The Pathway to Larger-Scale Solar in MN 

How much can the CSG model be scaled up? (Part 3)

Author: Ralph Jacobson

What have we accomplished with the CSG model?

By the end of 2019, about 650 MW of CSGs had been installed and brought online, with another 200 MW under development. For comparison, Xcel is proposing to bring 4,000 MW of solar online by about 2035 and would prefer that most of it not be under the Community Solar Garden (CSG) model. Given that the CSG model appears as a place holder for larger scale solar in the Solar Potential Analysis report, as mentioned in Part 1, we need to consider the issues that exist now in that market segment. 

Then we should ask whether it makes sense to stretch the CSG model into duty for a much bigger role than it was designed for, or do we set a course to develop other models for larger solar? One thing to keep in mind is how much uncertainty attaches to the CSG model, and how likely this is to hinder the flow of capital into vigorous deployment of larger solar in the crucial decade ahead. 

Moving a half-step away from the net-metering paradigm

The CSG model was the first opportunity in Minnesota to develop larger-scale solar. There was no size cap per Garden site, and no overall planning target, until the regulators agreed to end the practice of collocating one-megawatt Gardens, which effectively limited the size to one-megawatt per site. Through this program, the local solar industry, Excel Energy, and the many affected communities have become familiar with the complex of land-use, engineering, financing, permitting, and other issues which pertain to larger-scale solar. We have all gone up a steep collective learning curve!

Although it was intended to be a step away from the “early market” net-metering framework, addressing the issue of cross-subsidization, some aspects of that paradigm have followed into the CSG model for Xcel Energy. First, it creates an open market where solar developers can originate and propose projects, instead of responding only to utility RFPs. As Gardens become more numerous and/or larger, Xcel will experience more uncertainty in its ability to plan for the timing, location, and financing of new generation. 

Second, the regulators set subscriber rates close to retail-level, using the Value of Solar (VOS) tariff for the first time in the state, as set forth in the 2013 Minnesota Solar Jobs Act, to enable the financing of one megawatt CSG installations. The intent of the VOS had originally been to address the tendency of net-metering programs to “cross-subsidize” one class of ratepayers at the expense of other classes and non-participating customers – to democratize solar by spreading the benefits over all rate classes. But has the ability to finance Gardens under the VOS adequately addressed the democratization issue? Most CSG developers find it easier and more profitable to find subscribers among municipalities, schools, churches, and corporations than among the multitude of residential customers. Although the issue is still unresolved, Minnesota is now host, over Xcel’s protests, to the most vigorous CSG market in the nation. More about the VOS further on.

Uneven access to the CSG model 

The language to enable the CSG model, under the 2013 legislation, was aimed only at Xcel Energy. While other utilities in the state have experimented with CSGs, such Gardens are only built as a service to those members who wish to participate. This will not support a market the way that the Xcel program does. Even in Xcel’s service territory, because of the requirement that subscribers reside in the same or an adjoining county as the CSG, farms which are located on slivers of Xcel territory in very rural counties of Minnesota do not qualify to host Gardens because there are not enough potential subscribers who qualify under that rule. Again, this seems to undermine the original intent of the program for broader access to solar.

Repeal of the contiguous county requirement would correct this uneven access with a “two-for” benefit: not only would those farmers be able to host gardens, but inner-city residents would have broader access to those solar gardens. This is because most of the CSG activity now is in a “doughnut” of counties which ring the metro area but are two counties away from residents of Hennepin and Ramsey Counties. Such a rural-urban connection could be constructed to help the program better meet the original intent. 

Impact on utility business model

Unlike net-metering, where most of the power is utilized onsite, the CSG delivers all of its power to the utility as a “merchant system.” Being on the large end of the net-metering framework, the CSG has more impact on the utility electrically and on the “wholesale to retail” business model. Without a better coordination regime to address hosting capacity and congestion, the utility loses control of the ability to target new generation siting in its planning, because solar developers are free to originate projects wherever they can. Furthermore, gardens capped at 1 MW are difficult to finance beyond a short distance from substations; this limits the number of good sites for solar gardens, clusters them near substations, and keeps the cost to build relatively high.

Two very different market structures

The CSG is a policy-driven market structure which the utility has had to accept from its regulators because, through the subscriber arrangement, consumers (ie: unsophisticated investors) are involved in the transactions. This complicates the model because it is illegal to take money from unsophisticated investors, and so capital has to be provided by third parties who expect to get a much quicker return on the investment than the utility is allowed to get on its investments. Furthermore, the cost of that power to the utility is set by a stakeholder process which the utility does not control; it is currently starts at just over 9¢ per kwh. 

By contrast, utility-scale solar transactions are almost entirely between the utility and its solar developer vendors. The wholesale market is more economics-driven, which aligns better with an updated utility business model where, unlike the richer context of the VOS approach, the goal is to generate electricity from solar arrays in the same cost range as from burning coal. This parity has already been achieved in some places, where the wholesale price of electric power from utility-scale solar arrays is under 3¢ per kwh (kilowatt-hour). 

Potential improvements to the CSG model

If claims made by us, the solar developers, at the legislature in 2019 are to be believed, the best sites for development of CSGs have already been utilized, and further sites are more expensive to develop (that was part of our argument). Adjusting the one-megawatt collocated cap on CSGs to two or three megawatts would somewhat alleviate this constraint and expand the range of sites for financeable installations; it would also somewhat lower the cost to build new Gardens. 

Allowing Xcel customers from non-contiguous counties to subscribe would fill out the CSG market in very rural areas and very urban areas of Xcel territory. Xcel  representatives consistently maintain that they originally believed that subscribers would mainly be residential customers. The “residential adder” incentive, which increases the subscription rate as more residential participants are included, will align the program better with the original intent. It will attract some developers to expand into cities and towns with urban rooftop CSGs. Further, having more residential subscribers could be made a requirement for allowing larger Gardens or subscriptions from non-contiguous counties.

The CSG program needs a cap for planning purposes

The trade-off is that any deal will most certainly require a cap on how many megawatts of solar gardens which Xcel will be required to greenlight each year. There is no agreement about that yet, but a realistic cap would be a useful planning tool for everyone’s purposes. The tug-of-war of the CSG pricing and rule-making process is a tough environment for utility planning. Recognizing that the utility needs a cap for good planning, the cap should be high enough to allow the solar developers to continue to build the program out over the next 5 – 10 years to an agreed-upon overall goal of perhaps 1,500 total MW of CSGs. 

How will the VOS perform at higher solar deployment?

The VOS tariff will need a different baseline as more solar comes online. The VOS is based on a thorough methodology for valuing solar in terms that are relevant to utility economics. However, the basis of the valuation is a comparison of the cost of the solar build-out, against the cost of distribution system upgrades which may be deferred or eliminated because of the solar. But at higher levels of penetration of solar into the electric power market, perhaps associated with grid modernization and microgrid development, there will be new costs for system upgrades needed in order to accommodate more solar and other DERs (distributed energy resources), and deferral-based valuation must give way to valuation based on new build-out. 

Would the VOS then become obsolete?

Consider that the genesis of this approach was the desire to move past a frustrating debate about the catch-all of “externalities” which could be mitigated by solar energy. By creating an itemized list of market-oriented benefits of solar to the utility and its customers, the VOS is a rational method to price solar in an already complex electric power market. Far being discarded, the VOS could be a foundation for the even more complex challenge of valuing DERs in a more interactive and time-oriented power grid, requiring optimization between solar, energy storage, curtailment, gas peakers, and load management. Let’s celebrate what the VOS methodology given us that can be applied going forward !!

A limited growth forecast for the CSG model

Here is a recap of the issues I have with the Xcel CSG program:

– CSG market only functions in Xcel territory

– Priced too high to be a major power source

– Doesn’t address utility planning needs well

– Hasn’t effectively addressed ratepayer cross-subsidization

– VOS tariff will need update for valuation of DERs

Here are some of the suggested improvements to the program :

– Remove the contiguous county requirement under conditions minimizing cross-subsidization

– Set a yearly cap for the Xcel CSG program

– Raise the Garden collocated size to at least 2 megawatts 

– Firm up incentives for more residential subscriptions

We have a strong Community Solar Garden program right now, viewed by many as the best in the country. Although Xcel chafes under some aspects of the program, and the solar developers chafe about others, the process has brought us all into a better understanding. We will need that going forward. Rather than watch the program fizzle out over the next couple of years, a better strategy would be to make all of the improvements to the program that we can, including agreement on the ultimate scope, and keep the industry healthy by letting the program make a strong finish at 1,500 megawatts of Gardens by 2030. That’s about 10% of the solar we will need by 2050, as mentioned back in Part 1 of this article. And then  let’s get to work on the DG solar models for the other 20% to 50% of the solar that we will need.

– Ralph Jacobson, May 2020

Next: Public Benefits and Distributed Solar

The Pathway to Larger-Scale Solar in MN

The 4th market bucket of Dispersed Solar (Part 2)

Author: Ralph Jacobson

What Do We Mean By The 4th Market Bucket?

Let’s look at this through the lens of tariffs offered by the utility for distinct segments of the solar market, affectionately called “buckets.” A tariff is a standard contract, approved by the utility’s regulators, which defines the transaction between the utility and its customers who own solar. The net-metering tariff is offered to residential, commercial, and industrial customers for PV systems up to 1,000 kilowatts. This first bucket for solar has been the foundation for the solar industry for decades.

The second bucket is the community solar garden, which uses a tariff based on the “value of solar” concept to price the bill credit given to subscribers. Utility-scale solar, a third bucket, is just entering the market in Minnesota as the price of solar continues to come down. Being larger and relatively few in number, these transactions involve power purchase agreements (PPAs) and other purchase contracts where price and longevity are the key drivers.

Creating The 4th Market Bucket: Dispersed Solar

Dispersed solar arrays, DG for short and sized from one to ten megawatts, may be too large to be supported by policy-driven incentives, and too small to be competitive by a wholly economics-driven analysis. But recognizing that DG solar can utilize smaller parcels of land closer to loads, be quicker to deploy, AND be more compatible with utility business models, DG solar models will actually gain more traction in the solar marketplace than the CSG model.

To facilitate DG solar, we would do well to identify what need there is in the clean power market for solar arrays at mid-scale, how this market differs from what we already know, and what is needed to make it work for both utilities and solar developers. This will be a planning-driven market, and this should be seen as the goal of the distribution planning process initiated recently under the auspice of the Minnesota Public Utility Commission.

Why Consider Dispersed Solar?

A recent article, “Is Bigger Best in Renewable Energy,” by Maria McCoy of the Institute for Local Self-Reliance, makes the case that there are limits to the economics of ever-bigger power plants. Very large solar arrays will likely require investment in new transmission lines, adding significant cost and longer timelines to utility-scale arrays. Other factors such as the cost of other infrastructure, powerline losses over longer distances, uncertainty in the market, and public attitudes about the use of agricultural land will take a great deal of political capital to overcome. In comparison, DG solar can be quicker and easier to plan and implement, as will be discussed further along. 

Another advantage of DG solar is that more widespread dispersal of solar arrays will tend to minimize the edge effects of clouds. The leading edge of a cloud bank can cause a sharp drop in power production, while a sharp increase in production can occur as the sun comes out from behind the trailing cloud edge. While electronics can minimize the edge effects of clouds by smoothing the ramping up or down of production, the fact remains that the more compact our solar is (i.e., fewer but larger arrays), there will be more impact from edge effects to be dealt with.

How Will Dispersed Solar Fit Into The Power Grid?

Utility-scale solar arrays are located on the transmission side of the power grid, more like central-station power plants. Dispersed solar arrays can be located on the distribution-side, much nearer to the farms, factories, and cities where the energy will be used. It may be more accurate to describe them by function or location in the electric system, such as feeder line support, than it is to describe by other categories.

A legitimate question to ask is, if community solar gardens are really taking off and very popular with electric customers of Xcel Energy, why can’t the model just be scaled up to take its place alongside utility-scale solar to realize the full potential for clean power? And furthermore, since it costs a little more per kilowatt-hour to build a dispersed solar array than it does to build a utility-scale solar array, what are the benefits which justify the extra cost and work of creating this 4th bucket for DG? So, let’s examine the market potential for community solar.

– Ralph Jacobson, March 2020

Next Time: How Much Can The CSG Model Be Scaled Up?