Energy-saving solar power sparks interest at uplands farm eventFriday 14 December 2012
Energy saving must be at the forefront of farmers’ minds at the moment judging by the turn-out at Myerscough College's most recent resource efficiency demo event for the RDPE Northwest Livestock Programme.
Thirty farmers came along to The Hill at Higher Tatham,near Wray, Lancaster by kind permission of Andrew Staveley and family, to look at the different options for supplying electricity and water to the dairy farm. A variety of speakers were also present to give a good overview of the practical ways in which farmers can make savings at their own farms.
Andrew recently installed solar panels on some of his barn roofs and is already seeing savings. As the panels were installed before the feed-in tariffs changed (installed July 2012) Andrew has maximised the returns that he is getting from the energy generated by the solar PV (photovoltaic).
To date the farm has generated over 2,500 kWh of electricity and is expected to produce over 8,500 kWh in total over the year - almost a fifth of his total usage (54,000kWh).
This power can be used on-farm to reduce the amount of mains electricity that Andrew needs to buy in, and in addition he is also paid a tariff for generating the power. Any power not used on farm can also be exported back to the grid for further income.
Peter Hitchen and Andrew Ronan, from Solar Power PV Ltd who installed the panels at The Hill, spoke to the group about the various factors which must be taken into account when deciding whether or not solar PV is a viable option for your own farm:
1) Electric supply
What is the location of the incoming service and the distribution around the site?
Is it a three phase or single phase supply?
Where is the nearest transformer and what is the condition of the cabling?
2) What are the current daytime electric demands on the site?
3) Where are the suitable locations for the PV array?
This is dependent on roof mounting, aspect ( ie south/south east or south west), the structure and roof finish and the age of the suitable roof.
How close is it to the incoming electric supply?
Are there any suitable locations for a ground mounted installation as an alternative?
4) Planning requirements
Is the farm building in an AONB (Area of Outstanding Natural Beauty) or National Park location?
Are there any listed buildings on the site?
Will the array be highly visible?
5) Energy Performance Certificate (EPC)
This will be necessary on any habitable property that cannot be isolated from the solar generation. Level D will be necessary to claim the higher tariff. Old farm houses will generally fail without significant upgrading in performance.
6) Electric North West (G59/G83) submissions are necessary for systems above 10 kWp on 3 phase and 10kWp single phase.
This can take 50 days but may be shorter depending on the circumstances.
7) Summary of the current tariffs
Financial benefits ended the talk with example /typical quotes for a 30 kWp installation. Advice provided on limiting the system size to avoid the need for a costly export meter.
If anyone would like to contact Peter Hitchen for further information on design and installation of solar PV his contact number is 01254 823885.
Unfortunately our water expert Chris Coxon from DairyCo was unable to attend due to illness so the main points from the presentation he supplied are summarised below:
- Andrew has both a borehole and a spring supplying water to the farm, which over the years will certainly have saved him a bit on his water bill. In addition to this Andrew recycles all his plate cooler water into the cow drinking troughs.
- DairyCo costings show that the average dairy farm spends £31/cow/year on water, with some units spending over £100.
- Costs of water continue to rise, with mains water costing between £1.20 and £1.50/m3. However the cost of disposal of dirty water in slurry must not be forgotten – this can range from 50p to £1.50/m3, effectively doubling the cost of your water.
- Up to ¾ of the water on dairy farms is used for cattle drinking and obviously this amount cannot be reduced at all. Another 25% is used in the plate cooler, which is necessary to keep the electricity bill down for cooling the milk. The rest is used for washing down and cleaning the plant.
- Check for leaks as a few leaks can soon add up! During periods of low water use check your meter to see if it is running as a sign of any leaks.
- Washing down the parlour – do you use a volume washer or a pressure washer? A volume hose will use 80-150 litres/min compared to a pressure washer at only 8-12 l/min. Also do you get carried away when you are washing or lose concentration and end up using it for longer than is necessary? Just think of the cost of disposing of all the water which is running into your slurry/dirty water store!
- Plate cooler water – up to 25% used to cool milk and help reduce the electricity required for cooling. This water can potentially be re-used either for drinking in troughs (cows actually prefer drinking warm water to cold) or for washing down the parlour. However it is only saving water if ALL the water is reused – if some is running to waste then don’t forget the costs of disposal.
- Rainwater collection – calculate the potential water for collection by multiplying the area of roof space by the average annual rainfall. Collection can be kept relatively simple and does not require a lot of expensive equipment or filters. If water is being used for washing down then only limited filtration is required. However water for drinking or washing the milking plant is required to be of higher quality and in some circumstances collected rainwater may not be suitable. In terms of storage 1-3% of annual collection is required.
- Borehole water – if you are thinking of digging a borehole the first thing you will need to do is contact a driller who will visit your site and carry out surveys and test bores to determine whether or not a borehole is possible. The location will depend on the underlying geology and also the presence of elements such as salt and iron which can affect water quality.
Boreholes can cost from £5000 up to £18000 depending on the drilling depth and also the distance from buildings and electricity supply etc. A few of the farmers at the event had boreholes on their own farms and commented that the savings made greatly outweigh the cost of installation and will soon pay for themselves. However water quality can be variable and is not always suitable for plant washing (must be potable).
Energy – electricity and diesel
Ruth Kendal from SAC finished with a look at the two main forms of energy used on farms, electricity and diesel, using The Hill as an example.
Steps to managing your energy consumption:
a) How much do you use?
b) Where and when do you use energy? In order to reduce usage you need to find out which processes are using the most energy and when.
c) How much does the energy cost? Are you on the right tariff for your usage and are you getting the best deal from your supplier? If you want to change supplier how long is the notice period that you need to give?
d) How can I reduce energy usage?
e) Can I use a cheaper source of energy?
This will help to determine how much energy you are using and where. By recording and monitoring energy usage this will help you to identify any changes in consumption promptly eg. if a timer switch isn’t working properly and appliances are running for longer than they should.
An audit will also allow you to monitor the changes/savings in energy usage when you install new equipment or change procedures, and you will be able to benchmark your own business against other similar businesses to see how you compare and if you could be more efficient.
When Ruth audited The Hill she found that electricity usage was relatively low but there is still potential to make savings, whilst diesel use was more efficient than average and there is very little scope for reducing this further given the size of farm.
SAC do resource auditing for farms across the North West. For the meeting Ruth carried out a new audit to find out how energy efficient the farm was today in 2012.
In 2009 Promar International carried out a subsidised plan through the Livestock Programme. In three years the farm's energy usage has remained the same (54,000kWh) but The Hill is now using 15% more energy at night on a cheaper night time tariff (47% of total energy is now used at night compared to 32% in 2009). The farm was already on a split tariff and had a plate cooler and a DX tank at the time of the first audit in 2009. Water from the cooler is used in drinking troughs too.
Subsidised Audits available: Offered through the RDPE Northwest Livestock Programme, Promar International do subsidised Resource Efficiency audit reports - see the support and grants pages of this website for more information or Click Here
Or watch our case study below of how Cheshire Dairy farmer Ed Friend improved energy efficiency on his farm with a resource audit.
Options to reduce electricity use:
- Water Heating – ensure that all pipes and tanks are well lagged so energy is not being lost and where possible maximise your usage of cheap electricity eg. ensure that timers are set so that water is being heated at night on a cheaper tariff if you are on economy 7. Investigate the use of heat recovery units which use the waste heat from a process such as milk cooling to pre-heat water so that less energy is needed to heat it to the required temperature.
- Milk cooling – look at whether an ice bank or DX tank is most appropriate for you. Using a plate cooler to cool the milk before it entering the tank will reduce the electricity needed for milk cooling (make sure you re-use all the water from the plate cooler though to keep water costs down!)
- Variable speed drives – these can be used for pumping and ventilation where the output requirement changes. By reducing the speed of a pump or fan by 20% you can cut energy usage by up to 60%. Two representatives from ABB Ltd were on-hand to demonstrate a variable speed drive and how it works.
- Lighting – the most efficient form of lighting is using sodium or LED bulbs as opposed to conventional bulbs. Ruth demonstrated this using 3 different bulbs each with an energy monitor attached. Replacing 2 x 150 watt bulbs with one sodium light can save £100/year. In addition keeping light covers clean will mean that fewer need to be switched on to emit the same light, and having lights on timers will mean that they are only coming on when needed.
Options to reduce diesel use:
Simple top tip – minimise mileage!
By not using your vehicles (tractors, quad bikes, landrovers) as much fuel usage will be reduced – simple but effective.
- Avoid unnecessary journeys by planning in advance eg. if you are going out to the auction then collect your drugs order from the vet at the same time to avoid having to go out twice. Ask yourself if you really need to take the tractor down the field to check stock, can you walk instead!
- Reduce the amount of dirty water entering your slurry and minimise the trips you need to make with the slurry tanker.