Re-printed from The Bridge
by Anne Watson, city council member
How much money is in your checking account right now? I bet you have at least some idea of that number. What if we planned and managed our energy needs like we manage our money? How might that change our decisions or investments? Well, an early step toward managing an energy “budget” is to know what we’re spending. Where, when, and how do we consume energy, and how much of it is clean and renewable? You may have heard of Montpelier’s city goal to be a net-zero energy community. Simply put, a net-zero energy community is a community that has greatly reduced energy needs through efficiency gains, such that the total amount of energy required for vehicles, thermal processes (heating and cooling) and electricity within the community is met by renewable energy.
Recently the Montpelier Energy Advisory Committee set out to determine the energy demand of the facilities and operations of the Montpelier city government. How close are we to our net-zero energy goal? The following graphs are from the report delivered to the city.
I tell my physics students that graphs are stories, and these graphs tell the story of our city government’s energy history. There’s a lot of data in this chart, so let me outline some of the highlights, some of the stories hidden in these numbers.
More than half of our municipal energy consumption is to satisfy our thermal demands. This was surprising to me, because for most households, this chart is typically split into thirds, with transportation taking up more of the pie. But then, the city is not a household, and they have more buildings than vehicles.
What building or facility uses the most energy? For the electrical and thermal portions, the single biggest consumer is the wastewater treatment facility. During a recent visit to our facility, I learned that wastewater treatment plants, in general, tend to be incredibly energy-intensive operations. Having said that, our wastewater treatment facility Chief Operator, Bob Fischer, has done an incredible job of reducing electrical and thermal demands while maintaining a high standard of effluent. In fact, since 2008, his team has cut the facility’s energy demand by at least a third, while significantly increasing the volume of wastewater treated. What’s more, the treatment facility now uses some of the methane generated onsite from the anaerobic digestion process to heat the buildings in the winter. Prior to the modifications that Bob’s team initiated, this methane, a potent greenhouse gas, was escaping into the atmosphere.
While the previous graph shows our demand, the next graph shows our production. We’re burning some biogas (methane) at the wastewater treatment facility and wood pellets to heat the senior center. We’ve also already had some photovoltaic solar generation (PV) at the facility and Department of Public Works (DPW). You can see in the bottom rows that our energy efficiency and the percentage of our demand met by renewables have been increasing. We’re headed in the right direction.
Better yet, the percentage of demand met by renewables is likely to jump when we include the FY2015 data. During FY2014, the District Heat project was in a start-up phase and burned oil. It was during FY2015 that District Heat fully came on-line, burning renewable wood chips to heat many buildings downtown. These include City Hall, the police and fire stations and Union Elementary School, all of which will show up on this chart. Additionally, the city and school district are in the process of substantially increasing the percentage of electricity they receive from solar installations (70 percent and 50 percent, respectively). The city’s installation alone will save approximately $50,000 per year.
In the graph below, the brown line shows municipal energy demand over time and the green line shows our energy generation from renewables. As it explains in the middle of the graph, to achieve Net Zero Energy in Municipal Operations and Facilities, we need to get these two lines to meet. This means that investments in energy efficiency and investments in renewable energy both contribute to achieving the city’s goal.
City personnel have started to examine the city’s energy habits, and from the data, it looks like a lot of home and business owners are starting to do the same. According to Efficiency Vermont, more than 10 percent of Montpelier’s residences have been weatherized through their Home Performance program with ENERGY STAR. That’s one of the highest percentages in Vermont.
Solving the net-zero energy puzzle for Montpelier will not be easy, but we’re making progress and saving money. I find these graphs particularly encouraging, and I’m excited to share the updates with you as more data come in. Montpelier still has a long way to go — learning and addressing challenges as they arise. But the good news is that we’re already on our way, and there are significant opportunities for efficiency gains and cost reductions in the short-term and mid-term. While there’s plenty of work ahead, this is a moment to celebrate the good work that’s been done so far — we’ve increased our energy efficiencies, we’ve reduced our emissions, we’re saving money on energy, and the best is yet to come.