Readers react to Minnesota 100% renewable report

What a 100-percent renewable electricity system in Minnesota might look like on a week in January.

Monday’s post, “Could Minnesota get by on 100 percent renewables?,” has generated quite a few comments. A report released this week by the Institute for Energy and Environmental Research (IEER) claims the state could meet all its electricity needs through wind and solar, provided they were matched with the right mix of energy storage and efficiency improvements. I decided to check back in with Arjun Makhijani, IEER’s president and senior engineer, and ask him to respond to some of your questions and comments.

PwrSavy commented “As I understand it, if you’re relying on typical [compressed air energy storage]; they couple with combustion turbines when supplying energy, so this is not a ‘100% Renewable’ scenario… unless that is you’re burning some kind of biofuel.”

On this point, the reader is correct, says Makhijani. The scenario described in IEER’s report actually does rely on a small amount of natural gas for generating power from the compressed air energy storage. The amount of natural gas used in generating from compressed air storage is about one fifteenth the amount of gas used in a conventional natural gas combustion plant.

“The amount of natural gas is so small that I believe it could be replaced with biogas,” says Makhijani.

Another option that could become economical at some point is pairing compressed air storage with hydrogen powered generation.

Mary is alarmed about how expanding commercial wind farms in the state could affect bats and birds. “If we pepper this state with the turbines required to produce enough energy to provide for households alone, we will have an environmental disaster of biblical proportions down the road,” she writes.

Makhijani says improved turbine design has largely resolved the problem of bird collisions at newer facilities. He thinks the bat issue is a bigger problem and one that we need to pay attention to. He hopes that careful siting of wind farms might help reduce the impact.

“I think wind farms should be carefully sited, and I think we do have the luxury of doing that in Minnesota because the available resources are enormous,” he says.

About a third of the state’s land area is rated as having relatively high wind potential by the National Renewable Energy Laboratory. The state’s total wind generating potential, depending on turbine height, is 20 to 30 times the state’s current consumption, says Makhijani. Achieving the 12,000 to 15,000 megawatts of wind capacity called for in his report would require developing on about 5 percent of the state’s high-wind-potential land.

“It’s not huge. It’s not negligible,” Makhijani says.

Mouli Vaidyanathan comments that the data used in the report to estimate Minnesota’s solar potential is about 10 percent to 15 percent optimistic. “Such over estimates could harm our renewable energy industry in over promising and under delivery.”

While the report includes an Average Solar Radiation map for Minnesota, Makhijani says they didn’t calculate the state’s solar potential based on land area. Minnesota is unlikely to have large-scale PV or concentrated solar thermal, he says. Instead, the more likely application of solar is smaller, distributed installations on commercial rooftops, of which there are more than enough to provide the kind of solar capacity called for in the report.

“The solar generation in our scenario is not very big. It serves mostly to reduce the variability of the renewable resource rather than as a big source of supply,” Makhijani says. “Solar generation plays a role of moderating the storage requirement and the seasonal variability of your renewable resource. It improves the economy of the system.” That’s because solar generation tends to peak with demand on hot summer days when air conditioners are running.

Rolf Westgard doubts whether the state could ever build enough storage to moderate wind and solar’s variability. “There is no storage supply to compensate for the erratic nature of those sources. Imagine a warm muggy summer night when all AC’s run and there isn’t a ‘breath of air’.”

Makhijani admits building energy storage will be expensive and challenging. Under his report’s scenario, the state would need about a $9 billion investment in storage. Siting issues would undoubtedly arise, although he believes enough sites do exist. The state could shrink its storage requirements by further improving efficiency and expanding the use of demand dispatch, in which customers agree to have certain appliances or equipment powered off for short intervals when electricity demand is high, usually in exchange for a discount.

“The whole idea was to show that you can actually run a renewable system though all of the erratic supply and all of the variability in the existing demand with out doing anything to the existing demand,” says Makhijani. “You can get through all of these warm muggy nights.”

(Also, as noted previously, the IEER is a member of RE-AMP, which also funds Midwest Energy News.)

7 thoughts on “Readers react to Minnesota 100% renewable report

  1. Unfortunately too few of the state’s political leaders get it..and I’m skeptical that they care enough about renewables or more importantly clean energy to actually do something smart even if substantial evidence shows there is economic advantage to facilitate such projects…especially with a view to the future. It’s too complicated for most of them so they listen to status quo. Utilities/the fossil fuel industry have too much to lose and are very good at twisting things to their benefit….and they have a lot of money to do that. Their influence is waining, though, so who knows? Maybe legislators will start paying attention and do what’s right.

  2. I appreciate all the follow-up! CAES’s one-fifteenth the gas consumption of typical CT’s is impressive & not something I’d heard before.

    Rolf is correct in that siting so much CAES would be difficult, but developing what’s feasible & relying on distributed solar & DR would go a long way. As Manitoba Hydro expands its capacity, coupling hydro with wind variability is something that will likely come along much sooner than a lot of MN CAES as MISO and some MN utilities are already studying the potential. Just decrease hydro output when wind peaks, and increase when wind diminishes; variability issues resolved.
    Thanks again!

  3. Ask the Bonneville Power Authority which has to shut down low cost hydro when expensive erratic wind peaks.

  4. Improved turbine design hasn’t done a thing to reduce bird collisions with wind turbines. The larger turbines have a larger rotor sweep, hence a larger kill zone and the barotrauma that kills bats has also increased accordingly. I am appalled, absolutely disgusted, with the nonsense spewed by wind energy proponents who want the truth to be what they say it is instead of admitting to ugly truths.

    This report is based on fluff and nonsense and has absolutely no scientific basis in fact. Yes, Minnesota could power itself on renewable energy if the wind blew at the right time of day and at the right speed, and if we could store the power that is generated when it is not needed. But the reality is that wind is unreliable, turbines are inefficient, and Mother Nature cannot sustain the damage this spinning crap causes without collapsing ecosystems everywhere. Hydro and wind are already coupled in Denmark. There would be NO wind energy without hydro. It cannot support itself.

  5. Actually, Rolf, what’s happened is FERC has ordered BPA to pay wind farms for curtailment in the spring runoff, when the dams produce more power than the grid can absorb. Hydropower is variable too, though on a much more macro scale.

    I’m not an expert, but I don’t think the rivers in Manitoba have nearly as much seasonal variation as the Columbia.

  6. And Mary, if I’m understanding right, instead of “nonsense” about wind power, you want us to report that it’s “collapsing ecosystems everywhere.”

    Could you provide an example of where that’s happened?

  7. I agree with Ken on the potential of hydro to back up wind and solar. More transmission from Canada may be needed or may not depending on efficiency, conservation and DR use. Nuclear fission could be used but if required to buy insurance and and store waste responsibly would be high cost and politically more difficult. And the only way coal can be used is with CCS likely to be expensive and not proven for long term use.
    At present Global Warming would have much greater negative effects on wildlife habitat than wind farms.
    So efficiency and conservation first, then DR/smart grid, third wind/solar and then storage.