Geothermal applications in Agriculture, Food & Beverage
Posted on Thursday, May 25th, 2023
Posted on Thursday, May 25th, 2023
One of our favorite sectors is agriculture, food and beverage. While it’s not of the biggest sectors in terms of energy demand, it’s a priority for us for a number of reasons.
The sector is fundamental to our modern society in providing nutrition. Indeed, agriculture was the catalyst for humanity’s growth into complex societies when farmers found that they could use surplus food to trade with others – the foundation of our economic system. Of course, it wasn’t until we discovered how to extract and use dense energy sources like coal, oil and gas that industrialization accelerated.
Now as we appreciate the consequences of unabated combustion of fossil fuels and those resources are depleting and declining in quality, it is imperative to radically transform our energy systems to be lower carbon, less wasteful and to be locally sourced.
The food industry’s need to be “reshored” comes from an understanding that emissions related to food products are as much to do with transport as well energy and land use to grow and process produce. It’s therefore important that new food production processes are designed with land, water and energy efficiency in mind. That’s where geothermal energy and storage comes into the picture for this sector, enabled by heat pumps and other energy efficient systems.
Today’s industrial heat pumps can provide heating and cooling in the full temperature range of -10 ºC to 160 ºC, although the technology is still developing at the higher end. This means that we can serve most if not all of the processes in agriculture, food and beverage with heat pumps, and use local thermal energy sources from the typically most efficient, geothermal through water bodies like lakes and rivers to the least efficient across the seasons, air.
Greenhouse horticulture is an excellent opportunity to apply geothermal heating, cooling and storage. Geothermal heat can be used directly without the use of a heat pump if the subsurface resource is hot enough, but in many if not most case we believe that installing a heat pump system and using the geothermal resource as an energy store between seasons will enable the greatest energy efficiency. The greenhouse is kept closed in the summer and is cooled internally by heat exchangers chilled by the heat pump in reverse mode, with the extracted heat injected into the geothermal battery. In the winter, that heat is recovered for heating the greenhouse so temperature is maintained and only electricity is used to power the system.
Most of food processing is currently done with fossil fuels. Our systems are designed this way because of the past cheapness of gas and oil and lack of awareness of the risks to climate and the environment in general. These combustion-based thermal systems are often very inefficient with higher temperatures being generated than are necessary and much heat wasted to flues, chimney and to the air spaces of the facility. Most if not all of this heating can now be done with heat pumps, although the heat pump efficiency – known as the Coefficient of Performance (COP) – will drop at higher delivery temperatures. However, Causeway is working on technology developments to deliver high temperatures without compromising COP or the cost efficiency of the system.
In our engagement with clients, we often notice that heating is seen as a combustion problem where as cooling is an electrical problem. We see them both as electrification solutions and are always seeing opportunities to hook cooling loads together with heating loads in the same system, thus making it overall more than 20% more efficient.
The same opportunities for fossil-fuel replacement and we have blogged before about how the beer brewing process can be electrified with fossil-fuel heat replaced by geothermal heat pumps. Heating and cooling needs in the manufacture of other beverages from milk through flavoured drinks to wine and spirits can all be done with heat pumps.
The last point to make about our approach to engineering low/zero carbon energy systems in this sector is about taking a holistic energy systems approach and integrating both electrical and thermal energy supply and demand points. For example, in one ongoing assessment we are doing, we have found that if we phase on the onsite making of heat by the heat pump system to nighttime, our client can avail of radically cheaper electricity from the existing grid connection. An alternative approach to be considered in a future phase of that project, or one similar, is to instead have onsite electricity generation. Onsite generation, if fully utilized, can work out much cheaper again and of course if its wind or solar PV will substantially further reduce the carbon footprint of the energy system.
Clients who are interested in our services please hit the button at the top right of the page and get in touch with us for a consultation. We’d love to help.