Tag Archives: grid

Getting to a Zero Carbon Grid


Price vs. Value



 Sources of Energy



However, in the Flexible base camp, we are not. Today that’s being provided by Natural Gas and Coal plants, and some aging Nuclear that’s struggling to compete with so much cheap Natural Gas on the market.

How the mix changes under different limits



Crank down the emissions limit and you get more solar / wind, but you get a lot of curtailment. This is a 70% renewable grid. It’s also got a ton of over build to deal with the curtailment.



Which is the share of renewables goes down. They are used more efficiently, there is less curtailment. These are “cost optimal” projections with emissions targets fixed. They represent the cheapest way to get to a goal.

The important take away is that we’re in this very interesting point in our grid evolution where cheap Natural Gas is driving other zero carbon sources out of business because we aren’t pricing Carbon (either through caps or direct fees). A 40 – 60% renewables grid can definitely emerge naturally in this market, but you are left with a lot of entrenched Natural Gas. Taking that last bit off the board with renewables is really expensive, which means taking that path is unlikely.

But 100% Renewables?




Storage Reality Check

The Jacobson study (and others) make some assumptions about season storage of electricity of 12 – 14 weeks of storage. What does that look like? Pumped hydro is currently the largest capacity, and most efficient way to store energy. Basically you pump water behind a dam when you have extra / cheap energy, then you release it back through the hydro facility when you need it. It’s really straight forward tech, and we have some on our grid already. But scale matters.



Pumped hydro storage is great, where the geography supports it. But the number of those places is small, and it’s hard to see their build out increasing dramatically over time.

Does it have to be Nuclear?

No. All through Jenkins presentation Nuclear was a stand in for any zero carbon flexible base power source. It’s just the only one we have working at scale right now. There other other potential technologies including burning fossil fuels but with carbon capture and storage, as well as engineered geothermal.

Engineered Geothermal was something new to me. Geothermal electricity generation today is very geographically limited you need to find a place where you have a geologic hot spot, and an underground water reserve, that’s turning that into steam you can run through generators. It’s pretty rare in the US. Iceland gets about 25% of it’s power this way, but it has pretty unique geology.

However, the fracking technology that created the natural gas boom openned a door here. You can pump water down 2 miles into the earth and artificially create conditions to produce steam and harvest it. It does come with the same increase in seismic activity that we’ve seen in fracking, but there are thoughts on mitigation.

It’s all trade offs


In the North East we actually have a ton of existing zero carbon energy available in Hydro Quebec, that’s trapped behind not having enough transmission capacity. Massachusetts just attempted to move forward with the Norther Pass Transmission project to replace shutting the Pilgrim Nuclear facility, but New Hampshire approval board unanimously voted against it.

Vermont’s shutdown of their Yankee Nuclear plant in 2014 caused a 2.9% increase in CO2 in the New England ISO region, as the power was replaced by natural gas. That’s the wrong direction for us to be headed.



Final Thoughts

