SmokeyGeoJul 12, 2023
@drifthood @chrisnelder @TransitionShow @supernovae my recollection was, he gave local solar considerable value over utility scale due to "flexibility," but without attributing significant costs for the flexibility (eg costs of storage)
Show threadSmokeyGeoJul 12, 2023

@drifthood @chrisnelder @TransitionShow @supernovae just looked at one of their reports again: https://www.vibrantcleanenergy.com/wp-content/uploads/2020/12/WhyDERs_TR_Final.pdf

Chart 4.10 shows their cost assumptions. For distribution solar and especially, storage, the numbers quoted are grossly low- no wonder using #'s like this he obtains cost for distributed solar < utility scale. He's just not grappling with reality here but needs to go talk to developers what real costs are- not NREL or academics

Show threadChris Nelder šŸ¤˜Jul 12, 2023
@smokeygeo @drifthood @TransitionShow @supernovae Iā€™m sure @drchrisclack can explain where the cost figures come from.
Show threadDr Chris ClackJul 12, 2023
@chrisnelder @smokeygeo @drifthood @TransitionShow @supernovae the costs were from Developers views from NREL numbers. The costs are much higher (installed costs) than utility by 2-3x. So not low at all.
Show threadDr Chris ClackJul 12, 2023
@chrisnelder @smokeygeo @drifthood @TransitionShow @supernovae To be additionally clear. We had Costa for distributed solar & storage split to residential and commercial/industrial. There was additional interconnection costs as well. AND the connection to the utility grids as well. All co-optimised.
Show threadSmokeyGeoJul 12, 2023

@drchrisclack @chrisnelder @drifthood @TransitionShow @supernovae

database of actual distributed solar costs is available on the link to "Solar PV Systems in MA" here: https://goclean.masscec.com/article/solar-costs-and-performance/

Solar Costs and Performance - Massachusetts Clean Energy Center

Massachusetts Clean Energy Center
Show threadDr Chris Clack
@smokeygeo @chrisnelder @drifthood @TransitionShow @supernovae yes, and match ours very nicely. Since our costs are in $/kWdc. Before interconnection to the grid.
Jul 12, 2023 at 4:42pmWeb
Show threadDr Chris ClackJul 12, 2023
@smokeygeo @chrisnelder @drifthood @TransitionShow @supernovae since we also have regional cost multipliers for each state as well, which pushes costs higher even more.
Show threadSmokeyGeoJul 12, 2023
@drchrisclack @chrisnelder @drifthood @TransitionShow @supernovae I think the issue is by 2028 the cost projections for distributed solar drop off like a rock, if I am not missing anything... the storage costs quoted there are puzzling- perhaps cell only costs (around $150/kwh). It's practically against all laws of physics and engineering to say distributed solar costs less than utility scale, where there are huge economies of scale in construction, procurement and permitting. What am I missing??
Show threadDr Chris ClackJul 12, 2023
@smokeygeo @chrisnelder @drifthood @TransitionShow @supernovae because what you are quoting is not true. Thatā€™s the issue. Solar and storage in the model are NEVER less than utility scale. So, I donā€™t understand your points.
Show threadDr Chris ClackJul 12, 2023
@smokeygeo @chrisnelder @drifthood @TransitionShow @supernovae solar and storage in the distribution grid lowers the cost for all customers. It allows more utility scale and reduces over building as well. In addition it adds resiliency.
Show threadChris Nelder šŸ¤˜Jul 12, 2023
@smokeygeo @drifthood @TransitionShow @supernovae I suspect you are still missing the original point that I was making. You are still looking at what a developer's costs might be. The point is that the full system costs--a superset of the developer costs--can make local solar cheaper (i.e., to society) because of co-optimization, as @drchrisclack's model shows.
Show threadSmokeyGeoJul 13, 2023

@chrisnelder @drifthood @TransitionShow @supernovae @drchrisclack the developer's costs include the transmission, thus inclusive of the full system costs (with proposals some places to make developers responsible for ancillary services costs).

Looking at Clack's cost assumptions for generation- they are 1. low for PV (developers say $1-1.50/W for utility scale, and $2.50 for the cheapest large scale rooftop; Massachusetts shows an average of $3.80/W across distributed < 30kW); 2. a narrowing cost differential between utility scale & distributed that's hard to believe- with only a 25% premium for distributed past 2030. The time and effort getting permits for a 6 kw project, design & engineering, signoff from the utility... I've worked on a couple of these and don't see how distributed could ever come close but if there is a specific roadmap with feasible milestones would like to look at

Show threadDr Chris ClackJul 13, 2023
@smokeygeo @chrisnelder @drifthood @TransitionShow @supernovae You are making a straw man. This will be my last response. These costs are 1. DC, 2. Donā€™t inc interconnection, 3. Donā€™t inc our regional multipliers, 4. Donā€™t inc ITC (or PTC), 5. We see a closing in cost over time, 5. We did not split different distributed in the images (C&I vs R). I have stated all this before, but you ignore. Most important, w/ higher cost still saves system money!
Show threadSmokeyGeoJul 13, 2023
@chrisnelder @drifthood @TransitionShow @supernovae @drchrisclack and Clack's assumptions showing storage costs dropping like a rock- I've been working on storage 10 years and the cost has only budged a little. Supply chain issues have pushed utility scale costs over $400/kwh for now, with smaller projects (1-2MWh) in the $500-600/kwh range. Sure, $100/kwh has been the storage nirvana target for a long time. In the meantime, distribution companies are not excited about heavily subsidized rooftop solar lowering their system demands because their substation equipment is not setup for low or reverse flows, where costly upgrades would be needed to fix. Taking power delivery at a 115kV substation is easier than dealing with the issues and is certainly not higher cost. I just don't understand charts like this. But yes, if storage costs get that low then I can see how distributed solar could complement utility scale renewable generation by relieving congestion during peak demand times. The headline here would be showing storage costs could ever get this low.
Show threadDr Chris ClackJul 13, 2023
@smokeygeo @chrisnelder @drifthood @TransitionShow @supernovae Final response. The cost of storage is 2 components. BOTH power & energy. Costs have actually come down a lot. But more in cells than inverters. these plots are for utility-scale. DistrD is more expensive! Moreover, the arguments you have all donā€™t hold because even if costs are lower than you ā€œbelieveā€ the distr ones R much more expensive for both solar & storage. Yet saves system costs!
Show threadSmokeyGeoJul 13, 2023

@drchrisclack @chrisnelder @drifthood @TransitionShow @supernovae
you are right that storage has power & energy cost components- it's helpful to reference for example costs/kwh in terms of a 4-hr duration resource. I'm not as sure costs have come down a lot. 10 years ago a couple famous (now bankrupt) startups were quoting at $400/kwh for a 4-hr system but it's still in that ballpark (they had to work hard to get the costs down to $400/kwh).
A good public source is PNNL in the unlikely case you haven't already seen it: https://www.pnnl.gov/ESGC-cost-performance
they seem reasonable for pre-supply-chain issue #'s.

At $100/kwh it makes sense to use local storage to peak shave the transmission system but peak shaving is uneconomical at costs anything close to $400/kwh unless you have dependably frequent $3000/MWh power market spikes (ERCOT). I still don't understand how developers there get financing even if their financial models are OK

Energy Storage Cost and Performance Database | PNNL

Show threadDr Chris ClackJul 13, 2023
@smokeygeo @chrisnelder @drifthood @TransitionShow @supernovae we have also modeled this a LOT with many different costs for solar, storage and other technologies and it all still holds true!