CoreSite DE1 - Denver Data Center

Operating · CoreSite · 910 15th St., Denver, CO

CoreSite DE1 occupies Denver’s historic Denver Gas and Electric Building at 910 15th Street. CoreSite reports more than 152,000 square feet and access to 150+ networks, with dark fiber to DE2. A 2023 expansion added a reported 500 kW; a 2025 project proposed another 3 critical MW. These are increments, not total utility capacity. PSCo is DE1’s balancing authority; SPP’s reliability-coordinator role does not make the site part of the SPP RTO.

Website Open in grid

Overview

Exact-site power: 3 MW; Critical IT Load · Target
Status: Operating; Operating facility
Facility size: 171,000 sq ft; 1 reported building · Facility
Compute profile: Colocation · Telecom Edge; Performance-sensitive, mission-critical IT services and infrastructure · Hybrid and cloud-connected IT deployments
Cooling design: Chilled water.; N+1 CRAHs, chillers, chilled-water pumps, and chilled-water heat exchangers.

Power and grid

Capacity	Basis	Status	Scope	As of
0.5 MW	Leasable IT Load	Target	Exact Asset	2023-05-23
CoreSite announced an addition of 3,420 square feet and 500 kW of IT load at DE1; the announcement said design and permitting were complete and projected customer availability in 2H 2023. The 500 kW figure is expressed here as 0.5 MW; it is not a utility-service or interconnection rating.
3 MW	Critical IT Load	Target	Exact Asset	2025-04-08
CoreSite announced plans to add approximately 3 critical megawatts (CMW) of data-center capacity associated with DE1. This is a planned capacity addition, not a stated utility-service or interconnection capacity.

Utility: Public Service Company of Colorado (PSCo), doing business as Xcel Energy.
Balancing authority

Facility and development

Gross floor area (sq ft): 171,000
Site area (acres): 0.43
Buildings: 1
Construction: DE1 is operating at 910 15th Street in the Denver Gas & Electric Building. CoreSite lists the DE1 facility at 152,000+ sq ft; a local report described the purchased building as 171,000 sq ft, the figure used here for gross floor area. CoreSite announced a 3,420-sq-ft, 500-kW expansion in May 2023 after completing design and permitting, with customer availability targeted for 2H 2023; a later trade report says that expansion was completed in 2023, but gives no separate actual commercial-online date. In April 2025, CoreSite announced its acquisition of the building and plans to add approximately 3 critical MW; that announcement gives no construction start or expected online date for the additional capacity. This summary covers DE1 only, not the separate DE3 development.

Organizations

OrganizationRoleScope

CoreSiteOwner · OperatorExact Asset

Xcel EnergyUtilityExact Asset

Spectrum General ContractorsContractorExact Asset

AH Architecture, PC

Sources

PublisherReferenceType

puc.colorado.govElectric Utility Providers | Public Utilities CommissionGovernment filing

sec.govamt-20250630Government filing

coresite.comColocation Data Centers in Denver - CoreSiteOfficial source

Map Markets Assets Forecasts Data StoriesPricing

CoreSite DE1 - Denver Data Center

Operating · CoreSite · 910 15th St., Denver, CO

CoreSite DE1 occupies Denver’s historic Denver Gas and Electric Building at 910 15th Street. CoreSite reports more than 152,000 square feet and access to 150+ networks, with dark fiber to DE2. A 2023 expansion added a reported 500 kW; a 2025 project proposed another 3 critical MW. These are increments, not total utility capacity. PSCo is DE1’s balancing authority; SPP’s reliability-coordinator role does not make the site part of the SPP RTO.

Website Open in grid

Overview

Exact-site power: 3 MW; Critical IT Load · Target
Status: Operating; Operating facility
Facility size: 171,000 sq ft; 1 reported building · Facility
Compute profile: Colocation · Telecom Edge; Performance-sensitive, mission-critical IT services and infrastructure · Hybrid and cloud-connected IT deployments
Cooling design: Chilled water.; N+1 CRAHs, chillers, chilled-water pumps, and chilled-water heat exchangers.

Power and grid

Capacity	Basis	Status	Scope	As of
0.5 MW	Leasable IT Load	Target	Exact Asset	2023-05-23
CoreSite announced an addition of 3,420 square feet and 500 kW of IT load at DE1; the announcement said design and permitting were complete and projected customer availability in 2H 2023. The 500 kW figure is expressed here as 0.5 MW; it is not a utility-service or interconnection rating.
3 MW	Critical IT Load	Target	Exact Asset	2025-04-08
CoreSite announced plans to add approximately 3 critical megawatts (CMW) of data-center capacity associated with DE1. This is a planned capacity addition, not a stated utility-service or interconnection capacity.

Utility: Public Service Company of Colorado (PSCo), doing business as Xcel Energy.
Balancing authority

Facility and development

Gross floor area (sq ft): 171,000
Site area (acres): 0.43
Buildings: 1
Construction: DE1 is operating at 910 15th Street in the Denver Gas & Electric Building. CoreSite lists the DE1 facility at 152,000+ sq ft; a local report described the purchased building as 171,000 sq ft, the figure used here for gross floor area. CoreSite announced a 3,420-sq-ft, 500-kW expansion in May 2023 after completing design and permitting, with customer availability targeted for 2H 2023; a later trade report says that expansion was completed in 2023, but gives no separate actual commercial-online date. In April 2025, CoreSite announced its acquisition of the building and plans to add approximately 3 critical MW; that announcement gives no construction start or expected online date for the additional capacity. This summary covers DE1 only, not the separate DE3 development.

Organizations

OrganizationRoleScope

CoreSiteOwner · OperatorExact Asset

Xcel EnergyUtilityExact Asset

Spectrum General ContractorsContractorExact Asset

AH Architecture, PC

Sources

PublisherReferenceType

puc.colorado.govElectric Utility Providers | Public Utilities CommissionGovernment filing

sec.govamt-20250630Government filing

coresite.comColocation Data Centers in Denver - CoreSiteOfficial source

Project scope

DE1 is operating at 910 15th Street in the Denver Gas & Electric Building. CoreSite lists the DE1 facility at 152,000+ sq ft; a local report described the purchased building as 171,000 sq ft, the figure used here for gross floor area.

Power and grid

CoreSite announced plans to add approximately 3 critical megawatts (CMW) of data-center capacity associated with DE1. This is a planned capacity addition, not a stated utility-service or interconnection capacity.

Compute role

CoreSite operates DE1 as a colocation facility in the Denver Gas and Electric Building. It offers partial and full cabinets, private cages and custom buildouts, alongside cloud-provider connectivity, network interconnection, peering, 24x7x365 security and remote-hands services.

Cooling and environment

N+1 CRAHs, chillers, chilled-water pumps, and chilled-water heat exchangers.

Existing DE1 facility

Existing DE1 facility at 910 15th Street. CoreSite lists the facility at 152,000+ square feet; an exact original construction or commercial-online date is not established here.

DE1 3,420-sq-ft / 500-kW expansion

CoreSite announced an additional 3,420 square feet and 500 kW of IT load after design and permitting were completed. Customer availability was targeted for 2H 2023; a later trade report says the expansion was completed in 2023. The availability target is not treated as an actual online date.

Planned additional DE1 capacity

In connection with acquiring the building, CoreSite said it planned to add approximately 3 critical megawatts of data-center capacity. The announcement does not specify the phase's square footage, construction start, or expected online date.

Public Service Company of Colorado (PSCo).

Redundancy

Three Xcel utility feeds are reported; generators are N+1 redundant; UPS/PDU/RPP redundancy is listed as N and 2N.

Backup generation

N+1 redundant generators; the facility specification lists 24 hours of on-site fuel storage. Generator capacity and fuel type are not specified.

Storage

High-efficiency UPS systems with N/2N redundancy are listed; battery-storage technology and energy capacity are not specified.

Power sources

Xcel Energy utility service; three redundant feeds are reported. · On-site backup generators; N+1 redundancy is specified, but capacity and fuel type are not.

Land transaction

CoreSite acquired the Denver Gas and Electric Building at 910 15th Street and its related operating businesses in 2025. BusinessDen reported a $38 million purchase from DGEB Management LLC on a Wednesday in its April 4, 2025 report (April 2); a Denver landmark application later described the purchase as occurring in March 2025. CoreSite announced the acquisition on April 8, 2025.

Facility class

Colocation · Telecom Edge

Workloads

Performance-sensitive, mission-critical IT services and infrastructure · Hybrid and cloud-connected IT deployments · Network interconnection and internet peering

Availability tier

No Uptime Institute tier is stated. CoreSite publishes a 100% uptime SLA, N+1 generator and mechanical redundancy, and N or 2N UPS/PDU/RPP redundancy.

Cooling systems

N+1 CRAHs, chillers, chilled-water pumps, and chilled-water heat exchangers.

Cooling medium

Chilled water.

Fiber and connectivity

Lit fiber supports up to 100G metro Ethernet, with dark fiber linking DE1 to DE2. The site provides access to 150+ networks, the Any2Exchange peering exchange, major telecom carriers and internet backbones.

Operating context

CoreSite operates DE1 as a colocation facility in the Denver Gas and Electric Building. It offers partial and full cabinets, private cages and custom buildouts, alongside cloud-provider connectivity, network interconnection, peering, 24x7x365 security and remote-hands services.

Air permits

An EPA ECHO-derived disclosure record identifies an air permit held by CoreSite for CORESITE - DE1; it does not publish a specific permit number or conditions.

Environmental commitments

Portfolio-wide: CoreSite says its sustainability approach embeds energy and water efficiency into all data centers, evaluates equipment and design, and improves airflow; this is not a DE1-specific performance result. · Company-wide: CoreSite says it is committed to reducing its carbon footprint as a member of the iMasons Climate Accord. · Company-wide operating commitment: CoreSite says it minimizes generator use as much as possible.

Tax abatements

A 2023 Denver Downtown Historic District property-tax rebate application is identified for the Insurance Exchange Building / Denver Gas & Electric Building at 910 15th Street. The cited record does not state an approved award or dollar amount.

Utility agreements

Xcel Energy is identified as the utility provider for the 910 15th Street building, with a three-feed redundant power source. No site-specific service-agreement terms are stated.

Permits and dockets

In 2023, CoreSite reported completing design and permitting for a DE1 expansion of 3,420 square feet and 500 kW of IT load. · Denver LPC docket 2026-COA-961: 910 15th Street façade-restoration and window-replacement application, considered at the October 6, 2026 meeting. The staff report proposed a motion to approve; the report does not establish the Commission’s final action.

Transactions

In April 2025, CoreSite acquired the Denver Gas and Electric Building and related operating businesses at 910 15th Street. Local reporting put the building sale price at $38 million and identified DGEB Management LLC as the seller. · American Tower’s SEC filing describes a $5 million seller-financed portion of the DE1 purchase price, payable in monthly installments through March 31, 2028, with interest at the Bank of America prime rate plus 200 basis points.

Identity and campus: CoreSite Denver campus
Also reported as Denver Gas and Electric Building.
Grid record: Public Service Company of Colorado (PSCo), doing business as Xcel Energy.
Regulatory record: In 2023, CoreSite reported completing design and permitting for a DE1 expansion of 3,420 square feet and 500 kW of IT load. · Denver LPC docket 2026-COA-961: 910 15th Street façade-restoration and window-replacement application, considered at the October 6, 2026 meeting. The staff report proposed a motion to approve; the report does not establish the Commission’s final action.
At 910 15th Street, CoreSite reported in 2023 that design and permitting were complete for a DE1 expansion of 3,420 square feet and 500 kW of IT load. The 2026 Landmark Preservation Commission docket 2026-COA-961 concerns façade restoration and window replacement; the staff report contains a motion recommending approval, but does not establish the Commission’s final disposition. The separately reported proposed sales-and-use-tax refund of up to $9 million concerned CoreSite’s new campus at 5050 Race Street, not DE1, and CoreSite withdrew that proposal in 2024.
Availability tier: No Uptime Institute tier is stated. CoreSite publishes a 100% uptime SLA, N+1 generator and mechanical redundancy, and N or 2N UPS/PDU/RPP redundancy.

Design Firm

Exact Asset