I’m going to try to get into the habit of more frequent updates to my ongoing solar-farm-project, because stuff is starting to happen now. Here is a brief run-down on whats happened since the last blog post on April 3 2023.
Well we had a meeting about the farm progress on 12th May, and there was a lot to discuss. We finally had the details from the DNO about the earthing requirements for the farm, so our high-voltage engineer could look at that and then design the earthing layout for us.
There was then some bad news about the inverters. We were going to use Solis inverters, but the ones we wanted were no longer available, so the plan was now to switch to Huawei inverters instead. These are Chinese, and some people have views of using kit made my Huawei but I don’t. I really don’t think there is a backdoor in them that will let the Chinese communist party turn off my solar farm, but I do think there are a lot of conspiracy-theorists that probably do :D. This change to different inverters might seem like no big deal, but its actually hellishly complicated…
Changing inverters means you suddenly have a different number of strings, and the way the panels are wired up is suddenly different. You might assume (as I did) that the panels were in nice neat rows, and there was an inverter for each row, or each two rows. No! Apparently thats not how its done, especially on undulating land. Its actually a lot more complex than that, and the positioning of the inverters and which panels get attached to each inverter is hellishly complicated, and done by some complex solar-farm management software.
Anyway, this was generally a good news meeting. Mounting frames were ordered, people booked in to do work.
There was then a LOT of emails back and forth about voltages and another meeting on 26th May. This is where stuff got super involved…
I had assumed that you always connected a solar farm at high voltage, and needed a transformer up to 11kv, at which point the DNO takes over. BUT NO. Suddenly the DNO says they have changed their internal regulations regarding what size inverters they let connect directly to them, and it had gone from 50kw to 200kw. Our inverters are about 110kw, so they were suddenly chill about us effectively giving them nine cables from 9 110kw inverters at low voltage (about 410v I think).
This is a BIG DEAL, because it vastly changes who pays for what, and whats included. Suddenly we arent doing ANY high voltage cabling, or switchgear, and we wont need a transformer at all. This saves a LOT of money in terms of connection offers. Apparently I will get a new connection offer tommorow, and the old one will be cancelled.
In theory this is good, but I wouldnt be surprised to find that the lower connection offer is offset by all the other materials and labor price increases that have happened since we started. Sure, its GOOD news to have a number actually come DOWN instead of up, but I’m not getting too excited by it.
Its hard to convey just how complex a project like this is. The change to the offer would mean that we can move our (much smaller) substation closer to the one for the DNO. That means the site layout can be slightly smaller, which means less fencing (which would be cheaper!). However, it also totally screws up our earthing design, because we now have different stuff, in a different place, at a different voltage… arggghhh. The one bright spot is that apparently moving our substation will not be a planning issue. Thank Christ.
Anyway, the truly exciting news is that a ground survey was done 2 days ago, and the ‘setting out’ engineer will visit the site this week, I think wednesday. Thats the very last step before people show up to build an access road and start building stuff with concrete bases and installing ground mount frames and the security fence. This is all getting very close!
The current plan is for setting out on 31st, then the fencing, then access road. 26th June is pencilled in for the day they start building the ground mount frames. I will nip up there when that happens and take a look at it all, and take a stupid number of photos. Its looking quit likely that we get energised this year, and start generating power, and maybe (gasp) earning revenue this year!