Global cumulative PV capacity will overtake that of wind by 2021, according to a report from US-based market research firm Clean Edge.

With annual PV installations having narrowly edged out wind for the first time in 2013, Clean Edge predicts the ongoing trend of falling PV prices will push total solar installations beyond wind within the next seven years.

The 2014 instalment of Clean Edge’s annual ‘Clean Energy Trends’ report confirms other recent PV market analysis, noting that buoyant end-market demand in 2013 has given the industry a strong platform for growth over the next few years.

Although it noted cumulative wind capacity is currently 2.5 times greater than solar PV, PV’s 1GW margin over wind in 2013 marked the beginning of a catch-up process that will see PV eventually forge ahead, the report said. By 2021 global PV capacity is expected to hit 715.8GW against wind’s 697.3MW.

A major factor in this will a continuing drop in PV prices. Clean Edge predicts prices will fall an average 7% per year over the next decade to reach US$1.21 per watt by 2023.

However, this will not result translate into a fall in revenues for manufacturers as in previous years, the report notes; double-digit growth in end-market demand will push total revenue in the industry to US$158.3 billion by 2023.

“The adoption of clean energy is set against a bigger-picture context that finds many of the world’s largest energy-using nations struggling with critical choices for their energy future,” said Ron Pernick, Clean Edge co-founder and managing director. “Climate disruptions, smog alerts, planned and unplanned nuclear power shutdowns, and resource scarcity are all driving significant change, accelerating the double-digit adoption growth of solar PV, hybrid and electric vehicles, green buildings, and other clean-tech solutions.”

However the report does highlight a number of challenges PV will have to contend with.

Chief among these is an increasing “pushback” by utilities and vested interests against the perceived threat from solar and other forms of distributed generation to established business models. This process has already begun, particularly in the US, where fossil fuel lobbyists are seeking to overturn solar net metering policies in a number of states.

Another trend the industry will have to contend with is the diminishing availability of early-stage venture capital as a source of clean-tech funding.

According to the report, VC investments in US-based clean-tech firms dropped to US$4.4 billion in 2013 from US$5.8 billion in 2012 and the lowest level since 2009.

The report highlighted that popular media in the US continued to portray the clean-tech industry as a “government boondoggle and venture capital investment disaster”.

But the report noted that some of the slack from falling VC deals had been taken up by later-stage project financing investment and corporate deals.

As examples of this it cited the US$3 billion acquisition by internet gian Google of smart thermostat maker Nest in early 2014 and Goldman Sachs’ US$500 million fund to finance SolarCity PV installations.