It’s here! Our new working paper w/ @WildeEcon explores the role of Canadian hydro in deep decarbonization, & shows we can get to zero CO2 faster & at lower cost by *both* deploying renewables in the US & making the most of existing hydro. THREAD.
ceepr.mit.edu/publications/w…
ceepr.mit.edu/publications/w…
@WildeEcon A growing number of Northeastern US states (New England states and New York) is making commitments for zero-carbon electricity by 2040 or 2050. greentechmedia.com/articles/read/… via @JMPyper
In New England we are taking a step back by retiring nuclear.
In New England we are taking a step back by retiring nuclear.
@WildeEcon In 2016 Massachusetts solicited bids for 9.45 TWh of clean energy. Projects to bring Quebec hydro via new transmission won. One died (Northern Pass). The other (NECEC) is being contested by communities along the line. See @JesseJenkins on that here:
@WildeEcon We chose not to address the near term effects of any specific transmission project but instead take a step back and consider the role of Quebec hydro in deep decarbonization. So we model an optimal power system for NE, NY, QC in 2050 under decarbonization goals from 80% to 100%.
We simulate an optimal technology mix and hourly operation of the power system given a number of operational constraints for all 8760 hours of the year, using GenX (hat tip to its developers @JesseJenkins @nsepulvedam).
We asked: 1) what does deep decarbonization in New England (NE), NY, QC look like 2) what effect would new transmission lines to QC have in a low-carbon future; 3) what is the economic impact of additional transmission. There were surprises…
First, cost-optimal deep decarbonization entails expanding wind and solar and phasing out gas. For very deep decarbonization (beyond 90%), synoptic and seasonal renewable intermittency pose a serious challenge. CCS begins to play a role in the optimal technology mix. 
While we initially thought of QC reservoir hydro as a continuous source of cheap power to the U.S. (the way it is used today), we find that in a low-carbon future it will be optimal to use transmission between Quebec and the U.S. for two-way exchange of electricity.
In our simulations, QC imports excess, cheap wind/solar from the US (accumulating more water in its hydro reservoirs) & exports when US renewables are low. In other words, Quebec hydro begins to play the role of virtual energy storage, rather than a continuous generation source.
To give you a sense, QC’s hydro has a huge reservoir storage capacity of 176 TWh (New England’s annual demand is ~120 TWh). The hydro’s power-to-energy ratio (a measure of storage duration) is 400 times that of a typical pumped hydro plant. It is a long-term storage juggernaut.
However, current transmission to QC limits trading. We test what role transmission expansion can play in deep decarbonization by adding 4 GW of lines between NE and QC (also for NY and QC). Adding more transmission facilitates additional balancing from QC hydro.
If QC hydro is a battery for the Northeast, adding transmission effectively raises the rate at which this battery can be charged & discharged. As the chart above shows, new lines result in more trading in both directions. Net imports to NE actually drop in most of our scenarios.
The hourly operation of the system is illustrative of the impacts of new transmission. It increases imports from QC to NE when most needed, increases exports when NE renewables are in surplus, reduces curtailments, and reduces nuclear ramp-downs.
Also illustrative is how the energy stored in hydro reservoirs changes with more transmission, allowing them to fill up when US renewables are abundant and later discharge to help mitigate the long-term mismatch between peak NE demand and low wind output in the summer.
The overall results? New transmission decreases gas and increases renewable generation (as well as nuclear) in U.S. states. The net effects across NE and QC are the same: more renewables, less gas. New transmission helps us integrate more variable renewables.
This effect is driven by the fact we are modeling a renewable-dominant future. In today’s world, more transmission would likely mainly bring more imports from QC. But cost-effective decarbonization entails states build out wind+solar & tap into hydro to help with intermittency.
Adding transmission effectively helps Northeastern states transition to zero carbon electricity faster. In our 80% decarbonization scenario, adding new transmission increases the share that variable renewables contribute to New England demand from 60% to 72%.
Economists categorize products as substitutes & complements. For a while, we in New England have thought of hydro imports as a substitute for local clean energy. But our results suggest QC hydro may be better seen as a complement in a low carbon system. It’s a partnership!
And what about costs you ask? The cost across NE and QC of a zero-emission power system decreases by 17-28% (24% in our “Base Case”) with 4 GW of new transmission. New lines between NY and QC reduce costs in NY-QC by 23% in our Base Case.
New reservoirs can cause vast amounts of biogenic GHG not to mention ecological disruption. Though high GHG rates are the exception (squares in figure are medians), any climate policy that envisions large new hydro dams should be evaluated carefully on a case by case basis.
However, we find that the existing QC hydro capacity is sufficient to provide the balancing benefits we demonstrate. Yet, we do see new hydro in some scenarios where we push wind/solar costs up by more than 40%.
Our paper includes results from various alternative cases (whether states electrify other sectors or pursue renewable-only decarbonization). Across all cases tested, two-way trading between Quebec and Northeastern U.S. provides valuable balancing of intermittent renewables.
Transmission interconnection with similarly hydropower-rich Norway has already helped Denmark get to a ~40% wind energy share. greentechmedia.com/articles/read/…
Scotland is getting in on it too. energyvoice.com/otherenergy/22…
Scotland is getting in on it too. energyvoice.com/otherenergy/22…
Bottom line, it appears to me that for Northeastern states to maintain limited access to Quebec reservoir hydro would amount to pulling our punches in the fight against climate change.
We would love to hear any feedback, particularly as we prepare to submit this work for peer review. Fellow researchers who don't have access to the full paper can feel free to let me know. Make sure to follow co-author @WildeEcon on here too. /fin
@WildeEcon Tagging people who I have chatted with on this and whose expert feedback would be most welcome. @brendanpierpont @noahqk @JesseJenkins @MagnusKorpas @hausfath @ramez @JMGinNYC @mattasheridan @AriPeskoe @jacob_mays @gschivley @nworbmot @danrothenberg @ZeryaiHagos @benbaranrees
@WildeEcon To be clear, this work was not funded by Hydro Quebec or the QC government. The work was not sponsored or directed but supported by general CEEPR funds. CEEPR is consortium-funded by a mix of private and public organizations. ceepr.mit.edu/support/associ…
