Solar Energy’s Future Charted in New Study

Solar energy has the capacity to meet a substantial fraction of the world’s energy needs within decades, according to a new research paper recently published in the journal Science. The paper, ‘Terawatt-scale photovoltaics: Trajectories and challenges’ was authored by a highly-respected team of solar energy researchers with extensive industry experience, and was a collaboration between 21 authors from the US to Japan.

Between 2000 and 2015, the global growth rate of photovoltaic generation (PV) outstripped that of total demand and that of all non-hydro renewables, with its capacity growing by a factor of 57, from 4 to 227 GW [gigawatts]. The paper forecasts at least 3 terawatts (TW), or 3,000GW of cumulative installations of PV by the year 2030, a further 10-fold increase. The increase the authors discuss would only require a 15% annual growth rate, which the authors note is “substantially below what the industry has achieved over the past decade.”

With a “business as usual” scenario already likely to see the PV industry hit 3 TW of cumulative PV installations by 2030, the authors suggest the pathways for cost reductions, efficiency improvements and grid integration would see that curve bend sharply upwards to reach somewhere between 5 and 10 TW by 2030. These challenges are a complex, multi-faceted mix of moving pieces but, as the paper highlights, they are surmountable.

The researchers focus on a target to lower the installed cost of solar PV to $0.03 per kilowatt-hour (kWh), by both bringing down hardware and non-hardware “soft” costs while increasing module efficiencies to 25%. This would involve bringing the average module price to $0.30 per watt, which the researchers note is achievable, particularly given First Solar’s roadmap to reach $0.25 per watt by 2020. Using the historical ‘experience curve’, assuming the industry follows historical patterns, the authors suggest that the deployment of 8 terawatts of solar PV will result in a module cost of approximately $0.25 per watt. The ‘experience curve’ is a simple idea: the more experience an industry has producing a technology, the lower costs become.



The report is clear that despite falling prices, policy support is still driving markets, including incentives and “regionally tailored project-financing structures” to address potentially high up-front costs.

McCarthy Keville O’Sullivan Ltd. has been at the forefront of many of Irish solar energy sector over the last number of years, having already secured permission for or currently in the process of preparing planning permission applications for over 200MW of solar energy projects. If you would like to discuss any planning, environmental, ecological or landscape requirements on your current or future solar projects, contact our Galway office on 091 735611 or email

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