SOFT POWER: CONTEMPORARY APPROACHES TO ENERGY EFFICIENCY & MANAGEMENT
This article first appeared in the August, 2018 edition of The GrapePress Volume 171. Published by Wines of Great Britain Limited. https://www.winegb.co.uk
BY MARK O’CALLAGHAN
Wherever one is making wine around the world, from the Hunter Valley to Hampshire, the costs of energy are steadily increasing. With no signs of that changing soon, winery and vineyard managers should use and manage it as prudently as possible; improving consumption, costs and reliability.
Of course, there are the environmental benefits of being more efficient with carbon-based energy but frankly, if maximising carbon reduction per pound invested was one’s aim, overhauling the winery electricity system is highly unlikely to be the most effective way to do so.
This article recommends improvements to energy efficiency (mostly electrical) with a view to making the business more robust and not to try to save the world.
More with Less
It is human nature (and basic economics) to devote more focus to the efficient use of resources which are scarce and when it comes to energy, some early examples are very well illustrated in the original Yeringberg winery in the Yarra Valley. Built around 1870, before mains power or water, the building is replete with design features which make the most of the energy available at the time – mostly sun and sweat. Two of the more elegant examples are the use of frosted window panes on the north-facing windows and clear glass to the south, in order to even up the light within the building and moderate temperature (this would need to be the reverse in the northern hemisphere). When it came to loading red must into the fermenters, the use of rail tracks (Fig 1), trolleys and catwalks suspended from the ceiling was less about appeasing Gaia and more about efficient movement with the technology available at the time.
With respect to contemporary winery methods and equipment however, there are several new(ish) options which have slashed energy requirements per tonne, case or litre, depending on how you like to benchmark such things.
One of the first is flotation for the clarification of juices for some white and sparkling wines. While hardly a new or revolutionary method in 2018, the difference in energy consumption compared to traditional cold settling is enormous. For example, where one may have previously taken a tank of juice from 25oC (or more) down to 5oC for settling, then warmed it back up to 18oC for inocula-tion, the same tank can now be clarified and into fermentation within a few hours with only a fraction of the cooling energy requirement (for more information on flotation please see article in the Grape Press volume 165, August 2016).
“The best place to begin is with an energy audit. There are many experienced specialists who are able to measure and quantify the energy use patterns around a site so that improvement efforts can be focussed where they will make the most difference.”
The next example is not rocket science. It is so simple, but sadly too many wineries fail to grasp the significance of insulation and passive cooling options. Leaving aside the obvious example of storage tanks, the areas too often overlooked include things such as must lines and refrigeration lines, plus the simplest things like leaving warehouse or barrel store doors open. The energy savings from installing automatic warehouse-style doors (Fig. 2) on winery buildings can be incredible, especially during summer of course. Ordering staff to close the barrel store door each time they drive through is a simple idea but very poorly followed when things get busy.
Passive cooling options for buildings needn’t be expensive either. These systems simply monitor the external air temperature and if it is appropriate, pump it into the building to cool it rather than draw on refrigeration equipment.
Other off-the-shelf equipment which is deliv-ering real results in wineries today is heat recovery from refrigeration plants. There are many models and suppliers to choose from but the principle is straightforward – simply pre-warm water using the excess heat from refrigeration plants while they are working. If one is after hot water at, say, 80oC for brettanomyces control in barrel washing, it makes a big difference if the in-feed water is already at 40oC, rather than 10oC.
An example of the future of energy man-agement from Dr Roger Boulton’s brilliant presentation at the 2016 Australian Wine Industry Technical Conference was that of pulsed jacket flow for refrigerant brine. In this case, automated solenoid valves are used to hold cold brine in tank jackets to maximise heat transfer (increase of 3o-5oC). By sending a smaller volume of warmer brine back through the return stream, the refrigeration system works more efficiently in the long run.
There is usually some very low hanging fruit (so to speak) around wineries when it comes to energy efficiency improvements and even simple things such as switching to LED light bulbs or running the office air conditioning at 25oC instead of 20oC in summer can make meaningful differences to baseload power con-sumption. For example, those two examples may well cut consumption by 6 amps and 4 amps respectively, or 1.0 to 1.5 Kw.
“It’s the peaks…”
In addition to reducing the overall quantum of energy consumption, it is important to consider the use patterns and remember that infrastructure is usually designed with peak demand in mind – or at least as it is understood at the planning stages.
When it comes to electrical supply, the challenge is exactly the same as in so many other aspects of our field – the increasingly compressed nature of our processing. For example, a small winery may find itself drawing no more than 40 amps for most of the year but struggle to keep the draw below its maximum capacity of 100 amps during vintage. In addition to pushing the capacity of the board, some of the components of the costs of electricity supply relate to peak draw within a particular period – no matter how short that may be.
For these reasons, it is prudent to consider ways to manage these peaks which usually relate to start-up current draw of electrical motors and boils down to two key points: trimming peak load (per motor) and offsetting them from one another.
Many electrical motors found in the wine business, whether they be on irrigation pumps, air compressors, refrigeration compressors, must pumps or anything else, use Direct On Line (DOL) starters which tend to draw very high current at start-up. Another more expensive but increasingly popular method is the use of Variable Speed Drive (VSD) or ‘soft starters’ which can minimise it. Fig. 3 is a sketch of the two different types, showing start-up current draws typical of some winery equipment.
Fig. 4, while a little crude, illustrates the potential problem for a winery with a board capacity of, say, 100 amps if several DOL motors were to start up at the same time.
With this in mind, it is easy to see the potential value of integrated management systems which can ensure these peaks do not occur at the same time and the capacity of the site is not breached, leading to tripped circuit breakers or blown fuses.
Radio telemetry may sound exotic but it is a simple mechanism by which start-ups of motors can be staggered with the equipment readily available and affordable. Further-more, it is easy to set simple rules around a hierarchy of equipment where a must pump will take priority over the start-up of an air compressor for example. Much better to push the compressor back by a few seconds to avoid fruit spilling onto the floor!
Batteries and solar
There has been no shortage of media coverage about energy storage through the next generation of batteries. While it may be imprudent to hold one’s breath until a battery plant is able to supply a capital city during a blackout, it is certainly the case that some wineries (and breweries) are already operating perfectly successfully using industrial battery storage.
Despite some exciting signs of the future potential of lithium-air batteries (possibly 4 times the capacity), the ‘here and now’ reality is lithium-ion. Even though their efficiency has been difficult to improve, there have still been phenomenal commercial gains in recent years with costs (per kW of storage) being approximately 10% of that of 5 years ago and good improvements in production efficiency – witness Tesla’s ‘Gigafactories’, for example.
We are now at the point where solar and batteries are a key part of the energy mix at more commercial wineries around the world (if not the entire supply) and this shows no signs of slowing down. While some sites may remain restricted by their roof area for solar panels, the frustra-tions with power outages and cost increases show no realistic sign of slowing either.
Another, probably less familiar, example of how batteries can be used is a system which can be very helpful in remote areas or to tem-porarily supplement supply called a Remote Area Power System (RAPS). With systems such as these (Fig. 4), the batteries are supplied by solar panels but supplemented with a diesel generator as required. With the batteries acting as a buffer, the generators need only operate when required and only in their most efficient range of RPM which can yield reductions in diesel consumption of over 60%.
When it comes to solar power, the improve-ments in performance and price have been astonishing making it a much more realistic option to supplement supply or take over entirely. In the last three years, efficiency (yield per m2) has improved 25% alone, while prices continue to halve approximately every 10 years.
The technology is now at the point where batteries and solar are a genuine part of suite of energy options for modern wineries, worthy of careful consideration to improve the profitability of the businesses. They are certainly not expensive indulgences for the vanity of eco warriors.
Why pay more?
While not actually a method for improving energy efficiency, Power Factor Correction (PFC) is one which can help busi-nesses reduce their electricity bills for essen-tially the same production capacity.
Remembering that this is a piece by a winemaker for winemakers and not electrical engineers, PFC is frankly a little beyond your correspondent to explain in sufficient technical detail but it is the management implications that are most important. One simple way to think of it is as the difference between ‘real’ power (that which the site uses) and ‘apparent’ power (that which the site pays for). Therefore, the lower the Power Factor (PF), the more one pays for the same energy.
As a guide to its significance, it is perfectly possible that a winery with a poor PF could be paying per more for its electricity than it should. An experienced electrical firm can take the necessary measurements and direct the business towards the best set of equipment to improve it.
In modern manufacturing there are certainly some impressive and sophisticated process control systems available. At the elite level is a control system architecture known as SCADA (Supervisory Control and Data Acquisition) in which components such as sensors, telemetry systems, contactors are networked.
Applied to a winery environment, a SCADA system would be able to, for example, use weather forecasts of an upcoming hot spell to pre-emptively lower the temperature of a barrel store, warehouse or brine temperature. They could also manage peak demands by shifting non-critical activities to lower use periods such as pumping extra air into effluent system tanks or perhaps doing so when solar energy supply was abundant.
For most wineries in the UK however, systems such as these are currently not realistic, being too expensive, complex and/or difficult to manage. That said, it is worth remembering that 15 years ago, that is exactly how many people would have described solar panels and battery systems.
What gets measured gets managed
With so many options and jargon and with management teams still under so much pressure, it is understandable that one might be left wondering where to start. In that regard, the best place to begin is with an energy audit. There are many experienced specialists who are able to measure and quantify the energy use patterns around a site so that improvement efforts can be focussed where they will make the most difference. Without it, most of us would just be guessing.
Having a robust estimate of how much heat enters a warehouse or barrel store on a hot day through poor insulation, seals and leaving doors open will make it much easier to justify spending, say, $50,000 on maintenance and automatic doors.
This article is based on a paper published in the January-February 2018 issue of the Australian publication Wine & Viticulture Journal. Mark O’Callaghan is Senior Consultant and Director of Wine Network Consulting based in Victoria, Australia. He works with vineyards and wineries in Australia, in China and recently in England. Email: email@example.com Web: www.winenet.com.au
Mark O’Callaghan is Managing Director of Wine Network Consulting. Based in the Yarra Valley, but working on projects around Australia, the UK and China, Mark is a regular contributor to various wine industry bodies and wine show judge. The views expressed here are his own.