Energy resources exist in different forms – some exist as stocks and are exhaustible, others exist as flows and are inexhaustible. The effects of climate change, and the impact that greenhouse gas emissions have on the atmosphere, are ushering in a reassessment of where our energy supply comes from and, more importantly, how sustainable it is.
The first form mentioned above is fossil fuels such as petroleum and carbon energy, the second form relates to resources based on constantly replenishing flows of energy such as solar, wind, hydro and geothermal as well as quantities grown by nature in the form of biomass. All of the latter forms are (mostly) green, clean and renewable and therefore could provide an answer to the shortage in commodities and increasing energy demands. Rising consumption of fossil fuels is still set to drive up greenhouse gas emissions and global temperatures, resulting in potentially catastrophic and irreversible climate change. Alternative energy sources can help to reduce emissions of CO2.
The possibilities to use renewable energy are still developing: energy resources evolve dynamically as a function of human engineering ingenuity. There is still a lot to do with regards to installing and developing alternative energy production – energy demand is increasing worldwide, day by day with ongoing population growth and industrialisation.
Our reliance upon fossil fuels such as coal and oil is negatively affecting the planet. Burning these fossil fuels increases the amount of carbon dioxide (CO2) that is released into the atmosphere, leading to a heightened greenhouse effect and warming of the earth. With governments trying to reduce CO2 emissions, renewable sources of energy (such as those derived from wind, the sun and waves) are presenting themselves as a viable, eco-friendly options to meet the world’s energy needs.
US-based organisation the Union of Concerned Scientists did a numbers crunch that shows how much CO2 is emitted when using conventional forms of power as well as renewable sources.
“Compared with natural gas, which emits between 0.6 and 2 pounds of carbon dioxide equivalent per kilowatt-hour (CO2E/kWh), and coal, which emits between 1.4 and 3.6 pounds of CO2E/kWh, wind emits only 0.02 to 0.04 pounds of CO2E/kWh, solar 0.07 to 0.2, geothermal 0.1 to 0.2, and hydroelectric between 0.1 and 0.5. Renewable electricity generation from biomass can have a wide range of global warming emissions depending on the resource and how it is harvested. Sustainably sourced biomass has a low emissions footprint, while unsustainable sources of biomass can generate significant global warming emissions.”
In addition, renewable sources of energy release little or no particles that cause air pollution or negatively impact human health; wind and solar power consume virtually no water (geothermal and biomass require water for plant cooling), meaning the strain on local water supply can be significantly reduced; and sources of renewable energy are, generally speaking, vast and inexhaustible. By contrast, a 2011 study conducted by Harvard Medical Centre concluded that coal costs the US public up to 500 billion USD per year, with many of these costs relating to public health and waste management.
Types of Renewable Energy
Below is a brief outline of the various forms of renewable energy.
In basic terms, solar power is created by converting sunlight into electricity. The most commonways this occurs is via the installation and use of photovoltaic panels in areas that catch a lot of rays or via concentrated solar power systems.
One of the biggest benefits of solar energy is the inexhaustive, ready availability of the source – the amount of sunlight the earth receives per year makes the sun the most abundant source of energy worldwide, trumping coal and other fossil fuels.
Wind power has been around in one form or another for centuries – think conventional sail boats and agricultural windmills that pump water. These days, the power of the wind is being harnessed to generate electricity, using massive, tri-bladed, horizontal-axis turbines that stand on towers as tall as a 20 storey building.
The turbines – usually clustered together in so-called wind farms – are planted in areas with high winds and must face into the wind. These modern-day windmills convert kinetic energy into electricity: wind moves the turbine, which triggers and turns a shaft that’s connected to a generator that produces electricity.
Wind power is the fastest growing source of electricity in the world.
Hydroelectric power (sometimes known as hydro power) leverages the power of moving water, regardless of if the water is falling downwards, like a waterfall, or flowing like a stream. To make use of this power, large turbines are fitted with electrical generators. Water passing through the turbines causes them to spin, which sets of the generators that then convert the kinetic energy into electricity. The power of moving water (and therefore the amount of electricity derived from it) is influenced by both the volume and the height difference between the source and the water’s outflow and ”energy is derived to make power by the force of water moving from a higher elevation to a lower elevation through a large tube otherwise known…as a penstock.” (Source: Electricity Forum)
Norway has made great strides in adopting hydro power, with approximately 99 percent of the country’s energy needs met via this type of electricity. Hydro power does have some drawbacks namely, the building of dams to accommodate turbines can have a negative impact on local flora and fauna.
Another form of energy that humans have been making use of for a long time is ocean energy or tidal energy. Regardless, tidal energy represents a relatively small section of the current renewable energy market.
There are three different ways to harness tidal energy: tidal streams (where turbines are placed in fast-flowing bodies of water), barrages (where turbines are placed in dams. The dam gates are open as the tide rises and close when the dam is full, capturing an excess of water that is then run through the turbines) and tidal lagoons (where turbines are placed in pools of sea water hemmed in by natural or man-made barriers).
One of the big benefits of tidal energy is that, unlike other sources, tidal currents are reliably predictable. Depending on the type of generator being used, building and installing the necessary infrastructure can be expensive (barrages), can negatively impact the surrounding environment (tidal streams) or might not produce so much energy (tidal lagoons).
According to the Union of Concerned Scientists, ”Below Earth’s crust, there is a layer of hot and molten rock, called magma. Heat is continually produced in this layer, mostly from the decay of naturally radioactive materials such as uranium and potassium. The amount of heat within 10,000 meters (about 33,000 feet) of Earth’s surface contains 50,000 times more energy than all the oil and natural gas resources in the world….as of 2013 more than 11,700 megawatts (MW) of large, utility-scale geothermal capacity was in operation globally, with another 11,700 MW in planned capacity additions on the way. These geothermal facilities produced approximately 68 billion kilowatt-hours of electricity, enough to meet the annual needs of more than 6 million typical U.S. households. Geothermal plants account for more than 25 percent of the electricity produced in both Iceland and El Salvador.”
Derived from organic materials (such as plant and animal materials), biomass releases energy (as heat) when it is burned. Among the general sources for producing biomass power are: wood and forest residues (like bark and sawdust left over from the paper-making process); non-toxic waste (like biodegradable garbage); some crop resdiues; and manure. These can be burned in biomass power plants to produce steam which then triggers a turbine that produces electricity.
On the downside, the process of burning biomass does release carbon into the atmosphere, meaning that the emissions resulting from biomass must be weighed against the number of emissions that would result from any of power source biomass was looking to replace.
Renewable Energy Worldwide
Talk about the benefits of renewable energy may be rife however, the actual penetration and usage rates still have room to grow. The US Energy Information Administration puts global consumption of electricity from renewable sources at around 11 percent and total electricity generation from renewables at around 21 percent. The obstacles are manifold: lengthy permission procedures, import tariffs and technical barriers, insecure financing of renewable energy projects and insufficient awareness of the opportunities for renewable energy. Worldwide, renewable energy plays no decisive role although it offers clean alternatives to traditional energy sources as well as decentralised energy supply solutions to developing countries.
However, things are beginning to shift. After several years of being pegged as ‘too expensive’, the modern renewable energy industry is now being viewed as a cost-effective, more sustainable competitor to conventional forms of fuel and power generation. Data released by the International Renewable Energy Agency IRENA in early 2015 show that most forms of renewable energy have now achieved price parity with coal and some are even cheaper. “Any remaining perceptions that renewable power generation technologies are expensive or uncompetitive are at best outdated, and at worst a dangerous fallacy,” stated Adnan Z. Amin, the director-general of IRENA.
“Renewable energy projects across the globe are now matching or outperforming fossil fuels, particularly when accounting for externalities like local pollution, environmental damage and ill health.”
The world’s largest investor in renewable energy is China. As the world’s biggest importer of oil, largest consumer of energy and home to some of the worst air pollution, China is uniquely placed to drive adoption rates of renewable energy. According to Clean Technica, ”By 2014, China had created generating capacity from water, wind and solar sources of 378 GW – as compared with 172 GW for the US, 84 GW for Germany, and 71 GW for India.”
The European Union has set itself a mandate to fulfill 20 percent of its energy needs with renewable energy by 2020. Some countries within the EU have more tailored, loftier goals in mind such as Denmark, which aims to derive 70 percent of its electricity from renewable sources by 2020 and 100 percent by 2050.
A recent report from the US Energy Information Administration predicted that renewable sources of energy, including solar and wind, could be the fastest-growing sources of power until at least 2040. Since 2004, investment into the renewable sector has grown more than five times while the uptake and installation of photovoltaic systems continues to grow year after year.
The largest solar farm in Africa, the Jasper PV Project located in South Africa, was completed in October 2014, with the capacity to to deliver 180,000 megawatt-hours of electricity every year to over 80,000 homes. In mid-2015, the Africa Progress Panel launched a report that set out a plan to make electricity accessible to every single person on the African continent by 2030. The report, titled Power, People, Planet, Africa, called for this to be done with renewable electricity, effectively asking leaders of African nations to leapfrog using fossil fuels. The Africa Progress Panel aims to provide low-cost solar panels that would make energy accessible to the 621 million people lacking access to electricity today. The estimated amount of money needed is 55 billion USD. According to the Panel, half this amount could be generated from within the African continent by increasing sub-Saharan Africa’s tax-to GDP ratio by one percent of GDP. Another 20 billion would come from a new ‘connectivity fund’ of which half would come from Africa itself and another half from bilateral aid.
Connecting everyone in Africa to electricity and simultaneously making that electricity renewable is, however, easier said than done. According to a publication by the International Renewable Energy Agency (IRENA), it is currently more difficult to obtain financing for renewable energy power plants than for fossil fuel plants.
Everything Has Two Sides
Renewable energy sources can be useful and cause damage at the same time. One must always look at the whole picture. The use of alternative energy resources has to be evaluated by its eco-balance.
For example, heavy metals are used for the production of solar power cells which remain in the factory, though the finished solar module isn’t toxic at all. In response to this, scientists are researching and developing more sustainable methods of making solar cells, such as recyclable cells made out of trees.
Windparks are not without their controversies due to the irritation they can cause to birds and bats. Offshore windparks could be a problem for migratory birds.
Diverse hydroelectric power plants can also cause changes in existing ecosystems. Burning biomass can produce nitrogen monoxide, sulphur dioxide and respirable dust.
Using geothermal energy fluids drawn from the deep earth carry a toxic and explosive mixture of gases, notably carbon dioxide, hydrogen sulfide, methane and ammonia. Plant construction can adversely affect land stability.
Rising energy prices, increased import dependence and rising greenhouse-gas emissions are environmentally, economically and socially unsustainable. Achieving a more secure, low-carbon energy system calls for radical action by governments at national and local levels, and through participation in coordinated international mechanisms. Greater reliance on renewable energy sources offers enormous economic, social, and environmental benefits. As seen in many countries, developing and implementing alternative energy resources can provide a lot of jobs.
With centralised power, be it through coal, hydro or nuclear power, electrifying cities is the priority and rural villages, often at the tail end of the power grid, are literally left in the dark. Locally installed power plants for wind power, solar energy or biomass are decentralised sources of energy and thereby empower people at a grassroots level. It creates independence of power companies and low-cost options to bring energy to rural areas.
A first step at international level is the funding of the International Energy Agency IEA. 136 countries are part of it. IEA assumes that renewable energy could cover more than one fourth of the worlds primary energy demand by 2030.
The video below (put together by German non-profit /e-politik.de/) provides an excellent overview of the ins and outs of various types of renewable energy:
Last update: September 2015.