### Give Carbon a Seat at the Table

By: Chandu Visweswariah

*[Editor’s note: This is the third in a series of articles about Electric Vehicles marking Croton100’s observation of National Drive Electric Week, September 26 to October 4, 2020.]*

We live in a topsy-turvy world. Increasingly, from world affairs to local matters, we put the cart before the horse, opinion is more important than fact, echo chambers serve as the universe of information, and our priorities are jumbled and unclear. I wrote recently about a profound change that we can bring about by maximizing our quality of life instead of wealth, and described subtle shifts necessary to turn vicious cycles into virtuous cycles.

When we make choices, we usually have “must haves” and “nice to haves.” For example, my budget for a new car may be $20,000, so an affordable car is a “must have.” A fast car or a car with plenty of cargo space may be in the “nice to have” category. For far too long, carbon reduction has barely been in the “nice to have” category and concomitantly gets second shrift, if not third in decision making! How do we turn this around in a topsy-turvy world and make low carbon solutions “must haves” in our decision-making? How do we make sure to give carbon a seat at the table in all decision-making? Do we have to appeal to an alternate universe to make progress?

As a side note, an honest assessment reveals that low-carbon solutions are not even in the “nice to have” category. The world continues to increase total CO2emissions – we have not yet been able to flatten the curve, let alone get it to bend.

We all understand the imperative of achieving net zero by 2040 – perhaps the biggest challenge mankind has ever faced. We have all seen simulations of various “pathways,” whereby we postulate a certain rate and pace of decarbonization in the next 20 years, and plot global warming as well as various environmental risks to judge the effectiveness of the proposed pathways. Wouldn’t it be nice if in this topsy-turvy world we could *run time backwards*? In other words, start with the desired result of net zero by 2040 and work backwards to understand what we should do and how to sequence our actions? This ability to run time backwards would illustrate to us in a stark and unflinching manner the urgency of necessary actions *today*. In fact, running time backwards gives new perspective on the notion of a “countdown” – a countdown to environmental disaster if we don’t take drastic action now.

All this talk of a topsy-turvy world and turning “nice to haves” into “must haves” and running time backwards has analogies in applied mathematics. If the mere mention of mathematics has you balking or blanching, feel free to skip forward to ******* below (near the “Drawdown” book cover), and you will arrive at the same conclusion. For the rest of you, hang with me on this mini-mathematical romp for just a little while.

All optimization problems have *hard constraints* (the “must haves”) and *objective functions* (the “nice to haves”) which are minimized or maximized subject to the constraints. Optimization theory postulates a *dual *to every optimization problem in which the original constraint becomes an objective function, and the original objective function becomes a constraint. But what purpose does this dual problem solve? It turns out that solving the dual problem is equivalent to solving the original or *primal *problem, so we have a win if solving the dual problem is easier. But the dual serves more purposes than that: it allows us to measure the quality of any given solution (by a quantity called the *duality gap*) and most important, allows us to understand the *sensitivities *associated with the problem – i.e., if I could relax a constraint, how much better of an answer can I obtain. More on that in a minute.

Another applied mathematics concept is that of adjoints. Adjoints propose an alternate universe that makes the head spin like a devilish dervish! Every system (such as a mechanical or electrical system) has an adjoint in which *time and control are reversed*. A personal aside: my graduate advisor was one of the foremost proponents of adjoints in electronic circuits and systems, and I spent over a decade working on adjoints till I could instinctually feel them in my bones.

I took great solace from Einstein’s, “Do not worry about your difficulties in Mathematics, I can assure you mine are still greater” and “Since the mathematicians have invaded the theory of relativity, I do not understand it myself anymore.” End of aside. It is clear that the mathematicians will not be outdone when it comes to topsy-turviness!

In an adjoint system, not only does time run backwards, but control is reversed – if the switch controls the bulb in real life, the bulb controls the switch in an adjoint system. Let’s apply this to our need to reduce carbon emissions: instead of carbon emissions being an uncontrolled outcome, it becomes a hard constraint and controls the choices that we make – which we can only fully fathom by running time backwards from the required result of net zero in 2040.

The main point of both dual and adjoint systems is to give us insight on the original or primal system, and this insight is in the form of sensitivity. If I change a certain parameter, how does the system change? If I budge a certain constraint (e.g., by increasing my car-buying budget), how does the optimal solution change?

******* Here’s a summary of the mathematical detour: in mathematics, it is easy to propose alternate universes with nice properties that give us the insights we need to achieve our goals. With that little mathematical detour behind us, what matters is a way of deciding how best to give carbon a seat at the table. In other words, where is the biggest decarbonization bang for the buck? Project Drawdown and the Drawdown book tell us which climate solutions are the most economically efficient.

Marginal Abatement Cost Curves(MACCs) give us a nice way to visualize the true cost of carbon abatement. Negative MACC values remind us that most decarbonization steps pay for themselves and then some!

The bottom line is that many of us in Croton on Hudson and New York State have already conquered the “lowest hanging fruit,” that of electricity, by switching to efficient bulbs and appliances, and by relying on renewable electricity by means of Community Choice Aggregation, Community Solar or our own solar panels.

At this time, the next biggest bang for the buck is transportation, which accounts for about 35% of greenhouse gases in our area! Which brings us to why Drive Electric Week (DEW) is so important. DEW is a nationwide call to action for adjoint thinking.

My previous blog explained the benefits of buying an Electric Vehicle (EV). The main point of this blog is that the biggest bang for the buck in lowering carbon emissions right now is in cleaning up our transportation system. A horse-drawn cart is an anachronism in the modern world. Leaving carbon emission considerations to the back end of the calculus during optimal vehicle purchase decisions must also become a thing of the past. You can apply adjoint thinking by learning about available electric vehicle choices at NYSERDA’s clean rebate program. Let’s keep our heads straight in this topsy-turvy world and promise to give carbon a seat at the table in all future vehicle purchase and leasing decisions – an alternate universe with attractive properties is not so difficult to achieve!