Category: solar

I’m currently in the throes of building a 1.2MW solar farm somewhere in England. Its an adventure, to put it mildly :D. So far the planning process and bureaucracy has taken just under 2 years. In that time a lot has changed.

Originally the plan was for a 1.2mwp solar farm, and a battery of either 256kwh or 512kwh. The current situation is that I’m evaluating a 583kwh battery (they can basically pack a bunch more cells in there now), but the economics have got a bit trickier and it may not actually be viable. This does not mean the project itself is not viable, the farm likely still is profitable (I hope!).

First things first, I’ll explain why any of this would make any sense. You cannot just rent a field, fill it with solar panels (assuming the farmer lets you, and planning permission is granted), and make a pile of money. Its not that simple. (And trust me: none of that is simple). The main problem you face is the grid connection. Basically solar farms go in fields, so we are already limited to relatively rural locations. This means that the land is large enough, and also its not going to upset too many people. Our site is surrounded by fields and hills and generally…nothing, so there were zero objections. This is all good news..

…but it also means you are on the edges of the power grid. If you are REALLY lucky, you find a site that has a field to rent, thats rural, but also just-so-happens to be a site where a major grid connection cable runs right through it. This is super ideal, and no, there no sites left like this any more in the UK because all the canny early developers have already snapped them up :(

So…we end up with a perfect field, planning permission, and a happy landowner, but we are basically connected to the rest of the grid by what amounts to a thin USB cable (not really). This is the point at which you ask the grid to upgrade that line and send you the bill, they do, then you laugh at how they accidentally added a few zeroes to the bill, and then you start to cry. Basically upgrading a power line is a nightmare. They cant just add heavier cable and be done. That cable may then sag too much in summer, or be too heavy, so you need new pylons, and then the ground under the pylons is too weak so you need foundations and omg expenseahontas.

In practice, that means that the local DNO (power company) has told us ‘you can generate 900kw at any moment from here but no more’, and thats AFTER we pay for a major grid upgrade. This sounds nuts, but when you think about it, if a power cable was only ever built to supply 2 farm houses, its not ever expecting a power flow of more than about 40kw total maximum. Then suddenly we arrive on the scene with 3,000 solar panels and want to push 20x as much power through those cables…

What does this have to do with batteries?

You might have noticed the difference between our 1,200kw solar farm and the 900kw limit on export. Well spotted. Its quite glaring isn’t it? Actually, this is exactly what most people do, and if you have solar panels at home, you do it too. Its called inverter under sizing.

The inverter is the box that converts DC to AC, and is the device that determines the maximum power that can come from your solar panels. In many cases, its rated BELOW the maximum output of your panels. This must seem insane…because surely that means at peak sunshine some of your power is just wasted right? YES. This is exactly what happens, and its normally because the bigger inverters are very expensive, and the PEAK output of your solar panels only triggers quite rarely, maybe for just 1 or 2 weeks in summer around midday. This means that the extra spend on the ‘bigger’ inverter might not be worth it.

Example: You have a choice of a 2kw inverter or 2.5kw inverter. The difference is $1,000. You have 2.5kwp of solar panels. Which do you choose? Well its actually hellishly complex. You need to model the output of your panels for every hour for every day in a typical year, and then ‘clip off’ the top portion where output would have been above 2kw. You then need to value that power at whatever you get paid to sell it, or what it would have cost you to buy it. You do that for the lifetime of the inverter, then work out if its a good deal.

I’m currently basically doing a similar thing, except the limitation for me is export limits, not inverter sizing. Our site will have 10 inverters anyway, and the bigger you get, the more granular you can be with how many you have. (For those curious, yes, thats like 300 panels per inverter, but each inverter supports a bunch of strings).

What does this have to do with batteries?

Well batteries let you cheat the system! They can do it in home installs, with what they call DC-coupled batteries, and you can do it at the grid/utility scale with batteries the size of shipping containers. (I’m evaluating a 20ft long one). Before I get into this, I need to list the different ways the battery might make sense in our solar farm. The battery would generate revenue basically 3 ways:

Frequency support services:

This is where the national grid basically pays you to act as a sort of ‘cache’ or ‘buffer’ for the grid. If they suddenly have slightly too much power, then dump it on you, then grab it back a bit later (maybe even a few seconds or minutes). They do this to keep the electricity grid at 50hz, to prevent every transformer in the country going bananas and maybe even failing. This is a constant battle, fought every second of every day. Here is a chart of the last 36 hours of it:

You can make money from these services, just by having a battery connected to the grid, and being registered to rent out your battery to act as a local buffer.

Time-based arbitrage stuff

You might think the price of electricity is fixed for your current contract term. Ha. Yes, at the consumer level it is, but behind the scenes, the wholesale price of electricity fluctuates like crazy, not only each month, or each day, but each 15 minutes. And it fluctuates a LOT. You can decide to ‘keep’ some of that solar power you generated at midday and sell it later. In fact in theory this can be hugely profitable, based on the current volatility. Again, here is a price chart the last 36 hours:

In that chart, the price gyrated between negative £70 (They pay YOU to use power) to positive £200 for a MWH. In theory, if you could buffer the whole farms output, and only sell it at the peaks, you would make decent money

Peak-Shaving

This is a system where you take that extra power that you are not allowed to export, you buffer it in the battery, and trickle it out later. This transforms the usual bell curve of solar output into a different shape:

We fill the battery with the ‘red’ energy, then trickle it out later to extend the peak output duration of the site. This energy would otherwise be totally lost, and we would not earn a penny for it!

Ok, so these are three ways storage can make money alongside your solar farm. What the problem? The problem is two-fold. Firstly, there has been a HUGE increase in the amount of grid-connected storage in the UK, which means lots of batteries bidding for the same grid services regarding frequency and price arbitrage. That means that naturally, the profits from these mechanisms have dropped. There are a lot of VERY big companies doing this now, and tons more on the way. Plus, there are other technologies that you compete against. The main one would be hydro (basically a gravity-water battery), but also there are experimental things like gravitricity, and companies working with flywheels and other tech. Its VERY volatile.

Secondly, the price of the battery has gone fucking nuts. In 2 years, the price has gone up 50%. Thats crazy. This may partly be due to the EV revolution, which is scooping up all those lithium ion batteries I was hoping to pack my shipping container with. It might also be related to components shortages for power electronics (lots of chips in a stationary battery), and general inflation for stuff like shipping and labour to install a concrete base and so on…

So right now, with the first two potential battery income streams kinda poor, we have to think whether the basic and most obvious one (peak shaving) is actually worth it. It looks right now that a 583kwh battery cost is about a quarter the total cost of the entire project.

That MIGHT mean its just not worth doing. Sure, being curtailed at peak output for a few weeks each summer may suck, but the big question is how much? I don’t have access to the data yet, and do not have software that accurately measures it, nor is it likely worth the hassle of buying any. I am digging further.

The maths I need is pretty simple, IF you have the modeled data: Given the output each day, for 25 years, what amount of KWH is curtailed on the site given a 900kw power limitation. I then need to guess the market price for this and compare it to the battery install and maintenance cost for 25 years. (I know, its optimistic to expect the electronics to last 25 years, but hey).

Hopefully it DOES make a convincing case, because if not, I basically have to scrap the idea of a battery, or at least wait and see if prices fall. I can still install the solar farm in the meantime.

I should probably call this article ‘How I managed to get planning permission granted for a solar farm after initially getting refused’. But I’m sure the algorithm will find it anyway…

Its been a LONG time since the last update. Since then, we put in an application for planning permission and… got refused. This was pretty devastating, and I was fairly convinced that was the end. I’d close down the company, write off all the money already spent and spend my days grumpily complaining to people how the system was broken. Instead… we now have permission! and here is the epic story.

When we initially made our planning application, it included about 30 separate documents detailing stuff like what trees we would plant (to compensate for the horror of building a solar farm. We wont cut down any…), which roads our trucks would go down, what the soil was like, what bird species were common nearby, what panels we would use, what angle they would be at, where the substation would be, what the cables would be like, where the cables would go, what the mounting frames were like, whether or not any great crested newts had been seen in the vicinity of the site in the last decade…

The ridiculously long timeline for the council making a decision came to the end… and then they asked for an extension. We sighed and said yes (to be clear: you have zero real choice). Then when that expired they asked for another extension. We had to say yes again. Then eventually they turned it down.

They do not even email you to tell you. You have to keep checking the site. Yes I am serious.

The reason it was turned down was because its about half a mile away from a long hill (80 miles long in fact), called Offas Dyke. This is a historically interesting hill. Its technically a historical monument. There was absolute dread that there were places on this hill, that if you looked west, you might see our solar farm, and then presumably commit suicide out of horror. Thus we got turned down.

If you think this is insane, I haven’t even told you the best bit.

All the places on the hill that have an offensive view of our site… are private property. The public cannot even go there. I guess that the theory is that people trespassing on private property might interrupt their late night burglary attempts, look west and then recoil in horror at the sight? Needless to say there were no objections to our proposal from any residents.

To make it even more ridiculous, when you stand on the site of our farm and look at the dyke, there is a fucking house on it. A private house. How the hell did that get planning permission?

Anyway…

We decided that this decision was clearly insane, so we resubmitted, with some changes to the layout to mitigate the horrific devastation to the eyeballs that a 1.2mwp solar farm might cause. This resulted in a response from the council, from a hired consultancy company who they asked to appraise some of our paperwork, stating that our visual impact assessment was not good enough, because, among other comments, some of the photos were of low DPI, and one of the diagrams didn’t have a North-symbol on it. Yes really. And yes, amazingly, that company can be hired as consultants to do visual impact assessments which would have been much better. Oh yes, totally legit. Nothing to see here…

So how did we get it through this time?

I made a tactical error the first time, in that I thought if we include all the information, and make a reasonable proposal, it would be granted. This was naive. That time, the decision was made by a single ‘officer’ at the council (this is called ‘delegated powers’). Basically someone reads all 30 documents, then decides to grant or refuse, and they refused. This time around, that same planning officer was not available, so we got someone else, but the second time… I actually lobbied for support.

I emailed the local Councillors for the area, I emailed the mayor of the nearest town, I emailed every environmental pressure group I could find in the county. I emailed the local MP (who ignored me…too busy tweeting about renewable energy believe it or not), I emailed the Green party, The Labour Party and local conservative Councillors. I emailed and facebooked, and tweeted at everyone I could find who was remotely in any way associated with green energy, environmental politics in the local area, or local politics of any kind. I read every news article in every local paper that ever mentioned solar farms looking for names of people that might show their support.

Politically, the most supportive were probably the Green party, but in terms of practical help, it was mostly the conservative party. By a huge margin the least help came from the Liberal Democrats, who basically said ‘good luck, but we don’t get involved’. Thanks. Duly noted.

Anyway…

Eventually this all came down to a one hour planning meeting 3 hours drive from my house… so I went up there and arranged to speak. I was allowed to speak for 3 minutes, and not allowed to speak otherwise. This was a ‘planning committee meeting’ instead of a single officer’s ‘delegated powers’ decision. THIS IS WHAT YOU WANT. A single person will not want to be blamed for anything bad, so they default to refusing everything. In fact, the planning officer’s recommendation was REFUSE, due to archaeological and history concerns (again). Despite this, it was clear that every single Councillor on the committee was very very strongly in favor, and said so, sometimes pretty passionately, talking about climate emergencies and how ridiculous the claims of the history and archaeology groups were. It went to a vote and we won, unanimously! with a few easy conditions (every one of which is pointless, as they are all already addressed in the 30 documents in our proposal). I think it was overwhelming enough that my 3 minute talk didn’t ‘win’ it, but I do think it helped, as I preempted some concerns and addressed them.

It took about 3 days to get the website changed so it officially said granted. Again, obviously no email to tell me… *sigh*. The next morning after the meeting, we went along to the site for the first time to meet the landowner, who is a sheep farmer. He told me he has been trying to get renewable energy on part of his farmland since 1997. TWENTY FIVE YEARS. But yeah… we are totally going to be netzero soon right?

So what next?

Now we need to get a date from the DNO (power network company) for when they can finalize their grid connection and we can provide power. I am hoping for Q1/Q2 2023 but I bet it Q3/Q4. You basically have zero say in this, despite phenomenal cost. I’ve emailed them and am awaiting a reply. The site is muddy and hilly enough to preclude a winter build anyway, so we are looking at April next year to build it as a best case scenario. It would be amazing, but unlikely, to catch much of the 2023 summer output.

I still have 3,024 solar panels in a warehouse waiting to be fitted. I wont order battery or inverters until we get a connection date. Hilariously the panels have gone up in price since I bought them, so its not a bad thing I ordered early, especially given ongoing supply chain woes. There will likely not be updates on this blog for a few months, until I start ordering things and we have proper dates. I still suspect that the hardest part is over, because planning in the UK is so evil, it makes absolutely everything else look easy…

As a bit of background to this post, its worth noting that I am massively into solar panels. I have 10 in my driveway, and I even started an energy company to build solar farms. Bizarrely, I currently own over 3,000 brand new solar panels, and they are sat in a warehouse. Its a very very long story. Anyway…

Solar power has a problem. Its a problem that we are working around, but it also represents an opportunity, because if someone can seize the opportunity, its seriously going to help everyone. It will help energy security, it will help the cost of living, it will help equality, it will help fight climate change. An opportunity existing precisely because solar power has a problem:

Solar panels are things we all know about. You can get big ones, and small ones, even tiny ones that power something as small as a pocket calculator (remember those?) or that unroll and plug into your phone to charge on a sunny day. We all know about solar panels. What most of us are not aware of, is inverters, and how our home wiring works. The big thing I need to get across in this post is that right now there is a LOT of complexity and crap that goes in between those solar panels you see on someone’s roof, or in a field, and the wall socket you plug your TV into.

Solar panels generate DC power. Houses use AC power. Basically AC is safer. AC gives you a shock that throws you across the room. DC is the one that locks your hand in a grip, and makes you look like wile-e-coyote when he gets electrocuted. Its the one that will kill you. Because solar generates DC and we need AC, you need a gadget that swaps one to the other. This is an inverter, and in most solar installs its a pretty big box of electronics and wiring that is usually hidden in someone’s attic or a cupboard somewhere. Here is mine:

The solar panels get connected in one end, then you get AC power out the other end, that goes through a big DANGER cutoff switch and then onward to a meter that calculates how much of a feed-in-tariff I get (old discontinued subsidy), and eventually feeding into the main energy supply for the house.

There is a big bit missing (for another 6 weeks!) from this picture, which is battery storage. To be of any REAL use to me, I need to store that power somewhere so I can use it later. I need home storage. I have ordered 2 big 8.2kwh batteries that will get connected to all this, involving yet more cabling. Each one of those is about 50% bigger than the inverter, and they ALSO need their own inverter, and their own cutout switch, and will be wired up in the cellar.

So to recap, to have a decent bit of renewable energy and home independence that lets me help prevent climate change, gives me energy security and independence, improves the resilience of the national grid etc… I need… *deep breath* Some solar panels, an inverter, a cutout switch, cables, a battery, another inverter, another cutout switch, more cables and a meter.

Actually thats not really the problem. This is the problem:

To even have THE OPTION to have all that, I need: A roof that I own (or in my case a yard/driveway), a cellar or similar space to stick a big box or three… oh and about £10,000 minimum. ($12,000). Yikes.

So what this means is… solar is really a nice handy, excellent option for middle+ income homeowners with a house and access to twelve thousand dollars. Great news for us I guess. Go team us! But hardly much help to people who live in apartments, or who rent, or who frankly are having to struggle financially as it is, ironically in no small part due to high energy bills. How can we solve this?

What we really need. What we REALLY BADLY need, is a way for people in any situation to be able to do their bit. They may not have $12k to invest in renewable energy, they may not even have $1,200 to do so, but they might have a few hundred dollars, or even fifty dollars. We need a way to dramatically scale DOWN solar power so that pretty much anyone, regardless of circumstances, can do something.

The big problem we have is that the entire solar and storage industry is designed to scale up. Just like with wind energy, it seems the easiest way to get costs down per megawatt is to go big. Bigger panels, better panels, bigger batteries. Big solar farms, Big battery storage. Not powerwalls, but powerpacks, or megapacks, or bigger. Bigger is cheaper, so bigger is better right?

The trouble is, this strategy is a way for the rich to get cheap energy, and leave the poor in the dust. Its great news that solar panel prices are falling and battery prices are falling, fantastic news for people who already have a pile of money. But where is the solution for people who are struggling? how do we avoid leaving behind everyone on average or low wages? Are we heading towards a society where energy bills only matter to the poor (who are crushed by them) because the rich generate their own power quite happily, and don’t know what the fuss is about. Maybe they don’t even know the price of energy any more…

What we need is a gadget most people probably already think is there. We need a gadget that you can plug a solar panel of any size into, and then plug it into your wall socket, and have your own micro version of the 4kw + big battery setup that those people with money already have. It needs to be really cheap, and really easy to use. It absolutely needs to be something that does not involve an electrician to install, and is totally safe. Just like plugging in your TV, although you plug in your solar panel instead, and it automatically sorts out whether to charge it’s little mini battery, or feed that power immediately into the house to supply anything that’s currently running…

The thing is… batteries scale down really nicely. My car (Tesla model S) is just a big fat block of small cylindrical batteries known as 18650s. They are used in EVERYTHING. I noticed our vacuum cleaner uses the exact same batteries. You can even just buy a bunch of them on ebay, they are not super obscure tech. And solar panels… they are pretty much a commodity. There are differences at the high end, when you build a solar farm, but you want a 400w panel? a 200 watt one? a 50w one? a 2w one? you can get anything you want..to suit your budget.

The tricky bit is the integration with a small inverter, and the knowing what the house is doing. With current solar installs, this involves additional cables and things called CT clamps to work out if power is flowing in or out. Its complex, and messy, and annoying. Maybe electrical wiring means we just cannot do that, which means we have to go with a bit of a bodge solution, which is one of those small battery/inverter ‘powerpack’ gadgets that you CAN get on amazon:

These are obviously cool, but they are absolutely aimed at people who are going camping, and want to power a laptop or a small TV or whatever, while they are out of the house. Again…its a luxury product aimed at people who want to mess around with a mains-power TV while out on a camping trip. Its not designed to be something used as part of your house, and the assumption with most of these is that you are either charging from the house, or from solar… and then at some later time watching TV.

We need that…but as a permanent thing, in a fire-and-forget setup. In an ideal world you would output from this to a big powerstrip with a ton of devices that you use a lot on it. So TV, plus any speaker system, or streaming stick or DVD player…whatever, so it gets a bunch of use. Something you can buy once, and just use to reduce your household energy bills.

And we need this to ABSOLUTELY become a thing that people do. Not solar geeks, not environmentalists, not people who go on demonstrations, but it needs to become a thing that yeah…if you have $200, then you obviously get the powerpack+battery kit, you stick the solar panel in the window, and plug it in, plug some appliances in…and then your energy bills go down. Not a lot, for sure, and you would be WAY better off with 4kw of solar on a roof, but for someone in a small apartment who has high energy bills and a window that gets a ton of sun…we need this.

All the big tech companies are wasting their time, messing around with nonsense none of us asked for like ‘the metaverse’ or mobile phones that you can fold (why?) which cost $2,000. Or they are working out how to make your next unaffordable luxury phone just slightly thinner. Whatever…

Where is the apple iSolarPack? the google solarpack? the amazon solarpack? the brilliantly engineered (and produced in massive, massive volume) solution that helps absolutely anybody in the world feel like they can partake even slightly, even in a really small way in the revolution in renewable energy. We absolutely massively need this, and if you can make a thing that just unpacks and plugs in and saves everyone a bit on their energy bills, its going to sell like mad.

Even if we cannot do anything better than just make the existing idea of a powerpack much more affordable, and pair it with recommended solar panels in a nice easy package aimed at people whose idea of technology is plugging in alexa once… we really need to do this. Sadly nobody of any size seems to be bothering :(