What are the future sources of power generation?
It would be hard to imagine a world without power, but it is easy to forget that the convenience we rely on every day comes from sources that may one day run out or fail on us.
Fossil fuels have powered our society since the industrial revolution. But unless we reduce our reliance on them, they will eventually be gone. Before that happens, they may have irreparably damaged our environment due to carbon emissions.
Society is always looking for new avenues to meet its energy needs. Here is an overview of our current and future options for energy generation.
How long will we continue to use coal?
Burning coal has been a source of heat for mankind since ancient times. By the 1700s, 2.7 million tonnes of coal were burned in the UK every year.
Coal is plant material from millions of years ago that was buried. Through heat, pressure and time beneath the earth, these plants formed into the dense black substance we know today. Because it is made up of previously living, organic matter, coal is considered a fossil fuel.
There are other fossil fuels that developed in a similar manner, such as the natural gas methane. Then there is oil, like petroleum. As with coal, petroleum was the product of ancient organisms (zooplankton and algae) exposed to pressure and heat after being buried by time.
What makes fossil fuels unique for power generation is their molecular structure, consisting of hydrogen and carbon. Though both hydrogen and carbon are found in the world naturally, when they go through an organic phase, they can eventually form what is known as hydrocarbons. When burned, hydrocarbons generate heat in a highly efficient way, which is why they’re so useful to us.
But efficient or not, there is a problem with using hydrocarbons like coal, petroleum and methane for energy production: they will run out. The process that creates them takes millions of years. We are burning through our fossil fuels much, much faster than they are being created.
How long will the earth’s natural supply of fossil fuels last?
This is up for debate. However, many scientists are confident that we are likely to run out this century, even if the rate of consumption doesn’t increase in the meantime.
Fossil fuels may be the energy source of the present, but there is little chance of them being the energy source of our future. So we have to look elsewhere.
Can we survive on solar, wind and water energy?
When we think of renewable energy, most of us think of the trio of wind, water and sun.
It’s intuitive to us that these abundant sources of energy have advantages compared to fossil fuels. Light and heat from the sun won’t diminish for billions of years and, unless we do something catastrophic to our earth, we expect the wind to continue to blow and waves to continue to crash upon our shores indefinitely.
The big question is: do these sources provide enough energy?
To date, despite some heavy investment in wind farms, solar panels, and hydroelectric plants, these sources have only ever been able to supply a fraction of our energy needs. They have always been a secondary source of power that needed to be backed up by the non-renewable resources discussed above.
However, though the amount is insufficient on its own, it isn’t insignificant. In the US, approximately 18% of power is generated from solar, wind, and water. In the UK, we recently hit a high of 43% in 2020, for the first time exceeding fossil fuel usage.
So while renewables certainly have not eliminated fossil fuels yet, is this likely to change?
One challenge is the intermittent nature of these sources. The sun only shines during the day. The wind doesn’t blow all the time. And, waves crash on the coast on a schedule too.
A solution is to store excess energy in batteries, but current battery technology is inadequate to store the amount of energy needed to keep society running at times when direct power isn’t available.
The problem with solar, wind and water power is scale. It may one day be possible to build enough solar, wind and water farms with enough efficiency to meet our energy demands while also utilising future battery technologies to solve the intermittency problem. But today, there remains an energy gap that needs to be filled by another type of power, whether that be coal or, as is becoming more common today, nuclear.
Can nuclear energy replace some fossil fuels?
When we talk about nuclear energy, we are usually talking about nuclear fission, in which a controlled chain reaction is set off in enriched uranium or plutonium, creating heat.
Like a coal-burning power plant, that fission-produced heat turns water into pressurized steam that then turns a turbine generator, generating electricity.
The big difference is that when coal is burned, carbon is released, which damages the atmosphere. That doesn’t happen with nuclear power. And unlike solar, wind and hydro energy, nuclear plants can generate power 24 hours a day.
On the surface, nuclear energy sounds like the ideal solution we have been looking for. But nuclear power has issues of its own. When the uranium or plutonium is spent, it remains radioactive and dangerous for quite some time (from hundreds to millions of years). Though it does not pose much threat to people if it is appropriately disposed of, proper handling of nuclear waste is still an important consideration when it comes to nuclear power.
There is still great considerable interest in nuclear power. Today, about 20% of the UK’s electricity is generated from nuclear sources. Currently, there are 6 active nuclear power plants in the UK, with plans for 6 more in the coming decades.
With the clear advantages of nuclear power and the evidence of future investment in nuclear power plants, nuclear power will likely play a role as fossil fuel reserves become depleted over the coming decades.
But what are the other options?
Other options for future energy generation
There are a few lesser-known energy generation technologies that deserve a mention:
When pure hydrogen is combined with oxygen, the chemical reaction generates energy, the only by product being water. It is a clean energy source and, because hydrogen is so abundant in the world around us, it is sustainable. “In power generation, hydrogen is one of the leading options for storing renewable energy, and hydrogen and ammonia can be used in gas turbines to increase power system flexibility.” says the IEA in a report about hydrogen.
Biomass most commonly refers to using plants, especially crops such as soy, as a material for burning. First, the plants are dried, then formed into briquettes. At this point, the process is similar to the use of coal.
Biomass has pros and cons when compared to fossil fuels. There is less carbon stored in a recently living biomass briquette than in a lump of coal, leading to lesser environmental damage after burning. On the other hand, coal is still far more efficient. Unlike coal, biomass is easily renewable, but it does take a lot of space to grow the plants.
Geothermal refers to the heat from beneath the earth’s crust. There are multiple ways of harnessing the earth’s natural energy. One is to dig for steam beneath the surface to drive turbines directly. This is referred to as dry steam energy. A more modern approach is the flash geothermal power plant which seeks underground hot water. Or the binary geothermal power plant, which uses a heat exchanger to transfer energy from geothermal fluids into a secondary fluid with a lower boiling point.
Didn’t we already talk about this? No, that was nuclear fission: splitting atoms apart. Fusion is combining atoms, and it could produce even more energy even more cleanly. The downside is… we can’t do it yet, at least not commercially. The technology might be years or decades away, but there is certainly optimism that we can exploit nuclear fusion in the not-too-distant future.
It’s clear that the question ‘how will we generate power in the future?’ needs to be taken seriously. Science does not yet have all the answers. We will continue to use a mix of energy sources for the foreseeable future, each with its pros and cons. There may never be a perfect solution, but with science, government and culture at large pushing for it, a truly sustainable future may one day be reality.
To find out how Sterling Thermal Technology is contributing to the future of power generation, see our heat exchangers for the power industry page.