The following article is by Engineering PhD student Pádraig Daly in University College Dublin. With a Masters degree in Power Electronics, Padraig is pursuing further research on the topic of integration of wind energy into a national grid. Padraig is also a keen outdoors-man and great friend of mine.
The Need for Renewable Technologies
World energy demand is expected to double by 2050, with the globe’s population set to increase by 40% to 9 billion in the same period. This population increase is a source of concern, not because I’ll be competing with someone from India to buy the last box of cornflakes on the internet, but more importantly, the impending competition for energy supply. Is it morally wrong to tell developing nations to curtail their energy consumption for the sake of mitigating global warming, when they have not yet reached the same living standards as the west? Is it not right that all people in the world achieve the same standard of life as the western middle class?
There is an oft repeated and misunderstood expectation of meeting this energy demand through renewables. Currently, the world uses energy at a rate of 13 trillion watts. That might be hard to grasp. Put another way, our bodies consume energy at a rate of 2,500 watts (energy per second). Just as a reference, you probably produce 100 watts cycling to college every day. A typical incandescent lightbulb uses 40 watts. This 13 trillion watts is consumed unevenly, with a person in the U.S. consuming energy at a rate of 10,000 watts, and someone in Bangladesh at a rate of 200 watts. On current technology, we could possibly provide 7 trillion watts from renewables. So the simple answer is that we can't replace all fossil fuels with renewables - not with current technology.
The only reasonable expectation is that we reduce our energy consumption, and the reason why is global warming. The nuts and bolts of global warming is that in order to prevent or at least mitigate a 2°C rise in global temperatures - those at which irreversible damage to eco-systems and bio-diversity will take place - we need to limit the concentration of greenhouse gases in the atmosphere. Gases such as CO2, which stays in the atmosphere for 100 years, methane (10 years) and nitrous oxide (100 years). There are also the air pollutants such as nitrogen dioxide, sulphur dioxide, lead and particulate matter which all can cause significant respiratory and cardiovascular problems for human beings. In the animal world, there is a predicted reduction in the pollination of plants by bees (1 in 3 bites of food you take comes from a plant that was pollinated by a bee), or damage such as droughts in the basins of the great rivers of Asia such as the Brahmaputra, Ganges, Yangtze where 1/6th of the world live.
The world has to double the energy production and half the greenhouse gas emissions by 2050. Nobel Laureates have listed the provision of energy as the number one challenge facing humanity in the future.
The Energy Mix
The Energy Mix
Renewable energy, (excluding hydro generation for reasons which will be explained later), accounts for just 1.3% of current energy demand. So for the foreseeable future, fossil fuels will remain the world’s dominant energy source. Coal now accounts for 29.6% of energy demand, trailing only to oil, which holds a share of 33.6%. Coal has gained importance as an energy source due to its abundance, security of supply and ease of extraction.
I discounted hydro generation as the easiest locations have already been exploited. Anyway, hydro is not as clean as it is made out to be. There’s a high CO2 footprint in its construction, the relocation of people significantly reduces their social happiness, and the release of hydrostatic pressure at the far side of the dam causes landslides, continuously washing away villages in developing countries. Renewable generation must be sustainable. Sustainability is having the ability to meet the needs of a healthy lifestyle for all people in the present, without compromising the needs of future generations.
Current usage rates of the word ‘sustainable’: unsustainable.
Nuclear Power
Nuclear is not a form of renewable energy, but it is CO2 free. It is also a very safe form of energy in comparison to oil refineries and coal mines. The small death rate per watt of electricity produced by nuclear, in comparison to that of oil and coal is condradictory to our perception that nuclear is a dangerous form of power generation. However, nuclear waste is a huge social issue.
The use of nuclear energy is currently legislated against in Ireland, as well as its use being unachievable in the due to the comparatively low levels of energy demand and the requirement that the power plants be complimentary to a system which can accommodate the variability of wind energy.
On a global level however, nuclear could play an important role in greenhouse gas prevention.
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| Nuclear: barely killing anyone, at all, ish. Kind of. |
Wind Power
Wind generation is variable, needs to be forecasted and doesn’t provide the power system with the same suite of services fossil fuel-fired power plants do. However, wind generation has a much lower greenhouse gas footprint. Wind generation produces no such gases.
The paradox with wind generation is that wherever it’s windy, no one lives. Some of the windiest places in Europe are along the west coast of Ireland and Northern Scotland. There are no major cities in such areas, meaning transmission lines need to be built to deliver this renewable energy to the demand centres. That’s difficult. There is a public unease about the construction of powerlines. No one minds new roads as they can see the benefit; all the cars pouring into their local towns boosting the local economy. Society has had electricity ‘on tap’ whenever we’ve wanted it, and as a result we don’t see the need for new transmission. We don’t see the bottlenecks and weaknesses on a power line like we do on a road.
(By the way, overhead power lines don’t give you cancer. What is given off by a power line is an electromagnetic field, which is the same as what comes out of an air conditioning unit, for example.)
Solar Power
There are two forms of solar power: (a) solar thermal, where you use the sun’s radiation to heat the water for your shower, and (b) solar electric, where electricity is produced by solar panels. Electricity is a higher form of energy than heat, meaning solar panels are always more desirable from an energy perspective, though cost considerations might point you in the direction of solar thermal collectors (in Ireland anyway). There is also a paradox with solar energy, in that wherever it is hot, hot water from solar thermal units is not needed. Instead, you install solar panels that produce electricity, which again requires a transmission network to the cities.
Solar panels are currently about three times the cost of wind turbines in Ireland. The starting point of silicon, which most solar panels are made out of, is sand, and there’s loads of sand about the place. So you’d be right to wonder why solar panels are so expensive when there’s sand all over the shop. Well, the reason is that the purity of the silicon must be extremely high for solar panels to create sufficient levels of electricity.
Biofuels
Intuitively, biofuels sound good. It’s money for the farmers, and a strong rural economy means a strong overall economy. Another advantage is that the necessary infrastructure is already in place.
There are two types of biofuels: bioethanol, which is produced from sugar cane or corn, and biodiesel, which is produced from vegetable oils or animal fats. When looking at biofuels, you need to look at the life-cycle of the fuel; the embodied cost of such fuels. You get only ~100 units of energy from bioethanol for every 80 units you put in. The levels of efficiency are worse when you use corn.
The main energy input is the fertiliser that has to be mined and transported from somewhere else. Every product you buy has a transportation cost and a resulting CO2 footprint associated with it. The next problem is that biomass production displaces food production in Africa (the only place where its efficient to grow such crops). Farmers in Africa make more money growing corn for fuel than food, and as a result corn for food is scarce, increasing its price and putting it out of the reach of people in Africa. If you can’t afford food then you go hungry and die. Bioethanol production is also water intensive. For every litre produced, 14 litres of waste water are created, which can’t be discharged into rivers. The waste water uses up the oxygen in the water and all the fish die because they can’t breathe. Its oxygen demand is a thousand fold too high.
As for biodiesel, palm oil production in Indonesia is destroying the tropical rainforest. What’s the point in using biodiesel if it’s produced this way? However there is research being undertaken on using the oil produced by algae for biodiesel, which is wildly promoted as the panacea of energy production.
Electric Cars
Electric cars are no longer a purely academic research topic, with a lot of the technical issues associated with the roll-out of electric cars having been ironed out. All new electric cars have a fast-charge capability (30 minutes charge-time at a public charging point). However, it's important to note that we’ll only ever be able to slow-charge our cars at home (8 hours charge-time) due to there being a different electrical connection at houses. Although the technology is now ready, society is most certainly not. In the minds of the public, there is a link between electric cars and inflexibility; people believe that the inability to pop into the petrol station and refill the electric car will mean their travel ability is hindered. They might get stuck on the N77 to Portlaoise with a flat battery.
The fact however remains that 90% of journeys made by cars fall within the range of current electric cars. And for those long trips that we occasionally take to see our granny in the back-end of Ireland, hybrids could be used. Electric cars are essential in my view, as we’re unlikely to power our freight transport with electricity. So whatever oil is left in the future will be needed for that component of transport. The fact is that oil is used to produce so many consumer products, and that burning it to power your car, when reasonable alternatives exist, is ‘wasting’ this unbelievably valuable resource.
The fact however remains that 90% of journeys made by cars fall within the range of current electric cars. And for those long trips that we occasionally take to see our granny in the back-end of Ireland, hybrids could be used. Electric cars are essential in my view, as we’re unlikely to power our freight transport with electricity. So whatever oil is left in the future will be needed for that component of transport. The fact is that oil is used to produce so many consumer products, and that burning it to power your car, when reasonable alternatives exist, is ‘wasting’ this unbelievably valuable resource.
It is also worth nothing that electrifying the road fleet comes with a major caveat. If we increase our electricity demand due to the large-scale roll-out of electric cars, this increased demand must be met with renewable energy sources. It’s no good driving around in electric cars if the electricity produced for the charging of the car comes from combusting oil, coal or natural gas.
Final Comment
We should question modern thinking towards renewable energy. Their promotion should be balanced, reasonable and take into account the full environmental impact of their introduction. The issues of water, biodiversity and conservation should be the priorities of society's decision makers. A change in attitude and behaviour by the ordinary person can be the real driving force behind the positive powers of change.
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