Renewables generally refer to natural resources that are renewable. Renewable energy has been a hot topic in recent years. There are many desired features about renewables that make adopting them an important national and industrial strategy. In 2008, over 19% of global final energy consumption came from renewables and the capacity of renewable resources (the total of generating capability of all installed renewable resources) is 25% [Renewable status report]. More importantly, renewables are growing very rapidly. For example, the wind power harnessed by the human being on the earth is 8 times big today as 10 years ago in the capacity [Renewable status report]. Recent years have seen rapid developments in solar power.
Figure 1: Wind Power, existing world capacity [Renewable status report]
So what exactly are the desired features of renewables that made such change and will continue make the change? Are there any undesirable features associated with large growth of renewables, or are we too enthusiastic about renewables especially given today’s economy? Let’s briefly talk about the desired features about renewables, and then reveal most common myths about renewables.
Key benefits about renewables:
Feature #1: environmental benefits
Conventional power plants including coal plants, gas-burning plants and nuclear plants can cause many environmental issues such as air pollution, water pollution, toxic wastes, etc. Those plants are widely blamed as threaten to some plants and animal life and as well as contributing to global warming. On the other hand, renewables such as solar and wind don’t have those issues, or to a lesser extent. In general renewable energy is considered as clean energy or green energy, with a much lower environmental impact than conventional energy technologies.
[http://www.ucsusa.org/clean_energy/technology_and_impacts/impacts/public-benefits-of-renewable.html] lists all environmental issues associated with conventional power plants
Feature #2: cost benefits
Hydro power is the most significant source of renewable energy, and also they are cheaper than coal or gas-fired power plants. Wind power may have some capital costs and maintenance costs, but the production cost (fuel cost) is near $0. So apparently some types of renewables bring significant cost benefits to the society.
Feature #3: sustainability
As the name implies, renewable energy never runs out. This is unlike conventional energy sources which are finite and will someday be depleted. Renewables don’t have fuel transportation and storage issues either.
Feature #4: jobs and economy
Although it’s true that some renewables are expensive, renewables can also bring a lot of jobs, and most importantly, they are green jobs. This is because renewables are usually localized energy sources, and explore such sources, local jobs will be created. Also, investments have been spent on materials and technology innovations related to renewables. Those investments bring a lot of high-tech jobs as well. Therefore, there is no wonder that a large portion of government economy stimulus package is targeted to the renewable industry.
Feature #5: energy independence
The skyrocket gas price from time to time emphasizes the importance of energy independence for the nation. If we continue to largely rely on conventional energy sources which are vulnerable to many serious issues including political instabilities, trade disputes and other disruptions, we will feel less secure as a nation.
Myths about renewables
Myth #1: Renewables don’t cost much because they are renewable
Although it may be true that once installed, a renewable facility will just produce energy with no cost or at a minimal cost, renewable projects usually require significant amount of capital investment which is 5-10 times high as conventional sources on a $/kW basis. Renewables can look much more expensive when considering that their capacity factor (the actual output divided by the capacity). For example, the capacity factor of solar energy is only about 20% - it’s understandable that a solar power plant can’t generate any power during nights. The typical capacity factor for wind is about 30%, which is also low.
Myth #2: Once installed, renewables will reduce the total cost of energy consumption for consumers.
It’s true that once installed, the cost to produce power is $0 or very low for renewables. It’s also generally true that once connected to the grid, renewables will lower down the total production cost for all power consumed by the grid users if the capital cost of those renewables is not considered. So it’s generally true that the renewables would reduce the electricity bills for the grid customers if the capacity cost of the renewables is paid off or not shared by the grid customers.
However, as more and more renewables are integrated into the grid, some specific issues related to renewables will become more and more salient. Compared to conventional energy sources such as gas-fired power plants which are easier to control their output and better follow the load, it’s very difficult or impractical to control the output of most renewables. For example, the wind may blow during nights and stop during day time, which is opposite to the load pattern (load is high during daytime and low during nights). The output of solar plants may be more aligned with load patterns, but they are not controllable – their output depends on the sun. Because of those reasons, as more renewables are integrated to the grid, the grid needs more capability to deal with uncertainties and inflexibilities associated with the renewable sources. Often the grid needs more conventional units sit around on the grid to fill the gap between the load pattern (which is usually dynamic) and the intermittent renewables generation. It follows then, as more renewables are integrated, the cost to operate the grid may increase. Thus the total cost for customers does not necessarily reduce as they consume more renewables.
Myth #3: Renewables can be integrated into today’s electric grid without significant changes on transmission systems.
One of the issues with the today’s power grid is that it is not designed for large renewables in the system. Most of today’s transmission systems are designed without consideration on potential large amount of renewables integrated into the system. The requirements on the transmission systems under renewables are different compared to those from conventional energy sources. Most renewable energy sources are localized resources, usually remote from the existing transmission system. Therefore, significant amount of transmission system usually needs to be built to support renewable integration, which is very often hard to achieve given today’s stringent limitations on issuing land/site permits. Also, to reliably operate the grid under renewables it requires many other supporting transmission facilities such as reactive power equipment, control and communication equipment.
Myth #4: The design of today’s electricity markets supports renewables.
Today’s electric power industry is deregulated in U.S. and other countries in the world, and electricity markets exist to support competition among various generation technologies. However, most of the rules in electricity markets are designed for conventional energy sources, without serious consideration under significant amount of renewables integrated into the system. Given that those rules have not been fully examined for the new era under renewables, it’s possible that renewables could have undesirable impacts on the market, or vice versa.