Last day today and I’m not sure how I feel about it. Tim asked whether I’d like to stay longer given the chance and I replied I don’t generally play the ‘what if’ game (which is true, it’s pointless unless you can actually change something) but if the opportunity arose in the future I would definitely come back and would certainly consider staying longer than a fortnight so long as I could be useful around the farm and hopefully learn as much as I have this last fortnight.

After the usual morning checks and breakfast Tim and I headed out to complete what would be my last set of measurements from the fermenters and digesters. While Tim got on with the time-consuming titrating, I set to the dry matter analysis and then spent the time between samples finishing off the macros and spreadsheets Thorsten had asked for over the last few days.

Just before lunch we headed back to the house to send over what we’d finished and Thorsten showed us how he wanted the comparison data for the maintenance cost for the gas engines assimilated with the amount of operating hours and kWh generated. Thinking we’d probably need some help negotiating the huge spreadsheets in German (25MB in size!) we decided to have some lunch first.

True to form, lunch was a highly inclusive affair. The meal was pasta bake with salad and some leftover vegetables from yesterday and was very tasty, as were the three types of cake for dessert (the new addition being a very soft sponge cake slice with gooey faintly lemon-tasting icing with a splash of a liqueur of unknown flavour for good measure). As we finished our mains the three Sturms, Christian, Tim and I were then joined by the painters from upstairs as well as Suzie which meant the table was very packed but incredibly jovial. As Tim commented as we left after lunch, it would be rare for work(wo)men to be invited to join the dinner table as friends back home but it really seems a different way of life here, and very pleasant it is too!

After lunch we took the last electrics reading and headed back to the office for about 3 hours of serious spreadsheet work that involved us showing Thorsten the results from the two weeks and being able to pinpoint using the FOS/TAC, pH, temperature, gas analysis and electricity readings how things were changing through the whole process due to, for example, the addition of extra minerals, increasing the heating duty in the fermenter (massively increases the overall process efficiency) and how changing the addition of oxygen in attempt to control H2S also affects the other gas compositions and amount of auxiliary gas required by the gas engines. All in all it was fairly satisfactory to see things come together. We then moved on to comparing the actual cost variation of the gas engine (circa 38% efficient at converting thermal energy in the biogas to electricity) and the oil-injection gas engine (higher efficiency, reputedly 42%). After including a whole range of factors from capital costs, discount rate, range of costs of maize substrate, amount of oil needed, availability (and cost of lost revenue when out of service) and maintenance costs per kWh we were able to plot how much more efficient the more efficient engine needed to be to offset the extra cost of operating it against the price of maize (which governs the cost of gas entering the engine) and for this farm it turns out to be in the range of 4-7 % points, but for the current maize prices it’s towards the higher end of the scale. It’s pretty interesting to see how a higher efficiency engine doesn’t correlate to a more economical purchase.

So much spreadsheeting for two lines on a graph. Still, I reckon it was worth it in the end

So much spreadsheeting for two lines on a graph. Still, I reckon it was worth it in the end

We also showed Thorsten the gas analysis macro (explaining the frustration of the output from the analyser) and the pig-monitoring macro which he seemed pretty pleased with. So pleased in fact that he let us out to drive the loader and put a few bucketfuls of maize into the rotamat loader. I GOT TO DRIVE THE TRACTOR!

Me + tractor, Doing stuff. Yeahhhhhhhh

Me + tractor, Doing stuff. Yeahhhhhhhh

Sorry, a little excited there, but for city boys like Tim and I this is a lot of fun. I managed to drop over a tonne of maize into the hopper fairly successfully. Well, successfully if you don’t count the dozen (hand)shovelfuls that I managed to drop onto the tractor itself…oops!

....more practice needed, clearly!

….more practice needed, clearly!

After clearing up the mess Tim and I cleaned the lab as well and then put on a shirt for dinner at a thai restaurant in with Thorsten and Suzie to celebrate what has been a very successful (at least from where I’m sitting) fortnight. Thorsten very kindly bought dinner for us and the food itself was very tasty, even if the chips served with the thai salad were (I’m sure) bacon flavoured.

After a long day, a couple of white beers and the drive back (thanks Suzie for being the designated driver) to the farm we were all fairly shattered and we slumped into bed soon after barely even noticing the noise from the cows next door.

Dawn breaking over the flare and digester 1 as we do the composition testing on the gas intake to the engines

Dawn breaking over the flare and digester 1 as we do the composition testing on the gas intake to the engines

A nice early night last night meant a full eight hours before the alarm this morning which was bliss. Today was a fairly varied day all in all. There was a ground frost this morning which meant that Thorsten and Georg were devoted to trying to muck-spread while the ground was hard enough to hold the tractor and 19 tonne trailer. There hasn’t been a single snowfall this year and few frosts so there have been few opportunities to get the gulle (nutrient-rich digestate end product, effectively liquid manure) out on the fields over the winter which is important for a few reasons. First, spreading the digestate end product provides nitrogen, phosphorus and calcium reducing the need for (and cost of) conventional fertiliser. Second, this process closes the nutrient cycle (which is important for the sustainability of biogas). And finally, the enormous tank where the end product is stored was at least 80% full and once it’s full there’s no way of storing the digestate, and no where to put it!

Inside the digester during agitation. Looks like a Martian (or otherworldly) landscape apparently...?

Inside the digester during agitation. Looks like a Martian (or otherworldly) landscape apparently…?

Up to mid-morning we steadily got on with our testing and routine tasks while service engineers maintained one of the gas engines to ensure optimal efficiency and in preparation for upcoming emissions testing. Following the frosty early start, the day turned into beautiful sunshine in a cloudless sky and the PV installations in this part of the world started gearing up to donate to the grid. Thorsten dropped by around mid-morning to see whether Tim and I wanted to join him for some muck spreading as there’s a spare seat in the big tractor so we split the time and while I finished off that series of tests Tim helped fill the spreader and went about videoing the spreading in action. I got a similar slice of action later on and can understand why Christian enjoys muck-spreading so much. It’s thoroughly relaxing to switch on the radio, key in the range to which extend the spreader arms, set the cruise control on the tractor and give a decent amount of field (about 0.7 Ha) a nice wet brown covering before using the ipad/ ipod linked to the GPS tracker to check the field off of the schedule for the day. Yes, there really is that much technology in these tractors!

During a couple of spreading visits Thorsten told me of the importance of diversifying what is grown to spread the risk for crops (last year was terrible for corn but nearly a record for wheat – I think I’ve got that the right way round – on account of the amount of rain and when it fell). It also turns out that the farm is entirely plough-less which surprised me. Not that it was something I’d ever thought about in depth, I admit. It turns out that ploughing is highly energy intensive, kills large numbers of soil fauna and also oxidises the soil requiring a deeper humus layer. On the farm they tend to grow mustard instead during the off-season to control weeds and then when the frost comes it splits the bulbs and the plants die back returning all of the nutrients to the soil which is then rotavated instead before planting. See, not just biogas that’s being taught out here – to be honest I could write a tome on all of the odds and ends I’ve learned in a week out here (and several more on the now known-unknowns that have come to my attention – like why when you dilute digestate of pH 7-8 with distilled water of pH about 7 does the pH of the solution increase to about 8.2 when the digestate is already about 92% water?).

Back for lunch of baked rice with courgette and fennel and green salad which was delicious and topped off by a nut cake of which I had two pieces. I’ve been starving all day and am now going to blame it on the doughnut I had with breakfast (yes, that’s three pieces of cake by lunch time) that was made with a little bit of milk that didn’t really agree with me. (Nothing wrong with the doughnut, which was very tasty, just a bit wrong with me).

As another week’s worth of silage has now been fed to the fermenter there was some shovelling to do to get the remainder off of the ‘sausage’ of corn in the side of the silo. So, we set to that to work off some of the lunchtime calories before getting stuck into the afternoon’s routine.

Tim is king of the maize pile. Oh, and the white thing next to him is the 'sausage' of corn

Tim is king of the maize pile. Oh, and the white thing next to him is the ‘sausage’ of corn

Around 4pm Thorsten asked whether one of us was free to help him lift some boards for one of his friends. I jumped in the car with the friend and spent the next few hours unloading plasterboard from a forklift truck through an upstairs window into the newly built flat his friend has built on top of his girlfriend’s house. Now, when I say on top, I really mean it – they took the roof off, added a spiral staircase next to the front door and installed an entire other floor on the top of the house with the structural work taking about two weeks. Yes, two weeks! The additional storey is constructed entirely from wood and was largely made offsite and then clicked together in place and, although still work in progress, it looked great with high, vaunted ceilings in the eaves of the roof and loads of light flooding in through windows galore. Even though my fingers were now tingling from hefting pallet full of plaster boards – having not entirely recovered from climbing at the weekend – it was nice to have been able to help out a little bit and also great to see how the community here is close enough to help each other out (Thorsten picked up the pallet of boards from a storage yard with the forklift and drove it through the town to the house because he was asked if he could help while at dinner last night). I asked him about this and he said that the guy we helped was really good at exterior painting and woodwork so he’d just call in the favour if he needed some help in the future; isn’t that the way communities should be?

Back for dinner where I’ve got humous and tofutier (fake meat and vegetable) spread to cover the rye bread with before retiring early for a bit of diary writing and perhaps a little work too. Or maybe just preparation for work; we’ll see how tired I feel after this…

A week into the placement and now we’re starting to get used to the early rising schedule – I’m doing that thing of waking up about five minutes before my alarm goes off. I can’t decide whether this is good or not though. On the one hand it’s nice to be ready for the alarm, rather than have it rip you untimely from a pleasant dream, but on the other it’s five minutes of sleep I’m deprived of and, at the moment particularly, I do like my sleep.

Tim preparing the dry matter tests for the maize silage sampled from different heights of the silage pile

Tim preparing the dry matter tests for the maize silage sampled from different heights of the silage pile

Perhaps in response to mine and Tim’s discussion the day before (no, I’m joking before you get any ideas of sabotage) there was a disruption to the normal routine this morning. Surprised not to see the tractor headlights blaring through the dawn with Thorsten loading the feeders, we walked to the erratic flashlight beams that were emanating from by the side of the fermenter. It seems that the feeder had malfunctioned in the night and the alarm to Thorsten’s phone had brought him out at midnight to try to fix it then. Waiting instead for daylight and a bit of warmth (it’s really pretty chilly here out of the sunshine) it seemed that the screw-feeder had just clogged up with material from the macerator. After raking some of it out and restarting everything seemed to be working again and we went about our morning checks, really noticing the impact the feeder outage had on the fermenter on the amount and composition of gas in the plant and the chemistry of the liquid samples we took.

After breakfast we were given another task. Thorsten’s interest for the batteries it seems is to see whether a solar installation with battery storage would be able to power the pumps on the biogas plant that are running 24/7. To work this out, he has installed electricity counters at several points around the AD site, but has no way of recording them. So, we were given a tour of the monitors (on feeders, gas engines and grid connections) and a schedule to monitor them for. With a bit of spreadsheeting in a couple of days it should be possible to see how the demand for energy varies across the site throughout the day.

Before lunch I got the chance to change the oil and filters on one of the gas engines with Thorsten. Once you know what you’re doing I think it’s pretty straightforward but trying to understand the directions while stood between 300kW and 400kW engines it’s a bit difficult to hear!

Me, refilling the oil in one of the motors after filter and oil change...and at this point not completely covered in oil. Win.

Me, refilling the oil in one of the motors after filter and oil change…and at this point not completely covered in oil. Win.

Lunch today was homemade vegan pizza. A bit of a shock to the system for vegetarian Tim but he said he enjoyed it and it really hit the spot for me. This was also accompanied by another really good soup. Honestly, I could well come back the size of a house! For lunch we were also joined by the electrician who is reprogramming the gas engine control system who was telling us about his friend who had a vegetarian wedding last year. I asked if he knew if the wife had a sister and everyone laughed. I don’t understand why – I was deathly serious!

This afternoon we repeated the analysis but also took samples to be sent to an external lab so that we could compare our results with theirs…this could be interesting when the results come back next week. We spent the afternoon finishing off jobs that had accrued through the week and with me holding a ladder for Christian as he painted the support posts for the engine chimney stacks. My German is picking up a bit now with things from school starting to reawaken and I understood the majority of our conversation, which largely involved him joking with me that if I didn’t hold the ladder properly then everything would be bad and he’d be in the local hospital saying “well ****”. No pressure then as he’s at the top of a six-metre ladder resting against a flue pipe in the wind!

Just before dinner I borrowed some glue in an attempt to try to fix the hangers that broke when we returned in the evening to find my clothes rail had fallen over. In the workshop we found Thorsten rigging up a switching system to overcome the melting of the switch in all his 3-phase switching gear. As we walked back to the annex we’re staying in Tim remarked he really liked the view on the farm that everyone just has a go at fixing the problems they face.

Over dinner while speaking to Christa and learning more and more German we found out Saturday is just another day on the farm, which to tell the truth is pretty much what we’d expected. Sunday is apparently a day off (during which Thorsten and Georg only do their morning duties…that’s a day off?) and we’ll maybe be heading to an old walled city that everyone agreed was very nice.

With dinner finished I’ve just caught up on three days of this dear diary and realised I have a fair amount of corrections to start getting on with soon. Still, there’s always a couple of long train journeys too look forward to getting teeth into them in.

You get very pretty sunsets out here that nicely silhouette big bits of farm machinery like tractors...it's been a great week so far, let's hope it continues!

You get very pretty sunsets out here that nicely silhouette big bits of farm machinery like tractors…it’s been a great week so far, let’s hope it continues!

Well that didn’t last long. Writing the diary on the right day I mean, not the placement – I’m very much still here in Franconia.

Little new during the day today, just continued getting better at the testing procedure, getting up and down ladders and helping out occasionally with other bits and bobs on the farm where spare hands are needed, including an interesting method of hanging gateposts on walls. Lunch of roasted eggy potatoes and soup which was very welcome. Oh and I managed to cover myself in oil while topping up the levels in one of the gas engines. Oh well, it’s very much an outdoors coat now and may even buy a bit more kudos in a proper Yorkshire pub!

Perhaps not the best angle to take it from (sorry!) but here's Tim checking for methane leaks on the intake to the gas motors...and fortunately not finding any

Perhaps not the best angle to take it from (sorry!) but here’s Tim checking for methane leaks on the intake to the gas motors…and fortunately not finding any

We also started the snoop testing around the biogas plant looking for leaks with a ppm methane sensor. This tended to involve trying to get into all the nooks and crannies around pipework into and out of the fermenters and digestors eagerly anticipating the increasingly frantic beeping as the methane gets detected. Oddly, leak detection becomes a bit of a game and you feel oddly happy when the detector goes off. Deep down I know this means remedial work is needed in those areas (so it shouldn’t quite be so entertaining) but I somehow can’t get it out of my system.

Come the evening Thorsten invited us to go with him to a talk about battery energy storage as a complementary technology to PV which he’s organised as a representative for the local council. The talk is at a local gasthouse (bar/ restaurant/ hotel) and pretty well attended – the thirty or so men and sole woman in attendance pretty much fill the area set aside for the presentations. Both of the presentations are in German (naturally) but are spoken far too quickly for me to understand, save for the odd bit of technical detail that is sufficiently similar to English or numbers, numbers I can do (which it turns out in a sales pitch is quite helpful). Integrating battery technology with PV allows a shift in the demand/ supply balance of electricity from/ to the grid (allowing the solar supply peak to be balanced with the twin peaks in demand throughout the day).

Thorsten explains several of the slides and retells some of the anecdotes told by the presenters (there’s an island off the English coast that runs entirely off batteries apparently, and we don’t know what is round the corner – just look at the floods in England. Wales, I’m sure you were thought of too, but not mentioned I’m afraid, and I don’t know the German for Wales so I was hardly going to stick up for you there and then).

Far from the best photo I've ever taken (sorry, I was trying to be inconspicuous) but this was from the back of the pretty packed room who had turned out to learn a little bit about battery storage for PV

Far from the best photo I’ve ever taken (sorry, I was trying to be inconspicuous) but this was from the back of the pretty packed room who had turned out to learn a little bit about battery storage for PV

Another bonus of the presentation is that it is held in a gasthous and since this is southern Germany, everyone has a beer. And the beer was good, a nice smooth pilsner, but after the hard work and little sleep it hit me pretty hard so I was glad to stop at one.

We got back to the farm at around 10:30 and I was already feeling groggy just thinking about the morning when Thorsten mentioned he was probably up at 4:30 in the morning to make sure the feeder was full before he went to Mannheim. Well that put things in perspective I suppose!