A picture of a light bulbConstrained grid is an increasingly common problem facing the commissioning of renewables projects in various parts of the UK. With fixed validity periods for FIT Tariffs and the RO coming to an end in less than 2 years, lack of grid for commissioning will become a real project risk and one that funders will be alive to. So what are the options?

Can you accredit your installation at the installation capacity when grid capacity is constrained?

It may be possible to accredit your FIT installation at the full installation capacity even if grid capacity is constrained. For example, you could have a 500kW grid offer but only 50kW can be delivered in time for commissioning due to transmission constraints. You must demonstrate that the full capacity has been commissioned. Therefore the full capacity must be able to be used in a permitted way i.e. onsite loads, private supply or export. This will have to be independently verified e.g. witnessed G59 test documents and certification from installation contractor.

The position is similar for generating stations under the Renewables Obligation.

Can you commission an installation completely off grid?

We know that companies have been developing solutions for off grid commissioning but does it work under the rules?

For FIT projects, it generally depends what you’ve pre-accredited. If you have pre-accredited a grid connected project then you need to commission a grid connected project. If you have pre-accredited an islanded project then you need to commission an islanded project. Changing between the two is likely to invalidate your pre-accreditation. Worse still, if you fully accredit an islanded project then attempt to export to the grid you could invalidate your full accreditation and lose FIT payments.

Picture of a wind turbine farm on a hillOn the face of it, there is more flexibility for RO projects. Bear in mind that your RO period runs from the later of accreditation / commissioning, not export and so you wouldn’t want to commission too far in advance of a grid connection. But, for those projects aiming for RO accreditation with a grid connection date between September 2016 and 31 March 2017, off grid commissioning might be an attractive option. It could preserve the availability of the RO and access to grid grace periods and therefore make external finance with a riskier grid date a possibility.

What you need to do

Proceed with caution. Not all grid documents or site arrangements are the same. You need to check that your arrangements fit the requirements. Come and talk to us about your options.

Check all capacity options. Talk to your DNO about the capacity available, the application of constraint and the face value of the grid documents. Investigate the availability of onsite use. Commission a load bank if necessary.

Commission early. Allow time in your FIT pre-accreditation validity period to resolve any commissioning issues. Ensure you’ve got everything lined up for the RO grid grace period should it be required.

Sarah-Jane McArthur