So what are the facts?
Solar: According to NREL, current PV systems take 3.5 years before the energy they generate exceeds the energy used up in their creation and installation. Now, solar panels lose about 2% of their capacity in their first year of use, but thereafter capacity declines by 0.5% per year. This means that over 40 years, PV panels will lose a cumulative mere 20% of nominal capacity. Clearly, that's a positive energy balance. As a corollary, note that costings of solar power assume that project life is 25 years Even with low interest rates, the increase in the present value of the investment after 25 years is small, so that makes sense. But what that means is that after 25 years, the electricity generated is (virtually) free.
Wind: On-shore wind turbines produce 34 times the energy it "costs" to make them. As my source points out, though, this doesn't include the energy cost of batteries or backup. What is truly fascinating is that the energy payback ratio for coal is much less: between 2.5 and 5.1; and for CCGT (combined cycle gas turbine) is about the same (between 2.5 and 5). CCS (Carbon capture and storage) is even less efficient.: it reduces the coal payback ratio to between 1.6 and 3.1. These data mean that even if you include backup for wind for half the time, it still (obviously!) has a far better energy payback ratio than coal or gas on their own.
|Source (Click to enlarge)|
Conclusion: Renewables pay back the energy used to create them many times over. The soft denialist claim is just wrong.