Alternative Green Energy Sources: 3 Key Developments in Technologies
Green energy developments are picking up steam: Facebook is investing in wind farms, NextEra Energy surpasses Exxon in market value, and Tesla tops the S&P 500. The development of renewable energy technologies has been essential in reducing these impacts on the climate and saving our planet.
Green energy is the new normal.
But while solar and wind efforts dominate the green energy discourse, there are still other options that need to be explored.
Nuclear energy may be the most controversial of the green energy solutions. The processing plants are unsightly and require a significant amount of space. And after the Chernobyl catastrophe in 1986, global citizens are wary of the technology. But in the face of rapid climate change, nuclear may be necessary in order to meet carbon neutral targets.
The State of Nuclear Energy Worldwide
Nuclear technology was first developed in the 1940s and works by harnessing the energy released when an atom in an element is split. Today, 440 nuclear power reactors are providing energy to 31 countries as well as an estimated 50 further reactors under construction. When these nuclear reactors are up and running, 15% of the world’s energy will be generated using nuclear power.
Nuclear contributed 10% to the world’s energy production with the US generating most of this nuclear energy in 2019, followed closely by France and China.
At a total of 132, Asia has the most operable nuclear reactors as of 2020 - a stark comparison to regions such as Africa and the Middle East which only have two each. Researchers at Harvard Kennedy School believe that the lack of nuclear energy production in the Middle East is mainly due to the high construction costs of nuclear power plants as well as the risk of nuclear accidents.
A report by World Nuclear Association (2020) showed that 12 countries produced their 25% of their electricity using energy generated from nuclear. France in particular generated 75% of its electricity due to nuclear energy.
The nuclear industry today is made up of international compliance with many nations being involved in the construction of single projects. For example, a reactor being constructed in Asia may have components supplied by a number of different countries such as Japan or Canada and the uranium may be supplied from Australia.
The Advantages and Disadvantages of Nuclear Energy
The first (and possibly most important) advantage of nuclear is the minimal amount of pollution it produces. Although nuclear energy production can lead to a small amount of greenhouse gases such as carbon being released, it is not anywhere near as much when compared to fossil fuels.
Furthermore, the thermal energy from the nuclear reactor can also be used to help decarbonize other energy consuming sectors such as transportation which contributes heavily to carbon emissions. The thermal energy can be used to produce hydrogen which will discussed in more detail later on.
Additionally, nuclear plants do not rely on fossil fuels and so are unaffected by fluctuating oil and gas prices which can create problems for nations using them. Another advantage of nuclear energy is that unlike other renewable energy sources it has a high power input so a very small amount of uranium can be used to fuel approximately 1000 megawatts. This one reactor can power the industrial plant and an entire city.
Despite nuclear energy seeming like a promising alternative to fossil fuels, the biggest problem is that while this produces very little carbon emissions, it does lead to a large amount of radioactive waste. It’s known to transmit radiation and has a high temperature which means that it can damage storage containers after a certain period of time.
Furthermore, it irreversibly damages human life and the natural environment if they become exposed to it. Although nuclear fuel can decay to a safe radioactive level over time, it can take up to hundreds of years for this to happen by which time it may leak from containers. A good example of this can be evidenced from Runit Island, which resides in the pacific. This island was used by the US to store nuclear waste, however, in recent years there have been reports of the storage container beginning to crack. This could spill radioactive material into the Pacific Ocean, which will endanger millions of aquatic organisms and their ecosystems, as well as contaminate water sources for humans.
Another major problem is the risk of nuclear accidents that can happen during the splitting process. This has occurred at the Chernobyl nuclear power plant in Ukraine where the reactor suffered a critical failure during testing. This resulted in a fatal 300Sv/hr of radiation being released which is still affecting people residing in the area to this day. So while nuclear energy is nearly 100% carbon emission free, the long term effects remain a risk. And the risks involved with nuclear may be far more detrimental to life on Earth than fossil fuels.
Hydrogen energy employs the use of hydrogen and other compounds that contain hydrogen such as oxygen to generate energy. Approximately 95% of hydrogen is produced using fossil fuels by steam reforming, and a small quantity is produced by the electrolysis of water which is the process of separating oxygen and hydrogen using electricity. This is termed ‘green hydrogen’ as it has no other by-product apart from oxygen and hydrogen, thus does not emit greenhouse gases.
Hydrogen fuel cells are being used to power vehicles such as rockets, cars, trains and even airplanes. According to the International Journal for Hydrogen Energy, the transport sector is responsible for 30% of the world’s emissions, therefore decarbonizing this sector is important.
Many companies are currently researching the use of hydrogen as a green renewable energy source. Gigastack and Ørsted secured government funding for their hydrogen project, which would thoroughly investigate and identify methods to reduce the cost of producing hydrogen in the UK. This can help the UK cut emissions, decarbonize its industry, create hundreds of new jobs, and move towards a greener economy.
The Significance of Hydrogen
Hydrogen fuel will be an essential tool for fighting climate change. First, its only by-product is water, which won’t have a negative effect on the environment. Fossil fuels generate copious amounts of excess carbon into the environment, and nuclear energy’s by-product is radioactive waste. Hydrogen, however, poses no such threat and thus, it is extremely significant as it can help nations not only reduce their carbon footprint, but also avoid handling potentially dangerous substances.
Hydrogen also isn’t a finite resource. Hydrogen is available in every corner of the world, whether it is held in water or in rocks and minerals. This variety of sources ensures that a single nation cannot hold power to regulate the supply and distribution of hydrogen, unlike the current state of oil.
Plus, hydrogen is an excellent source for renewable energy systems. Hydrogen can be used to store energy when it is not in use as hydrogen is an energy carrier. Right now, one of the biggest struggles facing green energy technologies is storage (see more below): solar can only be used when the sun is out, and wind can only be used when the wind blows. But when electrolysis is used alongside these production mechanisms, excess energy can be converted into hydrogen fuel, and therefore no energy is wasted. Hydrogen energy conversion systems can transform hydrogen to a variety of different products such as power, cooling, heating, and plastics.
Hurdles and Disadvantages of Using Hydrogen
Recent research shows that the main hurdle to overcome when using hydrogen is that despite being easily split, hydrogen can very readily recombine with oxygen. If the hydrogen recombines with oxygen, it can no longer be used as fuel. Using a catalyst to keep the two elements separate can prevent this from happening.
Moreover, the process also creates oxygen which, despite releasing energy, is not useful for scientists. To prevent this energy from being wasted, it must be harnessed to increase the efficiency in the reaction.
Hydrogen is also difficult to store, especially in vehicles that use hydrogen fuels. It can be hazardous due to its high combustion energy and the fact that it can leak easily from storage tanks. When hydrogen does leak, it is hard to detect as it has no smell. Expensive sensors have to be placed and constantly checked. And because hydrogen is difficult to store, it cannot be moved in large quantities, so requires transport in smaller batches which can be costly.
The main problem, however, is that 95% of the hydrogen currently produced is during fossil fuel combustion, which contradicts the use of hydrogen as a renewable and ‘green’ resource. Therefore, more effort is needed to use alternative methods such as electrolysis to produce hydrogen and eliminate the use of fossil fuels.
However, most countries lack incentive to invest in hydrogen because it will raise the prices of goods and services in industries, most notably transportation. A report by Clean Energy Wire (2020) showed that hydrogen powered vehicles are three times as expensive as conventional vehicles. These issues may deter stakeholders and governments from investing in hydrogen.
But high upfront costs are an inevitable part of innovation, especially in green energy. Just as solar panels and electric vehicles were expensive to acquire and develop, normalization of these new technologies — including hydrogen fuel — is necessary for the survival of the planet.
Hydrogen is an effective storage option, but it may not be the most efficient (or affordable). Storage isn’t a new obstacle to the renewable energy movement, or for the industry for that matter. But it will play a crucial role in abandoning natural gas and coal for 100% green energy options.
Importance of Energy Storage
Electric grids require a balance between power demand and supply. This involves constantly adjusting the supply to meet the potential changes in demand.
For example, less electricity is used during the night, which means the supply is higher than the demand. Power plants store the excess electricity and release it when demand is higher than the supply, such as during power outages. Hydro-electric plants work in the same way by pumping water back behind the dam, which allows excess energy to be absorbed and stored in the grid.
Energy storage can help maintain this balance to create a more reliable grid system. It’s also increasingly important as homes and buildings located further away from transmission grids are more vulnerable to power disruptions in comparison to buildings closer to the grid.
Rural regions and islands often rely on energy storage for their power source as it ensures a constant uninterrupted supply of electricity. Plus, energy storage can improve the running of intermittent renewable energy sources such as wind and solar by storing the excess energy for when there is little wind and sunshine.
Development of Storage Solutions
Of the six storage types listed in the table “Different storage systems currently used around the world,” research shows that pump hydropower is the most common and popular storage system in the world. This system stores the potential energy produced from pumping water from a lower reservoir to a high reservoir.
During periods of high power demand, the stored water is released through hydro turbines to produce electric power. A study by Rehman et al. (2014) showed that pumped hydro energy storage was the most suitable technology for large energy stores and autonomous island grids as it produced an energy efficiency of 87% when tested.
Hydrogen is becoming an increasingly popular mode of storage. As previously discussed, hydrogen energy storage can use the surplus of energy produced by renewable sources to power electrolysis in order to separate hydrogen. The hydrogen can be further stored and re-electrified when needed.
In recent years, China has been researching into the development and application of hydrogen for fuel and storage to power the transport sector. However, China faces many challenges when trying to invest in hydrogen storage. The main issue is developing and obtaining the technology needed to produce green hydrogen, as well the high cost of this infrastructure.
As new energy storage technologies are researched and tested, some barriers are likely to slow the commercialization of these technologies. Energy storage is expensive, especially without policies that place a monetary value on the unique benefits of storage. Plus, there is no current need for additional storage capacity to maintain electricity grid reliability.
Without an operational need, it is difficult for storage to be cost-effective in the present. However, storage has the potential to eliminate the need for fossil fuels, and therefore help reduce greenhouse gas emissions and protect the environment.
The More, the Better
After wind and solar, the most popular renewable energy sources are nuclear and hydrogen, which produce significantly less greenhouse gases and have the power to reduce the carbon footprint of many sectors. While wind and solar are arguably the least environmentally damaging when compared to other sources like nuclear, which produces radioactive waste, the simple fact is that nuclear energy is just more reliable than wind and solar.
Especially with the increasing threat of climate change, weather conditions are becoming more and more unpredictable, which means that disruptions in the climate will reduce the efficiency of these sources. Nuclear, on the other hand, is a reliable source which can be used regardless of climatic disruptions. But making hydrogen and nuclear energy affordable and easy to distribute safely is an obstacle many companies and governments still grapple with.