Is a carbon-neutral city possible? What would a city have to do to achieve the lofty building standards? How much would it have to rely on purchasing renewable energy certificates (RECs) to get there?
To start, let’s clarify some of the green building jargon, by looking at the term “green” itself. Green seems to be lost to irrelevancy. My favorite example of the misuse of the g-word is when a bottled water company 1,600 miles from a continent in the middle of the Pacific Ocean claimed to have a green approach to bottling water, by switching to 100 percent recycled plastic by 2025.
There will never be anything green about a single-use water bottle that is shipped around the globe.
One of the aspirational building terms to catch the attention of the average consumer is zero energy. A zero-energy building essentially would be able to generate enough energy on-site to meet the consumption of the building, resulting in a net of zero energy required from somewhere else, over the course of the year.
Think of a solar street light in the middle of nowhere as a zero-energy example. It uses low energy consumption bulbs, harvests energy on the post and doesn’t rely on a power plant to operate.
Zero energy is achievable. You may know an engineer who has done this type of project already. It doesn’t require some theoretical technology and is happening now. A zero-energy building’s mechanical room could still have a gas boiler, but it may harvest that same kWh of energy from a ton of solar panels on the roof.
Realistically, the total energy harvested and consumed may not equal zero on all individual days, but could balance out over the year. Zero-energy buildings would likely still be connected to a standard electrical grid as backup.
Carbon neutrality of buildings
Carbon neutrality is another new phrase being tossed around. Similar to zero energy, it aims for a zero-balance equation. The difference is that a carbon-neutral building does not burn any fossil fuels on-site. It means no natural gas boilers in the basement. To achieve this, you are realistically looking at electric boilers or resistance heating throughout the building.
Electrification, in this building context, means using noncombustion sources for everything on your property or in your city. To achieve carbon neutrality, you would probably electrify. Essentially, no coal, natural gas, propane or anything resulting in CO2 emissions on-site.
It may also mean that all-electric cars are allowed to go to more places than standard combustion vehicles. As a hypothetical example, the blocks around a walkable historic district would only allow electric buses and electric cars to keep localized products of combustion to a minimum.
If you are a boiler manufacturer, don’t panic, but now’s the time to get a plan in order. There is a lot of momentum for natural gas in the United States, especially in the 99.9 percent of cities that won’t be early adopters of the progressive building standards. Outside major cities, propane or natural gas may be the most realistic backup to renewable energies.
However, if you are reading this magazine, you are a stakeholder in this new trend in a very real way. If you enjoy selling, installing, servicing or manufacturing gas boilers near a major city that might jump on the carbon-neutral bus, I would work on a Plan B this decade.
As a side note, electric resistance heating has been viewed as a bad thing by many environmentalists in the last few decades. Electrification alone doesn’t fix the broader sustainability issues. It also creates new infrastructure voids if the gas is cut off.
Both of the following are true. Electrification alone on the coldest day of the year could cause a brownout a carbon-neutral city. And if building codes are energy-efficient enough, you wouldn’t need as many kWh of energy, so reduced demand could be handled by electric only. There is some realistic middle ground here, and it starts with tight building envelopes and creative building design.
Do you REC?
Theoretically, if the city I live in decided to go carbon neutral next year, it likely wouldn’t have enough solar-ready rooftop space or wind potential to shoulder the whole electrification load. Now, I’m not suggesting that any northern Virginia town is proposing that type of timeline, this is just for the sake of argument.
Realistically, it may mean somewhere in West Virginia they would have to break ground on a new coal plant to keep electric-only buildings warm in my neighborhood. Would it solve a problem or create one? It depends on where you live. The residents of my city wouldn’t inhale much smog; the people downwind of the coal plant in West Virginia might be getting an extra dose instead.
Not every building on your block has enough space on its property for solar, wind, geo or any other clean power to become carbon neutral with current building loads, which are a crucial piece of this equation. Even building owners who decide to spare no expense on renewables and build super-insulated structures might still fall short. This is where renewable energy certificates could come in.
To make the zero-energy math work, many interested parties may or may not do any local renewable energy harvesting, but they could buy RECs from their utility companies, or others. The U.S. Energy Information Administration found that the average house in the United States uses 914 kWh/month of electricity.
The average house could call itself zero energy or even (locally) carbon neutral by buying 914 kWh/month of RECs, while not actually commissioning any new clean energy source or improving their structure. This seems to be well off the energy-efficiency core mission.
A story in Mother Jones dug into the details for one REC example. Author Laura McCandlish explains a conversation she had after moving to Oregon, “For less than an extra $10 a month, my utility, Pacific Power, would supply our home with electricity from wind turbines instead of coal.”
The more she researched, she discovered that Pacific Power only had one wind farm in Oregon at the time. (She wrote the article in 2010; the utility has more wind power now.) Like most utility companies, Pacific Power would then buy RECs from someone else, usually out of the market.
In some cases, wind or solar may make up a tiny fraction of the actual power generated in these distant REC facilities and methane-burning landfills might be what you and the utility company are paying for. With a REC, you are donating to a charity that your utility company is participating in, with the hopes that someone is using clean, renewable power, instead of just shopping around for some gas-based carve-out.
A zero-energy building that is paying for a methane plant on the other side of the country is off mission at this point. The Center for Resource Solutions is a nonprofit that runs the Green-e REC certification program. It isn’t the only certification game in town but has been widely adopted in the United States.
It claims to have “certified [more than] 62 million megawatt-hours in retail transactions in 2018, representing an overall increase of 4 percent compared to 2017 sales. This is the highest number of certified retail MWh to date, and enough to power [more than] half of U.S. households for a month.”
Many green building standards accept these RECs, but are they the same as local, clean energy?
RECs don’t contribute to the local economy the same way a city-specific program to add solar panels to local roofs would. If you incentivize local companies to install the panels, you have a higher demand for a local solar installer base. You also lose less of the money allocated to noninstallation work, such as paperwork between utilities 1,000 miles away.
Another option would be to partner with a group of neighbors and build a solar farm near your city. A solar farm is essentially a commercial-grade solar array that would benefit from the economies of scale, compared to many residential panels on many different roofs.
If I were a city planner, tasked with making a city carbon neutral, I would do these things in this order:
If you have strong feelings about how I have characterized these topics, feel free to write me an email. However, you will be best served to get involved with the plans your local governments are pursuing to make sure your voice is heard.
To read more about this subject, check out these websites: