Game Design, Programming and running a one-man games business…

Solar Farm: Everything you always wanted to know about power purchase agreements (PPA)

I just had another meeting about the solar farm. We are now talking in very confident and believable terms about the date to actually switch on the farm, which is absolutely amazing after the last fifty billion years oft development. Amazingly, humans continue to exist on Earth and the solar system has not been swallowed up by an expanding star and yet my solar farm may get energized. (Obviously an expanding sun would be, in the short term, great news for PV generation…

This week is an exciting week because the overhead line that initially was supposed to save money and make life easy, but actually ended up causing chaos and delays… is actually being buried this week. This is a 5 day process, because what is involved includes the burying of some new line, recovery of the old line, and the actual proper live connection of the high voltage part of the site (this is the DNO’s territory and problem). This should all be completed by this Friday, which is also the day I am next visiting the site to see how things are. I don’t think THAT much visible will have changed since my last visit, but that was a while ago so its good to have a final walk-around before the next visit which should be switch-on.

Now in theory, as maybe 80% of the site is built out, and the site gets actually connected to high voltage national grid connections on Friday, you might think that we could switch on 80% of the site while we finish the rest, but thats a logistical headache. The removal of the line lets us drill the piles for the last few mounting tables and final inverters, and then connect the last few hundred panels, but all those new panels need connecting to the earthing, and the final inverters need connecting to our switchgear (all at relatively low voltage, about 400V), and doing all of that while the rest of the site is live sounds like hell…

On a huge site, like a 50MWP site, it would be absolutely worth the hassle, because of the opportunity cost of not being connected, but on our site, its just not worth introducing complexity just for literally one month of generation for 80% of a farm in a wet cloudy September…

Anyway, there is still a bunch of stuff to do that you don’t think about, like the tree planting (a condition of our planning application), and a lot of incredibly tedious paperwork to claim REGOs (Renewable generation certificates you get for producing green energy that er traded like a commodity). Honestly if someone like Elon Musk saw the bureaucracy and inefficiency behind the REGO system he would explode, but it has to be done as they are worth about £12/MWH.

The REALLY exciting part though is the arrangement of the power purchase agreement which I expect to sign tomorrow. I will go for either a 1, 2 or 3 year fixed price for each megawatt hour of energy the site produces. The actual calculation is a real paid, because there is the raw traded price per megawatt hour (about £70/MWH) and then the ’embedded benefits’ (about £20/MWH for my site) which are payments for being good enough to generate power where it is needed, and not put a strain on the main transmission network…and then the REGOs (about £12/MWH).

The embedded benefits stuff is interesting. If you think of electricity like traffic, then you have local roads, A roads and then Motorways (highways). As anybody who has built a road will tell you (We did!) the cost per mile goes up a LOT as your road gets bigger. So if generation requires an upgrade to a major transmission line (motorway) its stupidly expensive. If you can generate power that never leaves the local roads, and in fact therefore puts less pressure on even the A roads, then there is value in that, and you get compensated. To put it another way, building a small local solar farm helps supply a rural(ish) community, and puts less pressure on the connections to and from that community. In practice, my energy will certainly never leave Shropshire, and will probably never even leave the local town within Shropshire. I’ve made the job of managing the transmission network easier!

Anyway, for reasons that escape me, it seems that you lock in power purchase agreements for 1-3 years, but the price fluctuates on a DAILY basis, so you have to sign the deal the same day (before 4PM) that you get the quote. So at some point tomorrow I may well make a financial decision that affects my business for a few years. Still, I’m playing the long game here. I might lose money for 15 years then suddenly reap the rewards of madly high prices. Who knows. Doing this stuff is not for the meek. I’ll probably have pics to share on Friday!


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