HVAC

This humble residence equipment could possibly be San Francisco’s secret local weather weapon

When it comes to clean energy, some sexy technologies – solar panels, electric cars – are making the headlines. I blame you, the reading audience. Click on it!

But the clean energy transition workhorses, especially in the early years, tend to be boring old technologies that no one writes about, some of which may already be in your home. For example, the increasing demand for energy storage can be partially answered by … the water heater, that unsightly white cylinder thing in your basement.

I recently ran into another unlikely hero: the heat pump. (Try to contain your excitement.) It does take a little setup, however.

A closer look at what it takes to cut emissions in San Francisco

Siemens – a major player on both the hardware and software side of the “Smart Cities” division – has developed a tool for modeling CO2 emissions in cities. It enables the company to run scenarios that show how different technologies and practices can reduce emissions. It’s called the City Performance Tool or CyPT.

Siemens recently reached out to San Francisco to use CyPT to evaluate the city’s ambitious sustainability goals. In the long term, the city’s CO2 emissions are to be reduced by 80 percent by 2050 compared to 1990 levels. (They are already 14.5 percent below the 1990 level.)

Siemens used CyPT to analyze how a number of different technologies can contribute to the San Francisco goals. Three scenarios were run. The first part modeled the aggressive but achievable use of a whole range of technologies, mainly focused on sustainable modes of transport and buildings. Here you are:

(Siemens)

As you can see, electric cars, car sharing, and congestion charges are the biggies on the transportation side. In buildings, home automation and “performance optimization” do most of the work.

However, this scenario only brought Siemens a 63.4 percent decrease in emissions by 2050 – just before what San Francisco needs.

For the second scenario, a carpeted city floor was modeled with solar panels to provide a source of electricity that is cleaner than what the electrical grid can provide. With panels on almost any suitable roof, the city could get an additional 776,600,000 kWh / year of carbon-free electricity. Regardless of the other benefits, this strategy only secured a further 3.6 percent in emissions reductions, so that it rose to 67 percent by 2050.

How do I get from 67 to 80 percent?

You got it: heat pumps.

A heat pump is a “mechanical compression cycle refrigeration system” that can function as both an oven and an air conditioner (in fact, many air conditioners are just one-way heat pumps). From manufacturer Trane:

There is heat energy even in air that is too cold. When it is cold outside, a heat pump extracts this external heat and transfers it inside. When it’s warm outside, it reverses direction and acts like an air conditioner that removes heat from your home.

Since it only moves heat, not generating it, it is far more efficient than incinerators.

The main feature for our purposes is that heat pumps run on electricity. When Siemens modeled the shift of 80 percent of citywide heat consumption from natural gas to electric heat pumps, emissions decreased another 14 percent, bringing the total by 2050 to just above the SF target.

siemens sf

(Siemens)

Indeed, “the market introduction of electric heat pumps for 80 percent of urban heat consumption is the most powerful lever considered in this analysis,” he concluded.

I find that perversely pleasing. In the already boring category of appliances, electric heat pumps are possibly the most boring. Be honest – every time I write “electric heat pump” your eyelids droop a little. But they are important!

(Note: heat pumps are so good for decarbonizing San Francisco because of their clean electricity and mild climate. They don’t do the same in areas with dirtier and more expensive electricity.)

What heat pumps can teach us

In order not to just laugh at heat pumps, let me extract a few lessons here.

1) First, it shows that most of the decarbonization in the next few decades cannot be achieved through sexy new technologies with carbon nanotubes or whatever. Basically, it will not be a technical development work.

Instead, it will be the more mundane job of working through and reforming the rules, regulations and incentives offered by different levels of government to align with the adoption of existing clean energy technologies, including the boring ones.

A personal case study: Recently, my wife and I did some internal work on our house – new plumbing, new insulation, new electrical boxes, new water heaters, and new stoves (and a new kitchen faucet, which is part of the job that I actually do See day by day).

We still had the old oil stove installed in the house when it was built in 1957. It was that sickly peach color that was popular with appliances at the time – a real monster. Listen:

Oil stove

Look at this beauty. DR

I wanted to exchange it for a heat pump. That would have made my house almost fossil fuel free since Seattle has very water-heavy, low-carbon electricity.

But my utility, Seattle City Light (a pretty advanced utility in general) doesn’t offer discounts on air source heat pumps (just the fancier and more expensive ductless kind). In contrast, it offers significant discounts for purchasing an efficient natural gas stove. [Correction, 10/5/2016: Oops, got that a bit wrong. It’s true that SCL doesn’t offer rebates for air-source heat pumps, but it’s not true that they offer rebates for natgas furnaces — those rebates came through Puget Sound Energy, my gas utility.]

In the end, choosing a heat pump would have cost us $ 8,000 more than a natural gas stove, and since we were already in dire straits, we just couldn’t do it. It would have paid off at some point, but over about 20 years. Who knows if we’ll be in the house that long?

So I had to add another fossil fuel to my house. It was annoying. Especially since I live in a temperate climate, perfect for a heat pump.

Making sure rules and incentives are aligned to promote boring but important technology – this is the real meat and potatoes of decarbonization for the next decade or two.

2) Without rehashing this again, I’ll say that Siemens’ results fit perfectly with the decarbonization strategy I outlined in a post the other day: clean up electricity and electrify everything.

This is what the humble heat pump is: a way of converting heating and air conditioning from burning fuel to electricity. It’s not exciting – you won’t see it on any tech blog – but it matters.

(Thanks to @MackayMiller for the tip.)

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