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Could Heat Pumps be a solution to the Texas grid failure?

03/19/2021

The recent Texas blackouts were the result of multiple problems combining at the worst possible moment. Rather than contributing to the blame game, this post focuses on a potential solution. What could Texas, and other states, do now to reduce the probability of a repeat event?

At the peak of the grid crisis - just prior to the blackouts - grid operators desperately needed to find ~17GW in load reductions. Much of this additional load was driven by increased heating energy use due to the abnormally cold weather.

About 60% of Texas households heat with electricity and tend to use low-efficiency heat pumps with electric resistance back-ups (or straight electric resistance heating). At 5 degrees Fahrenheit, they have a coefficient of performance (COP) of ~1.

In contrast, modern cold climate air-source heat pumps use only half of the electricity at 5F. Northeast Energy Efficiency Partnerships (NEEP) publishes a list of ASHP performance test results and many of the centrally ducted units (i.e. furnace replacement) have a COP>2 at 5F.

 

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So, could we eliminate 17 GW of winter peak load by switching to cold climate heat pumps? Here is the back-of-the-envelope math:

  1. Number of households in TX: 9.7 million (Census)
  2. Number of homes that heat with electricity: 5.8 million (60%, Census)
  3. Electrical heat homes in ERCOT: 90%, or 5.2 million households
  4. Average TX home size: 1,750 sq. ft. (Energy Information Administration)
  5. Average electric heating load of 1,800 sq. ft. home at 5 degrees: 6 kW (Based on non-TX meter analytics by Sagewell
  6. Heating peak load at 5F: 5.2 million x 6 kW = 31.2 GW
  7. Savings going from COP=1 to COP=2 at 5F: 15.6 GW

Or, what if the peak heating load was 7 kW last week? Then the peak savings with COP=2 is 18.2 GW. We could play with the assumptions and get slightly different results, but it looks like the ERCOT winter peak savings would be in the range of 12 to 18 GW.

How could we determine the real-world savings? Texas has a very high smart meter installation rate,  so data analytics companies like Sagewell are able to measure how much peak load could be reduced by looking at existing cold climate heat pump installs.

Large GW level savings are actually achievable with today’s technology. Organizations like NYSERDA and MassCEC have substantial campaigns promoting cold climate heat pumps, and Maine has a goal to install 100,000 units in the next few years.

If they work in Maine, they will work in Texas and other states. Many of the cold climate ASHP can deliver the required heating efficiency at 5 degrees (and operate at -15 F) so this is not some hypothetical future technology; one could get the equipment installed tomorrow.

It is a bit ironic that one of the largest cold climate heat pump manufacturing facilities in the U.S. is in TexasDaikin facility near Houston which makes Daikin, Goodman and Amana brand heat pumps).

There are over 70 heat pump brands on the market that are listed on the NEEP cold climate ASHP list at ashp.neep.org, including Mitsubishi, Trane, Carrier, LG, Lenox, Fujitsu, and many more.

The cost of achieving this is reasonably low: the difference in equipment cost between an inefficient heat pump and a centrally ducted cold climate heat pump is between $1,000 and $2,000 per installation, with no difference in installation cost. This cost difference would pay for itself in reduced energy costs for the consumer.

Designing a heat electrification program that could convert 30% to 40% of Texas heat pumps into cold climate heat pumps within five years is achievable, as about 7%-9% of installed equipment fails annually and there are ways to accelerate conversion by the rest of households. Sagewell offers an extensive marketing program to help utilities convert more homes to ASHPs.

If Texas wanted to accelerate adoption of cold climate air-source heat pumps, the vast majority of older pumps could be replaced in ten years. ASHPs can save money for the customers, reduce peak demand, AND maintain utility margins.

The icing on the cake: this clean heating and cooling technology results in significant carbon emission reductions.

Takeaways:

#1 Equipment selection in electrification really matters.

#2 The cost of reducing blackout probability is low.

#3 Everyone can win – customers, electric utilities, generators, etc.

#4 Big changes can be achieved in 5 years.

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