Rebooting marine energy. One year on.

A year ago I wrote a blog post entitled Rebooting Marine Renewables. Its centrepiece was an analysis of the electricity generated by wave and tidal-current plant in the UK as revealed by ROCs and REGOs. Now seems like a good time to update it by taking a fresh snapshot of the data to see what has happened since then. To keep this article short and sweet please read the original post for background and context. The most relevant part is where the graphs of the data are shown.

ROCs (Renewables Obligation Certificates) are tradable certificates that until this year (roughly) are the main way that renewables are subsidised in the UK. REGOs (Renewable Energy Guarantees of Origin) are certificates that are used by electricity suppliers for Fuel Mix Disclosure under EU law.

Data from Ofgem’s Renewables and CHP Register can be accessed by clicking on ‘View Public Reports’ and then choosing ‘Certificates’ from the list. This takes you to a form where you can formulate a query. When you execute the query the results are displayed in a table that can be dowloaded in various file formats. Although I have not been able to find it explicitly stated anywhere, I think Ofgem releases data only after a time lag of three months. This means that a query executed in February will return a dataset whose most recent time period is October of the previous year.

The closure of the Renewables Obligation means that ROCs will gradually cover less and less of the UK’s renewable generation. Also, the implications of Brexit for REGOs are as unclear as everything else about Brexit. The Renewables and CHP Register may therefore soon cease to be of use for this kind of analysis unless station-level production data will be available under the post-RO regime.

Table 1 below shows a list of stations accredited by Ofgem and thereby eligible to receive ROCs and REGOs. There are twelve of these, nine of which are described as ‘live’ and three as ‘preliminary’.

Table 1: Wave and tidal generating stations accredited by Ofgem as eligible to receive ROCs.
Generating Station Capacity (kW) Location Commission Date Organisation Device Status
Eday Berth 4 200 EMEC 04/06/2008 OpenHydro Group Ltd Open-centre turbine Live
SeaGen 1200 Strangford Narrows, Northern Ireland 17/11/2008 Sea Generation Limited SeaGen Live
Vagr Atferth 735 EMEC 11/10/2010 E.ON UK Pelamis P2 Live
Billia Croo Berth 6 800 EMEC 30/01/2013 Aquamarine Power Limited Oyster Live
CLADDACH FARM 147 Islay 01/03/2001 Voith Hydro Wavegen Limited Limpet shoreline OWC Live
brummer 1000 EMEC 20/07/2013 Voith Hydro Ocean Current Technologies GmbH & Co. KG Voith turbine Preliminary
Orcadian Wave 711 EMEC 18/05/2012 European Marine Energy Centre Ltd Pelamis P2 Live
Eday Berth 2 1000 EMEC 21/09/2010 Tidal Generation Limited TGL turbine Live
Eday Berth 1 1000 EMEC 06/11/2012 ANDRITZ HYDRO Hammerfest (UK) Limited Hammerfest HS1000 Live
Ness of Quoys 5700 Pentland Firth 06/06/2016 MeyGen Limited Various turbines Preliminary
Ramsey Sound DeltaStream 400kW 380 Wales 31/12/2015 Tidal Energy Limited DeltaStream turbine Live
S G E Tidal Array 500 Yell, Shetland 30/11/2016 Nova Innovation Nova turbine Preliminary

One ‘live’ and one ‘preliminary’ accreditation are new since last February. The live one is Tidal Energy Ltd (TEL)’s DeltaStream tidal turbine in Ramsey Sound, Pembrokeshire. The preliminary one is Nova Innovation Ltd, which is in the process of deploying an array of tidal turbines in Bluemull Sound, Shetland.

A few things immediately stand out from this list:

  1. None of the accredited stations are at Wave Hub.
  2. Some of the developers that have deployed devices at EMEC, such as Wello Oy, Seatricity, Scotrenewables and Atlantis’ AK-1000 and AR-1000, are not listed.
  3. Nova Innovation announced in March 2016 that it had delivered its first power to the grid but its accreditation is still listed as ‘preliminary’.

Table 2 below lists the total number of MWh in respect of which ROCs and REGOs were issued. These are calculated by multiplying the number of certificates by the number of MWh per certificate.

Table 2: Total MWh in respect of which ROCs and REGOs were issued to each station from its commissioning date to the present.
Generating Station MWh (RO) MWh (REGO)
Ramsey Sound DeltaStream 400kW 0 1
SeaGen 9251.5 6549
Eday Berth 2 1364.6 1452.85
Orcadian Wave 101.9 116
Eday Berth 1 1056.6 1160
Billia Croo Berth 6 0 12
Vagr Atferth 43.6 61

Table 1 lists nine stations as ‘live’ but Table 2 only has eight. The missing one is Eday Berth 4, belonging to OpenHydro. As pointed out in the earlier post, they said they delivered power to the grid in 2008 but must have forgotten to claim their certificates.

Figures 1 and 2 below show the data graphed against time between April 2006, the first time period in which any generation occurred, and October 2016.

Figure 1: Energy generated (MWh) by wave and tidal energy plant in the UK for which ROCs were issued.

Figure 2: Energy generated (MWh) by wave and tidal energy plant in the UK for which REGOs were issued.

The only difference between Table 2 and its predecessor in February 2016, and also between Figures 1 and 2 and their predecessors, is the entry for TEL’s DeltaStream tidal turbine in Ramsey Sound Pembrokeshire. They put in a heroic effort to claim 1 REGO in January 2016, though, strangely, no ROC.

In Figure 2, which shows data from REGOs, TEL’s MWh is not visible at normal screen resolution, but if you zoom in to maximum you can just see a small red blip slightly to the right of the 2016 tick mark! To do this you may have to right-click on the image and choose ‘Open image in new tab’. The other curves are all identical to their predecessors in February 2016, except for the colour scheme and the x-axis limits.

Apart from TEL, all the other numbers in Table 2 and in Figures 1 and 2 are the same as their predecessors. Before TEL’s MWh the last electricity fed to the grid came from SeaGen in February 2015, though that comes within the scope of the earlier blog post.

Yes, that’s right, between March 2015 and the most recent time period for which Ofgem has released data, which I think is October 2016, a period of 19 months, the UK’s world-leading marine energy industry generated 1MWh!

Some generation might have occurred since October in which case Ofgem won’t have reported it yet. Meygen’s November 2016 announcement that it had delivered its first power to the grid falls into this category.

One explanation for this state of affairs might be that, having demonstrated their devices at full scale, the main developers are now moving on to the next stage in the commercial roll-out of their technologies, namely array scale demonstration, and that there is inevitably a hiatus between these two phases. This explanation cannot be right, however. As discussed in the earlier post, the amount of energy shown in Figures 1 and 2 is simply not enough to demonstrate the commercial readiness of any of the devices featured. If any of them had performed well enough to be considered demonstrated Figures 1 and 2 would look very different indeed.


This data-snapshot it just a bit too early to have captured Meygen’s first power to the grid in November. If that project goes to plan then the next data-snapshot should contain so many MWh that it completely dwarfs everything that’s on there at the moment. Fingers crossed!

Overseas developments

Open Hydro claims to be producing electricity to the grid (in the present tense) from its 2MW turbine, also deployed in November, at the Fundy Ocean Research Center for Energy (FORCE) in Canada. I cannot find any actual data, though. OpenHydro’s other project, in France, began construction in 2008, with the first turbine installed in 2011 and a second unveiled in May 2016. Reports of power generation all appear to be written in the future tense, however.


  1. In terms of energy production, the year ending in October 2016 was a very bad one for the UK marine energy industry.
  2. The one ray of hope is that Meygen delivered its first power to the grid in November, which was just too late to show up in this data-snapshot. If that project goes to plan, a similar snapshot this time next year should show a huge amount of energy produced.
  3. Also in November OpenHydro deployed a 2MW turbine at the FORCE test centre in Canada and announced that it is producing power. I cannot find any hard data to back up this claim, however.

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