The Pathway to Larger-Scale Solar in MN
Community Benefits and Distributed Solar (Part 4)
Author: Ralph Jacobson
DG Solar is a nimbler non-wires alternative
A recent article in the New York Times documents the organized public opposition to utility-scale solar farms in upstate and western New York. That state has created some very effective incentives to attract big solar development, but there is no agreement among the public about how much solar is too much, and which landscapes are right for big solar arrays in the first place. This is a hard fight that’s heating up, not just about what we value besides money and property rights, but who has a voice in those decisions.
We have seen similar fights in Minnesota about wind farms, and it won’t be too long before bigger solar is caught up in the fray. Several counties, townships, and cities have declared moratoria on any further permitting of the one-megawatt sized CSG, which occupies a ten-acre parcel of land. What kind of opposition will arise when the locals are asked to approve solar arrays which occupy several square miles of nearby land? Public attitudes toward larger-scale solar are driven by unrealistic expectations due to seeing miniaturization in most electronics. Unfortunately, the solar resource is extensive: if you want ten times more solar power, you have to deploy ten times more area in solar.
As we shape the market for bigger solar arrays, we would do well to position DG solar as a smaller and nimbler alternative to the truly utility-scale solar. When sited to provide multiple local benefits, as discussed below, it can be more acceptable to locals and require a shorter development timeline. DG solar can play a key role as a non-wire alternative (NWA) to help minimize the overbuilding of distribution infrastructure.
Sacrificing System Efficiency for Economics of Scale
In a 2005 article, “Critical Thinking About Energy: the case for decentralized generation of electricity,” Thomas R. Casten and Brennan Downes show that electric power industry efficiency peaked at about 65% back in 1910, and decreased to 33% by 1960, where it has remained. The drive to lower the cost per megawatt of generation, by building bigger plants to harness the economies of scale, did not result in greater efficiency. Quite the opposite: in 1910, plants were much smaller and located near thermal loads which could utilize the “waste” heat as combined heat and power (CHP). By 1960, large coal-plants were situated nearer to coal fields and further from cities, and the heat was devalued and wasted as an acceptable loss.
Keeping city air cleaner and economies of scale were valid reasons for building coal plants far from population centers and their loads. Following that trend, utility-scale solar is far from loads, as we see the largest solar plants built in desert areas. As mentioned above, ground-mounted arrays do take up a significant amount of land, and much of that land in Minnesota is considered prime agricultural land. This might be the toughest of a handful of issues to wrestle with in determining how much of the solar build-out should be DG solar and not utility-scale. A more complex web of issues may pull much of the expected deployment closer to towns and cities.
Land use issues
As was true for coal power plants, the further we build large solar arrays from cities and major loads, the more we have to overbuild them to make up for more line losses through the wires. In the US, large power plants must burn up to 15% more fuel to overcome just the transmission line losses. Because DG solar is closer to loads, it is inherently more efficient, and as a bonus its smaller footprint may result in fewer land use battles. Battles over land use can drag on for years and could become a major impediment to the solar contribution toward clean energy targets at 2030 and 2050. It would also make matters easier if we could move away from the single-use approach to land use. There would be more public support for putting solar arrays on prime ag land if the solar could be providing other benefits to a local community, as well.
Don’t boil DG solar down to commodity electrons
There is a false dichotomy underlying the discussion about the economics of utility-scale versus DG solar that must be addressed in order to do serious planning. Anyone who was watching attempts at solar legislation at the Minnesota Legislature in 2019 saw the utility narrative make a stark U-turn from past years. Where previously the claims were that “solar is too expensive, so we shouldn’t be spending money on it” the message morphed into “utility-scale solar is so much cheaper, why do anything else?” As we saw in the last century around ever-bigger coal plants, that argument works if the only consideration is the cost of generating a flow of electrons, and other multiple benefits are cast aside as having little value. But little value to whom, as we consider it in the context of land use?
Aligning solar with multiple community benefits
The methodology for calculating the Value of Solar tariff includes the social cost of carbon, which utilities have balked at including in the rate structure because solar provides a benefit to the broader community, not just their customers. But it may be much more fruitful to consider this in the context of DG solar: to identify a variety of more specific public benefits, creating a pathway to monetizable value not paid by a commodity electron.
This would be similar to the concept of renewable energy certificates, or RECs, which can be separated from the tariff with other funding mechanisms. In recognizing that environmental benefits have a value in allowing prime agricultural land to be used for solar, there is an implicit opportunity to monetize some of that value to help overcome the extra cost of DG solar arrays above utility-scale costs, to help make DG solar financeable. We could also go the other direction and apply disincentives to utility-scale solar to address the loss of opportunity to use solar to meet such public or societal benefits.
Identifying other public benefits
Aware that aggressive solar policies are getting pushback in mature markets like that in upstate New York State, Minneapolis-based Great Plains Institute is organizing a campaign of “Siting Partnerships” to build broad public support for use-cases in which solar arrays that are ground-mounted on agricultural lands would align with an environmental benefit. The campaign will enable the solar industry and the utilities to link arms with municipalities and other stakeholders to create site-specific agreements where deployment of solar arrays on prime agricultural lands can be defended. In each of five use cases identified, the landowner will benefit from payments for the use of their land, this aligns their interests with the solar deployment:
Protection of municipal water supplies
Siting appropriately designed, vegetated solar installations on Drinking Water Management Supply Areas and Wellhead Protection Areas currently under agricultural production.
Siting strategically designed solar arrays in impacted watersheds to serve as infiltration areas or buffer areas to limit non-point pollution.
Solar development designed to maximize ground cover or buffer areas to sequester carbon in the soil. Minnesota farmland has an enormous potential to help reverse the build-up of carbon in the atmosphere by building up black dirt.
Solar development designed to buffer critical habitat core areas and limit opportunities for development that would degrade habitat functions (pollinator-friendly, for example).
Buffer against unchecked urban sprawl
Use solar development to discourage sprawling development patterns, limit infrastructure expansion, and protect areas designated as having rural character.
Utility locational benefit plus community benefits
Although this will not explicitly favor DG solar over utility-scale, the opportunities for both will be quite literally “all over the map,” as communities cultivate local awareness and support. Any community benefits of solar arrays will be location-specific, as determined by the communities themselves. This can augment the work already being done under the Mn PUC Docket #13-867 to identify locations where solar arrays (as non-wires alternatives) could be electrically beneficial to the power distribution system.
DG Solar Plays to the Modernized “Smart Grid”
In the electric power grid of today, power flows in one direction: from remote central station generators to the cities and towns where the loads are; utility-scale solar follows this model. DG Solar, on the other hand, can fit with the network architecture of the modernized grid, where power flows whichever direction is needed on the wires from local generation points to provide power for loads in the area. Every device will have an IP address identifier for communication and balance of power flows around the network. In this context, DG solar is considered as a distributed energy resource (DER), along with demand response, energy storage, efficiency measures and other non-wires upgrades to the electric power system.
Are we trying to pack too much into a DG solar tariff?
Larger-scale solar will have fewer non-utility players: contract guidelines may be more useful than tariffs. A tariff is a standardized contract, approved by the Public Utilities Commission for offer to the general public. Under net metering and CSGs, potential users of the tariff are mostly utility customers who wish to self-generate or subscribe to a CSG; they may number in the hundreds of thousands.
However, DG solar developers will likely number in the dozens and will be working in a more complex market. While selling energy or through a PPA, the system owner might simultaneously be aggregating multiple solar and storage installations to participate in the wholesale power market, or be selling community benefits. This means that contracts must be useful to several participating entities and dovetail with other transactions which may be involved in making a financing scheme viable, and a tariff need only represent one piece of the cash flow.
Where there are specific locational or functional benefits, or other income streams involved, the particular benefit or function may determine location, contract terms and conditions, and even which utility will be involved.
The 4th market bucket of DG solar in 2050
By 2050, as little as 10% and as much as 60% of total solar deployment in Minnesota could be in that 4th market bucket. How much DG solar actually is deployed will depend heavily on how we go about shaping the market for it. Because locational and community environmental benefits will play key roles in making DG solar financeable, much of the opportunity is across the state in municipal and cooperative utility service territories. And we will need the support of utilities and municipalities to deploy bigger solar arrays on prime ag land.
The “tried and true” strategy of asking the legislature and/or the regulators to make the utilities pay higher tariff rates for DG solar, will only reach the investor-owned utilities, and they will fight that. This will only get us a little past that 10% mark. To reach the lightly regulated coops and munis, and gain their support for a larger statewide market, we must limit how much we try to pack into DG tariffs. More effort must then be put into creating linkages with capital sources to monetize environmental benefits and unlocking the market for grid benefits with the addition of energy storage to the electric power system.
– Ralph Jacobson, July 2020
Next: Energy Storage Will Enable Higher Solar Deployment