A couple of years ago now I asked some questions here about the costs of running diesel generators for domestic power. Some of the numbers I got back almost put me off buying the house, but I, with my partner, did buy the place.
The power set-up as we bought it comprised three diesel generators, all Listers of different power outputs, 1.75kVA, 3.5kVA and 11kVA. This system had evolved over the years.
Historical side note: We have recently made contact with the, now, 94 year old woman who lived in the house from the 30s through to the 70s. She and her husband put in the two lower powered Listers. She, in fact, poured the concrete floors we still have today. Perhaps I should get her back to do the tower foundations!
The house could run directly from any of the generators, the choice of generator was based on what you wanted to do. The lowest was fine for TV etc., the next for a washing machine, the largest was put in by later owners to run a blacksmith's forge.
The generators were used only when needed, evenings, weekends. Thus we don't use a video, say, and we have a gas (lpg) fridge---came with the house.
In addition to the diesel system the previous owners added a couple on small wind turbines (one 50W, one 400W) on the gables of an outbuilding., and a couple of small battery banks with a 600W inverter. This system allowed for lights being used in the middle of the night but not much more.
The whole system is very ad hoc with lots of switches being used depending on what you need to use. So, we decided last year to look at a more modern system or going on the grid.
Going on the grid would cost around 20K. We quickly realised we could spend a lot less than that and have a system based on solar and wind power. We then had to decide whether to go the DIY route or get a supplier fitted system. Luckily we have a company that does renewable systems just a few miles away, which makes for good service. Their quote for a full system was about 15K but as it is an 'approved' system we can get 3-4K of grants to cover some of that.
The DIY route would get any grants and the kit would attract 17.5% VAT instead of the 5% we paid. However, there's probably not much in it in terms of the hardware costs after the sums.
The system we went for, based on our location and needs, comprises 6 110W Solar PV panels, one Whisper H40 (900W) windcharger, a very clever 3.3kW inverter and a bank of 16 6V deep-cycle batteries. In addition there's a solar controller and a wind controller in there. The inverter is also wired to the 11kVA Lister as its back-up charger. It can also patch us straight through to the genset if we use very heavy loads.
All the wiring has been done by the company we got in but the groundworks and preparations are DIY.
The first stage was just the inverter, batteries and genset wiring. This immediately made a tremendous difference as the genny was turned on just for charging for 2.5 hours every 3 to 5 days.
The solar was added next, on the shortest day of all days! We have been surprised at its effect. Even at this time of year it is delaying the need for diesel charging by a few days. The last few days have had record daily inputs of over 60Ah. This is more than enough to cover our normal nightly demand.
The final part is the wind turbine. The charger we have chosen is designed to work in high wind areas and has been used in similar locations to ours (exposed!) in the north of England. We are predicting that the diesel generator will be used very little once the turbine is up and running. In fact we may have to make a decision as to whether to divert its dump load to some use other than heating the inverter shed---possibly to a secondary immersion heater.
We then have to decided what to do with the old system. The Air 303 did suffer some damage in recent storms and an electrical storm fried out 600W inverter. The new inverter is protected from this and the new turbine is better suited to our conditions and will be better installed, though obviously there are no guarantees.
We still feel we need to hang on to the 3.5kVA genset as we like the idea of backup systems. We will probably try to sell the smallest generator, it was built in 1960 so it may be of interest to a collector.
We may used the older wind/battery system to run a DC lighting circuit for the outbuildings with a small inverter there for emergencies.
In fact this raises a final question about the recently discussed regulations on electrical work. Does it apply to a situations such as mine on the other side of the 'meter'? We don't actually have a meter but how does it apply to the old inverter system itself?