But the STA said the reduction in the number of renewable energy certificates (ROCs) given to solar power generators, from 2 to 1.6 ROC/MWh was still too steep.
In its review of the Renewables Obligation placed on electricity suppliers, DECC had proposed reducing from 2 to 1.5 the number of tradable ROCs given for each MWh of electricity generated from solar, with that amount falling to 0.9 ROCs in 2016-17, in line with the reduction in value of FIT payments to owners of household photovoltaic systems.
The STA had argued that comparing utility-scale installations with rooftop systems was unrealistic and in its final decision, DECC opted to reduce the figure to 1.6 ROCs with a special allowance of 1.7 for mid-size rooftop systems, thus rewarding STA’s lobbying for additional help for installations in the 50 kW to 5 MW bracket.
Commenting, Paul Barwell, the CEO of STA, said, "There are pros and cons here but DECC has at least agreed an improvement on previous proposals and the degression rates are much more sensible.
"However, it means solar deployment could be overly constrained when, even with a fraction more support, it would still be cheaper than many other low-carbon technologies. It is difficult to understand why the government is aiming for ‘slow growth’ in this cost-effective technology."
DECC also accepted the STA’s argument that a 25-year lifespan should be accorded solar installations for cost-comparisons, rather than the 20-year figure originally considered.
The STA called for more prompt grid access for solar generators and questioned a statement from the U.K. National Grid that adding more than 10 GW of renewables generation to the grid could be problematic, considering there is, in its view, technical potential for 20 GW to be added.
The organization’s PV specialist Ray Noble commented, "German grid engineers are overcoming the challenges of integrating considerably more solar than National Grid anticipate. We have every confidence in the competence of British engineers to accommodate new technologies."