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The largest energy efficiency project for Brazil (my suggestion)

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The largest energy efficiency project for Brazil (my suggestion)

We have 70 million homes in Brazil, which consume an average of 170 kWh/month of electricity. It is equivalent to an average load of 0.25 kW connected 24x7.

The instant electric shower, which is the most popular water heating, has a nominal power of 6 kW. Its monthly energy consumption can be estimated at 50 kWh, about 30% of the total consumption of the average household.

The challenge is that the electric supply chain needs to be able to offer 6 kW during the bath, when the monthly average is a mere 0.25 kW.

Increasing the capacity of the electric sector's production chain by 1 kW to meet the supply requires R$ 8 thousand (USD 1 500).

The replacement of the 6 kW shower by an 2 kW electric heater 25 gallon accumulation requires an investment of R$ 2 thousand per kW installed.

If 1/3 of the households go for this retrofit, the country will open dozens of GW of capacity. For many years there would be no need to build new generation plants, transmission lines and distribution systems.

PS This is an example. Gas and solar heaters options should be also considered

Rafael Herzberg's picture

Thank Rafael for the Post!

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Discussions

Roger Arnold's picture
Roger Arnold on Jul 14, 2020 6:24 pm GMT

Replacing a high power resistance heating hot water system with a lower powered resistance heating system with a hot water tank won't do anything to reduce overall energy consumption. Not by itself. It might defer the need to upgrade the distribution system to provide higher service capacity to homes, but the homes would simply end up drawing less power for a longer period each day.

To reduce energy consumption, you need to reduce the amount of hot water consumed, or increase the efficiency of the water heaters. The latter can be done by replacing resistance heaters with heat pumps. That would be expensive, however.

Rafael Herzberg's picture
Rafael Herzberg on Jul 15, 2020 10:02 am GMT

Hi Roger,

We both agree that the energy consumption in both cases is the same.

My point is precisely that with instant heating the required kW capacity of the grid is a lot higher (and way more expensive) than the alternative.

Around the globe the investments in the pwer value chain are a fixed cost in USD/installaed kW anbd a variable one USD/kWh (basically to coiver for the fuel, O&M.

If a lower capacity is needed less investment is required. That's precisely the concept of the Demand Response (DR) progrmas. 

Bottom line - this suggestion is only but a DR alternative!

Rafael Herzberg's picture
Rafael Herzberg on Jul 15, 2020 10:06 am GMT

Hi Roger,

Another way to put it: if you were an utility company executive or a share holder , what would you prefer:  a) a customer who demands 6 kW for an energy consumption of 50 kWh/month or b) a customer who demands 2 kW for the same power consumption - considering that in both case the revenue would be only calculated in terms of kWh consumption?

Matt Chester's picture
Matt Chester on Jul 15, 2020 12:21 pm GMT

If 1/3 of the households go for this retrofit, the country will open dozens of GW of capacity. For many years there would be no need to build new generation plants, transmission lines and distribution systems.

Is this assuming that the capacity needs are heightened by all households operating their showers at the same time? Isn't there at least a somewhat natural spread of when those kW are being used, even if you still assume they're all happening in the same 3ish hour period in the morning, they are distributed throughout those hours and not all turned on all at once

Rafael Herzberg's picture
Rafael Herzberg on Jul 15, 2020 4:51 pm GMT

Hi Matt,

Of course there is a spread BUT electric instant showers are the most impostant home load for the vast majority of Brazilian homes. And here in Brazil the two prevailing times of the day used to take a shower are in the begining and at the end of the day.

So the country's "concidental peak" as measured by the local Independent System Operator (ONS) - happens from 5h30PM to 8h30 PM. The electric instant showers are the main responsible for that since there are millions of them installed.

The "beauty" of having a tank type heater is: using a lower kW load AND by using a timer program the heating up hours when the electric system if off-peak.

Thanksfor your comment!

 

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