Solar photovoltaic (PV) electricity generation originally dates back to the 1950s, but in the early days, it was so expensive that it was only considered for epic endeavours like powering satellites. Yet as research has continued, prices for the technology have declined and more commercial applications have become feasible, which has helped drive economies of scale. And so the feedback loop has continued to present day. Learning curves is the term used to describe the regular patterns of declining costs in new technologies, and solar has been on one heck of a steep learning curve. Within the past 40 years, the price per watt of a solar cell has declined by 99.6%³