Where does heat power come from?

Heat power has the potential to replace main contributors of CO2 by supplying the world with a baseload of clean electricity. That’s because heat power comes from pre-existing heat. In other words, we don’t have to first generate that heat with the help of fossil fuels.

Two main sources of heat

There are two main sources pre-existing heat: the heat within the earth (geothermal) and waste heat that’s left over when heat is generated for other purposes, like industrial processes.

Geothermal heat power has been used around the world for hundreds of years. You can find it in 24 countries, 5 of which use it to produce at least 15 percent of their electricity. But the potential is so much greater.

In the past decade, drilling techniques have improved, and there are enough hot water sources at 90 degrees Celsius to provide a new baseload power source. There is also massive potential to harness heat power from low-grade heat sources.

Read on to find out more.

#1. GEOTHERMAL

Geothermal plants harness energy from the earth. The U.S. is the largest producer of geothermal energy, yet the electricity it produces accounts for only a small percentage of the country’s power supply. In Iceland and El Salvador, however, geothermal provides more than 25 percent of their electricity. And some countries like Indonesia could easily meet all their energy needs with geothermal energy.

Here’s a map that shows all the countries where geothermal could be harnessed in different forms, using different technologies. As you can see, it can be found just about everywhere. It is not restricted to “hot spots” as we once assumed.

The city of Munich, for instance, has a target to supply 80% of their district heating with geothermal sources. In that region, they only have to go a few kilometers down to reach usable temps between 80-100 degrees Celsius. In other regions of the world, however, you simply have to drill a bit deeper. In Finland, for instance, they are drilling for district heating down to a depth of 7 km.

Since about half the cost of installing geothermal plants comes from drilling, abandoned and inactive oil wells represent hundreds of thousands of potential locations to harness heat power with today’s advanced ORC technology. But you might also be able to generate heat power in your own backyard using simple technology called a heat pump.

Wikipedia says geothermal “has the potential to meet 3-5% of global demand by 2050”. We believe that the potential is even greater, especially if you consider the whole heat power market - geothermal, waste heat recovery and district heating. If we incentivize these along with other forms of renewable energy, and implement a carbon tax, we could curb global warming.

#2. INDUSTRIAL WASTE HEAT

Industries generate a lot of heat. More than half of this heat is wasted, even though it could be converted into electricity. The steel, aluminum, cement and shipping industries are all primary contributors. In all of these industries there are massive opportunities to save energy – and money – by utilizing that heat. Not to mention that they would be contributing toward CO2-free electricity production.  

From steel production

If the amount of global waste heat from steel production were efficiently converted to electricity, it could produce at least 540 TWh of green electricity. That’s enough to replace all the coal-fired plants in Germany.

From the oil and gas industry

Most people aren’t aware of this, but when oil and gas companies take these fossil fuels from the ground, most of what comes up is water. Hot water. And before these companies can let this water into local aquifers they must first cool it and clean it! And it costs them billions of dollars. It’s an ideal source of carbon-neutral electricity just waiting to be put to use.

From shipping

Transporting goods is a significant contributor of CO2 and other greenhouse gases – and shipping plays a significant role. While there is hope that hydrogen-powered engines will replace combustion engines in the next 30-50 years, it is simply not fast enough to make a dent. However, if ships could convert their waste heat into electricity for use onboard, they could drastically reduce their fuel use and therefore their greenhouse gas emissions. They could be doing this today.