Diesel Keepwarm System


Sustainability Issue

New York City Electricity Demand Response

New York City is losing Indian Point Nuclear Power Plant soon and is looking for solutions to make up for the 2,000 MW produced by the plant. In addition to adding peaking plants in Westchester, Conedison is looking for customers to individually curtail their demand.

Technology Solution

I know this probably isn’t the sexiest idea in the world, but it’s so effective. Every Emergency Diesel Generator (EDG) has a jacket with water that is heated through an electric filament. That electric filament is usually around 5-8 kW and keeps the jacket warm to somewhere between 105 and 120 degrees-F. It’s necessary to keep the EDG’s this warm to start immediately when called. The utility costs for each EDG can be from $7k to $10k per year. See picture below:


Typically in large buildings, these EDGs are grouped together. I’ve seen groups from four to eight in a row.

This was brought to my attention a few months ago by a company I used to work for told me they started selling a heat pump to heat these diesel generators, which drastically reduces the electricity consumed and can save $5k-$8k per year, per EDG.

When I started walking through buildings looking at EDGs, I noticed something even more interesting. More often then not, there is a source of heat (steam pipe, boiler plant, etc.) nearby. Most NYC is on ConEdison steam, and they have to quench the condensate before returning it back to the utility. Quench is when they run city water over the pipe to cool down the condensate to a certain temperature. This wastes both heat and city water.

The heat pumps would work great, if there wasn’t a source of heat nearby. My idea is to put a HX from the source of heat to the EDGs and heat them in series. The cost to do this would be from $50k to $100k per system and can save as much as $10k per EDG. For systems of 4 EDGs, the payback is under 3 years and for systems of 8 EDGs the payback is less than 18 months.

On a larger scale, there are 700 skyscrapers in New York City. Let’s say they have a total of 2,000 EDGs that can be heated this way. We’d be taking 10MW to 20MW peak demand off the grid. The cost to do all this work would be around $70M. Based on current demand response programs, incentives would cover $22M to $44M of that cost. The energy usage rebates could cover another $14M to $22M of the cost. The rebate money is there and if Conedison limits the rebate to 50% of the project cost, the payback periods above to the customer are cut in half.

To wrap this up, because this is supposed to be about a pressing sustainability issue, according to the NYC Electricity Outlook, we’re losing Indian Point Nuclear Power Plant and replacing it with natural gas peaking plants (in conjunction with demand response programs). Cutting 10-20MW would definitely help with that. Also, from a GHG perspective, this system would save around 90M-140M kWh per year. EPA’s GHG Calculator projects this save 65k to 105k metric tons of eCO2 per year, the equivalent of taking 13k to 22k cars off the road.

Organizational Stakeholders

  • ConEdison
  • Building Owners
  • Mechanical Contractors
  • Controls Contractors

Steps to Deploy

  1. Form relationship among utility, building owner, and contractors to perform pilot project to include Measurement and Verification.
  2. Develop case study from the pilot project.
  3. Sell, sell, sell!


ConEdison Demand Response Program

ConEdison Custom Rebate Program

UNI: bmb2189



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