SOCO Interconnection at a glance
Quick facts | SOCO |
|---|---|
Who runs it | Alabama Power, Georgia Power and Mississippi Power, with Southern Company Services as their agent, run one transmission system and balancing area. They aren’t part of an ISO. FERC approves their shared transmission tariff, and each state’s PSC oversees retail service. |
Governing rules | The shared transmission tariff’s large generator procedures (Attachment J) for generators over 20 MW, plus Southern’s technical requirements and integration process for large loads, both updated in May 2026 |
Generator study process | One annual cluster, filed through Southern’s ICON portal: a 45-day window, a 15-day review, a 60-day engagement window, a 150-day Cluster Study, a 150-day restudy if needed, and an individual facilities study of 90 or 180 days |
Current cluster | The 2026 cluster has 84 requests totaling about 22 GW. Its Cluster Study is due November 20, 2026, with the report meeting by December 8. |
Next window | Opens in mid-February 2027. The tariff sets February 15, which is Presidents’ Day in 2027, and in 2026 the window opened February 17. Southern hasn’t posted the 2027 date yet. |
Generator timeline | About 4 to 5 years from request to readiness for commercial operation, per Southern |
Generator costs | A $5,000 non-refundable fee and a study deposit of $150,000 to $250,000 for projects of 80 MW or more, plus a readiness deposit of twice the study deposit. The readiness deposit rises to 5% and then 10% of upgrade costs, with 20% total security at the interconnection agreement. |
Withdrawal penalties | None before the Cluster Study. After that, at least the study deposit, rising to 5% of upgrade costs during a restudy, 10% during the facilities study and 20% after signing. |
Site control | At least 90% at filing, with minimum land by technology: 6 acres per MW for solar, 30 acres per MW for wind, 40 to 60 MWh per acre for storage and 40 acres for conventional plants. 100% is due at the facilities study agreement. |
Large load threshold | Loads connected above 40 kV that typically exceed 50 MW of long-term projected demand |
How large loads connect | Through a service contract with Alabama Power, Georgia Power or Mississippi Power. There’s no queue for loads under the transmission tariff. Co-ops and city utilities serving a load request service from Southern instead. |
State contract rules | Georgia: contracts up to 15 years with minimum bills for loads over 100 MW, under a 2025 PSC rule. Alabama: PSC review of each data center contract, with a vote within 90 days, under a law effective October 1, 2026. Mississippi: special contracts approved by the PSC. |
Large load demand | 31 contracted projects totaling 17 GW, with more than 75 GW in the wider pipeline, as of Southern’s October 2026 customer forum |
Last updated | November 3, 2026 |
SOCO Generator Interconnection Process
Generator interconnection,
step-by-step
Southern Company studies generators in one annual cluster for Alabama Power, Georgia Power and Mississippi Power, with a 45-day window that opens in mid-February. Deposits rise at each decision point, and Southern estimates 4 to 5 years from request to readiness for commercial operation.
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Check OASIS, the heatmap and the request list. Southern’s SIGHT heatmap shows how a new plant would affect nearby lines at a chosen point of interconnection.
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Confirm which process applies. Generators over 20 MW join the cluster. Smaller projects, and those connecting below 40 kV, use the small generator process or go to the operating company.
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Apply during the February window. Submit through Southern’s ICON portal with a $5,000 fee, a study deposit, a readiness deposit of twice the study deposit and at least 90% site control.
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Review and engagement. A 15-day review is followed by a 60-day engagement window, with scoping meetings and the Cluster Study Agreement.
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Cluster Study. Southern studies the cluster over 150 days. To continue, developers raise their readiness deposit to 5% of upgrade costs.
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Restudy and facilities study. Southern restudies the cluster if needed. Developers then show 100% site control and raise their deposit to 10% before an individual facilities study of 90 or 180 days.
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Sign the interconnection agreement. Developers post total security of 20% of upgrade costs and sign the agreement. Delivering the plant’s output also needs separate transmission service.
SOCO Large Load Interconnection Process
Large Load interconnection,
step-by-step
Southern Company has no queue for large loads. Data centers sign a service contract with the utility under rules that differ by state, and then follow Southern’s technical requirements for large loads. Confirm current requirements with your operating company.
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Start with the operating company. A new data center works with Alabama Power, Georgia Power or Mississippi Power, depending on where the site is.
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Check whether it’s a large load. Southern’s large-load rules cover loads connected above 40 kV that typically exceed 50 MW of long-term projected demand.
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Retail or network customer. A co-op or city utility serving the load instead asks Southern to study it as future load growth, with a $30,000 study prepayment and a 135-day target.
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Load study and contract terms. Southern studies the substation and upgrades the load needs while the customer negotiates its contract, which typically includes a long term, minimum bills and collateral.
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State approval. In Georgia, contracts for loads over 100 MW go to the PSC. In Alabama, the PSC must vote on each data center contract within 90 days. In Mississippi, the PSC approves special contracts.
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Meet Southern’s technical requirements. The load must meet Southern’s large-load technical requirements and follow its integration process, both updated in May 2026.
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Energize. The load comes online once the substation and any upgrades are in place.
What's changed recently in SOCO interconnection
Last updated November 2026
Southern Company’s territory has become one of the busiest data center markets in the country, with 17 GW of large load already under contract. Alabama passed a new law on data center contracts in 2026, Southern updated its technical rules for large loads, and its 2026 generator cluster is nearing its first study results. If your project is in Alabama, Georgia or Mississippi, check which of these changes apply before the next window or contract.
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February 17 – April 3, 2026: Southern’s 2026 cluster window drew 105 applications totaling about 27.9 GW. 84, totaling about 22 GW, entered the Cluster Study.
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May 2026: Southern updated its technical requirements for large loads and published a new integration process for them.
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July 15, 2026: Georgia Power filed a 25-year contract to serve OpenAI’s 3.2 GW campus in Effingham County, which the Georgia PSC approved in late August, according to press reports.
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October 1, 2026: Alabama’s new data center law took effect, requiring the PSC to vote on each data center contract within 90 days. The PSC adopted its review rules on October 6.
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October 2026: At its customer forum, Southern reported 31 contracted large-load projects totaling 17 GW, with more than 75 GW in its wider pipeline.
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Coming up: Stakeholder meetings on November 4 and December 3, the 2026 Cluster Study report on November 20 with a results meeting by December 8, and the 2027 window, expected to open in mid-February.
How LandGate Helps with SOCO Interconnection
Southern Company covers three states with one generator cluster, and developers also deed a substation site to Southern after construction. For data centers, each state has its own contract rules, often with long terms and minimum bills LandGate brings the data behind these decisions into one platform.
Get your projects on the grid faster with reliable transmission data.
Compare sites across 3 states
One cluster covers Alabama, Georgia and Mississippi, so you can apply wherever the grid is strongest. Search parcels by criteria such as distance to a substation and available offtake capacity, and see available transfer capacity at transmission-level injection points across the whole footprint.
Find enough land for the substation
SOCO requires 6 acres per MW for solar and 30 for wind, plus up to 60 acres for the substation, which is deeded to them after construction. LandGate pairs parcel search with proprietary landowner leads and a map-based CRM to help you secure parcels that fit, including off-market properties with the right infrastructure.
Know your exposure before deposits rise
After the Cluster Study, staying in means raising your deposit to 5%, then 10%, of upgrade costs. LandGate shows queued projects at the substation level, and its automated capacity studies show substation details, capacity results, limiting elements such as transmission lines and transformers, and queue information.
Pick a site before signing a contract
Southern’s large-load rules start at 40 kV, and contracts in Georgia can run up to 15 years with minimum bills. LandGate maps the subtransmission grid with hosting capacity and available transfer capacity at the line level, and its Data Center Due Diligence Report ranks the closest substations by available capacity.
