Electrification Without Grid Overload: Carbon Bridge vs. Heat Pumps

As cities push for aggressive decarbonization targets, particularly under New York City’s Local Law 97 (LL97), the electrification of building heating systems has become a central focus. However, electrification is not simply a choice between heat pumps or nothing—it’s about how and when electricity is used.

Most policymakers assume air-source heat pumps are the optimal pathway for building electrification. However, our Carbon Bridge technology presents an alternative: it enables electrification by using off-peak electricity to produce renewable natural gas (RNG) from captured CO?, which can then be burned in existing boilers without disrupting building operations.

We compare the electrical infrastructure upgrade requirements of both pathways, providing a clear, data-driven evaluation of which approach is more feasible, cost-effective, and scalable for full decarbonization.

Electrification Comparison: Carbon Bridge vs. Heat Pumps

1. Carbon Bridge Electrification: Using CO? to Produce On-Site RNG

The Carbon Bridge pathway captures CO? emissions from an existing steam boiler and converts them into CH? (methane) using off-peak electricity. The system runs only during off-peak hours (10 hours per night) to avoid peak grid demand and high electricity prices.

Step-by-Step Calculation: Electrical Load for Carbon Bridge

• Annual natural gas consumption of the boiler: 100,000 therms
• To replace this gas with RNG from CO?, the system needs 100,000 ÷ 60% = 166,666 therms equivalent of electricity
• 1 therm = 0.0293 MWh, so total electricity required: 166,666 therms × 0.0293 MWh/therm = 4,883.35 MWh per year
• Since the system operates only 3,650 hours per year (10 hours per day, off-peak only): 4,883.35 MWh ÷ 3,650 hours = 1.33 MW electrical demand

?? Electrical service upgrade requirement: 1.33 MW

CO? Storage Clarifications

Since natural gas consumption is seasonal, the Carbon Bridge must be able to store CO? when heating demand is low for later use. However, large-scale CO? storage does NOT need to happen on-site.

Instead, nearly all of the seasonal CO? storage can be centralized, with CO? delivered to the property as feedstock during the heating season. This eliminates the need for large-scale on-site CO? storage.

For reference, if 100,000 therms of gas produces 529 tonnes of CO?, about 33% of this must be stored for non-heating season operation, or 176 tonnes of CO?. If stored on-site, this would require:

• 173.3 cubic meters of storage (equivalent to 3 NYC rooftop water towers)
• 50-atm liquid CO? tanks, which are already commercially available

However, with a CO? delivery network, the property only needs minimal buffer storage, as the bulk of the seasonal CO? supply would be delivered as needed during the heating season.

This approach eliminates the need for additional electrolyzer capacity and keeps on-site storage requirements manageable, similar to existing oil and propane delivery models.

2. Air-Source Heat Pump Pathway

The alternative is direct electrification using an air-source heat pump, such as the Gradient Window Heat Pump, which has a coefficient of performance (COP) of 1.8 at -7°F. The major challenge with heat pumps is that they require electricity in real time, which forces buildings to upgrade their electrical service significantly.

Step-by-Step Calculation: Electrical Load for Heat Pumps

• Assume 75% of annual heating occurs in the 3 coldest months
• Annual heating load: 100,000 therms × 75% = 75,000 therms
• Convert to MWh: 75,000 therms × 0.0293 MWh/therm = 2,198 MWh
• Dividing by operating hours (3 months, 30 days/month, 24 hours/day): 2,198 MWh ÷ (3 × 30 × 24) = 1.02 MW base electrical demand
• When accounting for safety factors, peak demand fluctuations, and reliability needs, the electrical service upgrade must be at least 2 MW

Comparison of Electrical Service Upgrades

Key Takeaways

1. Carbon Bridge requires 50% less electrical service capacity than a heat pump despite its lower efficiency, because it shifts electricity consumption to off-peak hours and relies on stored energy (RNG) for peak heating.
2. Heat pumps require electricity in real time, often during peak electricity hours (8 AM – 10 PM), which not only requires larger electrical service upgrades but also increases exposure to demand charges.
3. Large-scale CO? storage is NOT needed on-site—seasonal CO? storage can be centralized, with feedstock delivered as needed, eliminating infrastructure concerns.
4. Heat pumps require expensive infrastructure upgrades, while Carbon Bridge leverages existing boilers, reducing capital costs and tenant disruption.

Why Storage-Based Electrification is Superior

The fundamental difference between these approaches is how they interact with the electricity grid:

• Heat pumps must operate in sync with grid demand, forcing buildings to upgrade electrical infrastructure significantly.
• Carbon Bridge stores energy in the form of RNG, allowing it to consume electricity only during off-peak hours, which: Reduces stress on the grid Eliminates peak demand charges Avoids expensive electrical service upgrades

This aligns with a key principle of electrification and decarbonization: it’s not just about efficiency—it’s about when and how energy is used.

Electrification Without Disruption

• Heat pumps require massive tenant disruption—replacing existing heating distribution systems.
• Carbon Bridge integrates into existing steam infrastructure, requiring no tenant-level intervention.
• Property owners overwhelmingly reject tenant-disruptive upgrades, making Carbon Bridge the only viable solution for full electrification in many cases.

The Case for Carbon Bridge

While heat pumps appear more efficient, they require massive electrical service upgrades and force buildings to operate at peak grid times—leading to higher costs, greater emissions, and increased infrastructure burdens.

Standard Carbon’s Carbon Bridge achieves electrification while:

• Cutting electrical service upgrade needs by 50%
• Using off-peak electricity exclusively
• Avoiding tenant disruption
• Maintaining existing heating infrastructure
• Eliminating exposure to peak-hour emissions from gas-fired peaker plants
• Leveraging centralized CO? storage to remove on-site constraints

As cities like New York move toward full decarbonization under LL97, the choice between peak-demand electrification and storage-based electrification will define whether this transition succeeds or collapses under infrastructure constraints.

The data is clear: true decarbonization must embrace energy storage.