How much storage is even feasible?

Ross Baldick ConsultingIn response to my last post, about the challenges of wind integration, a reader asked: “Is building storage of this scale even feasible?”

If you had asked me in 2000, “Could wind get to 18GW wind in ERCOT by 2016?” I would have answered no!

I would have been concerned about technical feasibility as well as cost. Technical feasibility has not turned out to be a  problem at that level of penetration, so I would now shy away from claiming technical non-feasibility for storage.

Indeed, I think one can contemplate large-scale dispatched storage (end even some way to dispatch small scale distributed storage) that would make it compatible with existing grid control paradigms at even very high penetrations of storage. Certainly, the battery regulation AS providers are taking ISO signals that look like standard dispatch signals.

The big stopping point continues to be cost. If Elon Musk can make it cheap, and can add some dispatchability, there could be a lot of storage. However, I’d prefer to first wring out from the thermal generators as much controlability as we can get before we blow a lot of money on storage.

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ERCOT: meeting the challenges of wind integration

Ross Baldick (left) receives Outstanding Engineer Award 2015 from Joel Sandahl, Chair of Power and Energy Society, Power Electronics Society, Industry Applications Society, and Industrial Electronics Society Austin Texas Chapter.

Texas has, by far, the highest penetration of wind among the three main US interconnections (Eastern, Western, and Texas), and the Electric Reliability Council of Texas (ERCOT) has met the challenges of wind integration. ERCOT is set to get even more wind power, which will present even greater challenges, because of the relationship between wind production and electricity demand.

Several of my students, most recently Dr. Duehee Lee, have investigated the statistics of wind production to understand this relationship. Recent joint work with Lee (reported at Wind Farms in Dallas in May, and more recently at the Austin IEEE Power and Energy Society chapter meeting and the Berlin Conference on Energy and Electricity Economics) analyzed the relationship between wind and load variation at various timescales. We want to understand how the variability of wind at various timescales will affect the operation of ERCOT, and what resources will therefore be necessary to compensate for this variation, whether it is agile generation or battery storage.

West Texas inland wind presents a particular problem, because it tends to be negatively correlated with load, while near-coastal wind is weakly correlated and therefore a better match to load. This means that increased amounts of inland wind will not offset the need for other generation capacity to cover the peaks in demand. Moreover, this generation capacity will also need to be increasingly flexible to accommodate wind production that occurs off-peak.

Furthermore, while aggregating large numbers of farms tends to smooth intra-hour fluctuations of wind, in contrast, the longer term fluctuations of wind, and particularly the negative correlation of inland wind and load will not be “solved” by aggregation of West Texas wind.

Coastal Texas wind has better correlation with load from this perspective, but it may be more difficult to build much more coastal wind due to environmental and other considerations. An open question is how much more wind can be accommodated in the ERCOT market before we need to build large-scale storage.

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Solar in a Quito hotel

I recently had the pleasure of staying at a hotel in the old town of Quito, Ecuador, and saw a photovoltaic (PV) installation that would seem strange in most of the world.

We typically see PV panels tilting toward the south in the northern hemisphere or toward the north in the southern hemisphere, in order to capture the sun’s rays. A variation is to tilt toward the west in afternoon-peaking locations, such as Austin, Texas, where air conditioning drives peak loads. (Click here to read the work by Pecan Street that considers the tradeoffs between maximizing energy production and maximizing the value of that energy).

At my hotel in Quito, however, the courtyard had been covered by horizontal PV panels:

quito-solar-1 | Ross Baldick Consulting

As well as being an attractive building-integrated PV awning, it was also perfectly oriented, since Quito is almost on the equator. It allowed some light through to the courtyard below, because the PV cells were mounted on a transparent support (see below), and also provided shade for the courtyard.

quito-solar-2 | Ross Baldick Consulting

The combination of an old colonial building with updated decor and energy sources made for a lovely stay in this charming town.

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Renewables research collaboration in Chile

Ross Baldick Electricity ConsultingIn May I had the pleasure of visiting colleagues at the Pontificia Universidad Catolica de Chile and the Universidad de Chile, in Santiago, Chile. Like Texas, Chile is moving toward ever higher levels of renewable power, ours in wind, theirs in solar.

Universidad Catolica colleagues and I have been jointly awarded seed funding to investigate models of flexibility in power systems that are needed to accommodate higher levels of renewable integration.

Over the coming months we will work toward a larger proposal on flexibility aimed at cost-effectively facilitating the integration of increasing levels of renewables. Unlike in California and Germany, where renewable integration seems to proceed without any regard to cost or without any attention to the endowment of resources, we aim to make high levels of renewable integration cost-effective in the locations where the resources are abundant.

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While in Santiago I met with the local electricity industry and presented a summary of UT research relating to the flexibility and integration of renewable enery. (Click here to download that presentation.)

It was a great experience to meet colleagues in Chile, including old friends Hugh Rudnick and Rodrigo Palma, and my collaborators Matias Negrete-Pincetic (pictured, at left) and Daniel Olivares Quero (pictured, in center). Later this year, a Universidad Catolica student will be visiting The University of Texas at Austin to work with me, and one of my students will be visiting Universidad Catolica.

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