Challenges with Renewable Energy and How Biofuels Can Help

By Janelle Christensen, MESM, ORISE Science Communication fellow for the USDA Northwest Climate Hub

Wind turbines over a grassland with livestock
Renewable energy like wind power could help to reduce some of the biggest impacts from climate change. Photo: NRCS Montana.

In the face of climate change, much of the world looks to renewable energy. It offers the promise of preventing some of the worst impacts from climate change while allowing us to continue to live similar to how we do currently. Although we need to change how we live in addition to using renewables, without them, we would need to completely revert to pre-industrial times. However, I can guarantee that as I write this on my laptop in my air-conditioned house at my remote job that that is out of the question. With a power grid that runs off clean energy, the changes and reductions we make in our day-to-day lives have a larger impact. If we choose public transportation over driving, it makes a bigger difference if that train runs off a renewable energy powered grid. If we change to more efficient, long-lasting light bulbs and we use solar to power those bulbs, we are wasting less and not emitting carbon dioxide to power our house. The combination of action and renewables is powerful, but switching to 100% renewable energy has some challenges.

When people think of “renewable” or “clean”, they are likely thinking of wind, solar or hydropower. The issue with any of these options is that they are dependent on natural conditions. As the conceptual Figure 1 highlights, natural energy is variable throughout the day. As the sun reaches its peak midway through the day, the amount of energy generated increases, but it goes away entirely at night. When power use is at a peak in the evening, there is commonly no solar energy being generated locally, and we would rely entirely on wind and hydropower. Both wind and water experience fluctuations, depending on how wind is blowing or water is flowing. But even if the sun is not shining and the wind is not blowing, I still expect my electricity to be reliable. I want my lights to turn on when I flick the switch and my internet to work for my next meeting. So how do we fill in the gap when our energy sources are not as active?

Conceptual figure showing the changes in energy demand and production from renewable sources over a 24 hr period.
Figure 1. A conceptual example of what power use may look like in the Pacific Northwest. The red area is unmet need from renewable resources and the green area is the total of renewables – solar, hydropower, wind and nuclear. This example of renewable energy supplies does not include all types of renewable energy available to the Northwest. It’s also not necessarily reflective of exactly what our power grid looks like, it is just intended to illustrate that with renewables, there may be a deficit. Figure by Janelle Christensen, data is entirely self-generated to be an example. Although not on a daily timescale, these summaries of energy generation for Washington (https://www.eia.gov/state/analysis.php?sid=WA), Oregon (https://www.eia.gov/state/analysis.php?sid=OR), and Idaho (https://www.eia.gov/state/analysis.php?sid=ID) from the U.S. Energy Information Administration help to provide context for what we are currently producing and using in the Northwest.

We can fill this gap in several ways. One option is to store energy during times of low use and release it when there is an unmet demand. Although the example above does not show renewables creating much “excess,” it could be possible in the future. The other option is to install these facilities in places with reliable conditions and then distribute it as electricity throughout the country. For example, hydropower from the Northwest could be used to provide electricity for California at night, and in exchange, California could provide solar power for the Northwest during the day.

Seems easy, right? Unfortunately, we currently do not have the infrastructure or the technology to support large scale energy storage or transfer. Although there are many promising technologies for storage, they are not established enough to support our energy needs. Our systems aren’t well designed for making energy somewhere far away from where it is used, and when energy is transferred long distances, some is lost along the way. This means that we do not have the best resources to make our power grid based 100% on solar, wind, and hydropower. We may in the future, but not yet.

Apples dropping from a chute to the ground
Using uneaten food as energy could help to reduce our reliance on fossil fuels. Photo: USDA.

Another way to fill this gap is by using biofuels. Biofuels are renewable, but they have gotten a bad reputation for not being carbon neutral lately. It is important to be aware though that there are many types of biofuels, and not all biofuels are unsustainable. In the Northwest, sustainable biofuels sources include slash (the tops and branches removed from longs during tree harvest), wood from fuel treatments, agricultural waste, trees grown on marginal agricultural land, and food waste. They are products whose natural decomposition already contributes to carbon emissions and that do not use arable land. Food waste, for example, contributes about 4% of greenhouse gas emissions in the United States. Slash and fuel treatments are often burned in the forest to reduce wildfire risk, releasing carbon in the process. Using these byproducts to create fuel essentially makes energy out of products that would release greenhouse gases anyway. Biofuels can solve two problems at once: preventing waste from contributing useless carbon emissions and reducing fossil fuel use.

Lastly, we could (and do) fill this gap with non-renewables – coal, oil, natural gas and nuclear. For the time being this is still the only reliable option we have. If we wanted to transfer some of that reliance to a less harmful source, certain types of biofuels are a great option. The more we transfer away from fossil fuels, the more we build systems that support other forms of energy, and the less reliant we become on sources of energy with high emissions. We are capable of solving the climate change problem, and finding ways to reduce our use of non-renewable sources will be a crucial piece of the puzzle.