In regions that are “100% powered by renewable energy”, what happens to the traditional power plants?
In: Engineering
I’m in the industry and am part of a group involved in answering this complicated question. I’m not sure if the answer you’re looking for is related to the impacts on jobs, on the local peer grid, the jobs in the local community, the environment, or power bills for customers. It impacts all of them in important ways, and those answers will be nuanced usually.
My area is finance, so I’ll speak to that more specifically. In most of the US, electric utilities are are regulated monopoly, meaning since there is no competitive market the government audits the utility to ensure the rates being charged grant a reasonable profit and recovery of operating and maintenance costs. Accounting rules require plant and equipment to be depreciated over the course of the expected life of the asset. In other words, a utility that built a coal-fired power plant and expected it to operate for 40 years would make financing arrangements which allowed it to collect 1/40 of the cost of the plant through customer’s bills each year + the cost of capital (interest and dividends).
When a major asset like a power plant shuts down ahead of the original depreciation schedule (less than 40 years in this case), power company and the regulator need to make decisions about how to pay off the remaining debts associated with the assets.
Beyond the financial, there are important questions about what makes the most sense as a replacement power resource, requirements for environmental remediation, local workforce retraining resources, etc. Many complicated issues, and every state will address them differently.
I live in Vancouver BC. We could get all our electricity from hydro electric dams, but we actually buy a lot of power from coal fired plants in Alberta.
Here’s why:
The coal power plants in Alberta burn coal to heat water to make steam, and then they use the steam to spin a generator. Just like boiling a kettle takes time, starting up a coal fired plant takes time. So they prefer to run coal power plants almost all the time. But in the middle of the night people don’t need much electricity.
A hydro dam can go from zero to full power and back to zero much faster than a coal plant. So I’m the middle of the night BC buys power from Alberta and then in the morning when everyone in Calgary turns on their lights and coffee makers we sell them a bit of our hydro power.
We also sell power into the United States during summertime heatwaves. In that case everyone in Los Angeles is turning on their air conditioning at the same time, so they need extra power. We just open the taps at the hydro dams make more and sell it.
There are even bizarre times when BC is buying power from Alberta at the same time as they are selling power into the US.
This happens because all the power companies are connected to the same electricity grid which spans all over North America and can buy and sell energy from each other.
I live right next to an old coal power station. It was decommissioned 6 or 7 years ago. It has been demolished slowly over the past year, mostly due to covid causing delay. It was part of a bigger site but 4 of the 8 cooling towers were demolished in the late 90’s. The old boiler house was demolished near the beginning of the year. 4 cooling towers remain and one big chimney as well as some smaller buildings.
The taller chimney is due to be demolished the beginning of January shortly followed by the remaining cooling towers and buildings. The land has plans already set in place for it to become housing and a few shops, schools too!
It’s pretty cool to watch them demolish parts, my sons especially enjoy it!
Edit: Forgot to mention i am in the UK
Manitoban here. 97% of our electricity comes from hydroelectric power. We also have 2 large wind farms. We have 2 plants that are natural gas (1 is mixed use with coal) powered, but are there for peak demand. There are also apparently 4 isolated communities that use diesel power generation, but they only make 3 or less megawatts of power each.
there are very few regions (or jurisdictions, in energy community parlance) that really use 100% renewable power. and that’s just electricity – you won’t find a jurisdiction with 100% renewable energy supply across *all sectors*. these are Albania, Iceland and Paraguay, with Norway at 97%.
At least for Albania and Iceland, there never really was any fossil (or “conventional” power plants). “Old school” renewables such as hydro and geothermal have simply been abundant and cheaper.
Where you actually see fossil fuel power plants (as well as nuclear) being driven out of the market is where modern renewables, primarily wind and solar Photovoltaic, have been deployed at scale. Germany, Spain and Denmark are your typical poster children. The rise of modern renewables has been part policy (most notably feed-in tarrifs and more recently, CO2-price), part advances in technology and costs (in turn also to a large extent driven by policy), and changes in market regulation, most notably liberalisation and vertical desintegration of power companies (again, policy).
what this did to conventional power generators was to push them out of the market, and fast. UK is almost without coal at the moment, whereas it was a pillar of it power system a bit more than a decade ago. Germany has seen coal generation drop precepitously, as low marginal cost renewables have suppresed the power market prices and the CO2 price has risen recently. in many regions with good solar potentials it’s cheaper to *build new solar PV* than operate existing fossil generators. natural gas generators have been less badly hammered, and low gas prices have helped them, but they’ve also been suffering.
so coal power plants are shutting down in many places simply because of economics.
the irony of this that with rising share in the power mix of variable renewable sources such as wind and solar, you have to complement this with power generators that can be regulated. hydro is perfect, but potentials are limited almost everywhete in the world (with few exceptions such as Albania, Iceland, Paraguay and Norway). natural gas is the next best thing. but with whoselase power prices suppressed, new gas capacity is not comimg online. and there’s no easy fixes for this. in Germany, coal power plants that are due to go offline, will be kept in strategic reserve at billions of euro in costs, and at grave environmental consequences if they turn out to be needed.
tl;dr fossil power generators are getting pushed out of market, but in case of natural gas, that’s not an unequivocally good thing. the whole power system needs to evolve beyond just adding renewables in order to be able to reach 100%.
EDIT: apparently, this was understood by some as stating that a nearly 100% renewable energy supply across all sectors is not possible, or at least that we shouldn‘t rush it. in fact, it’s actually possible with today’s technologies. the harder questions are non-technical, e.g. how fast can we deploy, how do we re-organise markets to set the necessary incentives, how do we solve the IT side of a truly IoT energy system, how can we get away with such a massive change from a social and political perspective, etc.
but if we can manage these non-technical aspects, different studies show we can achieve a global 100% renewable energy *across all sectors* by 2050 and not just that, it‘s cheaper than the current, largely fossil-based system if you put a monetary price on environmental destruction wrought on by unmitigated climate change.
so the point many of the energy transition pioneers have been increasingly making lately is, don‘t worry about the last 10% of the fossil fuels you‘ll need to get out of the system 30 years down the road, where the non-technical problems make it look like an impossible thing from today‘s perspective. focus on the 90% that you can already achieve now and push ahead. don‘t make perfect the enemy of the good.
that is because time is critical and even the 90% energy transition that we can achieve with today‘s technologies is an insanely complex challenge. there isn‘t one size fits all solution.
batteries can be a big part of the solution – if they were another notch cheaper and could be scaled much, much fastet than what we are able to fo now. that is because, with the exception of places near the equator, you need to store power not for the night, but for the winter. if you have one charge-discharge cycle per year, the necessary quantities are huge and cost per unit of energy deployed is just not acceptable.
pumped storage could play the same role but here too, capacity is limited almost everywhere. it‘s often said that Norway can store enough power in their high-above-the-sea-level dams to get at least Scandinavia through the winter. well, no, because you can’t pump sea warer into fresh water lakes if you’re not willing to kill off their entire ecosystems.
electrolytic hydrogen and synthetic fuels (known as Power-to-X) look promising right now because they’re based on mature technologies and theoretically, enough renewable power can be converted into chemical energy to provide seasonal storage for entire continents. but here, you also have your problems, namely low efficiencies and high costs. hydrogen as such is also a nightmare to transport and store; if you go a step further and produce synthetic methane, diesel, kerosine or ammonia, you can use existing fossil-fuels infrastructure, but you’ll add furthet conversion losses and increase
once more the costs. that’s why the current hydrogen hype is largely just that. hydrogen as such an synthetic fuels will probably end up occupying niches that electrification and other technologies can’t decarbonise, but won’t become the new oil.
another solution to renewables’ intermittency is to build out the power grid. the sun always shines somewhere, after all. but this is neither cheap, fast or popular.
you can always theoretically just build more renewables so that even in the winter, sun will provide enough energy to power your electric car and your heat pump, even if you’ll have to waste a lot of it in the summer because you’ll just have no need for it. modellings show this will actually likely be an important part of the solution for a 100% renewable system. at least PV (wind less so) is actaully on the track to het so dirt cheap that this would make economic sense on its own. the problem is
what this does to your power *market* – if you have zero-marginal cost renewables covering your entire power need for 3/4 of the year, all the other technologies that you need to get you throught the winter only have have three months a year to refinance themselves.
what else is there … ah, nuclear. current gen4 reactors are too expensive and too slow to deploy. typically, a nuclear power plant takes 10
years from the where the investment decision is made to where it comes online. that’s just too long at the pace we need to decarbonise at. also, the investments are huge and companies all over the world have always been relying on governements to step in and bail
them out when they had costs overruns. then, in EU, Japan and Korea, power markets got liberalised and companies in the nuclear business just didn’t have the chops to build new plants. all that said, as long as existing nuclear power plants are able to *safely* provide you carbon free power, they should do so and shutting them down early (as many countries are in the process of doing) is absurd from the standpoint of fighting climate change.
on last thing that gets mentioned a lot is flexible demand. basically, use power when the sun is shining and the wind is blowing. that works to some extent but you probably won’t ask a hospital to go offline for a couple of hours. also,
if you want to cram daily power demand into a few sunny and windy hours, you’ll need to transport much more at once, and the current power grid can‘t handle that. bulking it up enough to do that is far from your economic optimum.
the last solution I will mention here which should perhaps be the first is energy efficiency. it‘s the least sexy of them all but absolutely essential to achieving a 100% renewable energy system, and the most economic partial solution across different sectors.
a combination of these technologies and approaches is what a 100% renewable *power* system which is the backbone of a 100% renewable *energy supply across all sectors* could look like. i‘ve skipped some important parts but the point is that we already have the tools to get to at least 90% already. the last 10%, we can figure out as we go. not knowing how we‘ll manage the last 10% shouldn‘t be the reason not go full steam ahead with the first 90%.
Almost always, fossil fuel plants stay online to support renewables. Nuclear has the least fuel support, then hydro, but their mix hasn’t really changed over time. There are small, rare, rural examples of almost completely renewable.
Many are converted to run natural gas as backup for the renewable generators. Most 100% renewable energy regions are 100% for like 48 hours at most, but that will change as more renewable sources are added to the grid. I’m particularly excited about Eavor-loop geothermal energy generation, which could be outfitted to an existing steam driven turbine plant.
In many cases they still have them and use them (particularly during peak usage or during times when renewable means aren’t producing enough like night/low wind for solar/wind) but much less. The trick is many “100% renewable” numbers are often “net” so if they make a ton of renewable energy during the day (more than they can use) and sell it to neighboring regions (and reduce those regions reliance and use of fossil fuels, etc) they count that as an offset to the limited use of fossile fuels they may still use.
There are no sizeable regions outside Iceland with significant populations which achieve this claim. There are gas-fired peaking plants or separate industrial power plants.
Old power plants are often recycled, you can take out a coal boiler plant and use a new gas-fired plant to feed steam into the coal plant’s old turbines. Sometimes it’s worth it to move the turbine to a new location, so the old facility can be sold on the real estate market.
To the best of my knowledge “traditional” power plants were never really a thing here in Iceland, except for 2 small islands that aren’t connected to the main grid, they use diesel generators.
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