Final words

This blog has been a bit of a bumpy ride to say the least! I initially came into this blogasphere thinking I would write some grand posts looking at the impacts of our greed for all resources...

With all my best intentions, this was never my passion. I ultimately wanted to look at energy, and how it shapes and controls our lives. 

This became a firm reality when I hit upon an article in The Times which explored our future energy security. From there I have explored our excessive use of energy through reporting on COP21, and how to mitigate against our exploitative habits through renewables (here, here and here.. oh, and also here). But renewables are old news, over-discussed and a tad boring... so I wanted to incorporate some of the issues in measuring and understanding energy consumption (something of vital importance if you are going to define exploitation (which can be found here and here)), as well as other issues people usually cite when faulting renewables (because people always complain about things!), and how to mitigate against the main issue (reliability) with storage solutions (here, here and here). My aim across all of my later posts was to discuss the current research being published in mainstream journals to understand how the scientific community was approaching a contemporary topic of astronomical future (and arguably current) importance.  

Wooo! Hope! (Source)

Ultimately, my opinions have changed. I have gone from someone who was a little sceptical (maybe cynical) of the potential that renewables could have in mitigating carbon emissions, to being incredibly hopeful.

Previously I would always argue that nuclear is the most promising energy source, as it is the most efficient and least polluting fuel. However efficiency isn't everything, and provided the initial investment hurdles can be overcome, the future for renewables could be bright. Two posts have really inspired me: Morocco and its quest to become a renewable powerhouse and the potential host for COP22; and the creative solutions for energy storage that are being developed and discussed. However the most heart-warming article I have read is the first-order investigative research report on Ontario's potential to become a fully renewable city! We are now at the stage of scientific understanding and development where we could develop fully renewable cities. Whether we will be a matter for politicians, lobbyists and people with money to decide!

Renewables are our best friend and worst enemy. They are cause for both optimism and concern. I will try to explain why.

Our future depends on renewable resources - in a world that thrives on consumerism and excessive consumption of resources, the limitless resources will always be most valuable. However, the means of collecting and generating electricity from these resources is expensive, technologically difficult and require a shift in perceptions. They are also expensive and tend not to provide the same standalone reliability compared to a fossil-fuel power station, as they must be used in conjunction with other renewable sources or energy storage solutions, further making them more expensive. Above all, it's worrying to know that amongst all the COP21 talks and investment in recent months and years, the dawn of renewables may be quickly over in the UK (a fellow blogger, Caitlin, discussed this topic in fantastic detail over at her blog)!

However from my blogging I hope you can see the optimism in academic literature. Scientists are trying to improve the situation through developing new and innovative ways to power our future. The models, experiments and investigations, although may seem silly ("why would you model the potential for renewables to fully power desalination plants?" you might ask), the results show that renewables have the capacity to do the things we need them to do.

At the beginning of these blogs I discussed the potential for a centralised resource system which efficiently distributes resources based on demand, instead of based on their value. I now think that idea is wrong. The distribution of resources equally and efficiently, although reduces the potential for greed and exploitation, does not mean we are not harming the environment. A means of efficiently collecting resources whilst having little impact upon the environment is of even greater importance. Although I have only focused on energy and the potential of renewable solutions, I believe other resources, when investigated could be efficiently and substantially consumed.  

Scientists have done their work. Its now time for everyone else to join in and provide a means to make renewables work. Our exploitation, greed, reliance and demand for electrical resources will never cease. However, how efficiently and environmentally friendly we collect, modify and distribute these resources can change. it just requires someone to take that first step.

*Little bit of a brain dump, sorry....*

TL;DR: renewables are promising, scientists are great; however only time will tell!

Renewable Solutions: Novel Ideas

As previously discussed, energy storage for renewables is important, especially when relying on them for a greater proportion of global energy production. The innate unpredictability of natural renewable energy resources (wind, sun, river discharge, tides) makes energy storage facilities vital for supplying constant levels of electricity to our constant (exploitative) demand.

The most wide spread and popular energy storage technologies include (taken from Perna et al., 2015):

• Electrochemical batteries
• Supercapacitors
• Thermal-storage materials
• Flywheels
• Pumped hydro reservoirs
• Superconducting magnetic energy storage
• Chemical (hydrogen, synthetic natural gas, etc.) storage
• Compressed air energy storage (CAES and ACAES)

Each method is suited to different applications and vary in stored capacity and efficiency, and discharge rate. Electrochemical batteries can be highly efficient and store large amounts of energy, but have limited life cycles and discharge stored electricity at a slow rate (Perna et al., 2015). CAES systems similarly have a high efficiency, but contrastingly have longer life cycles and can store a varied amount of electricity, depending on the built capacity. Hydrogen-based energy storage systems (water electrolysis) tend to have lower efficiencies, but has a high storage of energy per mass, whilst having a long life cycle (Perna et al. 2015). However, this post will look at some of the more interesting solutions published recently!

Perna (et al., 2015) undertook an interesting study looking at how hydrogen-based energy storage systems could be integrated with biomass powerplants, making the biomass production more efficient. Overall, electrical efficiencies of the integrated systems ranged between 40-43%. To me this is incredibly low, but compared against incineration or biomass gasification (which has an efficiency of 20-24%), efficiency levels look great! Furthermore, integration provides a demand for electricity when consumer demand is low, reducing electrical fluctuations across the supply networks and improving reliability!

Another unique and new means of storing energy is the use of using liquid carbon dioxide. Wang (et al., 2015) investigated different systems by which to pressurise liquid carbon dioxide. During off-peak or low demand periods, liquid carbon dioxide is pumped from one tank to another through a series of compressors (consuming excess power). When additional power is required, the pressurised liquid carbon dioxide is released through turbines to generate electricity. Heat exchangers are cooled using oil, and the heated oil is used as a secondary source of electrical generation, heating water to turn turbines. 

Figure 1: Comparison of methods of energy storage with
RTE (Round Trip Efficiency - total efficiency) and EVR (energy:volume ratio) (Wang et al., 2015)

Wang's paper explores a number of schematics, suggesting that the improvement of thermal energy storage (heated oil) can improve overall efficiency (RTE) to 56.7%. Furthermore, the energy to volume ratio (EVR) is a reasonable 36.kWh/m3, making liquid carbon dioxide energy storage a more efficient (in terms of volume to energy ratio) means of storing energy compared to CAES and Pumped hydroelectric reservoirs (Figure 1).

When combined with storage mediums, renewables can be very useful. A mixture of various renewable resources combined with storage capacities mitigates reliability issues. To wrap up this post, I have found an exciting article which provides a model for a completely renewable-powered city.

Richardson and Harvey (2015) have modelled the renewable potential surrounding Ontario, Canada, investigating what would be required to move from conventional fuels to a fully renewable system which includes pumped hydroelectrical and battery storage. The model results aren't particularly detailed, as rough estimates are used based on existing literature or known specifications. However they optimistically conclude that Ontario could move towards a renewable-based electrical generation system which is reliable and a renewable-fuelled city "can be maintained without excessive generation costs". The idea, they explain, is technically feasible, however there are issues surrounding potential demand fluctuations with electrification of transportation, which could prove to be problematic.

The results from all 3 studies are optimistic. There are an abundance of methods and means to cope and sustain our excessive demands for energy, and when scaled up to a city-wide model, the level of technology we currently are at seems to prove that we can indeed live sustainably (whist still exploiting the abundance of energy)!
As a side note, Richardson and Harvey do note that a change in behaviours would probably help to make renewable-based cities a reality for more parts of the world. I completely agree with this, but that conversation is for another blog!

Renewable Solutions: Compressed Air

My last few blogs will revolve around the topic of making renewables more suitable for the world. One of the largest issues that renewables face is they only work when the wind blows or when the sun shines (or when earthquakes occur...!). This is fantastic for sunny countries, where this can work to power high energy-demand installations with few issues. However, for countries where it isn't always sunny or windy, renewables are used to top up fossil-fuel generation, as their unreliability is too great to make them a dominant source of electrical generation.

This is where stored energy comes into play! Storing energy during off-peak or excess supply periods provides a more reliable and constant supply of electrical energy to renewable-dominant countries during periods of low supply or high demand. Storing energy on large scales is known to be inefficient, hence why power stations are switched on and off to meet demands of energy (Steadman, 2013). However more efficient means of storing energy is being developed. 

(There are a vast number of other electrical storage systems. A good summary of the literature was conducted by Chen (et al, 2009). Newer technologies, such as hydrogen storage are not included in the review, but are an important technology that is efficient and has lots of potential (Schiller, 2014).)

Compressed air storage uses off-peak excess electricity to power air compressors. The air is compressed into large vessels or geological formations, such as old mineshafts, mixed with natural gas, and then released to generate electricity through thermoexpanders (Pendick, 2007).  The mixing with natural gas increases the efficiency of electrical generation. There is one down side to the Compressed Air Energy Storage (CAES) method: there is still a pollution aspect. CAES is predicted to be approximately 60-90% efficient, depending on methods used (Brown, 2013). 

Two examples of CAES in operation are: Huntorf in Germany, built in 1978 and has a capacity of 290 MW and facility in McIntosh, Alabama, USA, built in 1991 and has a capacity of 110 MW, with both facilities using salt mineshafts as a means of storing the air (Succar and Williams, 2008). Both facilities run efficiently (~60% efficiency) and prove that this is a suitable low-cost energy storage technology. However, CAES, as briefly mentioned previously, has a pollution element, and requires natural gas. It has previously been found that CAES makes wind power less profitable and is heavily reliant on fossil fuel markets (Greenblatt, et al., 2007).

The solution: adiabatic CAES (ACAES). Now I would attempt to explain this, but there is a video with a far better explanation available... so let's rely on that instead:

To summarise, the heat energy is used and conserved, negating the need for natural gas to be used in the thermoexpanders to regain the stored electrical energy. 

So, how do we understand which is best? Well of course I would not ask that question if I did not already know! 

Boumana (et al., 2015) recently published a model examining the lifetime (from mining material out of the ground to make metals, etc., to the decommissioning of the facilities) environmental impacts of both CAES systems. They found that the most significant environmental impacts are from the natural gas consumption (CAES) and thermal-storage tanks construction (ACAES) (insulation, considerable amount of plumbing work, and overall construction). However, overall, ACAES is deemed to be the least environmentally impactful and cheaper in the long term, due to not requiring a constant natural gas consumption.

So, what should we take home from this? Renewables  can be unreliable, but their reliability can be improved!

Dusty PV

Energy is of vital importance in today's world, but creating sustainable energy sources is even more important for the future sustainability of Earth. When assessing sustainable energy sources, renewables come to mind. But they always come with a warning label. There are those who will always criticise renewables for being inefficient and costly. There is one notable issue with renewables that people always reference - a lack of reliable renewable resources. If the sun doesn't shine or the wind doesn't blow, they are useless (that isn't strictly true as solar can still produce energy with little sunlight). But if you're lucky enough to live in a sunny, windy, hydrologically and geologically active, that tends not to be an issue.

In sunny countries, solar makes an ideal renewable energy. However dust can be an issue as it settles on the surface of PV modules, covering the surface and reducing the amount of solar radiation hitting the surface. This is a real issue for sunny desert countries, but what are the implications? Well I suppose I wouldn't be writing a blog or asking the question if I hadn't found a rather nice recent article that looks at the issue!

Zarei and Abdolzadeh (2016) modelled the thermal and optical impact of dust on solar PV panels. The authors compared and validated their model with literature values. They modelled the amount of "6.44 μm sized mono-disperse dust particles" which withstand average angles of solar PV installation. At a 30° tilted dusty PV cell, Zarei and Abdolzadeh (2016) found the maximum power with 0.224 mg/cm2 of dust (the amount of dust that tends to stick to the module at 30°) is 13.53% lower than a dust-free solar PV cell (figure 1).

Figure 1: maximum power output of PV cells at different dust densities (Source)

This information is very useful, especially in modelling the effectiveness of solar PV cells in dusty countries. Furthermore combined with average local dust or sand sizes, the model can be localised to find the maximum electrical output of dusty solar PVs. Finally, in national and international energy models, this information is vital for recreating realistic and accurate understandings of renewable energy production.

Resources are vital, but our over reliance on energy is incredible. For a sustainable future, we need to rely on clean and un-exploited sources of fuel. These small studies can help our fuller understanding of global energy consumption and potentially calculate and reduce the impact of climate change!

Dry Islands

In a previous blog, I likened energy to water (or more specifically virtual energy to virtual water). On the whole, we can survive without electricity. I mean, us younger folk who are glued to our phones and various other devices, it may be more of a necessity... but on the whole, we can survive.

This is where the similarities between water and energy diverge. Water is a necessity of life, and when humans decide to live in dry places with limited surface water and also use up all the groundwater, there are issues. Quality and quantity of water is vital, especially for inhabited islands which find themselves in these predicaments. In some regions of the world, tankers of water are used to supplement groundwater supplies to reduce reliance and exploitation of groundwater.

Desalination plants offer a limitless (okay almost limitless) source of freshwater, especially for islands which, by definition, have lots of water around them. They also require vast amounts of energy to evaporate the water to remote the salt. Traditionally fossil-fuel derived electricity has been the go to supply of this required energy, which has unnecessarily high carbon emissions, especially considering if the water supplies were managed more efficiently to begin with, the islands may not have to resort to such lengths.

So, seeing as this blog looks at exploitation and ways around it, can renewables be used to reduce the impact of desalination plants? Well it turns out, yes (woo!!).

Desalination and Renewables

A team lead by Mentis (et al., 2016) looked at designing a tool to design and plan the most efficient size of desalination plant with the available renewable supply. The tool uses an excel interface linked with a local database of the water demand for the region. It requires tourism and domestic population estimates for the next 20 years, along with wind and solar levels, desalination efficiencies, fuel and production costs and taxes and tariffs (Mentis et al., 2016). Finally, a 50% increase in demand is added to the predicted demand value to produce an estimated required supply.

This tool is especially useful across Greek Islands, which currently experience high levels of groundwater salinity and have high renewable resource availability (Prodromidis and Coutelieris, 2011). Compared to the cost of supplying water per m3 of water in Athens (€0.70 per m3), the Dodecanese and Cyclades Island groups pay considerably more (€7.30/m3 and €9.30/m3, respectively), due to having to ship water from the mainland (Mentis et al., 2016). The tool was run using data from 3 Greek islands (two islands from the Dodecanese Island group and one from the Cyclandes Island group). The substitution of fossil-fuel powered desalination plants for renewable-powered (and more specifically solar PV) desalination plants considerably reduced the operational and maintenance costs of either shipping fuel or shipping water. The results of the model show that water costs could range from €1.45/m3 for larger islands to €2.60/m3 for smaller islands. 

Desalination plants are boring...
So here are some pictures of Patmos, a Dodecanese Island (I wish I were there!)
(Source and Source)

The results from Mentis' (et al., 2016) work not only show that there are considerable economic benefits, but also environmental benefits, reducing the carbon emissions of the islands and improving the sustainability of the region. In Greece's economic state, this can only be a good thing!

Hope

The model presented in the article shows that renewables are something that can be useful in even the most remote situations. Granted, Greek islands get an unfair amount of sunshine, but the model demonstrates the potential for renewables. In our ever growing carbon- and consumption-heavy world, it's research like this that will ensure the sustainable growth of human populations whilst having a (slightly) lower impact on Earth's resources.

The glimmer of hope in COP21

In light of COP21 and this blog's (slowly developing) aims to investigate resource utilisation with regards energy production, it makes sense to look at renewables! Essentially, renewables can provide countries with unlimited, free electricity, if the conditions are correct. Therefore, it shouldn't be surprising to know that sunnier countries have pledged high levels of solar energy investment to contribute towards their carbon targets.

Morocco has made great strives towards reducing their reliance on coal. In 2011, Morocco was heavily reliant (47%) on coal for energy production. However, this has considerably reduced from 2001 (77%). Furthermore, they have made great steps through commitments at COP21, agreeing to reduce GHG emissions by 32% by 2030 through 50% renewable electricity generation by 2025 and reduced energy consumption of 15% by 2030. Finally, and most significantly, they have offered to host COP22, solidifying their drive and dedication to meeting their climate objectives.

To do this, Morocco requires support. The UN Green Climate Fund can be of some help; however investment by private companies is becoming increasingly significant in efforts. Saudi investment has been important in the Arab region.

The shining hope in COP21 (Source)

A solar thermal plant planned to open next month will aim to eventually supply energy for 20 hours a day from energy collected from the sun and thermally-stored in liquid salt. The potential renewable generation capacity could provide export capacity to Europe, instead of the heavy importation of electricity from Spain.

Another great blog post has questions the hopefulness of COP21, citing Morocco and Ethiopia as leaders in setting targets internationally. I agree that more needs to be done - but maybe the baby steps will eventually make more of an impact in the future? I think there is some hope from COP21, even if it is only the smaller and less developed countries providing that hope.

Bad Coal, Good Alternatives

Coal is an important resource and is predicted to become of increasing importance in new energy production. In light of COP21 and a global push to keep carbon emissions to a minimum this is an important issue.

Coal has become a staple across the energy landscape (Source) 

Analysis which was presented at COP21 suggests that if all coal plants planned to be built by 2030 are built, coal emissions would increase by 400%. Even with no additional coal plant construction, predicted emissions from coal are 150% too high to keep global temperatures below 2 degrees.

Calculated carbon increase from analysis results (Source)

This is a slight issue... And considering temperatures have already gone up by an average of 1 degree since pre-industrial times, the threshold of 2 degree temperature rise is becoming more and more problematic.

For many countries, providing their citizens with electricity is of far more importance than cutting carbon emissions, even for those countries may have agreed Intended Nationally Determined Contributions (to cutting carbon), or INDCs. Ultimately, this can lead to a number of issues which will impact the final result of COP21: increases in carbon emissions and displacement of renewable energy. These countries, many of which are developing, such as India and China, are still investing in renewable energy sources, but the uptake, cost and generation is too small to be effective in bringing electricity to the masses.

So how do we approach coal? I believe we need to appreciate it is a cheap, very widely recognised and used technology globally. What can be changed is the types of coal and the technology used within coal plants to mitigate the issues. Furthermore, pushing cleaner technologies, such as gas may be a more suitable, cleaner and (potentially) more efficient solution (and one which will be dominating the UK energy space for the next 20 years).

Technology:

Carbon Capture and Storage (CCS)? I feel CCS is a utopian idea which is and will continue to be only suitable in a hypothetical world. CCS has had has limited testing. It provides us with an additional carbon sink. But continues to allow our exploitative approach to carbon for energy. There are also risks to CCS. The principle is to pump the carbon back into old oil fields, but contamination and leakages could present themselves as a large issue.

Renewables? Could be a solution for developing nations. Funding must be available, however renewables do provide grassroots-scale energy production without the need for expensive infrastructure development - an especially important issue in fast growing cities.

These two latter aspects are items I will look at and investigate in my next two blogs: carbon sinks (afforestation) and renewable production (solar farms) - how can our use of the sun and trees mitigate against our exploitative use of electricity?

Edit: the second photo was added at a later date to provide some visualisation to the figures discussed above

Bill Gates and Energy

It's always interesting hearing from world icons on subjects that will impact our future, and how we solve the issues of today for a better tomorrow.

With COP21 around the corner and this blog's focus on the exploitation of resources, Bill Gates' summary of the issues at the heart of the talks is current and helpful.

One of the interesting aspects Gates includes is the notion that providing the world's poorest with very cheap energy is a means of helping them out of poverty. This, along with government  and industry investment can provide long term clean energy solutions for the globe. 

The quest goes on!

Growing the solution?

In my previous post, I discussed a news article regarding the future of Britain's energy status. As with many EU states, the UK has pledged a reduction in CO2 emissions by 80% compared to 1990 levels by 2050. Many of the solutions which have and will be discussed will need to be implemented.

Whether or not the DECC's time, resources and energy has been entirely focused is debatable (and if your focus is strained at all whist reading this, you too can procrastinate by playing their carbon reduction game)! If you prefer a direct, informative (and less interactive and fun, in my opinion) understanding of how the government will approach its carbon targets, then the 2050 Pathway analysis is a great indulgence!

The aim of the game is to reduce, prevent, or reverse our CO2 emissions. There are various means we can do this, but ultimately it means moving to low- or no-carbon solutions. One fantastic solution which is carbon-negative are biofuels.

So biofuels! Biofuels are an interesting addition to the analysis report. I personally do not see the advantage of biofuels, they take away land which could be used for food security. Within the report, biofuels play a large role in mitigating against transport emissions, without the need for technological innovation in the form of electric cars and fuel cells, i.e. a low tech, low carbon solution. In industry, they could play a role, provided they produce enough energy for production.

Before writing this, my naïvety of biofuels extended to a romanticised image of wheat or another cereal crop growing under a blue sky...

Never a grey sky with biofuels.. (Source)

Although this is not far from the truth, this less beautiful and more informative image from the report gives a much fuller understanding of the alternative (and less glamorous) sources of biofuels.

A summary of biomass sources and processes for conversion to biofuels (Source: p148)

As you can imagine, this put a dent in my simplified understanding of biofuels. There are various sources? And different types of biomass? An hour of scanning various articles and abstracts on the topic, I came across a nice piece of analysis on the impacts of biofuels on land exploitation and the wider carbon cycle by Fargione et al (2008). 

It turns out the government's approach to biofuels to reduce carbon emissions depends heavily on the source of the biomass. Clearing rainforests, grasslands and other productive biomes for biocrop production creates up to 17 to 420 times more CO2 than the fuels that it replaces (so much for a negative-carbon fuel!). However, the analysis does acknowledge that biofuel production from food waste or abandoned farmland would have little or no CO2 impact, and could become a carbon negative fuel source in some cases.

Biofuels are interesting, it seems. They have the potential for being a sustainable source of energy for the future. We could quite literally grow our own energy! But the sources and overall environmental impact really need to be fully considered before opting for mass adoption of biofuels. Also, I think there might be a few petroleum companies, not to mention a few people in the Treasury that might have something else to say about biofuels... 

Positive energy crisis?

With our life-or-death reliance on energy, it might come as a surprise that the UK is struggling. For the first time, next year, Britain will not have enough "dispatchable energy generation capacity" (essentially, power plants which can be switched off and on to meet excess demand, contrasted against wind and solar energy which is a non-reliable, non-programmable energy source). 

Is this our future? (Source)

Over the last 5 years, Britain has lost 20% of its baseload dispatchable energy and have no replacements planned in the near, with the further hope of shutting down the remaining 13 coal power stations, which generate a third of the UK's energy. This would mean the potential to have power-cuts!

From this point we can go two ways. We can build cheaper, coal-powered stations and provide us with the energy we need in a short period of time. 

Alternatively, this gives us the opportunity to invest in cleaner more energy and carbon efficient fuels. The UK has a great opportunity to move into gas-fired and nuclear power stations, cleaner fuels with less environmental impact. A great blog on the intricacies of nuclear can be found (here). At this point, most people would say, "oh, but why not invest into wind and solar?". Well the government advocates no longer relying on subsidies, urging the private sector to take the burden of the investment. 

Maybe it's a good move? Only time will tell!