Synopsis: The potential goes beyond just being ‘green’.
Consider home solar. With solar panels you can reduce your electricity costs, but to go ‘off grid’, you need a battery or other energy storage for the solar power. What size battery depends on how long before there will again be sufficient solar. With enough to power the home and charge the battery on a sunny day, the battery will need to last until the next sunny day. But with more panels it may be possible to power the house and charge the battery even on a rainy day, which means a far smaller battery will enable being completely off grid. The right balance will depend on the relative cost of solar panels and batteries.
Of course, if there is sufficient solar energy even on a rainy day…… then on a sunny day there will be spare power to enable doing much more.
The same applies at state or national levels, to go ‘off grid’, or in this case ‘off fossil fuel’, again requires a mix of extra capacity to achieve “low threshold baseload” even with less-than-ideal weather, plus some storage and/or some other green predictable energy. This is an exploration of the barriers that mean the ‘green’ technologies like solar and wind, alone will never quite allow exiting fossil fuels for power. To replace fossil fuels for power, requires continuous green energy or storage and strategy, and most countries are not there yet.
Disruption is rarely one-for-one replacement. Solar and wind that can replace fosil-fuelled power, inherently can provide bonus-electricity that has almost zero marginal cost and can deliver a competitive advantage for energy intensive industries.
Applications: The need for power.
Portable power for vehicles: Solutions being deployed, but not connected.
A Long History of use of renewables.
Vehicles have a long history of perfecting methods to deal with the unreliability natural sources of energy.
Vehicles have long history using direct wind energy, and more recently with solar energy in the World Solar Challenge. Even in the air, gliders can operate on direct energy from air movement, but like sail boats and solar cars, the use of direct energy from nature is relegated to recreation and competitions.
Stored Power for Vehicles has a long history of adaptation.
1819: The first ships that were built using steam power began to cross the Atlantic Ocean. Steamships used a combination of wind and steam power to move.
1845: It was in the mid-1800s that the first ocean liners built from iron began to appear. The ocean going liners were also driven by a propeller instead of sails like many earlier ships.
1880: River boats that were driven by steam were called stern wheelers. Other similar boats featured paddle wheels on each side and were called paddle steamers. Paddle steamers were mainly used for transport on rivers.
1910: Ships that were previously powered by burning coal started to be converted to diesel power, and started to use oil as opposed to steam.
A TIMELINE OF SHIPS, BOATS, AND YACHTS
It took less than 100 years to complete the progression from wind to stored energy in vehicles, and there is no sign of any return to some form of direct energy.
Overwhelmingly, commercially viable vehicles currently rely on stored energy. The lesson is, while renewables are more economical, they are not competitive without storage.
Vehicles: Necessity drives Innovation.
In fact the race to power vehicles with alternatives to fossil fuels has, in contrast to the electrical grid, focused on alternative stored energy, and not the source of the energy itself. So while the electrical grid has focused on sources of energy: Hydro, Nuclear, Wind, Solar, Geothermal etc, the motor vehicle industry has focused on how to store energy: Batteries and Hydrogen.
As a result, batteries from Car companies such as Tesla have found their way into the electricity grid. Hydrogen cars look like losing out to batteries in cars, but the technology developed could find its way into aviation and shipping.
Leading the way on electrical energy storage technologies.
Breakthrough battery technologies were first deployed in mobile phones, with with Sony as the first, introducing them in 1991. Once electric cars such as the Nissan Leaf and Teslas entered production, the market for battery technology grew significantly, as did the focus on larger batteries more relevant for grid storage.
EVs: The potential energy storage solution being deployed, but often overlooked.
Current sales of EVs are already seeing many more times the grid battery capacity deployed by electric vehicles. Grid storage, even in countries such as the US or Australia where EV sales are still low, is not matching the storage in consumers EVs. As EV sales rise, batteries deployed could soon surpass the equivalent of 100 times the rate of grid storage expansion.
There are challenges and infrastructure required to enabling EVs to assist with grid storage, but so far, no country seems to have any plans utilise this huge potential asset.
Stationary Power: Traditional grids mainly use stored energy.
The traditional grid, powered by Stored Energy: Fossil fuels, hydro, nuclear.
Ever since the days Pearl Street Station in 1882, our use of electrical energy has been based two types of power source:
- predictable ‘base load power’: turbines providing continuous supply.
- on demand supply: a limited ability to provide increased supply at relatively short notice
Every technology prior to solar and wind fits with these patterns as they are driven by stored energy that consumed at the rate the power station determines.
Gas, Coal, Geothermal and Nuclear power stations all heat steam in order to drive turbines.
Hydroelectricity is based on releasing water from dams to drive water turbines. All the heat/steam systems require hours if not days to start once shut down, leaving only hydro systems as particularly flexible. Starting turbines requires time and is costly, so turning turbines off comes at significant expense.
The turbines can be kept running at peak efficiency because the source of energy to power them is stored energy, ready for use as required. Gas and Coal are long term stored solar energy, converted from solar to chemical potential energy long ago, and accessible by burning the fuel. Hydro electricity is based on water with gravitational potential energy accessed by letting the water run downhill. Atomic energy is present in the atoms used as fuel and is accessed by initiating atomic reactions.
The nature of ‘continuous supply’ base-load power has made electricity less expensive during ‘off peak times’, as the electrical potential is available whether or not it is required.
Direct Solar and Direct Wind Power: Limited Replacement of Coal and Gas.
With solar and wind, the source of energy is not ready at the site of the generator waiting to be converted to electricity, but instead is immediate converted to electricity and supplied to the grid.
Having Solar and Wind that can generate enough power to match annual demands is within reach. What is not within reach is Solar and Wind generation that can deliver required power when it is needed, including at night when there is no wind, or other times of minimum generation.
Because weather can be predicted with reasonable accuracy, the ‘base-load’ parts of the grid can have an advanced expectation of the power available from solar and wind, and can adjust their output, lowering their consumption of their stored fuel. This reduces emissions, but does eliminated coal and gas or the running costs.
There still may be some variability despite forecasts, so there will be times of excess power, when grids can lower their prices to enable customers who are flexible on when they use power to make use of lower cost power, but there is always some inefficiencies due to the need to allow for any difference between forecasts and real time power.
The biggest restriction is that there will be days when there is almost no solar power, and other times when there is almost no wind power. There is significant variation between ‘best scenario’ generation and ‘worst scenario’ generation from solar and wind.
It becomes necessary to design the power grid around ‘worst scenarios’. But what is worst given the nature of weather? Do you design around weather than may only happen for 10 days per year, or find another way to cope for those ten days? Can you cope if those ten days all occur at a similar time, which due to the seasonal nature of weather, can be very likely?
Provision for these worst cases means coal and gas that could otherwise be shutdown, can need to be still operational, and to be still operational, they often need to keep running even if at reduced loads, in order to avoid the shutdown and start-up processes.
Like with roof-top solar at home, without a battery, you can reduce electrical bills, but you still need traditional power. In fact the more people with roof top solar, the less that can be saved without a battery. When few other people have rooftop solar, you can sell excess power to the grid. When everyone else has rooftop solar, not only is there no longer a market for electricity on good solar days, the grid can longer cope with extra power put back by people and may need to institute penalties to stop overloading the grid with power that cannot be used.
These same scenarios have parallels on a wider scale for commercial solar and wind.
Energy Storage and the Grid: Challenges, but with a Solution.
Update: As discussed in this you tube video (at the linked point at around 40 minutes) that is pro-renewables, without storage, the problem is not solved.
Having Solar and Wind that can generate enough power to match annual demands is within reach. It may seem that if sufficient storage could be added, then an entire grid from solar and wind would be possible. Although the fact that storage is never 100% efficient, means that even though more solar and wind would be needed, the goal is within reach. If only we had that sufficient storage available.
The reality is, in many countries, the batteries of electric cars are being deployed into the market and providing more energy storage than any other initiative, if only that resource could be tapped.
Storage technologies.
Batteries.
The prices, weight and size of batteries for a give storage capacity has been dropping.
The fact that energy can be stored in batteries is well known. 🙂
Distributed Consumer Batteries.
Batteries are expensive for anything beyond a short term solution, unless you can get them at a discount, which could be feasible. Consumers are expected to purchase massive amounts of battery storage to back up home solar, and in terms of electric vehicle batteries. If this stored power can be make available to the grid, it alone could solve the problem.
Green Hydrogen (not to be confused with blue Hydrogen).
Hydrogen is an much hyped, and often misunderstood, way storing energy as explored in more detail in a separate exploration.
‘Green’ hydrogen is the use of hydrogen for storage for ‘green’ energy, in order to produce a reliable, available on demand source of energy from by Solar energy and/or Wind power.
‘Blue’ hydrogen is where fossil fuels (mostly gas), are used as a source of hydrogen. The resulting hydrogen is a ‘clean’ fuel, but the same amount of CO2 as using fossil fuel is produced at the blue hydrogen factory. Many see ‘blue’ hydrogen as an attempt to ‘greenwash’ the use of fossil fuels.
In contrast to pumped hydro, Hydrogen storage does not require any particular terrain and can even be stored underground and in locations such as a dessert, or abandoned coal mine.
However, so can compressed air which is more efficient than splitting water in to hydrogen and oxygen and then recombining them.
Pumped Hydro.
Most of us are familiar with Hydro-electricity. The principle is a dam is used to contain water at raised altitude (an upper reservoir), allowing energy to be obtained by turning a turbine as that water flows to a lower altitude. The spinning turbine is used to produce electricity.
Having large volume of water available by either having a dam or simply a large water body at the point of discharge (a lower reservoir), adds the ability to store energy from the grid for later use by using energy to pump water back uphill into the original raised altitude dam.
Pumped Hydro has been in operation at Ffestiniog Power Station in Wales since 1963. The first pumped-hydro implementations were designed to provide power in the event of an outage of the normal power source, typically a coal-fired power stations, and were designed to provide power until operation the of the normal power source could be restored.
Newer pumped-hydro systems are designed around the provision of power during both daily and longer term periods when Solar and Wind systems cannot deliver power at required levels to the grid. This means the new ‘pumped-hydro’ operations are designed to be supplying power far more often than older designs.
Pumped-hydro can have huge capacity, but can only be located in locations where there is a water supply, evaporation is not excessive, and there is significant changes in elevation.
Compressed Air.
As described in this video, compress air storage is an alternative for locations where the terrain, or evaporation rates, make pumped hydro a problem. The principle is similar to pumped hydro, except the low energy store is the atmosphere, and the high energy store is the container of compressed air. By having the compressed air deep underground, and using water pumped between a surface and underground tank to allow the atmosphere compress the air, it becomes even more like pumped hydro, just requiring less water, and without elevation or evaporation.
Stored Heat.
The Sun provides heat, so why not just store that heat? The simplest storage of solar energy is to just capture the heat, which is exactly the technology of the first ‘home solar’, which was ‘home solar hot water‘. As solar cells dropped in price and became more efficient, solar hot water has become an outdated technology. There are other limited applications of storing energy as heat, but it is generally for more efficient to store electrical energy, and solar cells are now more efficient than heat capture.
Stored Mechanical Energy.
Another way of storing energy for later use is to store the energy as mechanical energy. This is of most use when the energy being stored is already mechanical energy, which is not the case with solar, and while it could be used to store energy from a wind turbine, I have not seen any practical use with wind energy either. Formula one cars store mechanical energy in a flywheel using a Kinetic Energy Recovery System, KERS but there is very limited use of flywheels for storage as friction limits them to short duration storage.
Green Baseload strategies: Reliably reducing or eliminating the need for storage.
Continuous ‘baseload’ alternatives: ‘Green’ predictable energy sources.
An alternative to adding storage to get around the problems of the variability of Solar and Wind power, is to use alternative energy sources that are by nature predictable and dependable. Power generation matching the description of “baseload” power in this that it can deliver power in a completely predictable manner and is available regardless of the need for power.
The advantage of most ‘green’ energy sources, is that there is almost zero marginal cost, as for example, geothermal energy is there whether we use it or not..
Note, that while reliable power vastly reduces storage capacity required, there is still the problem of smoothing energy supplies to match demand. Stored energy still solves the problem of storing excess capacity in times of lower demand and assisting in delivering base or additional capacity in times of peak or unexpected demand. Almost all power generation other than hydro or storage, are limited in their ability to be ‘turned down’ for low demand or ‘turned up’ for extra power.
Tidal, Geothermal.
Tidal and Geothermal both work only in specific locations. Iceland runs on over 99.9% renewable electrical energy through geothermal and hydro.
I could be wrong, but I see continuous or at least fully predictable energy sources such as tidal and geothermal as potentially particularly cost-effective contributors to the electrical grid, but their role is more determined by the specific geography and availability than the desires of governments or energy companies. This makes them great in some places, but difficult to scale to provide a large percentage of energy requirements.
‘Green’ Fission: radioactive material can be eliminated, but at a cost.
The nature of atoms is that the process of converting any atom with a larger number than Iron into a smaller atom still larger than Iron, a process known as nuclear fission, produces enormous amounts of energy.
Nuclear Fission has four major problems:
- It is is expensive.
- It is difficult to keep under control.
- The easiest ingredients to work with are dangerous radioactive materials with long half lives.
- The products of reactions are more dangerous radioactive waste also with extremely long half lives.
The website ‘how stuff works’ does a great job of explaining how current Nuclear Power Plants operate, so I do not need to repeat their work.
Chernobyl and other accidents have demonstrated the reality of problem number 1.
What is not explained on the ‘how stuff works’ site is that U-235, the main fuel and Plutonium-239, the main wastes for these plants, have half lives of 703.8 million years and 24,110 years respectively. They leak radiation for a long time. The biggest concern is the waste, because if all goes well the fuel will be used, but what do you do with all that waste?
The reality it is possible to use particle accelerators to reduce nuclear waste to non radioactive elements, but it is expensive. You can also start with non-radioactive elements, but the process becomes far more difficult, and again, far more expensive. The reality is that while you can technically make nuclear fission reactions waste free, they are simply not commercially competitive if you do. Profit before safety and sustainability.
Clean nuclear: Fusion, one day.
The nuclear alternative to fission, splitting big atoms into smaller ones, is fusion, which is joining smaller atoms into bigger ones. It may sound strange that these two opposite processes can both generate masses of energy, but they can. Why not go back and forth, big to little and back? Because it is not all fission or all fusion that generates energy. Fission generates energy only as long as the atoms are bigger than Iron, and fusion generates energy while the atoms are smaller than Iron. With both processes, it ends at Iron, which is one reason there is so much Iron.
Nuclear Fusion or Hydrogen into Helium, the same as the main process powering the Sun, not only generates massive energy, it also is free of radioactive waste!
The problem is, for nuclear fusions, you need enormous temperature and pressure, and creating enormous temperature and pressure requires a lot of energy. So far, there are no working reactors that capture more energy than is required to make the reactions happen. It is being worked on, and is technically solvable, but we are just not there yet.
Biofuels.
Bio fuels are using solar energy to directly produce store energy such as sugars or alcohol. The problem is you need water, and time, as well as the solar energy, and unless you use prime farming land for production, solar energy and generating hydrogen is more efficient.
The advantage is that in theory at least, biofuels have all the good points of fossil fuels, without the bad points. Their problem is they are a more expensive source of energy than wind or solar and require more resources, but there are applications where, as long as the scale is limited, they have a place.
Baseload solar and wind: Design for a high-reliability, low-threshold renewable energy.
The ‘base load’ principle is well established, but for renewables it does require a tweak.
With conventical fossil-fueled grids, “baseload” power is the minimum power available to the grid and is produced even if demand falls below the “baseload” level. Part of the logic is that the lowest cost power sources, historically coal but it could apply to other sources, can be very slow to “ramp up” or “ease off”, and are best kept generating at a constant rate. It has been argued that the concept is no applicable with renewable energy, but one part of the concept, that of defining a level of power generation to be always maintained, or at least to be able to be permanently maintained, is still worth preserving. With a traditional grid, before key baseload generators are shut down for maintenance, which is normally required several times per year, backup generation is organised.
The adage is “the sun does not always shine, and the wind does not always blow”. The truth is, outside of eclipse which affects only a limited area for a short time, there is always some light from the Sun during the day, and over a large enough area, there is always some wind.
While it is common to think of solar power as the power from a sunny day and wind as from when there are typically levels of wind, the principle of baseload solar is to plan solar output around cloudy days and wind power around a very low threshold of wind.
Not necessarily unpredictable: can be equivalent to mainetnance shutdowns.
Study of annual patterns will reveal the depth and frequency of periods of “dunkelflaute“, periods of very low sunlight and wind, for any given year. While the number will depend on the depend on the actual depth and duration of the fall in sunlight and wind over the area in question. Wikipedia currently states in norther Europe “There are 2–10 dunkelflaute events per year“.
A slight tweak for solar and wind base load is required, as instead of delivering the base required power from solar and wind at all times, the goal is to deliver the minimum power required at almost all times, with the occasions when grid power will fall below “baseload” sufficiently rare they can be considered like maintenance events, which means only very limited storage is required to fill the worst possible gaps.
There can also be more routine “gaps”, but these only last hours. Although solar can be configured to deliver the necessary level of power even on a relatively very dark day, it is limited to daytime. This means that an evening peak between 4pm and 7pm (1600 and 1900) would need to every day be served by wind, storage, or other energy sources in locations where the Sun sets at 4pm for part of the year.
Instead of the potentially many weeks of energy storage required in the case of a grid where mostly sunny days and typical wind levels are required to meet energy demand, a low-threshold baseload approach can be designed to require only a few days of storage for the very worst on record possible weather event.
Balancing storage vs base-load renewables at low levels of sunshine and wind.
Adding more solar and wind generation capacity that operates at a low threshold of wind and light lowers the storage requirements.
Solar and wind with the only capacity to meet energy needs is insufficient for dependable power as it needs to run at full capacity and will require use of alternate energy anytime the system is operating below full capacity.
Solar and wind with the capacity to meet double the required energy needs is far more reliable, as there is sufficient energy even when the system is operating at 50% capacity. Such a system can feed into energy storage systems whenever there is more than 50% of generation available. Storage is only required for occasion when less than 50% of genearion is possible.
To be able to generate sufficient energy on all occasions with the exception of “dunkelflaute” as defined by Wikipedia, generation must be capable of meeting required demand when receiving only 20% the full level of energy.
The more solar panels and wind farms, the less storage that is required. The optimum balance will be determined by the relative cost of adding more storage or adding more generation.
If the grid is in part powered by continuous green energy sources, then even less power would be required.
Bonus electricity: Extra near zero marginal cost electricity as an overcapacity byproduct.
A grid with capacity to provide sufficient energy down to the threshold of “dunkelflaute” at 20%, would at times be able produce up to 80% more energy than required, at near zero marginal cost.
With traditional fossil-fueled power “off-peak” electricity is less expensive because it is being generated by lowest cost “baseload” generation would be wasted if not sold. However, generating using fossil fuels always consumes fuel that must be mining and has a cost. However, with wind-and solar, the excess capacity can be available even during peak periods as long as sunshine and/or wind are above the minimums, and there is zero extra fuel cost, as the sunshine and wind are fee. The only marginal cost from electricity at these times are the maintenance costs, which are very low with solar panels and wind turbines.
This enables powering everything from aluminium smelters to steel mills and hydrogen generation at very low cost as long, as these facilities can “pause” in response to weather warnings for periods of lower available energy.
The Economics of Solar and Wind overcapacity plus storage.
Storage and/or overcapacity: An Added Cost to deliver dependability.
After considering all the alternatives, Solar and Wind are the most attractive source for new power generation. They generally produce the most cost effective power available today, if only they can be made dependable.
Enter storage and overcapacity to solve the dependability problem. But is Solar and Wind still economically attractive once you add the cost of storage and overcapacity? That becomes the big question.
The first step has been solar and wind that reduce use of fossil fuels. Once you move into storage, the cost of the renewable sourced energy is increased, making it less competitive with using fossil fuels. However, there is another payback, with enough storage, you can close down fossil fuel power plants, saving more than can be gained by allowing the fossil fuel power plants to run at a lower output when solar and wind are available and thus reducing the amount consumed and some of the cost of fossil fuel. Without storage, the old plant is still needed for when there is less wind and solar, but with enough storage, you can progressively reduce the number of traditional power plants.
The Economics of providing All Power Generation.
With every power system there is an initial capital outlay which has to be amortized over a number of years, and once amortised, only operation and maintenance costs must be covered to reach profitability.
Most coal plants in developed countries are old enough to have already recovered the initial capital costs, making power from an existing coal plant much less expensive than new coal plants.
Replacing Older Power Plants: The Economic Payback from Adding Storage.
Storage and overcapacity have the potential to reduce costs to a network, by allowing the retiring of older, often coal powered, high maintenance power generation, for an overall cost saving. Electricity supply can be less expensive as a result, so storage and overcapacity are not simply an extra cost, but an opportunity for cost savings.
Having reliable power enable removing the costs of plant operation, maintenance and the fuel costs, from plants which need to at least be on standby if the only alternative is direct solar and/or wind power.
Being able to shut down older plants becomes most attractive when there are power plants of an age where a new, replacement power plant is required. New coal/gas power plants, with a new period amortization of the costs of building the plant, can be one the least cost-effective options for new power.
Why was storage or overcapacity not provided with wind and solar from the outset?
There are four main reasons:
- The highest cost power the on-demand grid power so that is the first to be replaced.
- There was no requirement for the power storage or overcapacity until solar and wind power was in place.
- With no requirement for storing power until recently, the technology was not ready, or even developed.
- The economics favour amortising the cost of the initial installation before then investing further on storage or even more reneables.
This means, even now, many power storage options are on a steep learning curve. For example, there is significant investment in hydrogen storage, while less efficient than battery storage that is on a faster cost reduction curve. Perhaps hydrogen can be scaled to capacities where batteries would always be too expensive, but at this time hydrogen is mostly investment, not yet deployment.
Strategy: Adapting to the new energy landscape.
The world has moved from fossil fuels, to wind and solar as the lowest cost source of energy.
But to match the ‘available anytime’ and ‘easily transportable’ properties of oil and gas, stored energy is required which comes at a higher cost.
This introduces an entire new dynamic, where direct use of energy for solar and wind is less expensive than stored energy.
This means any energy intensive industry, such as steel or aluminium production, will be more cost effective if production can be scheduled when solar or wind energy is available, and in close proximity to where solar or wind energy is available.
Coal, Oil, Gas post ‘Fossil Fuel’: Not Dead Yet.
Just as stones were still used after the stone age, copper was still used after bronze age, and horses still used in the age of motor vehicles, Coal, Oil and Gas will still have uses even if/when we get to the point of storage or other technologies bringing an end to their uses as fuels.
From plastics, to fertilizers, to bitumen and coking coal, there will remain uses of fossil fuels for a long time. Some of these other uses are also problematic, but it we stop using them as fuel, then the CO2 risk may pass.
Another reason fossil fuels are not dead is because of the economic and resulting political power behind them.
- Worlds richest countries have given us$190-244 billion to fossil fuel industry since 2020 alone.
- Small privately held companies like Hillcorp takeover problematic greenhouse gas emitting projects.
Conclusion: Solar and Wind Can end Fossil Fuel Age, but only when we have storage and strategy.
Solar and Wind are booming for energy generation. But just because countries like Denmark who in 2020 reached 50% of energy from Solar and Wind, does not mean they are half-way to all solar and wind.
No amount of Solar and Wind alone allows turning off fossil fuel power plants, and overcapacity is required go get close. Sufficient Solar and Wind combined with storage does allow replacing fossil fuel power plants, with the potential to reduce prices and have a supply more reliable than ever, as well as bonus electricity that is at almost zero marginal cost.
This makes Solar and Wind just the first step on a journey. A journey that requires the addition of a new ingredient before reaching the end goal. The end goal requires adding storage, and will take time, . Much of the technology requires improving what has been done before and can required development time.
Adding storage can provide a solution and is feasible. It has even commenced in many locations, but it will take many years to achieve what is needed.
Critics of Solar and Wind raise a valid point when they claim Solar and Wind cannot replace fossil fuels. Yes, but Solar, Wind and Storage can replace fossil fuels.
Updates.
- 2023 May 16th: Updated synopsis and added more on “green baseload” strategies.
- 2021 April 14: First version.