Is it Time for Grass Heat in the Keystone State?

Introduction

When Pennsylvanians think of biomass heat, the most common fuel that comes to mind is wood. And that's understandable, given that the state has large reserves of forest and there is a need for wood markets to support thinning, species management, and other timber stand improvement activities. Pennsylvanians regularly use cordwood in woodstoves and outdoor wood boilers to heat homes and small businesses, wood pellets in purpose-built pellet boilers to supplement winter heating in homes, and wood chips by the truckload to heat schools and businesses at many locations in the state.

While wood may be quite suitable as a renewable heat source in general, it may not always be the most appropriate option. This article explores the successful use of switchgrass fuel in our southern "nearly neighbor" of Virginia, and the potential for grass heat to be an option for supplying renewable heat in Pennsylvania as well.

Success to the South

I recently chatted with Roger Cushwa of CRC Biofuel Solutions of America to learn more about the biomass plant at the Piedmont Geriatric Hospital in Burkeville, Virginia. They have been utilizing a grass-fired heating plant year-round since 2017, successfully producing upwards of 50 million pounds of steam per year. The steam is used for heating, hot water, and other processes at the hospital. Roger has worked as a boiler mechanic and then operator at the plant, learning about the system from the ground up. Biomass is a bit of a family love for the Cushwas, as Roger's dad worked at the Piedmont facility since its early days of using switchgrass, and his daughter founded CRC Biofuel Solutions of America, the consulting firm where Roger now works.

History of the Operation

The hospital originally moved from using coal to burning sawdust as their fuel, but had difficulty obtaining reliable supply and good performance in their boilers. While sawdust can have great availability when the wood products industry is booming, it can be a real challenge to find affordable material when the mills are quiet. The hospital needed a more steady source of fuel, so they "made the switch" to switchgrass, and found it fully capable of meeting their needs for steam heat (Figure 1).

Figure 1. Monthly Steam Production at Piedmont Hospital from 2014 to 2023. 2014-17 includes switchgrass test burns, while 2017-present is 100% Switchgrass.

Changing to another solid fuel like switchgrass was expected to be pretty straightforward. However, the folks were in for a bit of a surprise, as they found out just how different biomass could be. "It took a while to get things working," says Cushwa. But their persistence paid off, and after several test burns and a lot of tweaking, they arrived at a system that works consistently and effectively. In Pennsylvania, some attempts have been made to use grasses as a renewable heating fuel, but the approach has yet to catch on.

Positive Impacts

One of the benefits of switchgrass as a fuel is related to public health, which is important for all businesses and institutions, but especially hospitals. Switchgrass fuel does not have either sulfur or mercury, which are both contaminants found in coal. As a result, switchgrass boilers have no emissions of those harmful pollutants. Ecological benefits are also significant, as switchgrass is a native prairie grass widely known for its soil benefits, water benefits, and wildlife habitat. Its extensive root system also has the potential to sequester large amounts of carbon in the soil. They estimate that the switchgrass fields supplying Piedmont Hospital are sequestering over 3,000 tons of carbon per year into the soil, and the boiler is avoiding the emissions of a similar amount of CO2 to the atmosphere by using switchgrass instead of fossil fuel.

Hospital officials also like the annual nature of the switchgrass crop (as opposed to forests, which can have a 40-80 year growth cycle in the Northeast US), and they appreciate the noticeable positive impact they are having on the local farm economy by buying their switchgrass from nearby land owners. And while it's hard to factor aesthetics into an economic analysis, there is no denying that switchgrass is an attractive component of a rural landscape. Further afield, coal-fired power plants may be interested in utilizing switchgrass as a co-fired fuel as a way of improving their carbon footprint.

Making It Work Well

Reliable feedstock supply is an important component for a biomass facility like this, and Cushwa is convinced that they have developed the ideal approach, where a single grower-contractor provides long term rental payments to landowners, plants, grows, harvests, and delivers the switchgrass fuel to the hospital boiler plant.

Once the fuel arrives at the plant, there are several steps in the process that need to be followed to ensure good performance, including proper treatment of the fuel and proper tuning of the boiler. In the past, some facilities have tried to run their boilers with switchgrass as if they were still burning wood or coal, and that just doesn't work well. Silicate deposits, known as "slagging" and "fouling", are a particular concern for a fuel like switchgrass, and while there are several ways to address the issue, Roger is convinced that their approach of careful fuel handling and innovative boiler management is the key. "You can't burn grass like you burn wood" says Cushwa. "It's a matter of training. If you don't know how to use it, it is problematic". The reverse, they have found, is also true, that if you know how to use it, switchgrass can be a reliable, high performance fuel.

Replicating Success?

After working with the system for a number of years and seeing how well it was meeting the needs at Piedmont Hospital, Cushwa started to wonder "why isn't this being done all over?" His conclusion has been that it's largely a matter of lack of experience and expertise. With that in mind, he now provides consulting support to companies that are interested in switching to a grass-based boiler system for their building or factory. "Essentially, we shorten the learning curve for people".

Is switchgrass the right fuel for every large building and industrial operation? Certainly not. Wood will always be an attractive option in regions where forest resources are plentiful, and the ease of use for fossil fuels like Natural Gas is a big temptation in regions where supply is available. However, there are probably quite a few locations where grass-fired boilers would be a preferred option if people knew about the possibility and had access to the skills and know-how that is required.

Could grass-fired boilers catch on in Pennsylvania? We already have a fair amount of switchgrass that is grown in the state, and groups like the Association of Warm Season Grass Producers (AWSGP) are working to promote its use. Expanded production of switchgrass could have big benefits for the state's waterways, including the longsuffering Chesapeake Bay watershed. And the example of long-term success in Virginia certainly provides a blueprint for making these systems work. As government incentives for low-carbon and negative-carbon economies continue to grow, it may well be that switchgrass boilers will start "sprouting up" in the Keystone State and beyond.