The "effective date" for changes to small PV tariffs has now passed, despite the fact that the consultation on the change remains open (!).

Recent data shows just how quickly the industry responded to ramp up the deployment of PV. Installations which had been running at two or three thousand a week rocketed after the Government gave 6 weeks’ notice of a material cut, rising to an astonishing 29,880 installations in the last week before the change, with 126MW of capacity installed that week. That means that in one week (week ending 11/12/11) the industry installed more than the Government had originally anticipated would be installed through the whole of 2011.

That level of installation will leave the Government and industry with a number of headaches, not least what to do about the "budget" which looks like it will be largely exhausted already from PV installation alone.

Taking data from the MCS database for sub 50kw installations and from the CCL register for greater than 50kw implies the following very rough calculations for an "annual" spend on PV generation FITs - assuming an average insolation of 900KWh/KWp (i.e. some self-selection to favourable sites relative to national average) and that all installations above 50kw achieved accreditation before August 1st or under the extension "loophole":

0-4kw                    623,313kw@43.3p X 900KWh     = c.£243m

4-10kw                 39,725kw@37.8p X 900KWh        = c.£14m

10-50kw               93,666kw@32.9p X 900KWh        = c.£28m

50kw-5mw          140,871kw@30.7p X 900KWh      =c.£39m

The above calculations make a number of simplifying assumptions about tariff tiers and other matters, but should give a reasonable sense of the scale of current implied spend. And  the total level of annual spend guesstimated by the above of £324m should be seen in the context of the "budget" imposed on FITs at the time of the Comprehensive Spending Review which anticipated a maximum annual spend in 2014-15 of £360m. Before even accounting for wind, hydro and AD schemes already accredited, that would appear to leave little to no room for new schemes from any technology.

This very successful scheme should not be peremptorily closed as a result of the Government's policy errors and miscalculations on solar PV - so we have to hope that money can be found from elsewhere to increase the level of "budget" DECC can allocate to Feed-in-Tariffs.