Michael Goggin's Comments

October 10, 2008

Addressing the Variability Factor: Can Wind Power Reliably Be Part of the Electricity Mix?

Thanks to all for taking the time to comment. A few responses:

Rod, you are correct that many areas of the country, including Texas, have very little hydroelectric capacity that can be used for accommodating variability on the electric grid. Fortunately, around 75% of Texas's generating capacity is supplied by natural gas plants, so the inherent flexibility of these plants can simply be put to greater use without a need for new plants. This is the case in many regions -- with improved operational procedures the already built-in flexibility of plants on the grid can be put to use. Also, your fear about zero-emission nuclear plants being turned down to favor flexible natural gas plants is unfounded. For one, the NRC prohibits nuclear plants from being turned down, and second high-emission high-fuel cost coal plants would be turned down first.

Greg, you are absolutely correct that demand response is a very cost-effective tool for accommodating variability on the electric grid, including that caused by wind energy -- I neglected to mention it simply due to limited space.

Jay, energy storage does have the potential to help accommodate variability on the electric grid. However, it does not make sense to use storage to even out variability in wind energy alone -- in many instances wind output and electricity demand will be simultaneously changing in the same direction so using storage to balance out wind output alone would actually make it harder to balance the grid. Storage can be much more cost-effectively deployed as a resource for the overall grid, not just for wind energy. At present storage is not cost-effective compared to other sources of flexibility on the grid, which explains why European nations have been able to achieve high wind penetrations but still have not needed to build energy storage. Similarly, studies in the U.S. have found that wind energy can provide 20% or more of our electricity without storage being necessary or cost-effective.

September 27, 2008

Curtailment, Negative Prices Symptomatic of Inadequate Transmission

Thanks to all who took the time to comment. I have a few responses:

First, I strongly share your support for decentralized power generation, and you should know that AWEA strongly advocates for policies to increase the use of distributed wind turbines. You are correct that distributed renewable resources have many benefits and that they can play a role in addressing our climate change and energy problems.

However, opposing a renewed investment in the transmission grid will only help ensure the failure of vitally urgent efforts to significantly reduce our use of fossil fuels and avoid the worst impacts of climate change. Given the enormity of the energy and climate problems facing our society, insisting that the largest near-term solution to these problems be taken off the table hardly seems like a step in the right direction.

Because of the fact that the energy in the wind is proportional to the cube of wind speed, there are huge disparities in the productivity and thus economic viability of wind power production between areas with good wind resources and those with poor wind resources. Unfortunately, the vast majority of Americans live in areas with poor wind resources. Unless you are going to forcibly relocate people to areas with better renewable resources, making use of our renewable energy resources in a way that is economically feasible will require a means of transmitting energy from where it is produced to where it is used.

Because transmission is a public good, even the most free-market economist will tell you that the government has an important role in planning transmission. A high-voltage transmission grid is the most cost effective and environmentally benign way to move energy from one place to another. The amount of power a transmission line can carry increases with the square of the voltage, which is why a 765-kV line can carry as much power as six 345-kV lines, using one-fourth as much land and with one-tenth of the electricity losses.

July 31, 2008

Interstate Transmission Superhighways: Paving the Way to a Low-carbon Future

I have a few points in response to the comments by "Stop killin our wilderness:"

First, I strongly share your support for decentralized power generation, and you should know that AWEA strongly advocates for policies to increase the use of distributed wind turbines. You are correct that distributed renewable resources have many benefits and that they can play a role in addressing our climate change and energy problems.

However, opposing a renewed investment in the transmission grid will only help ensure the failure of vitally urgent efforts to significantly reduce our use of fossil fuels and avoid the worst impacts of climate change. Given the enormity of the energy and climate problems facing our society, insisting that the largest near-term solution to these problems be taken off the table hardly seems like a step in the right direction.

In your comment, you inadvertently stumble upon the main reason why transmission is an important complement for renewable generation. You suggest that those living in "prime solar and wind resource areas" should install "oversize" PV and wind generators and provide their excess power to other regions. Yet how do you expect this energy to be transmitted from region to region without transmission lines?

Unless you are going to forcibly relocate people from areas where renewable resources are inadequate to meet their energy needs, making use of our renewable energy resources in a way that is economically feasible will require a means of transmitting energy from where it is produced to where it is used.

As I explained in the article, a high-voltage transmission grid is the most environmentally benign way to move energy from one place to another. The amount of power a transmission line can carry increases with the square of the voltage, which is why a 765-kV line can carry as much power as six 345-kV lines, using one-fourth as much land and with one-tenth of the electricity losses.

June 11, 2008

Storage Boosts the Power of Renewable Energy

Thank you for the interesting report on the Energy Storage Association's Annual Meeting. However, I wanted to point out that many in the clean energy community would take issue with the statement that "storage options are essential for expanding renewable energy sources." European countries like Denmark, Spain, and Germany have successfully integrated large amounts of wind energy without having to install additional amounts of energy storage. Similarly, numerous studies in the U.S. have concluded that wind energy can provide 20% or more of our electricity without any need for energy storage.

How is this possible? The secret lies in using the sources of flexibility that are already present on the electric grid. Grid operators constantly accommodate variability in electricity demand and supply by increasing and decreasing the output of flexible generators -- power plants that can rapidly change their level of output. In this way, the water kept behind a hydroelectric dam and the natural gas held in a pipeline is effectively used as energy storage, with operators releasing this energy when it is needed and storing it when it is not.

These sources of flexibility are already used to accommodate rapid changes in electricity demand that occur as people turn appliances on and off, as well as GW-scale changes in electricity supply that can occur in a fraction of a second if a large power plant goes offline. In contrast, changes in wind output occur very slowly over the course of an hour or even hours, so it is relatively easy to use these existing sources of flexibility to accommodate wind's variability.

In addition, many changes in wind output actually cancel out opposite changes in electricity demand. For this reason, it makes more sense for energy storage to be viewed as a system resource that can help even out the aggregate variability of all generators and all demand on the electric grid, not as a dedicated resource for a single generator or load.

June 24, 2008

Storage Boosts the Power of Renewable Energy

Kevin,

You are correct that at very high levels of wind penetration, energy storage may become an attractive option for the electric grid. However, this is not likely to occur until the penetration of wind energy on the U.S. electric grid drastically increases from its current level. The U.S. Department of Energy recently released a major report that concluded that the U.S. can obtain 20% of its electricity from wind energy by 2030 without the need for energy storage. While we are excited by advances in energy storage technology, transmission limitations and other obstacles to continued renewable energy growth are more pressing issues for the foreseeable future.

There is also no reason to think that wind energy needs to be "firmed" or "backed up." Wind energy is primarily an energy resource and not a capacity resource, meaning that it is primarily used to reduce fuel consumption, not meet peak demand. As my colleague Jeff mentioned, a number of studies have documented that it is far more economically efficient to use other generators and other sources of flexibility on the grid to provide capacity as needed to balance supply with demand than to couple wind generators with storage.

Finally, compared to Europe, the sheer geographic size of the U.S. and the corresponding diversity of our wind resources gives us a strong advantage when it comes to integrating wind energy. For example, if on a certain day there isn't much wind in one region, there's a good chance that there will be above average wind somewhere else to make up for it. You are correct that a robust electric grid with strong interconnections between neighboring regions makes it significantly easier to integrate wind energy (in addition to reducing the cost of electricity and making the grid more reliable), which is why building a more robust grid is one of AWEA's major near-term policy goals.

Michael Goggin

Michael Goggin

Michael Goggin joined AWEA in February 2008. He represents the wind industry on transmission and grid integration matters, coordinates member input on the development of policy positions, facilitates the exchange of information between...

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