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This applies widely across the globe, and it cannot be attributed to picking up the slack after a slow year (2014 was itself a record year in terms of new installations). What's more, it has been achieved in the face of steeply falling fossil-fuel prices and sluggish or declining demand for electricity, particularly in developed countries.

Our economics correspondent David Milborrow provides the background and analysis in his annual cost report to explain how wind is managing to flourish in these challenging circumstances. Simply put, the cost of onshore-wind electricity generation is too competitive and stable to be ignored.

That much has been apparent for some time, but 2015 also appears to have been the year when we could say with a reasonable degree of confidence that offshore wind has turned in that direction, too. Installation and O&M costs are on a downward curve, while energy generation from operating offshore projects is meeting, and often exceeding, expectations. Offshore wind remains, of course, much more expensive than onshore, but its potential for further cost cutting is also much greater, and it starts to make a lot more economic sense in a world weaning itself off coal and taking steps to properly account for the cost of carbon.

Storage for the future?

There is a practice popular in the aviation industry - recently termed 'mumbo-jumbo jet' — of promising highly speculative technology at some unspecificied time in the future that will eliminate all its emissions, environmental and noise concerns, thus, allowing unbridled growth in air travel and its associated infrastructure.

'Mumbo-jumbo' could also be applied to the search for carbon capture and storage systems that actually work and are not prohibitively expensive — something the coal industry seeks with some zeal.

Perhaps it could also be applied to utility-scale storage of electricity generated by renewables — the big fix for balancing out the variable delivery of their energy generation.

That looks some way off, as our investigation into the current state-of-play in energy-storage systems makes clear. The technology is still in its infancy, its capacity still too small-scale to make a significant difference, and while battery costs are falling rapidly, storage remains an expensive solution to a problem that can often be alleviated in other ways.

Happy days in the US

While it seems safe to assume that 2015 will have been another record-breaking year for wind power, it is rather harder to predict the outlook for 2016. Economists far and wide are predicting another global financial crisis, which would likely affect energy demand, commodity prices and currency exchanges, so the industry may be in for a bumpy ride.

Still, the sunniest predictions for growth must surely come from the US, already second only to China in current installations. Federal incentives mapped out for five years have cheered the industry, and even the prospect of a new president throwing out Obaman's Clean Power Plan post-November cannot keep the optimism out of experts' views. With state support and the federal incentive, they are predicting that not only will installations grow, but innovations can be planned, and wind in the US will be truly financially self-sufficient by 2021.