Friday, 12 July 2019

Alternative Energy

[Another draft from some time back. This post was began in 2015. And languished in my "Draft" folder for the last few years. I have some new thoughts on it.]

Every now and again, someone somewhere in sunny Singapore will ask, "why are we not using solar power? It's so freaking sunny here all year round!"

And some may even go as far as to ask if we can't harness other clean energy.

Here is the official position:
Challenging for Singapore to find alternate energy sources: Shanmugam 
By Faris Mokhtar 
08 Jul 2015 
SINGAPORE: It is a challenge for Singapore to find other alternative energy sources, according to Minister for Law and Minister for Foreign Affairs K Shanmugam. 
Mr Shanmugam made this point on Wednesday (Jul 8) at the inaugural Asian Undergraduate Summit organised by the National University of Singapore Students' University Scholars Club. The summit brought together undergraduates from leading Asian universities to discuss regional issues 
Currently, Singapore is relying on fossil fuels and its usage exceeds that of other nations.
Mr Shanmugam said Singapore is unable to build facilities that can generate wind power due to land and space constraints. This is unlike other countries like China and the United States, which can cut back on their carbon footprint because they can generate alternative sources. 
"For us, it's not a question of being more expensive. We just can't generate anything else. So, if they are internationally-binding norms and we're not exempted, that means a tremendous challenge for us. So, one of the things policy-makers are dealing with is to make sure that our case is heard. We are alternate energy-challenged,” Mr Shanmugam said.

Really? I don't believe you! (Actually I do. I'm just playing devil's advocate.)

I started writing this and researching this (sometime in July 2015 as evidenced by the date of this news extract) and documenting my research and writing, and this just got longer and longer, and the pieces in this blog already tends to be too long. This is a fascinating issue, but maybe you won't find it as fascinating. You may just want the bottom line. So, here's the summary.

Executive Summary

The three most promising and commercially viable alternative and renewable sources of energy are Hydroelectric power, Wind power, and Solar power.

Other promising alternatives are Wave power, and Geothermal power.

However, these two and in fact all 5 alternative sources of power are geographically determined. You can't put up a wind energy farm or a hydroelectric dam or a geo-thermal power plant anywhere you want. A Hydro generator needs a huge river with significant drop in altitude to have a water flow powerful enough to drive the turbines to generate electricity. Geo-thermal power plants need geothermal features, like a geyser or a hot spring or even a volcano. A wind farm needs a reliably windy place. Wave power will need strong persistent waves. Solar farms work best is sunny locales.

So we are alternative energy poor - Hydro, Wind, geo, wave and most other esoteric or exotic energy sources.

What we do have is the sun.

On the one hand, solar is one of the most researched and most developed alternative energy source.

But on the other hand, it is still only providing about 1% of the total energy needs of the world.

So? It's just a matter of ramping up the use of solar power, right? From 1% to say... 70%? 80%?

Well, no.

It's not that simple.

Firstly, Solar is a very diffused energy. Yes, 23,000 Terawatts of solar energy hits the earth each year. But it is ALL over the earth. ALL 510 million sq km of it.

But that's ok, you might say. We only need about 35 Terawatts.

Ok. And for that we might need 0.75 million sq km.

Which brings us to the next point.

The current technology to convert sunlight to solar energy is not very efficient. The average commercially available solar panel is only about 20 -25% efficient. The best solar panels today may be about 35% efficient. As technology improves, it can get better. But there is a theoretical limit of about 55%. Why are solar panels so inefficient? I'll let an expert explain.

But what this means is that although 35 terawatts falls on 0.75 sq km, our solar panels current technology is only able convert about 1/5 of that sunlight into electricity.

So we would need about 3.75 million sq km to be able to get 35 terawatts.

As technology improves (to say 50% efficiency), we might be able to reduce that to just 1.5 million sq km.

GREAT!

If the sun shines on those 1.5 million sq km everyday.

Sure there are places in the world (like deserts) where the sun shines everyday. But those places are also far from the major population centres. This is a problem because transmission of power over long distances have an energy and efficiency costs.

And we are not all going to move to the edge of the desert.

So for those of us not living next to a typical desert with uninterrupted sunshine, we will have to work with the reality of interrupted sunshine. Or less than a full day of sunshine.

But it is hard to work out the "average" weather or climatic conditions for various parts of the world. And in any case, we are only concerned about Singapore.

So how much sunlight does Singapore get?
There is an average of 2064 hours of sunlight per year (of a possible 4383) with an average of 5:39 of sunlight per day.
It is sunny 47.1% of daylight hours. The remaining 52.9% of daylight hours are likely cloudy or with shade, haze or low sun intensity.
So even though it seems ALWAYS sunny in Singapore, it is not quite so.

With less than 50% of sun, we would need a area twice as large to account for less than sunny days.

Or about 300 sq km or about half of Singapore.

Why Solar Power is not feasible for Singapore (Yet. Or Ever)?

Concentrated Solar Power (CSP) which is currently the most efficient solar power generator requires about 741 acres or 2.5 sq km to generate 100 MW.

Singapore uses 6000 to 6500MW of energy. Let's say with low power appliances, more efficient motors, aircon, fridge, we managed to cut our needs to about 5000 MW. This reduction is not easy. But I believe it is achievable.

To supply just 20% of our (reduced) electricity needs (or about 1000 MW) we will need to have 10 of these CSP or about - 25 sq km!

Photovoltaic (PV) solar cells which are about half as efficient, will cover about 12,000 acres or 48 sq km for the same output. And this is just to generate 20% of our REDUCED electricity needs. Finding 48 sq km of unused space in Singapore to be a solar farm to generate just 20% of our power needs is not very feasible.

[What is a watt? what is a watt-hour? Here's an explanation.]


What if we put these all on HDB roof tops?

CSP is out as the technology requires contiguous space (uninterrupted, unbroken space). So PV it is!

48 sq km = 48,000,000 sq m. There are about 10,000 HDB blocks, so that's 4,800 sq m of roof required per HDB block.

NO HDB block has a roof that big. That would mean about 48 four-rm flats PER FLOOR. Or at the very least on the top floor.

Assuming all blocks have on average about 800 sqm of roof, 10,000 blocks will yield about 8,000,000 sqm and produce about 1/6 of 1000 MW, or about 170 MW, or about 1/30 of our total needs. And this is assuming all HDB rooftop space are not required for water tanks, lift motor room, radio/cellular antennas, etc., and the whole roof can be used for solar power. (Or the varying space needs can be designed to accommodate all needs.)

So how about ALL the other buildings? Assuming the total roof area of Non-HDB blocks are equal to HDB blocks - in other words, if we DOUBLE the roof area to 16,000,000 sqm, we would have... 340 MW.

Okay, maybe there are more, let's assume that there are TWICE as much non-HDB roof area - 24,000,000 sq m of roof to be solar panelled. And we managed to generate... 500 MW.

OK. Maybe my assumptions are too modest. Maybe, the roof area of non-HDB flats are FIVE TIMES that of HDB roof area. So total roof area is... 48,000,000 sqm. YES! we can generate 1000 MW of electricity! Is this a fair estimate? Seriously, I do not know.

The point is, even if we cover every roof of every building in Singapore, we MIGHT just be able to generate 20% of our CURRENT energy needs.

ONLY 20%.

And that's with A LOT OF CONCESSIONS!


But, didn't Apple or some company manage to use solar power for their entire operations in Singapore?

Yes, it did. And here is an excerpt of that news report:
Due to land scarcity, companies are installing solar panels on their rooftops and this will be Apple's approach too, with one of the largest installations of solar panels in Singapore soon to come up on one of its two buildings in Ang Mo Kio.
In the first such arrangement in South-east Asia, Apple will purchase solar energy harnessed from panels on other buildings to supplement its needs.
Traditionally, companies buy only the energy harnessed by solar panels installed on their premises.
Note that it is not enough for Apple to install solar panels on their own roofs. They have to harness solar energy from panels installed on other buildings. (The solar panels will provide 33 MW peak capacity. Just for Apple. )

(Apple uses 800 other rooftops to generate the total power it needs. So what do residents or businesses under those 800 rooftops do for solar power?)


So, what if we just put aside some land to have a CSP solar power generator? What's the problem with CSP

As mentioned earlier, CSP requires 2.5 sq km to generate 100 MW. To produce just 1000 MW, we will need 25 sq km. 

How large is 25 sqkm?

That's approximately the triangular land area bounded by the TPE - PIE - KPE, encompassing Bedok North, Tampines, MacPherson, Paya Lebar Airport, and quite a few other bits. That means the whole place cannot be used for any other purpose (or will be of limited use). The population of Tampines alone is about 240,000 people. Of course we are not going to build the CSP there. The point is simply to illustrate that 25 sq km is large piece of land on a small island like Singapore. And any large piece of contiguous land that is going to be set aside for solar power will incur a significant opportunity costs (like homes for 240,000 people). And then it would still only provide 20% or less of our current energy needs.

To provide 100% of our current conservative energy needs, we will need 125 sq km. Or more than 150 sq km if we are unable to reduce our energy needs below 6000 MW.

China's Loong Yangtze Dam Solar Park in Tsinghai (sic) has 4 million solar panels on 27 sq km and that produces enough electricity for 200,000 homes. Assuming a Chinese home is equivalent to a SG home, that would be about 20% of our residential needs.

The biggest operating CSP power plant is the Ivanpah Brightsource Energy Power Plant, with 300,000 mirrors to focus sunlight on 3 boiler towers to generate almost 400 MW - enough energy to power 140,000 homes. (One major problem with CSP is that it needs water for generating power, and for cooling. And we are just barely solving our water problem here in SG.)

And there is at least one other problem with CSP.

Fried Birds.

I can't do justice to the various reports, so Google "Ivanpah birds". I don't think I should find it funny, but I do.

What is NOT funny is that we probably do not want to have a vast array of mirrors pointing skyward just km from a world-renowned airport. Or we might have an airport renowned for other reasons.

And this is also the reason why CSP on HDB roofs are probably not a good idea either.

Fried birds raining from the sky might solve our crow and pigeon infestation... and improve sales of umbrellas. But we might want to go with a more controlled solution, rather than as a side effect of CSP.

So we are probably going to stick with PV solar panels.


How about putting CSP on Water - over our reservoirs or in the sea?

Short answer, the reservoirs aren't big enough. The entire water surface of all our reservoirs is only about 11 sq km (Linggiu Reservoir in Johor, at 55 sq km is five times larger than all our reservoirs combined).  and covering the entire water surface with mirrors would have an unknown impact on the waterlife and possibly wildlife, and if the Nature society worries about the impact of an underground train line with no visible above surface infrastructure, we can be pretty sure they would be alarmed by a CSP  with very obvious infrastructures on the water's surface that can fry birds on the wing.

There may also be technical issues of locating the CSP over water - installation (with minimal environmental impact), maintenance, accessibility, etc.

But  even if all those concerns are addressed, 11 sq km is simply not enough. Or enough for about 80,000 homes, I estimate.

Still, our government is trying things out (with PV on our reservoirs, not CSP) because, we should try everything we can.

Or maybe the govt just wants to shut the "solar evangelists" (you know who you are) up.


What about over the sea?

Our seas are too busy. Putting a solar farm on the sea is technically possible, but will have opportunity costs. Can it be done? Nothing is impossible, if it is important enough. But our shipping industry is also pretty important.


What about improving the efficiency of PVs?

Good idea?

No. 

Or the best we can do is improve the efficiency by 2 or 3 times the current efficiency.

The computation suggests that PV needs to be 6 times more efficient, and if we can use ALL the HDB roofs and government and civic building, we might be able to supply 20% of our energy needs.

There is a practical upper limit to the efficiency of PV panels. It is unlikely to exceed 55% efficiency for technical reasons. The current BEST PV money can buy commercially (not experimental design) is about 35% efficient. The reasonably priced (cost-effective) commercial PV would be about 20% efficient.

So the technology is not going to improve by more than 2 times (for the best PV), or 3 times (for the reasonably priced PV). And there is no way we will have a super efficient (120% efficiency?) PV system.


Okay. Let's bite the bullet and convert 150 sq km into a CSP solar farm!

How decisive!

And what will you do on cloudy and rainy days?

The problem with solar power is of course that not every day is a sunny day. This is true of both PV as well as CSP.

150 sq km is the best case scenario when every day is a sunny day. Power generated in the day will have to be stored in batteries for the night. But 125 - 150 sq km is only sufficient to cover the energy needs of the day. If half the days are not sunny enough, then we would need 300 sqkm. Or almost half the surface area of Singapore.

And then we will need batteries to store the power. And right now we are assuming the batteries efficiency and reliability are 100%.

Which they are not of course. They are pretty efficient - about 90%. That is, if you "pump" 100 Wh into the battery, you will be able to draw out about 90 Wh later. There is an efficiency cost. Which means that if you want to draw 6000 MWh, you will need to "store" 6600 MWh or about 10% more. Which means we need more land/surface area to generate solar power.

And this is assuming that rainy or cloudy days do not occur more than two days in a row. Or we run out of battery on the third day (day 1, sunny generate solar, and store excess power. Day 2, cloudy/rainy, draw down on batteries. Day 3, sunny - good, recharge. Cloudy/raining, not good. out of energy).

Also... we're not going to concern ourselves with fried birds, and the possible hazard a 150 sq km of mirrors next to our airport would present?


What about that story about how Germany was able to produce so much renewable energy that prices went negative, and people were, in effect, paid to use electricity?

Well, technically it is true.

(Please don't ask me to explain the chart below. It just looks like the price of electricity plunged for a while.)





On Sunday, May 8, Germany hit a new high in renewable energy generation. Thanks to a sunny and windy day, at one point around 1pm the country’s solar, wind, hydro and biomass plants were supplying about 55 GW of the 63 GW being consumed, or 87%.
Power prices actually went negative for several hours, meaning commercial customers were being paid to consume electricity.
Why?
Germany’s power surplus on Sunday wasn’t all good news. The system is still too rigid for power suppliers and consumers to respond quickly to price signals. Though gas power plants were taken offline, nuclear and coal plants can’t be quickly shut down, so they went on running and had to pay to sell power into the grid for several hours, while industrial customers such as refineries and foundries earned money by consuming electricity.
The video below explains it better. But I will try here.

The problem with solar power is that it is unreliable, and unpredictable. And when solar power surges into the power grid, the mainstream power plants cannot be easily shut down momentarily. So for example, France has nuclear power plants, and if they were to shift to solar and wind, they would have to change their nuclear power plants (which are cleaner) to gas-fired power plants. Which are more pollutive. See video below.



The moment the sun goes behind a cloud, solar power generation drops off, and other sources of power needs to take up the slack. And you can't just switch Nuclear on and off. You need oil, gas or coal-fired power plants.

So not surprisingly, solar and wind are friends to oil and gas companies.

And so there is a limit to how much renewable energy can fit in. In Germany. And in Texas and California.

The problem with Solar and Wind is that these diffused energy sources requires huge land area to harness those diffused energy. And the problem as the previous video shows, is that in trying to save the climate, we are destroying the environment (from 14:52).

But you don't have to believe me. Here's a presentation from 2013 that covers the options for the UK:





So what are our options for a non-polluting energy source?

The more immediately implementable ideas are safer, nuclear power.

Yes. Nuclear.

And already many of you are screaming in your head, "RED ALERT! RAISE SHIELDS! ARM PHOTON TORPEDOES! SET PHASERS TO MAXIMUM!"

First, understand that you have been brainwashed into believing that Nuclear is dangerous. Well, it is dangerous but not as catastrophically dangerous as we have been led to believe.

Do you know how many people died of nuclear radiation from Fukushima?

Zero.

There were over 1500 deaths. Mainly from evacuation and panic. And people panic because of unreasoning fear. That has been mongered by anti-nuclear activists.

So once you have gotten over your panic over Nuclear Power, calm down and listen.

Fourth Generation Nuclear Power Plants are safer. They have passive (or "walk-away") safety systems.

The older generation nuclear power plants (like Fukushima) requires coolant to be pumped into the reactor core at all times to keep it cool.

What if, the reactor core was placed on a platform, over a big vat of coolant, and if the reactor overheats, the platform is designed to melt and drop the whole reactor core into that vat of coolant?

This is not how the passive safety works EXACTLY, but is just intended to illustrate what passive safety is supposed to do - that in the event that there is no one to shut down the power plant, left unattended, it would proceed to shut itself down. Unlike the earlier plants where active intervention is required to shut down a power plant.

There have been discussion about "Thorium Molten Salt Reactors" (Google that) for years. The problem is that it is still a few years in the future. China might have one commercially viable in about 2040. But they are hampered by lack of budget and lack of access to technology (the West is not sharing with China).

The West may be more ahead in Molten Salt Reactors technology, but nuclear power has a negative image in the West which is in the process of closing down nuclear power plants, whereas China is building more.

The West and China is also pursuing Nuclear Fusion. Which is also about 30 years away.




There is also talk about Small Modular Reactors, which are small, self-contained nuclear power plants that can produce enough energy (usually less than 100 MW) to power small communities, and would last about 20 - 25 years. However, these have also been promising since about 10 years ago, and no commercial version are yet available.



What are some Alternative Energy that are non-carbon emitting/polluting.

Geothermal? None. The hot spring in/near Sembawang? Good for cooking eggs. Slowly.

Wind? As Shanmugum explained in the news report, no. See also answer to suggestion below.

And this summary of alternative energies, extract on wind energy:
wind is unpredictable and often comes in intermittent surges, which isn’t very useful unless we can develop long-term storage of the produced energy. Not to mention the fact that wind turbines can be disturbingly loud, and dangerous to maintain.
In addition, large wind farms can have an immediate impact on local weather (by influencing air circulation) and local wildlife (turbines killing birds and bats). This may be mitigated by the development of bladeless wind turbines, but it’s still too early to tell
.
Hydro-electric power? We have no suitable rivers.

Tidal? We don't have the tides (large variation between high and low tide) nor the coastal features for this to work.

Don't want nuclear? Just want solar? Sure. Reduce your electricity usage by 90% permanently.



Suggestion: We can convert Pulau Ubin into a Wind Farm to generate electricity! And a Solar Farm too!

Do you know how much land is required for one wind turbine? Do you know how big is P. Ubin? Do you know if P Ubin is windier or has more steady wind than the rest of Singapore? Have you ever tried to fly a kite on P. Ubin?

Do you want to completely de-forest P. Ubin for solar and wind farms?

Do you know why no one has combined solar and wind farms together? (Hey! Maybe SG could be the first in the world... too bad we don't have the steady winds that would make that feasible...)

P. Ubin is about 10 sq km (IIRC). Do you know how much solar power can be generated if we completely cover the island with solar panels?

About 200 MW.

Is that a lot?

Singapore currently needs 6000 - 6500 MW.

We just deforested the whole of P. Ubin for 200 MW which is about 3% of SG's needs.

Conversely, a nuclear power plant on land about 4 football fields can produce enough power for 3 million Californians. Which may translate to about 6 million Singaporeans. :-)

Or even if it doesn't, two such power plants would meet our needs and lower our carbon emission.

Is solar energy in the future of Singapore? Very likely. Will it be enough? No.

Here's a relatively pro-solar article. This is the token "con" he came up with
Solar Power Cons On to solar power cons…. Actually, it’s really hard to think of legitimate solar power cons. Though, there might be a few.
One is that wind power is often a cheaper option for electricity generation than solar power, so rather than blindly supporting or installing solar power over wind power, one should examine both options. Of course, no grid should rely 100% on one energy source, and wind and solar are actually very complementary. So, more than competing, solar and wind are most logically partners that should jointly be used to move into a clean energy future.

Another potential solar power con is that the sun doesn’t shine 24/7. If it did, yeah, we could just rely on solar power for all of our electricity needs in many places. Since it doesn’t, again, we need a mix of clean energy solutions, and even energy storage to a small extent. But limited solar resources don’t mean solar isn’t the best option for many people, businesses, organizations, and governments. And, remember, solar energy resources dwarf all other energy resources on the planet. 
The biggest challenge with the timing of solar energy potential is that a lot of electricity is needed (or wanted) in the evening and early night, when solar resources dwindle away. This makes the importance of a mixed energy pie that much more important.
Solar power can supply some but not all our energy needs.

Another possible alternative energy is Algae farming for bio-diesel or biofuel. This can be farmed in the sea and would not (or should not) have a land cost. BUT, while this fuel is renewable, it still emits CO2 when burned. If the carbon emission measures discounts algae biofuels because the carbon is "new" (recently absorbed from the atmosphere), it may still be feasible. But if there is no discount for this, then this is not an option for reducing carbon emission.

Which leaves nuclear.

The problem we are facing is a difficult one. Reduce carbon emissions, in order to (hopefully) moderate climate change, or do nothing and see what happens. (Hint: what happens will likely be bad. Maybe not worse than a nuclear accident if it happens, but the risk of nuclear incident will be low, compared with the already happening climate change which will get worse.)

And yes, even if SG does what we said we would do (cut carbon emissions), China and the US (and other countries) may not and the world still goes to hell. Or becomes hell.

China in particular is not likely to be able to reduce their carbon emissions as they grow and develop and development spreads to the rural regions, and rural villages urbanise and modernise. They know this. Which is why China is building more nuclear power plants even as the West is closing nuclear power plants.

In summary, solar and wind are just too diffused to be of practical significance in powering Singapore.

The best option for 1) providing enough energy to power Singapore, and 2) reduce carbon emissions to meet our commitments to ameliorate global warming/climate change, is to use Nuclear.

Nuclear Fission Power Plants, to be exact.

Because there are advance research into Nuclear Fusion Power and that would change everything.

BUT...

There are signs that Global Warming and Climate Change is already beyond reversal. That no matter what we do, how much carbon we stop emitting, the carbon already in the atmosphere is on a runaway cascade and temperatures will rise.

Which will present the world with challenges.

We should just focus on what Singapore's challenges will be.





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