In October 2018, the Intergovernmental Panel on Climate Change (IPCC) warned that governments must make “rapid, far-reaching and unprecedented changes in all aspects of society” to avoid catastrophic levels of global warming. Global scientific authority was uncertain. At the current rate of warming, the planet will reach a critical threshold 1.5 degrees Celsius above pre-industrial levels as early as 2030. Effects include stronger storms, more erratic weather, heat waves, floods, food shortages and rising seas, and large-scale disruptions to migration patterns; will be felt among ecosystems, communities and economies worldwide.
To combat catastrophic climate change, we need to drastically reduce the amount of greenhouse gas emissions from economic activities such as fossil fuel use, deforestation, land use change and industrial farming practices. According to the IPCC, to ensure we maintain a 50-50 chance of limiting warming to around 1.5 degrees Celsius this century, we need to reduce CO2 emissions by 45 percent from 2010 levels by 2030 and reach what is called “net zero”.
Meanwhile, the global population is growing rapidly and by 2050, it will have reached approximately 10 billion people, most of whom will have emerged from extreme poverty and will have significantly higher energy needs. We are expected to increase current global energy production by over 50 percent to meet their demands.
Climate scientists say renewables must become the world’s dominant source of energy by the middle of the century, to maintain any chance of reasonably limiting global temperature rise. Also, according to the International Energy Agency’s World Energy Outlook, ‘renewable energy technologies provide the main pathway to achieving universal energy access’.
One way to achieve these goals could be to harness the power of the sun, which is the most abundant energy source available. In recent years, solar power has become cheaper and easier to collect each year, and rapid developments will almost certainly continue. In fact, solar photovoltaics (PV) are one of the cheapest ways to generate electricity in many parts of the world.
However, even after experiencing unprecedented growth in the last few years solar PV is still responsible for only a small portion of global electricity production, and electrical power currently only accounts for about 25 percent of global energy demand. However, according to the IEA, solar PV is currently ‘going forward’ and its increasing competitiveness is expected to surpass wind power generation capacity by 2025, hydro by 2030 and coal before 2040.
Announcing the latest World Energy Report, IEA General Manager Fatih Birol said, “If the world is serious about achieving its climate goals, there should be a systematic choice to invest in sustainable energy technologies as of today.”
KMT Solar R&D Laboratory is a research and design laboratory set out with the mission of creating better and more sustainable lifestyles. Exploring the potential of solar PV, the world’s fastest growing new energy source, is part of this mission.
This report kicks off our explorations in solar PV. It provides an overview of the current landscape and examines what solar energy is, how it is produced and how the market for it has evolved. The report also highlights key innovations and emerging technological trends.
In short, we believe we are on the verge of a radical change in how we consume, produce and sell energy. With solar PV growing faster than any other renewable energy source, we believe we need to accelerate its growth, use its electricity for more energy needs and, above all, make it more accessible and affordable.
Why is the sun the center of the world’s energy future?
On average, the sun provides about 90,000 terawatts of energy to the Earth’s surface. Don’t worry about what Terawatt is. The important thing is to compare this number with today’s aggregate demand worldwide. As of 2015, for all our energy needs, we need about 17.4 terawatts, or less than a quarter of that, for about eight billion people. In other words, if we could gather the power of the sun in just under two hours each year, we could meet all our current needs. (It’s not just electricity, it’s all our needs for transportation, our homes, offices, and industries.) If accepted, it will never be possible; About 30 percent of solar energy is either covered by clouds or reflected from the earth’s surface, while two-thirds hits the ocean. But even after these losses are taken into account, the sun provides a significant amount of energy that could theoretically meet all of our needs.
Of course, much of the earth’s surface is water, and where it’s more difficult to harvest solar energy. And at high latitudes, there are often periods of little sunshine in winter. Yet in many parts of the world the sun represents a reliable and truly enormous source of energy.
We can also refer to the available energy from the sun in relation to the worldwide reserves of fossil fuels on earth. We can’t be sure of the numbers, but in about a week the planet is getting more solar power than all the oil, gas and coal known to exist in the planet’s recoverable reserves.
Moreover, the sun’s rays carry much more energy than the world’s winds, which are the second most common sources of renewable energy. Compare 90,000 terawatts of solar energy with the less than 900 terawatts typically have winds blowing around the world (only a small fraction is found close to the ground and can be captured by wind turbines). This is a difference of twice the size, and in many parts of the world the wind barely stirs the trees. The sun is both more common and exists on a much larger scale. All other renewable energy sources, such as biomass or the power of falling water, are other ranks, even less important than wind.
Also, in 2017, researchers at the Potsdam Institute for Climate Impacts Research published their study of the full-life cycle greenhouse gas emissions of a range of electricity sources by 2050. The ‘Carbon Brief’ explained what this means: ‘Contrary to the claims of some critics, research shows that the hidden emissions from building wind turbines, solar panels or nuclear power plants are very low compared to the savings from avoiding fossil fuels. ‘
Now the world can decide to get its energy needs from nuclear fusion (the technology used in today’s nuclear power stations) or fusion (capturing the energy produced when atoms are violently combined to form a new chemical element).
However, both fusion and fusion have serious problems. For example, next-generation nuclear power plants have proven to be both expensive and extremely difficult to build. One scientist said these giant structures are like ‘cathedrals within cathedrals’, which adds greatly to the complexity of construction. Nearly all of the few new facilities being built around the world have typically been delayed by about a decade and spent billions of dollars over budget. Moreover, we have yet to find a cheap and safe way to store the waste from nuclear fusion.
Solar has other advantages as well. Most renewable energy sources become much cheaper as the size of an installation changes. Large industrial wind turbines, possibly with a capacity of 4 megawatts, can cost several million dollars, but expressed as a price per watt, they are much cheaper than smaller scale machines. This means that an increasing proportion of all wind power plants are indeed made up of very large turbines located on large farms.
Solar PV is very different. Building a very large solar farm is certainly cheaper per unit, but costs differ to a much smaller degree. Photovoltaics are more modular than wind; After all, PV panels are significantly smaller and more flexible than modern windmills. In some cases, putting 100 kilowatts in a 1 kilowatt warehouse or 10 megawatts in a solar field on the roof of a house is a good idea.
It may make sense financially.
This is a vital support for the rapid growth of the sun. This means that the decision to install PV can be made by homeowners and small businesses, as well as the major financial institutions that currently dominate the installation of large wind farms worldwide. This is a loose use of the word, but solar is inherently more democratic than other energy technologies. Among other benefits, this means that the world can use solar PV to bring electricity to regions with very limited availability until now.
The history of solar photovoltaics
NASA launched the Vanguard 1 satellite in 1958. This was the second US satellite to go into space in response to the Soviet Union’s Sputnik program. He sent signals to the ground for six years. The electricity for these transmissions came from small photovoltaic (PV) panels outside the satellite. This was probably the first use of solar panels for practical purposes, extending the satellite’s lifetime far beyond previous battery-powered devices.
The amount of power the panels produced was very small, probably a fraction of a watt. In the photo below is a replica of the Vanguard 1 satellite. Three of the six small solar arrays are visible, protruding slightly from the sphere containing the satellite’s electronics.
Today, satellites still use solar energy as their main power source. The International Space Station has huge wing-like panels that extend almost 75 meters from its fuselage. In total, these solar arrays can generate up to 120 kilowatts of electricity, perhaps half a million times the power of the photovoltaics in Vanguard 1.
The price of solar panels has dropped significantly since the early days of technology. Cost estimates from the 1960s are unreliable because the volumes bought and sold were very small, but we have good data on the price of panels from the next decade. In the 1970s, one watt of maximum capacity cost about €88 (the rated capacity of a solar module is power generated at midday at a panel temperature of 25 degrees in full sunlight and the panel is at an angle of 45 degrees horizontally). In March 2019, the number was around 35-47 euro cents and has declined by as much as 250 times over the last 40 years. This figure will almost certainly continue to fall.
The rate of decline is driven by a phenomenon commonly known as the experience curve, which assumes that the more experience a business has in making a product or providing a service, the lower its costs. As the world got better at panel building, costs have dropped predictably. Overall, the market price has dropped by about 20 percent as the total volume of panels ever made has doubled. It is the ‘experience’ gained by making panels that keep costs down almost non-stop. We see this phenomenon in a wide variety of industries, from semiconductors and gene editing to well-established manufacturing jobs like paper or glass manufacturing. Hardly anyone is arguing that solar cost reductions will stop anytime soon.
How do solar panels work?
Sun rays are actually bursts of energy called photons. When they hit the thin layer of silicon in a solar panel, a photon can displace the electron in one of the atoms. The electron will move from the silicon to the metal electrodes on the front of the panel. This creates an electrical charge between these electrodes and those behind the silicon. An electrical flow is generated as the electron returns to a circuit between the receptor electrodes and to the front of the panel.
The amount of energy in a photon changes. A photon with a relatively low energy, which humans feel as heat, will not displace an electron and will pass through the photovoltaic material. However, red light has enough energy and will result in electricity production. Photons at the blue end of the light spectrum, which carry much more energy, will result in electricity production, but most of this energy will be wasted as heat.
The theoretical maximum amount of solar energy that can be absorbed by today’s single-layer silicon cells is about 34 percent.
What else do we mean when we say ‘solar energy’?
Most attention is paid to solar PV, which is the conversion of photons of light into useful electricity. We should briefly consider two other ways of using solar energy.
Mankind has used the sun to provide hot water for hundreds of years. ‘Solar thermal’ collectors directly absorb the energy of the sun’s rays in a circulating fluid. The hot liquid is then passed through a heat exchanger in a home or business water tank, heating the water for use in showers or kitchens. Although some solar installations provide hot water for large buildings in sunny countries, they are never likely to meet most of the world’s energy needs.
Second, and increasingly important worldwide, is ‘concentrated solar power’ (CSP), which uses solar energy to create steam or to heat a complementary fluid, such as molten salt or synthetic oil, to very high temperatures. This steam or liquid is then used immediately to power a turbine to generate electricity, or is stored in a tank for later use when the sun goes down.
CSP is more expensive than photovoltaics – however, like PV, its price drops sharply. It will probably always be more expensive than traditional solar panels and maintenance costs will always be higher, but it makes up for this disadvantage by providing 24-hour electricity generation.
There are two main technologies for harvesting energy in a CSP plant. In the first, the heat is collected in a tube placed at the focal point of the parabolic arrays. The reflected heat is focused on the thin tube. Inside the tube is a circulating liquid that heats up to perhaps 700 degrees Celsius. This hot liquid can be stored for later use or used immediately in a steam turbine to generate electricity.
The second approach to concentrating solar energy is becoming more popular. A large number of mirrors (“heliostats”) are placed around a central tower. The sun’s rays are reflected by the heliostat into a heat collection tank at the top of this tower. This tank contains a salt such as potassium nitrate, which melts at high temperatures. The molten salt can be used as a fluid to transfer heat from the top of the tower to a storage tank at the bottom. As with a parabolic array system, this heat can be used immediately to generate electricity or held until electricity is needed, usually at night.
What is preventing the sun from taking control today?
In some sunny countries, energy developers set up solar farms at guaranteed prices of no more than 2 US cents per kilowatt hour. Recent examples of contracts at this level come from places as diverse as Saudi Arabia and Mexico. In other countries the price is sometimes higher. For example, India still pays 4 US cents for new developments. This is partly because the cost of investment capital is higher, but also because the connection to the grid is sometimes costly or less reliable.
Even with these variations, the cost of new solar power now falls below the cost of building and operating any type of fossil fuel power plant in many parts of the world. In less sunny countries, such as in northern Europe, onshore winds can sometimes be even cheaper. However, in most of the world, solar PV is outpacing a new fossil fuel plant.
This is good news. After six decades of research and production improvements, solar power now drives down the price of energy wherever it’s used. However, according to the International Energy Agency, it is still only 2 percent of world electricity production, and the growth rate of solar power generation in 2018 will be the lowest in many years. Still, this figure is still very high, at over 18 percent. And in 2017, more money was invested in solar PV than any other power source — $103 billion for fossil fuel power plants. compared to $161 billion.
So why isn’t the sun growing faster? If it’s cheaper than any other new power source, why doesn’t all our electricity come from PV? First, because a large amount of coal and gas generating capacity is installed and ready to generate electricity. Often fully depreciated, their operators will open power plants as long as they cover their immediate generation costs. They do not have to incur any capital costs. While their hourly use is declining, many coal plants around the world can make enough money to encourage their owners to keep them open.
Second, aggregate electricity demand is falling in some developed countries. It is more difficult to invest in solar energy if the energy need is met by existing power plants.
Third, the sun is both intermittent and unreliable in many places. Of course, it can only be used for an average of twelve hours a day, and clouds can interrupt the flow of power even during the day. Electric companies can often deal with these problems, but solar power requires energy management skills that aren’t needed in coal or especially gas plants.
Fourth, storage is still expensive. For example, electricity can be kept in a battery overnight, but this can double the cost of electricity at night in a sunny country.
Why will solar growth continue anyway?
Despite the obstacles mentioned above, the future of the sun is bright. It will probably get even cheaper in the uncertain future. Why?
First, solar PV panels using conventional silicon will likely continue to decline in price worldwide. The drop in price is due to many separate developments summarized above as the effects of the ‘experience curve’. New materials such as perovskites and organic molecules mentioned below can replace silicon, which uses a lot of energy to process and helps maintain the reduction rate.
Second, some solar experts are confident that the efficiency of the typical panel (the maximum percentage of energy that can be converted into electricity by the panel) will continue to increase, albeit slowly. Meanwhile, other improvements will increase the amount of electricity produced from a solar field. Electronic systems will evolve, and more importantly, more PV farms will use tracking systems that move panels to face the sun throughout the day. These monitoring setups can capture at least 25 percent more energy and will increase the electricity delivered, especially in the afternoon, when it tends to be more valuable.
Another major improvement is the use of PV, which collects energy on both sides, especially when combined with monitoring. These panels are called ‘bifacial’ and typically increase electricity by 11 percent.
As confidence in the reliability and longevity of solar energy continues to rise, the financial returns demanded by banks and other financiers worldwide are falling. This has bigger ramifications than we think. Very approximately, a 7 percent to 4 percent cut in demanded return cuts the cost of solar electricity by 25 percent.
What’s more, solar equipment of all types will likely last longer. Twenty years ago, manufacturers assumed that panels could lose more than 1 percent of their average production each year and would need to be replaced after 20 years or less. Today, leading manufacturers guarantee their products for significantly longer periods. Trina, the world’s largest manufacturer, promises more than 80 percent of initial efficiency 25 years later. The probable truth is that a solar panel purchased today will still continue to operate reasonably productively in half a century. And then it will either be recycled into materials for new panels or almost entirely for other purposes.
Solar can also provide some unexpected benefits to other users of the area where the panels are installed. For example, floating solar panels placed in reservoirs can help reduce evaporation, which is a key advantage in drought-prone countries like India. Meanwhile, solar panels in fields can provide shelter from rain and cold for sheep and goats, improving their growth rate and overall health. In a new development, the researchers say that in very dry climates, placing solar panels on tall frames well above the growing crop will increase yields because PV prevents plants from getting too much sun and losing water. Similarly, solar garages can now generate electricity to charge electric vehicles.
Finally, it is important to note that solar PV is becoming increasingly popular among citizens as an energy source. Even in states that mine coal in the US and get most of its energy from this source, residents still prefer solar and other renewable sources. Therefore, politicians have the freedom to promote the growth of solar energy. The sun’s electricity Companies that buy power from power plants can be advantageous in the eyes of their customers.
As noted above, new materials are emerging that will help make solar power even cheaper. Currently, most PV panels are made of very thin sheets of silicon doped with small amounts of phosphorus or boron. Other materials used include even thinner layers of cadmium telluride or gallium arsenide. However, most solar panels installed today are made of conventional silicon semiconductors. 20 years from now, this may not be the case. Although silicon-based modules are getting cheaper and cheaper, they still use large amounts of expensive energy to be encased and made with glass and aluminum.
Other materials can act as a photovoltaic material. There are two main types of panels that can replace silicone over time. The first are known as perovskites. The word ‘perovskite’ refers to a particular type of molecular structure. Many different chemical compounds have this shape, but some have strong photovoltaic capacity. It best contains metals such as bromine and halides.
Scientists around the world are rapidly moving forward with research to try to extend the life of solar cells made with these molecules. Britain’s Oxford PV is among companies trying to commercialize perovskite technology. He wants to make cells with a very thin layer of perovskite on conventional silicon. Perovskite harvests energy from different light frequencies into silicon, meaning the total amount of electricity these ‘tandem’ cells produce should increase.
Oxford PV hopes to convert its perovskite-and-silicon cells by up to 37 percent, while the value of solar power to electric power is 29 percent today well collected by silicon single cells. It is easy to coat a silicon cell with perovskite, so these molecules will improve solar PV economics. Oxford PV expects that over time solar cells will be made entirely from perovskites because it will be very inexpensive.
The second type of material that can replace silicon is known as organic photovoltaics. Many other molecules also collect solar energy and can convert it into electricity. Heliatek, based in Dresden and arguably the world’s most advanced next-generation photovoltaic manufacturer, uses relatively simple organic molecules called oligomers. (In this context, ‘organic’ means containing carbon.) Heliatek’s photovoltaic materials can literally be printed on a lightweight plastic backing paper and then stored in a roll. Currently, they are not as efficient as conventional silicon PV, but are expected to be inexpensive to make and easy to install. The testing grounds for Heliatek’s organic photovoltaic films include school roofs and the sides of factories.
Will perovskites completely replace silicon? Will every building be covered with light and flexible PV made from organic films? We cannot predict the future. But we can be pretty sure that solar photovoltaics will improve in terms of price, performance, durability and flexibility.
Dreaming of a solar powered world
The cost of solar power in the sunniest parts of the world can drop to just under 1 euro per kilowatt hour for large solar farms. To put this in context, a home owner in Germany currently pays the equivalent of 8-12.5 euro cents for a kilowatt hour. Of course, households have to pay for electricity transmission and many other costs, but the disparity between the costs of solar electricity at the point of generation and the normal costs of energy to be purchased is growing more and more from year to year. This will continue to encourage both large-scale solar generation and the installation of panels on roofs so home and business owners can save money on their electricity bills.
For energy from solar panels to be truly useful, we need to be able to store it for use when needed. Batteries are best for overnight storage or perhaps to protect against a cloudy day. These can operate on a small scale at home or be installed near large renewable farms to provide large amounts of storage. As of November 2018, the world’s largest battery is located at Hornsdale wind farm in Australia. When shipped at peak output, the battery can provide enough energy to power 33,000 homes. However, its main function is not to store electricity, but to help stabilize the electricity market by charging and discharging it at useful moments.
Other large battery systems are better suited to hold solar power for nighttime use. The Hawaiian islands, for example, are installing batteries to help increase the amount of solar power that can be installed productively. A typical recently announced project sees 120 megawatt hours of storage along with a new 30 megawatt solar system. Currently financially possible in most countries though not, an increasing number of homeowners around the world are installing battery packs in their homes.
Of course, homes tend to use most electricity at the beginning and end of the day. The business usage profile is very different and much more compatible with the power output from a solar panel. That’s why it makes more and more sense in large parts of the world for factory and warehouse owners to put as much solar power as possible on the roofs of their buildings.
In addition to short-term storage in batteries, we will use today’s advanced digital technologies to help solar owners make the most of their energy. Currently, an electricity producer usually sells its PV generation to an energy company that trades electricity or retails it to its customers. Some experts believe distributed ledger technologies will play a vital role in helping solar owners make the most of their power.
Blockchain, for example, is ‘a distributed, digital transaction technology that allows the secure execution of smart contracts over peer-to-peer networks independent of a central authority such as banks, trading platforms or energy companies/utilities’. It is envisaged that in the not-too-distant future, electricity will be traded directly between producers and consumers, even if they are not physically connected or even geographically close. In other words, it could allow people to buy energy directly from producers, and theoretically both parties could benefit from eliminating middlemen.
One of the visions is that millions of small producers will be able to sell their excess solar electricity to remote buyers. The process may be in units as small as possibly 1 kilowatt hour. The reconciliation of the transaction will take place at the same time or immediately after the production / consumption takes place. Direct trading will create opportunities to increase revenues and reduce costs. For example, a community-owned solar park could offer electricity in exchange for an initial investment. Or a hospital can buy electricity from the roof of a local factory. Blockchain also makes utilities and grid operators more efficient because they can balance supply and demand in near real time.
Additionally, if buyers knew when power was produced, they could adjust their own energy consumption. Imagine owning a domestic battery system and making a deal with the local solar farm. When it generates power, you can buy and store what you need at an affordable price. When the cloud becomes cloudy, you stop importing energy and use the battery to meet your needs. Utilities and technology companies around the world are running massive experiments linking users’ electricity consumption directly to generation from local solar panels.
Alternatively, imagine owning a stake in your city’s solar farm, located on farmland just outside the city limit. Blockchain-like technologies allow the farm to allocate a percentage of total output to properly charge your battery. When this is possible, you will still have to pay a fee for your connection to the grid, but your power will still be much cheaper than it is today.
Several examples of blockchains that form the basis of energy systems are in development. In New York, an energy company and a tech firm have launched a system that allows neighbors to buy and sell solar power from each other on a blockchain platform that documents their transactions. Similarly, a consortium that includes a development company, a nonprofit known as Solar One, a cooperative funding agency, and an environmental advocacy group is creating an 80,000-square-foot solar garden in Brooklyn. According to Fast Company, ‘once completion, it will be one of the first examples of cooperatively owned urban energy supply, potentially a model for other city coalitions to follow as they seek mutually beneficial avenues and public rooftops to be reused as shared solar energy sources. ‘
Moreover, where electricity grids are not available, solar will increasingly come to be seen as one of the best ways to supply the energy needed by families and small businesses. Although showing a downward trend, the number of people worldwide without access to electricity is approximately 860 million. Building the electrical distribution system to cover every home in major countries is an almost impossibly expensive task. That’s why so many companies have started offering kits for homes or household groups to install solar panels, batteries, and highly energy efficient appliances. These systems almost always rely on solar PV. A report from McKinsey optimistically predicts up to 150 million households in the developing world by 2020.
He suggests how much solar home systems he could be in a position to take advantage of.
Payment for electricity is usually made via a mobile phone transfer, including the groundbreaking M-Pesa mobile system in Kenya and its counterparts elsewhere. Until recently, locals sometimes resisted local solar systems because they wanted the grid operator to have full access to the electricity grid. But as the power from solar systems increases and the energy requirements of appliances such as televisions and refrigerators decrease, more and more people are served by small microgrids that perhaps cover a few homes and a community room.
More generally, solar power is helping the world’s process of gradually distributing its electricity supply. Twenty years ago, nearly all electricity was produced at a small number of large power stations, almost all of which used coal, gas or oil. Supply networks often span hundreds of kilometers to reach consumers far away. Today, generation can take place much closer to those who use power. The measurements are not exact, but the average distance between the point of electricity generation and its final use is probably falling for the first time in history.
Among many other beneficial results, this means that network companies have to spend less on maintaining or upgrading their power connections. In isolated areas with good solar resources, communities and businesses such as very remote mines are starting to develop microgrids that make the regions almost self-sufficient. Eventually, we may see smaller communities move away from centralized grids altogether to save on transmission costs. Solar makes this possible. After Hurricane Maria devastated Puerto Rico in September 2017, solar-powered microgrids using batteries for storage enabled hospitals and other essential facilities to continue operating while the electrical grid was unable to provide any power.
The potential role of distributed ledger technologies could be huge, but there are some caveats. First, both electricity suppliers and their consumers must pay the distribution company fees today – and it is unlikely that regulators will allow peer-to-peer merchants to avoid these fees. Similarly, most governments are unlikely to allow peer-to-peer trading, which eliminates value-added tax requirements. Third, many governments in Europe impose fees that depend on consumption levels (for example, the cost of renewable energy subsidies in some countries is a significant part of people’s energy bills).
Finally, some industry experts believe that advanced electricity metering systems for consumers and generators have an important role to play, offering demand management and storage incentives, and sophisticated life-cycle pricing plans. For example, the UK Energy Authority has introduced a tariff that offers incentives (such as a negative or ‘decline’) to consume energy when central wholesale prices fall below a certain level.
Solar Energy is on its way to becoming the world’s largest energy supplier!
It is estimated that by 2050, solar and wind will produce half of the world’s electricity. Success in keeping the Earth to a temperature rise of no more than 1.5 degrees will depend in part on sunlight meeting these optimistic projections and at least doubling within a few decades.
Is it possible? It will help the batteries grow because they allow the PV to function as a reliable 24-hour power source (perhaps powered by backup diesel generators). But the batteries are not enough. For example, they do not provide the high power density needed in long-haul air transport (a PV airplane, Solar Impulse, has flown around the world, but carries a person using an enormous array of solar panels). More importantly, they cannot offer enough power to store energy from one season to the next in countries where there are significant changes in sunlight.
Although we need batteries, we also need to have the capacity to store energy for months. How can we do this? While not yet financially feasible, the answer is surprisingly easy: We can use solar electricity to split water into its two constituent elements (hydrogen and oxygen) in a process known as electrolysis. Hydrogen atoms carry a large amount of energy that we can use as fuel for direct heating or other parts of the energy system. For example, as part of its efforts to have a carbon-neutral energy supply by 2020, the Dutch island of Ameland has successfully added sustainably produced hydrogen to its natural gas system.
However, storing hydrogen is expensive, in part because it uses a large amount of space per unit of energy. So we need to keep hydrogen in much more favorable forms . Ideally, we would combine it chemically with carbon dioxide that would otherwise have been added to the atmosphere. (Conventional fuels are usually either simple combinations of hydrogen and carbon, such as methane, or have some oxygen bonding, such as methanol.)
This will allow us to create synthetic fuels that can be used as a substitute for existing fuel sources. Over time, these “carbon neutral” fuels can replace all the fossil fuels the world currently uses, allowing us to run energy-intensive parts of the global economy – such as passenger jets – without contributing to the global warming crisis.
Of course, to make this solution (and others) financially attractive, the price of solar-generated electricity needs to be reduced to the lowest possible level. In terms of cost per energy unit, solar is already cheaper than oil at $75 per barrel, but natural gas is cheap enough for synthetic fuels to count on continued reductions in the cost of solar power.
However, if we want to stop climate change and reduce the rising cost of managing or mitigating its devastating consequences, there are few alternatives other than investing in renewable energy sources such as solar. Although we have a very long way to travel to achieve carbon neutrality, the advantages of solar power are so great that its future central role in the global energy supply system is warranted. The only question we face is how to accelerate its growth.
KMT Solar R&D Lab now hopes to explore ways to leverage edge technologies and digital services to finance, produce, distribute and consume solar power in more efficient ways. Ultimately, we want to upgrade traditional business models and systems to create more affordable inclusion for underserved segments of the global population.
About the author:
Chris Goodall is a British businessman, author and expert on new energy technologies. A graduate of St Dunstan’s College, Cambridge University and Harvard Business School, he is the author of The Switch, a book revealing solar, storage and new energy technologies. The website Carbon Commentary, part of the Guardian Environment Network, provides weekly information on clean energy developments around the world.