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Energy Resource and Network Resource Interconnection Service determine how your project connects to the grid — what gets studied, what upgrades you trigger, and how much risk you carry into the queue. Choosing your service level is one of the most consequential early decisions a developer makes. Here's how the two compare, and how to choose.
The short answer
ERIS (Energy Resource Interconnection Service) lets a generator connect and inject energy to the grid on an as-available basis — typically faster and cheaper, but with no guarantee that your full output is deliverable during system constraints.
NRIS (Network Resource Interconnection Service) is a higher level of service: your project is studied for deliverability across the network and can qualify as a Network Resource for capacity and resource adequacy — usually at the cost of more network upgrades and a larger study scope. Importantly, NRIS is layered on top of the ERIS analysis rather than being a separate either/or path.
ERIS vs. NRIS at a glance
The same point of interconnection can look very different under each service. Here's how they stack up across the factors that drive cost and risk.
Factor | ERIS | NRIS |
|---|---|---|
What it provides | The right to interconnect and inject energy when capacity is available | Capacity deliverability comparable to existing Network Resources across the system |
Deliverability | As-available — output may be curtailed during constraints | Studied for full deliverability under network conditions (still subject to dispatch & curtailment) |
Network upgrades | Generally fewer — narrower study scope | Often more — includes the ERIS set plus a broader deliverability analysis |
Cost exposure | Lower upfront upgrade costs | Higher upgrade costs, but capacity-market and resource-adequacy eligibility |
Capacity / resource adequacy | Does not by itself qualify as a Network Resource | Can be designated as a deliverable Network Resource |
Best suited for | Energy-only projects optimizing time-to-COD and cost | Projects needing capacity accreditation or studied deliverability |
One thing both share: neither ERIS nor NRIS conveys transmission service or the right to deliver energy to a specific customer. Moving power to load requires separately securing transmission service under the ISO's tariff.
What is ERIS?
ERIS grants a generator the right to connect and inject energy onto the transmission system on an as-available basis. The study tests reliability — thermal, voltage, short-circuit, and stability — across the monitored system and a full contingency set to confirm the project can inject power without creating violations. It typically requires fewer upgrades and offers a faster, lower-cost path to commercial operation — but the grid is not obligated to take your full output during congestion, so curtailment risk sits with the developer.
What is NRIS?
NRIS is a higher level of service that adds a deliverability test on top of the ERIS reliability analysis, studying your project's output for deliverability across the network comparable to existing Network Resources. Passing it lets the project be designated as a deliverable Network Resource — important for capacity markets and resource adequacy. Because the deliverability study tests a broader set of stressed system conditions and contingencies, it tends to surface more network upgrades and higher costs. Note that NRIS confers capacity deliverability — it does not guarantee firm energy delivery or freedom from curtailment, since the resource remains subject to economic dispatch and emergency conditions like any network resource.
Which service should you choose?
There's no universally “better” option — the right choice depends on your project's revenue model, the market you're entering, and how much deliverability risk you can absorb.
Lean toward ERIS when speed and cost matter most, your offtake doesn't require capacity accreditation, and you can manage curtailment exposure.
Lean toward NRIS when you need studied deliverability, plan to participate in capacity markets, or want the capacity accreditation that can justify higher upgrade costs.
Model both before you commit. The same POI can produce very different upgrade sets and costs under ERIS vs. NRIS — and across seasons and operating conditions.
How Nira Energy helps
Nira replicates ISO study methodology end-to-end — running ERIS and NRIS models across operating conditions so you can compare upgrade exposure, deliverability, and cost for every point of interconnection, in a fraction of the time it takes the queue. That means you can see how each service plays out before you ever submit:
Run both ERIS and NRIS analyses across all operating conditions
Surface the full set of upgrades and costs each service triggers
Make confident siting and service-election decisions, backed by ISO-accurate data
Frequently asked questions
What does ERIS stand for?
ERIS stands for Energy Resource Interconnection Service — the right to interconnect and inject energy to the grid on an as-available basis, without a guarantee of full deliverability during system constraints.
What does NRIS stand for?
NRIS stands for Network Resource Interconnection Service — a higher level of service that adds a deliverability study on top of the ERIS analysis so a project can be designated as a Network Resource for capacity and resource adequacy.
Is NRIS more expensive than ERIS?
Usually, yes. Because NRIS layers a deliverability study over the ERIS reliability analysis — testing a broader set of stressed conditions and contingencies — it tends to identify more network upgrades and higher costs, in exchange for capacity-market and resource-adequacy eligibility.
Can a project request both ERIS and NRIS?
Effectively, yes — an NRIS request includes the ERIS reliability study, so the two aren't a clean either/or. Developers commonly take ERIS for their full output and elect NRIS for some or all of their capacity. Modeling each option early is the best way to understand the cost and deliverability trade-offs before committing in the queue.
Terminology note: ERIS and NRIS are the terms used in MISO, SPP, PJM, ISO-NE, and NYISO. CAISO uses different names (Full Capacity Deliverability Status vs. Energy-Only), though the underlying concepts are analogous.
