Reid Maynard
The signs of the clean energy transition are all around us, from solar panels popping up on our roofs to electric cars cruising down our streets. Even more transformation is underway out of sight. Up and down supply chains, companies are busy changing how they generate energy, source raw materials, and manufacture products.
But what about the food on our table? The food system accounts for a considerable amount of global emissions, ranging from 21% to 37% depending on how you count everything from land clearing to farm activities to cooking and disposal. Given this sprawling challenge, how can our communities collaborate to reduce the impact of our grocery run?
My research focuses on these sorts of agricultural sustainability questions. I model environmental impacts in a process called life cycle assessment, and I explore how the dynamics of technological change will affect those outcomes. In my current work, I use the example of a sample crop, lettuce, to examine food system transformation from now to 2050. There are many factors affecting farm emissions like soil management and fertilizer use, but today I want to examine on-farm energy impacts. In particular, I am going to consider electrification, a key tool of the energy transition, to see how the environmental impacts of crops can change. With this example, we can consider how technological investments today could deliver ecological and economic benefits for years to come.
Many climate-friendly solutions fall under the motto “electrify everything:” replacing fossil fuels with electricity while transitioning that electricity to clean resources. When you drive an electric car, warm your home with a heat pump, or (sometime soon) sip a New Belgium beer, you’re participating in the electrification transformation. Often, energy efficiency enhances the benefits. For electric motors in particular, the transformation of electricity to motion is highly efficient, while combustion engines are comparatively wasteful with the energy in their fuels.
One easy “electrify everything” step for farms is well underway with electric irrigation pumps. Recent CSU-led research examined this progress and potential at a nationwide level; at the product level, my research shows the same effects. Depending on existing pump types and electrical grids, the on-farm energy-related climate impact of producing lettuce would decrease by 33% in 2050. Like other electrification steps, electric pumps could also save farmers money. They tend to be less expensive than their fossil fuel-driven counterparts, and the efficiency advantage of motors over engines means a lower operating cost. The one caveat, however, may be infrastructure; in remote areas, utilities would need to install connections from the grid to the pump. Thus, the farmer could face a high initial bill for either a traditional connection or off-grid technology like solar panels with batteries. This is a solvable problem, but one that requires upfront investment.
Beyond pumps, the road to electrification gets bumpier. In the lettuce model, the highest energy emissions footprint comes from heavy machinery like tractors. These machines need to haul heavy loads, energize powerful equipment, and operate for long hours. Add onto that the problem of soil compaction from machine weight, which affects important factors like water infiltration and root depth. Soil compaction is already a concern with agricultural machinery, and heavy batteries face the same scrutiny. Future electric tractors would need battery technology advanced enough to balance all of these demands and concerns; small wonder, then, that tractor manufacturers currently plan for battery electrification in lower-power applications while looking to renewable diesel or hybrid approaches for their high-power models.
It’s worth digging into the near-term advantages of renewable diesel to understand the challenges facing electrification. Unlike biodiesel, renewable diesel is a “drop in” fuel that can go directly into machines, so there’s little cultural or logistical change required. It’s already on the market, especially on the West Coast where state and federal incentives boost its competitiveness. The infrastructure exists to produce it, from soybean fields and used cooking oil supplies to converted oil refineries. Electric agricultural machinery does not yet have such ease of use, market presence, or robust supply chains; these would have to be built in the coming years to see a difference in the coming decades. My research thus models renewable diesel making near-term impact, but the impact of electrification will be limited and take place closer to 2050.
How might this limited rollout of battery tractors look? This is not like the simple task of electrifying a personal car. This is more like electrifying semi-trucks, which also face high demands for power, capacity, and payload-weight tradeoffs. Because these barriers are similar, technological progress towards electrifying heavy trucks (like lighter batteries) will also affect electric tractor feasibility. Thus, for this study, I used research that focused on heavy-duty vehicles. Where farm machinery information was not specified, semi-trucks were used as a proxy for electric tractors. Based on adoption scenarios from the National Renewable Energy Laboratory (NREL), only 10% of farm machinery would be electrified by 2050. Even with cleaner grids, this would only reduce the study crop’s on-farm energy carbon footprint by 4%.
But what if we are bold in our electric endeavors and instead get 75% electrified, the “High Adoption” scenario for all heavy-duty vehicles in NREL’s report? In that scenario, we would reduce the lettuce’s on-farm energy emissions by 31% in 2050. And if we’re even bolder with 100% electric machinery, the energy-related impact would be a 41% reduction or higher depending on the local grid.
There’s even a chance this move would save farmers money over the life of the tractor, much like how an electric car is cheaper over its lifespan than a gasoline car. Looking again to the semi-truck comparison, Argonne National Laboratory projects that the total cost of an electric truck — including the big battery — could be lower than that of a diesel truck by 2030 (again, thanks to the operational savings of electric motors over combustion engines). Such technological advancement in tractors could bolster the economics of farms while still meeting the climate challenge.
Think about how the climate impact on our tables could be transformed with the electrification toolbox. Reduce the on-farm energy-related impact of lettuce by over 70%, and then expand that effect to similar items across the grocery list. This sort of future-focused modeling helps us understand the range of possibilities our present-day actions can set in motion. When businesses and governments make major investments in infrastructure and technology, the consequences persist for decades, but a static look at today’s world may give us an incorrect impression of tomorrow. As we invest in this decade, electrification in farming will continue to play a role in the near-term and long-term progress in a greener food supply chain. With the right amount of infrastructure, research, and adoption, electrifying everything could bring a cleaner agricultural future to your dinner table.
About the Author
Reid Maynard is a PhD candidate in the Mechanical Engineering program and a trainee in the InTERFEWS program at Colorado State University. Reid applies life cycle assessment and techno economic assessment to evaluate the sustainability of emerging agricultural systems and technologies.