to this wiring by plugging it into a power socket contains a lot of copper. Copper is required for energy!
The same goes for the other metals. Iron, aluminium and alloy metals are needed for drilling, mining and tankers; special metals are required for batteries; cadmium, gallium and tellurium are needed for solar panels; and uranium is needed for nuclear power.
It costs a lot of energy to get the copper ore out of the earth, subsequently it takes a lot of energy to make copper out of copper ore and then it will cost a lot of energy to shape copper into the form you want it to take. Energy is required for copper!
The beauty of this is that everything is connected. But that also means that if a shortage presents itself, it will have an impact on everything else. For example, in almost every soil all over the world copper is present, but it is only called copper ore when it is feasible to retrieve the copper from the soil. The lower the percentage of copper in the soil, the more energy it will cost to retrieve it. This also means that the scarcer or more expensive energy is; the scarcer copper becomes.
Not too long ago it was easy to obtain energy, as it was all concentrated, but now energy sources are sparser. A gas company in the past would just drill one gas pipeline into the earth and thirty years the gas would flow. Nowadays, we are using shale gas, which means that not one, but many pipes, need to be inserted into the earth. Wind energy requires many windmills, and therefore many power lines to transport the electricity. In short: the more spread the energy we are trying to harness, the more materials we need to retrieve and distribute it.
When the shortage of metals will continue to grow, certain forms of renewable energy will be less or not feasible. So metal shortage and the sustainability of energy are impossible to consider separately. Which means that metal is energy is metal!