Today, fossil fuels are being used more than ever. Not only are they running out quickly, but they’re also harming the environment at an alarming rate. Exploring newer, more sustainable ways to create energy is becoming increasingly essential. Waste heat energy is one of them.
With an edge over solar and wind energy, it’s becoming increasingly apparent that waste heat energy offers more benefits than the former. It is not dependent on weather conditions and offers a lot more consistency day to day.
Although they were first discovered in the 1920s, it has only recently picked up momentum. Exergy, a major ORC supplier, gives a comprehensive system analysis. Waste heat recovery systems generate energy using industrial exhaust heat, empowering factories to become independent and reducing grid demand.
When the wind doesn’t blow
In 2021, Europe’s winds were 15% below average. One of the windiest years in 60 years hurt UK energy production. In September 2020, the wind supplied 18% of the UK’s energy. Moreover, in September 2021 UK activated two coal plants to compensate. According to Horizon, the world is getting less windy. By 2100, annual wind speeds could drop 10%, reducing wind power.
Problems can arise when winds exceed forecasts, too. Researchers urged west Scotland wind farms to reduce output by 25MW in May 2022 because the grids couldn’t sustain it. Meanwhile, waste heat recovery is dependent on internal activities. As long as operations produce waste heat, ORCs can provide energy. Refineries and cement mills can provide constant electricity. Predictability helps grid distribution, giving consumers reliable energy year-round.
Unfortunately, since waste heat recovery isn’t renewable, it’s not subsidised. Only 11 states in the US require waste heat recovery, but all 37 include solar and wind. However, recycling heat is as important as renewables. It’s a CO2-free form of energy generation, just like wind and solar energy.
Comparing CO2 emission reduction
ICF International conducted a study and concluded that WHR reduces grid emissions per MWh more than solar or wind. They compared 1MW WHP to PV, wind, and CHP systems; WHPs avoided grid emissions due to their high annual capacity. WHP systems displace more grid electricity and emissions per capacity. Los Angeles’ 1MW WHP system cut 7,332t/MW-year. Moreover, wind and PV fell to 1,373t and 2,456t.
In some regions, waste heat recovery can surpass renewables since installing solar panels, and wind farms can cause issues with neighbours. WHR systems are less likely to encounter barriers of this nature. Waste heat recovery prevents water wastage, and it’s also easier to set up at remote, grid-unconnected sites, unlike oil and gas, where pipelines or compressor stations are far from cities.
Waste heat recovery systems need enough heat potential and a safe temperature range. They’re a fine addition to zero-emission energy options and should be recognised for all they offer. WHP can play a significant role in our collective fight against carbon emissions.