Duh, It’s DER!

What’s in a name? Sometimes, it’s everything. DER, or Distributed Energy Resources, is the name given to a collection of energy solutions defined by small scale renewable energy sources combined with advanced information and control technologies that can be aggregated to provide reliable energy necessary to meet regular demand. Examples include: renewable generation, energy storage, energy efficiency, demand response, electric vehicles and any combination thereof.

Today DER means rooftop solar, with a little bit of Electrical Vehicle (EV) charging sprinkled here and there. Both rooftop solar and EV charging occur behind-the-meter, on private residential or commercial property, beyond the influence of the Investor-Owned Utility (IOU). In fact much of the rooftop solar going in today is provided by third party leases from companies like Solar City and SunPower, who are in direct competition with IOUs. Competition for rooftop solar DER is fierce, making it challenging for IOUs to play a significant role, especially when hamstrung by existing business models involving fixed rates of return. The only viable way for IOUs to leverage this class of third party (and customer-owned for that matter) rooftop DER is through program incentives. With the right incentives, participating customers can be persuaded to source energy from rooftop arrays or sync energy into EV batteries at meaningful times to the IOU just like they do with energy efficiency programs targeting thermostats, but the impact is small and indirect and may conflict with the financial benefits of these third party systems.

What will DER mean tomorrow? California may be first to decide. California has mandated (AB-327/Rulemaking14-08-013) that their IOUs deliver Distribution Resource Plans (DRP) by July 1, 2015 that include high levels of DER. In addition SB-43 , also known as “Community Solar”, mandates solar for everyone, not just those folks with sufficient rooftop real estate and credit scores. Both of these aggressive California mandates share a common problem – siting.

If you believe the Distribution System Operator (DSO) model is where we are headed, then the answer to the siting problem for DER and Community Solar may be along the low-voltage secondary distribution system, before-the-meter, on existing infrastructure and easements so that DSOs can own and operate these resources. Imagine solar generation added to existing outdoor light poles and then at the head-end of the lighting circuit, energy storage and power regulation are sited, sharing a common easement, interconnection point and information/control solution. Voilà, Local-Area DER!

Local-Area DER

Such a Local-Area DER solution has many benefits including:

  • Small-scale capacity with power regulation
    • Solar generation plus battery storage
    • Dispatch-able and load shifting
    • Resolve existing power quality issues w/regulators
    • New high-quality capacity w/smart microinverters
  • Located “before-the-meter”
    • DSO owned, operated & controlled
    • Meets incremental demand with co-located supply, reducing transmission losses
    • Adds value to distribution “wires”
    • Low-voltage: 120/240/480V, single or three-phase
  • Utilizes existing infrastructure
    • Quick, easy and economical to implement
    • Reduce or eliminate land use and permitting issues
    • Build up balance and reliability across interconnections from the edge
  • Deployable in lock-step with behind-the-meter grid issues
    • Similar sizing to “behind-the-meter” DER
    • Co-located along the same “wires” with issues
    • Economically scaled as grid issues scale

In addition to these benefits, siting Local-Area DER along existing roadside infrastructure where low-voltage distribution “wires” reside is democratic. Everyone lives near roadways, whether renting an apartment or residing in a structure incapable of hosting a rooftop solar installation, so Local-Area DER delivers on the Community Solar promise of environmental justice too.

Local vs Wide-Area DER

Wide-Area DER, sited further up the distribution system hierarchy at the sub-transmission or primary distribution level, does not deliver the same degree of benefit. Real estate remains a challenge to procure. Even though the amount of land required is less than a full-scale gigawatt solar farm, acquisition, permitting, land use, environmental and legal issues still abound. Plus the energy must traverse the distribution system to get where it is needed most, which may necessitate some of the very same switch and wire upgrades DER is intended to avoid.

There are scale matching issues as you move up the hierarchy as well. The number of circuits that can be addressed with a single solution increases as you move up the hierarchy, but the ability to target some circuits out at the edge but not others requires additional investments in power routing solutions. System sizing up the distribution system hierarchy can also be challenging. How much generation, storage and power regulation is needed today across all the rapidly evolving circuits, and tomorrow, and the day after that? IOUs are very skilled at modeling circuits and predicting load, so this would not seem like a concern on the surface. However, these well-oiled processes cannot match the pace of unpredictable change unfolding behind the meter.

Instead, a single circuit with occasional bi-direction power flow, power factor and harmonic issues can be targeted with a single circuit-sized Local-Area DER solution leveraging land and infrastructure whose cost is already sunk. Comparable sizing combined with co-location before the meter along the same circuit resolves these issues quickly and economically and helps the DSOs maintain control over their system while meeting their ever present reliability expectations.

So, what’s in a name? If the name is DER and it is preceded by the adjective Local-Area, it could be everything.

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