1. WIND TURBINES:
All wind turbines have moving parts, and moving parts means wear and tear... The particular turbines that we have chosen to install have been designed to cope with this extremely well: Most of them have been tested under rigerous conditions, far worse than a typical UK site (e.g. Falkland Isles, Outer Hebrides etc), and any parts that have been found to wear are upgraded and then re-tested by the manufacturer. This is why we only recommend turbines that have been tested over a period of many years.
All this means that once we put up a turbine it is rare for us to have to go back to site, except to perform it's annual service.
The annual service on a typical 6KW turbine is fairly straightforward, and anyone who has a little mechanical experience (e.g. minor car mechanics / DIY etc) may well be able to perform the service themselves.
This has two advantages:
1. The owner learns how the turbine works and is able to look after it themselves;
2. The owner saves themselves the small service charge each year.
So....what is involved in the annual service?
The turbine is lowered down using a special safety 'Tirfor' winch or hydraulic ram;
All components and nuts/bolts etc are checked for damage or looseness;
The bearings are greased up;
The electrical connections are checked for tightness;
The brake system and carbon brushes are checked for wear;
The protection covers are then replaced;
Lastly the turbine is raised up and checked for proper running.
All this should take around half a day. The turbine controller and 'Windy Boy' inverter that sends the power to the grid can also be checked.
2. SOLAR PHOTOVOLTAIC'S (PV's):
PV systems tend to have no moving parts at all (except sun tracking arrays), therefore the wear and tear is negligible. All our PV installations use tried and tested mounting systems and PV modules (panels), usually with 25 year guarantees.
Typical, infrequent, servicing involves:
Checking the actual power output against the expected output using an irradiance meter;
Every few years or so all fixings can be checked for tightness;
Some cleaning of the module glass may need to be done – rain and hail usually do this very well.
3. OFF-GRID / STAND-ALONE BATTERY SYSTEMS:
Off-grid systems have the most frequent and time consuming maintenance schedule, as well as being more costly (e.g. battery replacement etc). This is one of the reasons why we don’t recommend an off-grid system to customers with access to the mains grid network.
Once again we are very particular about which products we install, paying special attention to longevity and intelligent design (which saves wear and tear). Experience shows that cheap equipment simply doesn’t have the quality of internal components to be able to continuously run for many years without problems - i.e. you get what you pay for!
Annual off-grid system maintenance (in addition to Wind Turbine/PV maintenance):
Equalise batteries twice a year (some controllers do this for you);
Top up batteries with water if necessary;
Service diesel generator (if any) and check power output;
Five yearly off-grid system maintenance:
Perform specific gravity readings for all batteries (using hydrometer) and compare;
Check all electrical connections/cables – especially large cables;
A good battery bank (made up of recommended DEEP-CYCLE cells) should last 8-10 years before showing excessive signs of degradation e.g. not giving as many days back up anymore coupled with inconsistent specific gravity readings showing bad cells.
However it should be noted that degradation of batteries is much quicker if they are allowed to drop to less than 50% charged (i.e. half full) – this is very expensive in the long run and should be absolutely avoided!