Why DECC struggles to keep up with solar PV capacity data…and why SPP don’t


Ever since large-scale solar hit the UK, the Department of Energy and Climate Change (DECC) has struggled with keeping track of cumulative solar PV capacity deployed in the UK. And this is directly transferrable to any third-party organisation that uses government data as the gospel for actual solar capacity in the UK.

Let’s explain what the reasons are and how they manifest themselves.

First – the reason. This is easy to explain. It is due to the speed at which solar farms can be added to the grid; kudos to the solar industry and the developers and EPCs for their efficiency. The current methods – by which capacity added shows up on accreditation registers, gets transferred to Ofgem and finally used by DECC – is simply not capable of managing this. It was simply not set up to address solar, and still relies on non-industry personnel all along the chain. A good analogy is imagining putting a bullet train on a railway track installed by Victorians for the first steam engines. Simply put, the train is not going to get to 200mph.

The problems show up when a lot of solar capacity is added quickly – cue the Q1 tracking dilemma imposed by RO fiscal years, and it goes a long way to explaining the problems DECC has had in tracking solar PV deployment in the UK during 2014 and 2015.

Let’s look at the numbers to illustrate this. The first big solar deployment in the UK was during Q1’14 in the run up to the 1.6 RO closure on 31 March 2014. By the middle of April 2014, shrewd voices within the UK’s solar industry put the installed capacity during the quarter at above 1GW. In fact, the final figure was closer to 1.1GW. Now – let’s look, by way of a graph, at what DECC was saying for cumulative solar PV capacity installed purely in Q1’14 after March 2014.

Read the rest of this post on Solar Power Portal